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File: [cvs.NetBSD.org] / src / sys / netinet6 / in6.c (download)

Revision 1.104, Sat Jun 3 01:04:29 2006 UTC (15 years, 6 months ago) by christos
Branch: MAIN
Changes since 1.103: +11 -3 lines

This is ugly, but it is the simplest fix to avoid calling in the default
case:

    <driver>_ioctl(ifp, SIOCSIFADDR, struct ifreq *)

where it should be calling:

    <driver>_ioctl(ifp, SIOCSIFADDR, struct ifaddr *)

and "Bad Things Happen (TM)"

Returning an error is good enough because none of the drivers handle INET6.

The problem here is that handling SIOCSIFADDR is a kludge. The ioctl gets
passed a struct ifreq * from userland, but then in the control routines
SIOCSIFADDR is handled "specially", and we call:

	ifp->if_ioctl(ifp, SIOCSIFADDR, struct ifaddr *)

directly with the ifaddr we computed for that interface. It would be nice
if we called the ioctl routine if the original struct ifreq, and computed
the ifaddr, or passed it directly. This way all the ioctls would be treated
the same way, and we would not have the problem of pointer overloading.

/*	$NetBSD: in6.c,v 1.104 2006/06/03 01:04:29 christos Exp $	*/
/*	$KAME: in6.c,v 1.198 2001/07/18 09:12:38 itojun Exp $	*/

/*
 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the project 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 PROJECT 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 PROJECT 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.
 */

/*
 * Copyright (c) 1982, 1986, 1991, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *	@(#)in.c	8.2 (Berkeley) 11/15/93
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: in6.c,v 1.104 2006/06/03 01:04:29 christos Exp $");

#include "opt_inet.h"
#include "opt_pfil_hooks.h"

#include <sys/param.h>
#include <sys/ioctl.h>
#include <sys/errno.h>
#include <sys/malloc.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/sockio.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/time.h>
#include <sys/kernel.h>
#include <sys/syslog.h>
#include <sys/kauth.h>

#include <net/if.h>
#include <net/if_types.h>
#include <net/route.h>
#include <net/if_dl.h>

#include <netinet/in.h>
#include <netinet/in_var.h>
#include <net/if_ether.h>

#include <netinet/ip6.h>
#include <netinet6/ip6_var.h>
#include <netinet6/nd6.h>
#include <netinet6/mld6_var.h>
#include <netinet6/ip6_mroute.h>
#include <netinet6/in6_ifattach.h>
#include <netinet6/scope6_var.h>

#include <net/net_osdep.h>

#ifdef PFIL_HOOKS
#include <net/pfil.h>
#endif

MALLOC_DEFINE(M_IP6OPT, "ip6_options", "IPv6 options");

/* enable backward compatibility code for obsoleted ioctls */
#define COMPAT_IN6IFIOCTL

/*
 * Definitions of some constant IP6 addresses.
 */
const struct in6_addr in6addr_any = IN6ADDR_ANY_INIT;
const struct in6_addr in6addr_loopback = IN6ADDR_LOOPBACK_INIT;
const struct in6_addr in6addr_nodelocal_allnodes =
	IN6ADDR_NODELOCAL_ALLNODES_INIT;
const struct in6_addr in6addr_linklocal_allnodes =
	IN6ADDR_LINKLOCAL_ALLNODES_INIT;
const struct in6_addr in6addr_linklocal_allrouters =
	IN6ADDR_LINKLOCAL_ALLROUTERS_INIT;

const struct in6_addr in6mask0 = IN6MASK0;
const struct in6_addr in6mask32 = IN6MASK32;
const struct in6_addr in6mask64 = IN6MASK64;
const struct in6_addr in6mask96 = IN6MASK96;
const struct in6_addr in6mask128 = IN6MASK128;

const struct sockaddr_in6 sa6_any = {sizeof(sa6_any), AF_INET6,
				     0, 0, IN6ADDR_ANY_INIT, 0};

static int in6_lifaddr_ioctl __P((struct socket *, u_long, caddr_t,
	struct ifnet *, struct proc *));
static int in6_ifinit __P((struct ifnet *, struct in6_ifaddr *,
	struct sockaddr_in6 *, int));
static void in6_unlink_ifa __P((struct in6_ifaddr *, struct ifnet *));

/*
 * Subroutine for in6_ifaddloop() and in6_ifremloop().
 * This routine does actual work.
 */
static void
in6_ifloop_request(int cmd, struct ifaddr *ifa)
{
	struct sockaddr_in6 lo_sa;
	struct sockaddr_in6 all1_sa;
	struct rtentry *nrt = NULL;
	int e;

	bzero(&lo_sa, sizeof(lo_sa));
	bzero(&all1_sa, sizeof(all1_sa));
	lo_sa.sin6_family = all1_sa.sin6_family = AF_INET6;
	lo_sa.sin6_len = all1_sa.sin6_len = sizeof(struct sockaddr_in6);
	lo_sa.sin6_addr = in6addr_loopback;
	all1_sa.sin6_addr = in6mask128;

	/*
	 * We specify the address itself as the gateway, and set the
	 * RTF_LLINFO flag, so that the corresponding host route would have
	 * the flag, and thus applications that assume traditional behavior
	 * would be happy.  Note that we assume the caller of the function
	 * (probably implicitly) set nd6_rtrequest() to ifa->ifa_rtrequest,
	 * which changes the outgoing interface to the loopback interface.
	 */
	e = rtrequest(cmd, ifa->ifa_addr, ifa->ifa_addr,
	    (struct sockaddr *)&all1_sa, RTF_UP|RTF_HOST|RTF_LLINFO, &nrt);
	if (e != 0) {
		log(LOG_ERR, "in6_ifloop_request: "
		    "%s operation failed for %s (errno=%d)\n",
		    cmd == RTM_ADD ? "ADD" : "DELETE",
		    ip6_sprintf(&((struct in6_ifaddr *)ifa)->ia_addr.sin6_addr),
		    e);
	}

	/*
	 * Make sure rt_ifa be equal to IFA, the second argument of the
	 * function.
	 * We need this because when we refer to rt_ifa->ia6_flags in
	 * ip6_input, we assume that the rt_ifa points to the address instead
	 * of the loopback address.
	 */
	if (cmd == RTM_ADD && nrt && ifa != nrt->rt_ifa) {
		IFAFREE(nrt->rt_ifa);
		IFAREF(ifa);
		nrt->rt_ifa = ifa;
	}

	/*
	 * Report the addition/removal of the address to the routing socket.
	 * XXX: since we called rtinit for a p2p interface with a destination,
	 *      we end up reporting twice in such a case.  Should we rather
	 *      omit the second report?
	 */
	if (nrt) {
		rt_newaddrmsg(cmd, ifa, e, nrt);
		if (cmd == RTM_DELETE) {
			if (nrt->rt_refcnt <= 0) {
				/* XXX: we should free the entry ourselves. */
				nrt->rt_refcnt++;
				rtfree(nrt);
			}
		} else {
			/* the cmd must be RTM_ADD here */
			nrt->rt_refcnt--;
		}
	}
}

/*
 * Add ownaddr as loopback rtentry.  We previously add the route only if
 * necessary (ex. on a p2p link).  However, since we now manage addresses
 * separately from prefixes, we should always add the route.  We can't
 * rely on the cloning mechanism from the corresponding interface route
 * any more.
 */
void
in6_ifaddloop(struct ifaddr *ifa)
{
	struct rtentry *rt;

	/* If there is no loopback entry, allocate one. */
	rt = rtalloc1(ifa->ifa_addr, 0);
	if (rt == NULL || (rt->rt_flags & RTF_HOST) == 0 ||
	    (rt->rt_ifp->if_flags & IFF_LOOPBACK) == 0)
		in6_ifloop_request(RTM_ADD, ifa);
	if (rt)
		rt->rt_refcnt--;
}

/*
 * Remove loopback rtentry of ownaddr generated by in6_ifaddloop(),
 * if it exists.
 */
void
in6_ifremloop(struct ifaddr *ifa)
{
	struct in6_ifaddr *ia;
	struct rtentry *rt;
	int ia_count = 0;

	/*
	 * Some of BSD variants do not remove cloned routes
	 * from an interface direct route, when removing the direct route
	 * (see comments in net/net_osdep.h).  Even for variants that do remove
	 * cloned routes, they could fail to remove the cloned routes when
	 * we handle multple addresses that share a common prefix.
	 * So, we should remove the route corresponding to the deleted address.
	 */

	/*
	 * Delete the entry only if exact one ifa exists.  More than one ifa
	 * can exist if we assign a same single address to multiple
	 * (probably p2p) interfaces.
	 * XXX: we should avoid such a configuration in IPv6...
	 */
	for (ia = in6_ifaddr; ia; ia = ia->ia_next) {
		if (IN6_ARE_ADDR_EQUAL(IFA_IN6(ifa), &ia->ia_addr.sin6_addr)) {
			ia_count++;
			if (ia_count > 1)
				break;
		}
	}

	if (ia_count == 1) {
		/*
		 * Before deleting, check if a corresponding loopbacked host
		 * route surely exists.  With this check, we can avoid to
		 * delete an interface direct route whose destination is same
		 * as the address being removed.  This can happen when removing
		 * a subnet-router anycast address on an interface attahced
		 * to a shared medium.
		 */
		rt = rtalloc1(ifa->ifa_addr, 0);
		if (rt != NULL && (rt->rt_flags & RTF_HOST) != 0 &&
		    (rt->rt_ifp->if_flags & IFF_LOOPBACK) != 0) {
			rt->rt_refcnt--;
			in6_ifloop_request(RTM_DELETE, ifa);
		}
	}
}

int
in6_mask2len(mask, lim0)
	struct in6_addr *mask;
	u_char *lim0;
{
	int x = 0, y;
	u_char *lim = lim0, *p;

	/* ignore the scope_id part */
	if (lim0 == NULL || lim0 - (u_char *)mask > sizeof(*mask))
		lim = (u_char *)mask + sizeof(*mask);
	for (p = (u_char *)mask; p < lim; x++, p++) {
		if (*p != 0xff)
			break;
	}
	y = 0;
	if (p < lim) {
		for (y = 0; y < 8; y++) {
			if ((*p & (0x80 >> y)) == 0)
				break;
		}
	}

	/*
	 * when the limit pointer is given, do a stricter check on the
	 * remaining bits.
	 */
	if (p < lim) {
		if (y != 0 && (*p & (0x00ff >> y)) != 0)
			return (-1);
		for (p = p + 1; p < lim; p++)
			if (*p != 0)
				return (-1);
	}

	return x * 8 + y;
}

#define ifa2ia6(ifa)	((struct in6_ifaddr *)(ifa))
#define ia62ifa(ia6)	(&((ia6)->ia_ifa))

int
in6_control(so, cmd, data, ifp, p)
	struct	socket *so;
	u_long cmd;
	caddr_t	data;
	struct ifnet *ifp;
	struct proc *p;
{
	struct	in6_ifreq *ifr = (struct in6_ifreq *)data;
	struct	in6_ifaddr *ia = NULL;
	struct	in6_aliasreq *ifra = (struct in6_aliasreq *)data;
	struct sockaddr_in6 *sa6;
	int error, privileged;

	privileged = 0;
	if (p && !kauth_authorize_generic(p->p_cred, KAUTH_GENERIC_ISSUSER, &p->p_acflag))
		privileged++;

	switch (cmd) {
	/*
	 * XXX: Fix me, once we fix SIOCSIFADDR
	 */
	case SIOCSIFADDR:
		return EOPNOTSUPP;
	case SIOCGETSGCNT_IN6:
	case SIOCGETMIFCNT_IN6:
		return (mrt6_ioctl(cmd, data));
	}

	if (ifp == NULL)
		return (EOPNOTSUPP);

	switch (cmd) {
	case SIOCSNDFLUSH_IN6:
	case SIOCSPFXFLUSH_IN6:
	case SIOCSRTRFLUSH_IN6:
	case SIOCSDEFIFACE_IN6:
	case SIOCSIFINFO_FLAGS:
	case SIOCSIFINFO_IN6:
		if (!privileged)
			return (EPERM);
		/* FALLTHROUGH */
	case OSIOCGIFINFO_IN6:
	case SIOCGIFINFO_IN6:
	case SIOCGDRLST_IN6:
	case SIOCGPRLST_IN6:
	case SIOCGNBRINFO_IN6:
	case SIOCGDEFIFACE_IN6:
		return (nd6_ioctl(cmd, data, ifp));
	}

	switch (cmd) {
	case SIOCSIFPREFIX_IN6:
	case SIOCDIFPREFIX_IN6:
	case SIOCAIFPREFIX_IN6:
	case SIOCCIFPREFIX_IN6:
	case SIOCSGIFPREFIX_IN6:
	case SIOCGIFPREFIX_IN6:
		log(LOG_NOTICE,
		    "prefix ioctls are now invalidated. "
		    "please use ifconfig.\n");
		return (EOPNOTSUPP);
	}

	switch (cmd) {
	case SIOCALIFADDR:
	case SIOCDLIFADDR:
		if (!privileged)
			return (EPERM);
		/* FALLTHROUGH */
	case SIOCGLIFADDR:
		return in6_lifaddr_ioctl(so, cmd, data, ifp, p);
	}

	/*
	 * Find address for this interface, if it exists.
	 *
	 * In netinet code, we have checked ifra_addr in SIOCSIF*ADDR operation
	 * only, and used the first interface address as the target of other
	 * operations (without checking ifra_addr).  This was because netinet
	 * code/API assumed at most 1 interface address per interface.
	 * Since IPv6 allows a node to assign multiple addresses
	 * on a single interface, we almost always look and check the
	 * presence of ifra_addr, and reject invalid ones here.
	 * It also decreases duplicated code among SIOC*_IN6 operations.
	 */
	switch (cmd) {
	case SIOCAIFADDR_IN6:
	case SIOCSIFPHYADDR_IN6:
		sa6 = &ifra->ifra_addr;
		break;
	case SIOCSIFADDR_IN6:
	case SIOCGIFADDR_IN6:
	case SIOCSIFDSTADDR_IN6:
	case SIOCSIFNETMASK_IN6:
	case SIOCGIFDSTADDR_IN6:
	case SIOCGIFNETMASK_IN6:
	case SIOCDIFADDR_IN6:
	case SIOCGIFPSRCADDR_IN6:
	case SIOCGIFPDSTADDR_IN6:
	case SIOCGIFAFLAG_IN6:
	case SIOCSNDFLUSH_IN6:
	case SIOCSPFXFLUSH_IN6:
	case SIOCSRTRFLUSH_IN6:
	case SIOCGIFALIFETIME_IN6:
	case SIOCSIFALIFETIME_IN6:
	case SIOCGIFSTAT_IN6:
	case SIOCGIFSTAT_ICMP6:
		sa6 = &ifr->ifr_addr;
		break;
	default:
		sa6 = NULL;
		break;
	}
	if (sa6 && sa6->sin6_family == AF_INET6) {
		if (sa6->sin6_scope_id != 0)
			error = sa6_embedscope(sa6, 0);
		else
			error = in6_setscope(&sa6->sin6_addr, ifp, NULL);
		if (error != 0)
			return (error);
		ia = in6ifa_ifpwithaddr(ifp, &sa6->sin6_addr);
	} else
		ia = NULL;

	switch (cmd) {
	case SIOCSIFADDR_IN6:
	case SIOCSIFDSTADDR_IN6:
	case SIOCSIFNETMASK_IN6:
		/*
		 * Since IPv6 allows a node to assign multiple addresses
		 * on a single interface, SIOCSIFxxx ioctls are deprecated.
		 */
		return (EINVAL);

	case SIOCDIFADDR_IN6:
		/*
		 * for IPv4, we look for existing in_ifaddr here to allow
		 * "ifconfig if0 delete" to remove the first IPv4 address on
		 * the interface.  For IPv6, as the spec allows multiple
		 * interface address from the day one, we consider "remove the
		 * first one" semantics to be not preferable.
		 */
		if (ia == NULL)
			return (EADDRNOTAVAIL);
		/* FALLTHROUGH */
	case SIOCAIFADDR_IN6:
		/*
		 * We always require users to specify a valid IPv6 address for
		 * the corresponding operation.
		 */
		if (ifra->ifra_addr.sin6_family != AF_INET6 ||
		    ifra->ifra_addr.sin6_len != sizeof(struct sockaddr_in6))
			return (EAFNOSUPPORT);
		if (!privileged)
			return (EPERM);

		break;

	case SIOCGIFADDR_IN6:
		/* This interface is basically deprecated. use SIOCGIFCONF. */
		/* FALLTHROUGH */
	case SIOCGIFAFLAG_IN6:
	case SIOCGIFNETMASK_IN6:
	case SIOCGIFDSTADDR_IN6:
	case SIOCGIFALIFETIME_IN6:
		/* must think again about its semantics */
		if (ia == NULL)
			return (EADDRNOTAVAIL);
		break;
	case SIOCSIFALIFETIME_IN6:
	    {
		struct in6_addrlifetime *lt;

		if (!privileged)
			return (EPERM);
		if (ia == NULL)
			return (EADDRNOTAVAIL);
		/* sanity for overflow - beware unsigned */
		lt = &ifr->ifr_ifru.ifru_lifetime;
		if (lt->ia6t_vltime != ND6_INFINITE_LIFETIME
		 && lt->ia6t_vltime + time.tv_sec < time.tv_sec) {
			return EINVAL;
		}
		if (lt->ia6t_pltime != ND6_INFINITE_LIFETIME
		 && lt->ia6t_pltime + time.tv_sec < time.tv_sec) {
			return EINVAL;
		}
		break;
	    }
	}

	switch (cmd) {

	case SIOCGIFADDR_IN6:
		ifr->ifr_addr = ia->ia_addr;
		if ((error = sa6_recoverscope(&ifr->ifr_addr)) != 0)
			return (error);
		break;

	case SIOCGIFDSTADDR_IN6:
		if ((ifp->if_flags & IFF_POINTOPOINT) == 0)
			return (EINVAL);
		/*
		 * XXX: should we check if ifa_dstaddr is NULL and return
		 * an error?
		 */
		ifr->ifr_dstaddr = ia->ia_dstaddr;
		if ((error = sa6_recoverscope(&ifr->ifr_dstaddr)) != 0)
			return (error);
		break;

	case SIOCGIFNETMASK_IN6:
		ifr->ifr_addr = ia->ia_prefixmask;
		break;

	case SIOCGIFAFLAG_IN6:
		ifr->ifr_ifru.ifru_flags6 = ia->ia6_flags;
		break;

	case SIOCGIFSTAT_IN6:
		if (ifp == NULL)
			return EINVAL;
		bzero(&ifr->ifr_ifru.ifru_stat,
		    sizeof(ifr->ifr_ifru.ifru_stat));
		ifr->ifr_ifru.ifru_stat =
		    *((struct in6_ifextra *)ifp->if_afdata[AF_INET6])->in6_ifstat;
		break;

	case SIOCGIFSTAT_ICMP6:
		if (ifp == NULL)
			return EINVAL;
		bzero(&ifr->ifr_ifru.ifru_icmp6stat,
		    sizeof(ifr->ifr_ifru.ifru_icmp6stat));
		ifr->ifr_ifru.ifru_icmp6stat =
		    *((struct in6_ifextra *)ifp->if_afdata[AF_INET6])->icmp6_ifstat;
		break;

	case SIOCGIFALIFETIME_IN6:
		ifr->ifr_ifru.ifru_lifetime = ia->ia6_lifetime;
		if (ia->ia6_lifetime.ia6t_vltime != ND6_INFINITE_LIFETIME) {
			time_t maxexpire;
			struct in6_addrlifetime *retlt =
			    &ifr->ifr_ifru.ifru_lifetime;

			/*
			 * XXX: adjust expiration time assuming time_t is
			 * signed.
			 */
			maxexpire = (-1) &
			    ~(1 << ((sizeof(maxexpire) * 8) - 1));
			if (ia->ia6_lifetime.ia6t_vltime <
			    maxexpire - ia->ia6_updatetime) {
				retlt->ia6t_expire = ia->ia6_updatetime +
				    ia->ia6_lifetime.ia6t_vltime;
			} else
				retlt->ia6t_expire = maxexpire;
		}
		if (ia->ia6_lifetime.ia6t_pltime != ND6_INFINITE_LIFETIME) {
			time_t maxexpire;
			struct in6_addrlifetime *retlt =
			    &ifr->ifr_ifru.ifru_lifetime;

			/*
			 * XXX: adjust expiration time assuming time_t is
			 * signed.
			 */
			maxexpire = (-1) &
			    ~(1 << ((sizeof(maxexpire) * 8) - 1));
			if (ia->ia6_lifetime.ia6t_pltime <
			    maxexpire - ia->ia6_updatetime) {
				retlt->ia6t_preferred = ia->ia6_updatetime +
				    ia->ia6_lifetime.ia6t_pltime;
			} else
				retlt->ia6t_preferred = maxexpire;
		}
		break;

	case SIOCSIFALIFETIME_IN6:
		ia->ia6_lifetime = ifr->ifr_ifru.ifru_lifetime;
		/* for sanity */
		if (ia->ia6_lifetime.ia6t_vltime != ND6_INFINITE_LIFETIME) {
			ia->ia6_lifetime.ia6t_expire =
				time.tv_sec + ia->ia6_lifetime.ia6t_vltime;
		} else
			ia->ia6_lifetime.ia6t_expire = 0;
		if (ia->ia6_lifetime.ia6t_pltime != ND6_INFINITE_LIFETIME) {
			ia->ia6_lifetime.ia6t_preferred =
				time.tv_sec + ia->ia6_lifetime.ia6t_pltime;
		} else
			ia->ia6_lifetime.ia6t_preferred = 0;
		break;

	case SIOCAIFADDR_IN6:
	{
		int i;
		struct nd_prefixctl pr0;
		struct nd_prefix *pr;

		/* reject read-only flags */
		if ((ifra->ifra_flags & IN6_IFF_DUPLICATED) != 0 ||
		    (ifra->ifra_flags & IN6_IFF_DETACHED) != 0 ||
		    (ifra->ifra_flags & IN6_IFF_NODAD) != 0 ||
		    (ifra->ifra_flags & IN6_IFF_AUTOCONF) != 0) {
			return (EINVAL);
		}
		/*
		 * first, make or update the interface address structure,
		 * and link it to the list.
		 */
		if ((error = in6_update_ifa(ifp, ifra, ia, 0)) != 0)
			return (error);
		if ((ia = in6ifa_ifpwithaddr(ifp, &ifra->ifra_addr.sin6_addr))
		    == NULL) {
		    	/*
			 * this can happen when the user specify the 0 valid
			 * lifetime.
			 */
			break;
		}

		/*
		 * then, make the prefix on-link on the interface.
		 * XXX: we'd rather create the prefix before the address, but
		 * we need at least one address to install the corresponding
		 * interface route, so we configure the address first.
		 */

		/*
		 * convert mask to prefix length (prefixmask has already
		 * been validated in in6_update_ifa().
		 */
		bzero(&pr0, sizeof(pr0));
		pr0.ndpr_ifp = ifp;
		pr0.ndpr_plen = in6_mask2len(&ifra->ifra_prefixmask.sin6_addr,
		    NULL);
		if (pr0.ndpr_plen == 128) {
			break;	/* we don't need to install a host route. */
		}
		pr0.ndpr_prefix = ifra->ifra_addr;
		/* apply the mask for safety. */
		for (i = 0; i < 4; i++) {
			pr0.ndpr_prefix.sin6_addr.s6_addr32[i] &=
			    ifra->ifra_prefixmask.sin6_addr.s6_addr32[i];
		}
		/*
		 * XXX: since we don't have an API to set prefix (not address)
		 * lifetimes, we just use the same lifetimes as addresses.
		 * The (temporarily) installed lifetimes can be overridden by
		 * later advertised RAs (when accept_rtadv is non 0), which is
		 * an intended behavior.
		 */
		pr0.ndpr_raf_onlink = 1; /* should be configurable? */
		pr0.ndpr_raf_auto =
		    ((ifra->ifra_flags & IN6_IFF_AUTOCONF) != 0);
		pr0.ndpr_vltime = ifra->ifra_lifetime.ia6t_vltime;
		pr0.ndpr_pltime = ifra->ifra_lifetime.ia6t_pltime;

		/* add the prefix if not yet. */
		if ((pr = nd6_prefix_lookup(&pr0)) == NULL) {
			/*
			 * nd6_prelist_add will install the corresponding
			 * interface route.
			 */
			if ((error = nd6_prelist_add(&pr0, NULL, &pr)) != 0)
				return (error);
			if (pr == NULL) {
				log(LOG_ERR, "nd6_prelist_add succeeded but "
				    "no prefix\n");
				return (EINVAL); /* XXX panic here? */
			}
		}

		/* relate the address to the prefix */
		if (ia->ia6_ndpr == NULL) {
			ia->ia6_ndpr = pr;
			pr->ndpr_refcnt++;

			/*
			 * If this is the first autoconf address from the
			 * prefix, create a temporary address as well
			 * (when required).
			 */
			if ((ia->ia6_flags & IN6_IFF_AUTOCONF) &&
			    ip6_use_tempaddr && pr->ndpr_refcnt == 1) {
				int e;
				if ((e = in6_tmpifadd(ia, 1, 0)) != 0) {
					log(LOG_NOTICE, "in6_control: failed "
					    "to create a temporary address, "
					    "errno=%d\n", e);
				}
			}
		}

		/*
		 * this might affect the status of autoconfigured addresses,
		 * that is, this address might make other addresses detached.
		 */
		pfxlist_onlink_check();

#ifdef PFIL_HOOKS
		(void)pfil_run_hooks(&if_pfil, (struct mbuf **)SIOCAIFADDR_IN6,
		    ifp, PFIL_IFADDR);
#endif

		break;
	}

	case SIOCDIFADDR_IN6:
	{
		struct nd_prefix *pr;

		/*
		 * If the address being deleted is the only one that owns
		 * the corresponding prefix, expire the prefix as well.
		 * XXX: theoretically, we don't have to worry about such
		 * relationship, since we separate the address management
		 * and the prefix management.  We do this, however, to provide
		 * as much backward compatibility as possible in terms of
		 * the ioctl operation.
		 * Note that in6_purgeaddr() will decrement ndpr_refcnt.
		 */
		pr = ia->ia6_ndpr;
		in6_purgeaddr(&ia->ia_ifa);
		if (pr && pr->ndpr_refcnt == 0)
			prelist_remove(pr);
#ifdef PFIL_HOOKS
		(void)pfil_run_hooks(&if_pfil, (struct mbuf **)SIOCDIFADDR_IN6,
		    ifp, PFIL_IFADDR);
#endif
		break;
	}

	default:
		if (ifp == NULL || ifp->if_ioctl == 0)
			return (EOPNOTSUPP);
		printf("net %s %p\n", ifp->if_xname, ifp->if_ioctl);
		error = ((*ifp->if_ioctl)(ifp, cmd, data));
		printf("error = %d\n", error);
		return error;
	}

	return (0);
}

/*
 * Update parameters of an IPv6 interface address.
 * If necessary, a new entry is created and linked into address chains.
 * This function is separated from in6_control().
 * XXX: should this be performed under splnet()?
 */
int
in6_update_ifa(ifp, ifra, ia, flags)
	struct ifnet *ifp;
	struct in6_aliasreq *ifra;
	struct in6_ifaddr *ia;
	int flags;
{
	int error = 0, hostIsNew = 0, plen = -1;
	struct in6_ifaddr *oia;
	struct sockaddr_in6 dst6;
	struct in6_addrlifetime *lt;
	struct in6_multi_mship *imm;
	struct in6_multi *in6m_sol;
	struct rtentry *rt;
	int dad_delay;

	in6m_sol = NULL;

	/* Validate parameters */
	if (ifp == NULL || ifra == NULL) /* this maybe redundant */
		return (EINVAL);

	/*
	 * The destination address for a p2p link must have a family
	 * of AF_UNSPEC or AF_INET6.
	 */
	if ((ifp->if_flags & IFF_POINTOPOINT) != 0 &&
	    ifra->ifra_dstaddr.sin6_family != AF_INET6 &&
	    ifra->ifra_dstaddr.sin6_family != AF_UNSPEC)
		return (EAFNOSUPPORT);
	/*
	 * validate ifra_prefixmask.  don't check sin6_family, netmask
	 * does not carry fields other than sin6_len.
	 */
	if (ifra->ifra_prefixmask.sin6_len > sizeof(struct sockaddr_in6))
		return (EINVAL);
	/*
	 * Because the IPv6 address architecture is classless, we require
	 * users to specify a (non 0) prefix length (mask) for a new address.
	 * We also require the prefix (when specified) mask is valid, and thus
	 * reject a non-consecutive mask.
	 */
	if (ia == NULL && ifra->ifra_prefixmask.sin6_len == 0)
		return (EINVAL);
	if (ifra->ifra_prefixmask.sin6_len != 0) {
		plen = in6_mask2len(&ifra->ifra_prefixmask.sin6_addr,
		    (u_char *)&ifra->ifra_prefixmask +
		    ifra->ifra_prefixmask.sin6_len);
		if (plen <= 0)
			return (EINVAL);
	} else {
		/*
		 * In this case, ia must not be NULL.  We just use its prefix
		 * length.
		 */
		plen = in6_mask2len(&ia->ia_prefixmask.sin6_addr, NULL);
	}
	/*
	 * If the destination address on a p2p interface is specified,
	 * and the address is a scoped one, validate/set the scope
	 * zone identifier.
	 */
	dst6 = ifra->ifra_dstaddr;
	if ((ifp->if_flags & (IFF_POINTOPOINT|IFF_LOOPBACK)) != 0 &&
	    (dst6.sin6_family == AF_INET6)) {
		struct in6_addr in6_tmp;
		u_int32_t zoneid;

		in6_tmp = dst6.sin6_addr;
		if (in6_setscope(&in6_tmp, ifp, &zoneid))
			return (EINVAL); /* XXX: should be impossible */

		if (dst6.sin6_scope_id != 0) {
			if (dst6.sin6_scope_id != zoneid)
				return (EINVAL);
		} else		/* user omit to specify the ID. */
			dst6.sin6_scope_id = zoneid;

		/* convert into the internal form */
		if (sa6_embedscope(&dst6, 0))
			return (EINVAL); /* XXX: should be impossible */
	}
	/*
	 * The destination address can be specified only for a p2p or a
	 * loopback interface.  If specified, the corresponding prefix length
	 * must be 128.
	 */
	if (ifra->ifra_dstaddr.sin6_family == AF_INET6) {
#ifdef FORCE_P2PPLEN
		int i;
#endif

		if ((ifp->if_flags & (IFF_POINTOPOINT|IFF_LOOPBACK)) == 0) {
			/* XXX: noisy message */
			nd6log((LOG_INFO, "in6_update_ifa: a destination can "
			    "be specified for a p2p or a loopback IF only\n"));
			return (EINVAL);
		}
		if (plen != 128) {
			nd6log((LOG_INFO, "in6_update_ifa: prefixlen should "
			    "be 128 when dstaddr is specified\n"));
#ifdef FORCE_P2PPLEN
			/*
			 * To be compatible with old configurations,
			 * such as ifconfig gif0 inet6 2001::1 2001::2
			 * prefixlen 126, we override the specified
			 * prefixmask as if the prefix length was 128.
			 */
			ifra->ifra_prefixmask.sin6_len =
			    sizeof(struct sockaddr_in6);
			for (i = 0; i < 4; i++)
				ifra->ifra_prefixmask.sin6_addr.s6_addr32[i] =
				    0xffffffff;
			plen = 128;
#else
			return (EINVAL);
#endif
		}
	}
	/* lifetime consistency check */
	lt = &ifra->ifra_lifetime;
	if (lt->ia6t_pltime > lt->ia6t_vltime)
		return (EINVAL);
	if (lt->ia6t_vltime == 0) {
		/*
		 * the following log might be noisy, but this is a typical
		 * configuration mistake or a tool's bug.
		 */
		nd6log((LOG_INFO,
		    "in6_update_ifa: valid lifetime is 0 for %s\n",
		    ip6_sprintf(&ifra->ifra_addr.sin6_addr)));

		if (ia == NULL)
			return (0); /* there's nothing to do */
	}

	/*
	 * If this is a new address, allocate a new ifaddr and link it
	 * into chains.
	 */
	if (ia == NULL) {
		hostIsNew = 1;
		/*
		 * When in6_update_ifa() is called in a process of a received
		 * RA, it is called under an interrupt context.  So, we should
		 * call malloc with M_NOWAIT.
		 */
		ia = (struct in6_ifaddr *) malloc(sizeof(*ia), M_IFADDR,
		    M_NOWAIT);
		if (ia == NULL)
			return (ENOBUFS);
		bzero((caddr_t)ia, sizeof(*ia));
		LIST_INIT(&ia->ia6_memberships);
		/* Initialize the address and masks, and put time stamp */
		ia->ia_ifa.ifa_addr = (struct sockaddr *)&ia->ia_addr;
		ia->ia_addr.sin6_family = AF_INET6;
		ia->ia_addr.sin6_len = sizeof(ia->ia_addr);
		ia->ia6_createtime = time.tv_sec;
		if ((ifp->if_flags & (IFF_POINTOPOINT | IFF_LOOPBACK)) != 0) {
			/*
			 * XXX: some functions expect that ifa_dstaddr is not
			 * NULL for p2p interfaces.
			 */
			ia->ia_ifa.ifa_dstaddr =
			    (struct sockaddr *)&ia->ia_dstaddr;
		} else {
			ia->ia_ifa.ifa_dstaddr = NULL;
		}
		ia->ia_ifa.ifa_netmask =
		    (struct sockaddr *)&ia->ia_prefixmask;

		ia->ia_ifp = ifp;
		if ((oia = in6_ifaddr) != NULL) {
			for ( ; oia->ia_next; oia = oia->ia_next)
				continue;
			oia->ia_next = ia;
		} else
			in6_ifaddr = ia;
		/* gain a refcnt for the link from in6_ifaddr */
		IFAREF(&ia->ia_ifa);

		TAILQ_INSERT_TAIL(&ifp->if_addrlist, &ia->ia_ifa,
				  ifa_list);
		/* gain another refcnt for the link from if_addrlist */
		IFAREF(&ia->ia_ifa);
	}

	/* update timestamp */
	ia->ia6_updatetime = time.tv_sec;

	/* set prefix mask */
	if (ifra->ifra_prefixmask.sin6_len) {
		/*
		 * We prohibit changing the prefix length of an existing
		 * address, because
		 * + such an operation should be rare in IPv6, and
		 * + the operation would confuse prefix management.
		 */
		if (ia->ia_prefixmask.sin6_len &&
		    in6_mask2len(&ia->ia_prefixmask.sin6_addr, NULL) != plen) {
			nd6log((LOG_INFO, "in6_update_ifa: the prefix length of an"
			    " existing (%s) address should not be changed\n",
			    ip6_sprintf(&ia->ia_addr.sin6_addr)));
			error = EINVAL;
			goto unlink;
		}
		ia->ia_prefixmask = ifra->ifra_prefixmask;
	}

	/*
	 * If a new destination address is specified, scrub the old one and
	 * install the new destination.  Note that the interface must be
	 * p2p or loopback (see the check above.)
	 */
	if (dst6.sin6_family == AF_INET6 &&
	    !IN6_ARE_ADDR_EQUAL(&dst6.sin6_addr, &ia->ia_dstaddr.sin6_addr)) {
		if ((ia->ia_flags & IFA_ROUTE) != 0 &&
		    rtinit(&(ia->ia_ifa), (int)RTM_DELETE, RTF_HOST) != 0) {
			nd6log((LOG_ERR, "in6_update_ifa: failed to remove "
			    "a route to the old destination: %s\n",
			    ip6_sprintf(&ia->ia_addr.sin6_addr)));
			/* proceed anyway... */
		} else
			ia->ia_flags &= ~IFA_ROUTE;
		ia->ia_dstaddr = dst6;
	}

	/*
	 * Set lifetimes.  We do not refer to ia6t_expire and ia6t_preferred
	 * to see if the address is deprecated or invalidated, but initialize
	 * these members for applications.
	 */
	ia->ia6_lifetime = ifra->ifra_lifetime;
	if (ia->ia6_lifetime.ia6t_vltime != ND6_INFINITE_LIFETIME) {
		ia->ia6_lifetime.ia6t_expire =
		    time.tv_sec + ia->ia6_lifetime.ia6t_vltime;
	} else
		ia->ia6_lifetime.ia6t_expire = 0;
	if (ia->ia6_lifetime.ia6t_pltime != ND6_INFINITE_LIFETIME) {
		ia->ia6_lifetime.ia6t_preferred =
		    time.tv_sec + ia->ia6_lifetime.ia6t_pltime;
	} else
		ia->ia6_lifetime.ia6t_preferred = 0;

	/* reset the interface and routing table appropriately. */
	if ((error = in6_ifinit(ifp, ia, &ifra->ifra_addr, hostIsNew)) != 0)
		goto unlink;

	/*
	 * configure address flags.
	 */
	ia->ia6_flags = ifra->ifra_flags;
	/*
	 * backward compatibility - if IN6_IFF_DEPRECATED is set from the
	 * userland, make it deprecated.
	 */
	if ((ifra->ifra_flags & IN6_IFF_DEPRECATED) != 0) {
		ia->ia6_lifetime.ia6t_pltime = 0;
		ia->ia6_lifetime.ia6t_preferred = time.tv_sec;
	}

	/*
	 * Make the address tentative before joining multicast addresses,
	 * so that corresponding MLD responses would not have a tentative
	 * source address.
	 */
	ia->ia6_flags &= ~IN6_IFF_DUPLICATED;	/* safety */
	if (hostIsNew && in6if_do_dad(ifp)) 
		ia->ia6_flags |= IN6_IFF_TENTATIVE;

	/*
	 * We are done if we have simply modified an existing address.
	 */
	if (!hostIsNew)
		return (error);

	/*
	 * Beyond this point, we should call in6_purgeaddr upon an error,
	 * not just go to unlink.
	 */

	/* join necessary multicast groups */
	if ((ifp->if_flags & IFF_MULTICAST) != 0) {
		struct sockaddr_in6 mltaddr, mltmask;
		struct in6_addr llsol;

		/* join solicited multicast addr for new host id */
		bzero(&llsol, sizeof(struct in6_addr));
		llsol.s6_addr16[0] = htons(0xff02);
		llsol.s6_addr32[1] = 0;
		llsol.s6_addr32[2] = htonl(1);
		llsol.s6_addr32[3] = ifra->ifra_addr.sin6_addr.s6_addr32[3];
		llsol.s6_addr8[12] = 0xff;
		if ((error = in6_setscope(&llsol, ifp, NULL)) != 0) {
			/* XXX: should not happen */
			log(LOG_ERR, "in6_update_ifa: "
			    "in6_setscope failed\n");
			goto cleanup;
		}
		dad_delay = 0;
		if ((flags & IN6_IFAUPDATE_DADDELAY)) {
			/*
			 * We need a random delay for DAD on the address
			 * being configured.  It also means delaying
			 * transmission of the corresponding MLD report to
			 * avoid report collision.
			 * [draft-ietf-ipv6-rfc2462bis-02.txt]
			 */
			dad_delay = arc4random() %
			    (MAX_RTR_SOLICITATION_DELAY * hz);
		}

#define	MLTMASK_LEN  4	/* mltmask's masklen (=32bit=4octet) */
		/* join solicited multicast addr for new host id */
		imm = in6_joingroup(ifp, &llsol, &error, dad_delay);
		if (!imm) {
			nd6log((LOG_ERR,
			    "in6_update_ifa: addmulti "
			    "failed for %s on %s (errno=%d)\n",
			    ip6_sprintf(&llsol), if_name(ifp), error));
			goto cleanup;
		}
		LIST_INSERT_HEAD(&ia->ia6_memberships, imm, i6mm_chain);
		in6m_sol = imm->i6mm_maddr;

		bzero(&mltmask, sizeof(mltmask));
		mltmask.sin6_len = sizeof(struct sockaddr_in6);
		mltmask.sin6_family = AF_INET6;
		mltmask.sin6_addr = in6mask32;

		/*
		 * join link-local all-nodes address
		 */
		bzero(&mltaddr, sizeof(mltaddr));
		mltaddr.sin6_len = sizeof(struct sockaddr_in6);
		mltaddr.sin6_family = AF_INET6;
		mltaddr.sin6_addr = in6addr_linklocal_allnodes;
		if ((error = in6_setscope(&mltaddr.sin6_addr, ifp, NULL)) !=
		    0)
			goto cleanup; /* XXX: should not fail */

		/*
		 * XXX: do we really need this automatic routes?
		 * We should probably reconsider this stuff.  Most applications
		 * actually do not need the routes, since they usually specify
		 * the outgoing interface.
		 */
		rt = rtalloc1((struct sockaddr *)&mltaddr, 0);
		if (rt) {
			if (memcmp(&mltaddr.sin6_addr,
			    &((struct sockaddr_in6 *)rt_key(rt))->sin6_addr,
			    MLTMASK_LEN)) {
				RTFREE(rt);
				rt = NULL;
			}
		}
		if (!rt) {
			struct rt_addrinfo info;

			bzero(&info, sizeof(info));
			info.rti_info[RTAX_DST] = (struct sockaddr *)&mltaddr;
			info.rti_info[RTAX_GATEWAY] =
			    (struct sockaddr *)&ia->ia_addr;
			info.rti_info[RTAX_NETMASK] =
			    (struct sockaddr *)&mltmask;
			info.rti_info[RTAX_IFA] =
			    (struct sockaddr *)&ia->ia_addr;
			/* XXX: we need RTF_CLONING to fake nd6_rtrequest */
			info.rti_flags = RTF_UP | RTF_CLONING;
			error = rtrequest1(RTM_ADD, &info, NULL);
			if (error)
				goto cleanup;
		} else {
			RTFREE(rt);
		}
		imm = in6_joingroup(ifp, &mltaddr.sin6_addr, &error, 0);
		if (!imm) {
			nd6log((LOG_WARNING,
			    "in6_update_ifa: addmulti failed for "
			    "%s on %s (errno=%d)\n",
			    ip6_sprintf(&mltaddr.sin6_addr),
			    if_name(ifp), error));
			goto cleanup;
		}
		LIST_INSERT_HEAD(&ia->ia6_memberships, imm, i6mm_chain);

		/*
		 * join node information group address
		 */
		dad_delay = 0;
		if ((flags & IN6_IFAUPDATE_DADDELAY)) {
			/*
			 * The spec doesn't say anything about delay for this
			 * group, but the same logic should apply.
			 */
			dad_delay = arc4random() %
			    (MAX_RTR_SOLICITATION_DELAY * hz);
		}
		if (in6_nigroup(ifp, hostname, hostnamelen, &mltaddr) == 0) {
			imm = in6_joingroup(ifp, &mltaddr.sin6_addr, &error,
			    dad_delay); /* XXX jinmei */
			if (!imm) {
				nd6log((LOG_WARNING, "in6_update_ifa: "
				    "addmulti failed for %s on %s (errno=%d)\n",
				    ip6_sprintf(&mltaddr.sin6_addr),
				    if_name(ifp), error));
				/* XXX not very fatal, go on... */
			} else {
				LIST_INSERT_HEAD(&ia->ia6_memberships,
				    imm, i6mm_chain);
			}
		}


		/*
		 * join interface-local all-nodes address.
		 * (ff01::1%ifN, and ff01::%ifN/32)
		 */
		mltaddr.sin6_addr = in6addr_nodelocal_allnodes;
		if ((error = in6_setscope(&mltaddr.sin6_addr, ifp, NULL))
		    != 0) 
			goto cleanup; /* XXX: should not fail */

		/* XXX: again, do we really need the route? */
		rt = rtalloc1((struct sockaddr *)&mltaddr, 0);
		if (rt) {
			/* 32bit came from "mltmask" */
			if (memcmp(&mltaddr.sin6_addr,
			    &((struct sockaddr_in6 *)rt_key(rt))->sin6_addr,
			    32 / 8)) {
				RTFREE(rt);
				rt = NULL;
			}
		}
		if (!rt) {
			struct rt_addrinfo info;

			bzero(&info, sizeof(info));
			info.rti_info[RTAX_DST] = (struct sockaddr *)&mltaddr;
			info.rti_info[RTAX_GATEWAY] =
			    (struct sockaddr *)&ia->ia_addr;
			info.rti_info[RTAX_NETMASK] =
			    (struct sockaddr *)&mltmask;
			info.rti_info[RTAX_IFA] =
			    (struct sockaddr *)&ia->ia_addr;
			info.rti_flags = RTF_UP | RTF_CLONING;
			error = rtrequest1(RTM_ADD, &info, NULL);
			if (error)
				goto cleanup;
#undef	MLTMASK_LEN
		} else {
			RTFREE(rt);
		}
		imm = in6_joingroup(ifp, &mltaddr.sin6_addr, &error, 0);
		if (!imm) {
			nd6log((LOG_WARNING, "in6_update_ifa: "
			    "addmulti failed for %s on %s (errno=%d)\n",
			    ip6_sprintf(&mltaddr.sin6_addr),
			    if_name(ifp), error));
			goto cleanup;
		} else {
			LIST_INSERT_HEAD(&ia->ia6_memberships, imm, i6mm_chain);
		}
	}

	/*
	 * Perform DAD, if needed.
	 * XXX It may be of use, if we can administratively
	 * disable DAD.
	 */
	if (hostIsNew && in6if_do_dad(ifp) &&
	    ((ifra->ifra_flags & IN6_IFF_NODAD) == 0) &&
	    (ia->ia6_flags & IN6_IFF_TENTATIVE))
	{
		int mindelay, maxdelay;

		dad_delay = 0;
		if ((flags & IN6_IFAUPDATE_DADDELAY)) {
			/*
			 * We need to impose a delay before sending an NS
			 * for DAD.  Check if we also needed a delay for the
			 * corresponding MLD message.  If we did, the delay
			 * should be larger than the MLD delay (this could be
			 * relaxed a bit, but this simple logic is at least
			 * safe).
			 */
			mindelay = 0;
			if (in6m_sol != NULL &&
			    in6m_sol->in6m_state == MLD_REPORTPENDING) {
				mindelay = in6m_sol->in6m_timer;
			}
			maxdelay = MAX_RTR_SOLICITATION_DELAY * hz;
			if (maxdelay - mindelay == 0)
				dad_delay = 0;
			else {
				dad_delay =
				    (arc4random() % (maxdelay - mindelay)) +
				    mindelay;
			}
		}
		nd6_dad_start((struct ifaddr *)ia, dad_delay);
	}

	return (error);

  unlink:
	/*
	 * XXX: if a change of an existing address failed, keep the entry
	 * anyway.
	 */
	if (hostIsNew)
		in6_unlink_ifa(ia, ifp);
	return (error);

  cleanup:
	in6_purgeaddr(&ia->ia_ifa);
	return error;
}

void
in6_purgeaddr(ifa)
	struct ifaddr *ifa;
{
	struct ifnet *ifp = ifa->ifa_ifp;
	struct in6_ifaddr *ia = (struct in6_ifaddr *) ifa;
	struct in6_multi_mship *imm;

	/* stop DAD processing */
	nd6_dad_stop(ifa);

	/*
	 * delete route to the destination of the address being purged.
	 * The interface must be p2p or loopback in this case.
	 */
	if ((ia->ia_flags & IFA_ROUTE) != 0 && ia->ia_dstaddr.sin6_len != 0) {
		int e;

		if ((e = rtinit(&(ia->ia_ifa), (int)RTM_DELETE, RTF_HOST))
		    != 0) {
			log(LOG_ERR, "in6_purgeaddr: failed to remove "
			    "a route to the p2p destination: %s on %s, "
			    "errno=%d\n",
			    ip6_sprintf(&ia->ia_addr.sin6_addr), if_name(ifp),
			    e);
			/* proceed anyway... */
		} else
			ia->ia_flags &= ~IFA_ROUTE;
	}

	/* Remove ownaddr's loopback rtentry, if it exists. */
	in6_ifremloop(&(ia->ia_ifa));

	/*
	 * leave from multicast groups we have joined for the interface
	 */
	while ((imm = ia->ia6_memberships.lh_first) != NULL) {
		LIST_REMOVE(imm, i6mm_chain);
		in6_leavegroup(imm);
	}

	in6_unlink_ifa(ia, ifp);
}

static void
in6_unlink_ifa(ia, ifp)
	struct in6_ifaddr *ia;
	struct ifnet *ifp;
{
	struct in6_ifaddr *oia;
	int	s = splnet();

	TAILQ_REMOVE(&ifp->if_addrlist, &ia->ia_ifa, ifa_list);
	/* release a refcnt for the link from if_addrlist */
	IFAFREE(&ia->ia_ifa);

	oia = ia;
	if (oia == (ia = in6_ifaddr))
		in6_ifaddr = ia->ia_next;
	else {
		while (ia->ia_next && (ia->ia_next != oia))
			ia = ia->ia_next;
		if (ia->ia_next)
			ia->ia_next = oia->ia_next;
		else {
			/* search failed */
			printf("Couldn't unlink in6_ifaddr from in6_ifaddr\n");
		}
	}

	if (oia->ia6_multiaddrs.lh_first != NULL) {
		/*
		 * XXX thorpej@NetBSD.org -- if the interface is going
		 * XXX away, don't save the multicast entries, delete them!
		 */
		if (oia->ia_ifa.ifa_ifp->if_output == if_nulloutput) {
			struct in6_multi *in6m;

			while ((in6m =
			    LIST_FIRST(&oia->ia6_multiaddrs)) != NULL)
				in6_delmulti(in6m);
		} else
			in6_savemkludge(oia);
	}

	/*
	 * Release the reference to the base prefix.  There should be a
	 * positive reference.
	 */
	if (oia->ia6_ndpr == NULL) {
		nd6log((LOG_NOTICE, "in6_unlink_ifa: autoconf'ed address "
		    "%p has no prefix\n", oia));
	} else {
		oia->ia6_ndpr->ndpr_refcnt--;
		oia->ia6_ndpr = NULL;
	}

	/*
	 * Also, if the address being removed is autoconf'ed, call
	 * pfxlist_onlink_check() since the release might affect the status of
	 * other (detached) addresses.
	 */
	if ((oia->ia6_flags & IN6_IFF_AUTOCONF) != 0)
		pfxlist_onlink_check();

	/*
	 * release another refcnt for the link from in6_ifaddr.
	 * Note that we should decrement the refcnt at least once for all *BSD.
	 */
	IFAFREE(&oia->ia_ifa);

	splx(s);
}

void
in6_purgeif(ifp)
	struct ifnet *ifp;
{
	struct ifaddr *ifa, *nifa;

	for (ifa = TAILQ_FIRST(&ifp->if_addrlist); ifa != NULL; ifa = nifa)
	{
		nifa = TAILQ_NEXT(ifa, ifa_list);
		if (ifa->ifa_addr->sa_family != AF_INET6)
			continue;
		in6_purgeaddr(ifa);
	}

	in6_ifdetach(ifp);
}

/*
 * SIOC[GAD]LIFADDR.
 *	SIOCGLIFADDR: get first address. (?)
 *	SIOCGLIFADDR with IFLR_PREFIX:
 *		get first address that matches the specified prefix.
 *	SIOCALIFADDR: add the specified address.
 *	SIOCALIFADDR with IFLR_PREFIX:
 *		add the specified prefix, filling hostid part from
 *		the first link-local address.  prefixlen must be <= 64.
 *	SIOCDLIFADDR: delete the specified address.
 *	SIOCDLIFADDR with IFLR_PREFIX:
 *		delete the first address that matches the specified prefix.
 * return values:
 *	EINVAL on invalid parameters
 *	EADDRNOTAVAIL on prefix match failed/specified address not found
 *	other values may be returned from in6_ioctl()
 *
 * NOTE: SIOCALIFADDR(with IFLR_PREFIX set) allows prefixlen less than 64.
 * this is to accomodate address naming scheme other than RFC2374,
 * in the future.
 * RFC2373 defines interface id to be 64bit, but it allows non-RFC2374
 * address encoding scheme. (see figure on page 8)
 */
static int
in6_lifaddr_ioctl(so, cmd, data, ifp, p)
	struct socket *so;
	u_long cmd;
	caddr_t	data;
	struct ifnet *ifp;
	struct proc *p;
{
	struct if_laddrreq *iflr = (struct if_laddrreq *)data;
	struct ifaddr *ifa;
	struct sockaddr *sa;

	/* sanity checks */
	if (!data || !ifp) {
		panic("invalid argument to in6_lifaddr_ioctl");
		/* NOTREACHED */
	}

	switch (cmd) {
	case SIOCGLIFADDR:
		/* address must be specified on GET with IFLR_PREFIX */
		if ((iflr->flags & IFLR_PREFIX) == 0)
			break;
		/* FALLTHROUGH */
	case SIOCALIFADDR:
	case SIOCDLIFADDR:
		/* address must be specified on ADD and DELETE */
		sa = (struct sockaddr *)&iflr->addr;
		if (sa->sa_family != AF_INET6)
			return EINVAL;
		if (sa->sa_len != sizeof(struct sockaddr_in6))
			return EINVAL;
		/* XXX need improvement */
		sa = (struct sockaddr *)&iflr->dstaddr;
		if (sa->sa_family && sa->sa_family != AF_INET6)
			return EINVAL;
		if (sa->sa_len && sa->sa_len != sizeof(struct sockaddr_in6))
			return EINVAL;
		break;
	default: /* shouldn't happen */
#if 0
		panic("invalid cmd to in6_lifaddr_ioctl");
		/* NOTREACHED */
#else
		return EOPNOTSUPP;
#endif
	}
	if (sizeof(struct in6_addr) * 8 < iflr->prefixlen)
		return EINVAL;

	switch (cmd) {
	case SIOCALIFADDR:
	    {
		struct in6_aliasreq ifra;
		struct in6_addr *xhostid = NULL;
		int prefixlen;

		if ((iflr->flags & IFLR_PREFIX) != 0) {
			struct sockaddr_in6 *sin6;

			/*
			 * xhostid is to fill in the hostid part of the
			 * address.  xhostid points to the first link-local
			 * address attached to the interface.
			 */
			ifa = (struct ifaddr *)in6ifa_ifpforlinklocal(ifp, 0);
			if (!ifa)
				return EADDRNOTAVAIL;
			xhostid = IFA_IN6(ifa);

		 	/* prefixlen must be <= 64. */
			if (64 < iflr->prefixlen)
				return EINVAL;
			prefixlen = iflr->prefixlen;

			/* hostid part must be zero. */
			sin6 = (struct sockaddr_in6 *)&iflr->addr;
			if (sin6->sin6_addr.s6_addr32[2] != 0
			 || sin6->sin6_addr.s6_addr32[3] != 0) {
				return EINVAL;
			}
		} else
			prefixlen = iflr->prefixlen;

		/* copy args to in6_aliasreq, perform ioctl(SIOCAIFADDR_IN6). */
		bzero(&ifra, sizeof(ifra));
		bcopy(iflr->iflr_name, ifra.ifra_name, sizeof(ifra.ifra_name));

		bcopy(&iflr->addr, &ifra.ifra_addr,
		    ((struct sockaddr *)&iflr->addr)->sa_len);
		if (xhostid) {
			/* fill in hostid part */
			ifra.ifra_addr.sin6_addr.s6_addr32[2] =
			    xhostid->s6_addr32[2];
			ifra.ifra_addr.sin6_addr.s6_addr32[3] =
			    xhostid->s6_addr32[3];
		}

		if (((struct sockaddr *)&iflr->dstaddr)->sa_family) { /* XXX */
			bcopy(&iflr->dstaddr, &ifra.ifra_dstaddr,
			    ((struct sockaddr *)&iflr->dstaddr)->sa_len);
			if (xhostid) {
				ifra.ifra_dstaddr.sin6_addr.s6_addr32[2] =
				    xhostid->s6_addr32[2];
				ifra.ifra_dstaddr.sin6_addr.s6_addr32[3] =
				    xhostid->s6_addr32[3];
			}
		}

		ifra.ifra_prefixmask.sin6_len = sizeof(struct sockaddr_in6);
		in6_prefixlen2mask(&ifra.ifra_prefixmask.sin6_addr, prefixlen);

		ifra.ifra_flags = iflr->flags & ~IFLR_PREFIX;
		return in6_control(so, SIOCAIFADDR_IN6, (caddr_t)&ifra, ifp, p);
	    }
	case SIOCGLIFADDR:
	case SIOCDLIFADDR:
	    {
		struct in6_ifaddr *ia;
		struct in6_addr mask, candidate, match;
		struct sockaddr_in6 *sin6;
		int cmp;

		bzero(&mask, sizeof(mask));
		if (iflr->flags & IFLR_PREFIX) {
			/* lookup a prefix rather than address. */
			in6_prefixlen2mask(&mask, iflr->prefixlen);

			sin6 = (struct sockaddr_in6 *)&iflr->addr;
			bcopy(&sin6->sin6_addr, &match, sizeof(match));
			match.s6_addr32[0] &= mask.s6_addr32[0];
			match.s6_addr32[1] &= mask.s6_addr32[1];
			match.s6_addr32[2] &= mask.s6_addr32[2];
			match.s6_addr32[3] &= mask.s6_addr32[3];

			/* if you set extra bits, that's wrong */
			if (bcmp(&match, &sin6->sin6_addr, sizeof(match)))
				return EINVAL;

			cmp = 1;
		} else {
			if (cmd == SIOCGLIFADDR) {
				/* on getting an address, take the 1st match */
				cmp = 0;	/* XXX */
			} else {
				/* on deleting an address, do exact match */
				in6_prefixlen2mask(&mask, 128);
				sin6 = (struct sockaddr_in6 *)&iflr->addr;
				bcopy(&sin6->sin6_addr, &match, sizeof(match));

				cmp = 1;
			}
		}

		for (ifa = ifp->if_addrlist.tqh_first;
		     ifa;
		     ifa = ifa->ifa_list.tqe_next)
		{
			if (ifa->ifa_addr->sa_family != AF_INET6)
				continue;
			if (!cmp)
				break;

			/*
			 * XXX: this is adhoc, but is necessary to allow
			 * a user to specify fe80::/64 (not /10) for a
			 * link-local address.
			 */
			bcopy(IFA_IN6(ifa), &candidate, sizeof(candidate));
			in6_clearscope(&candidate);
			candidate.s6_addr32[0] &= mask.s6_addr32[0];
			candidate.s6_addr32[1] &= mask.s6_addr32[1];
			candidate.s6_addr32[2] &= mask.s6_addr32[2];
			candidate.s6_addr32[3] &= mask.s6_addr32[3];
			if (IN6_ARE_ADDR_EQUAL(&candidate, &match))
				break;
		}
		if (!ifa)
			return EADDRNOTAVAIL;
		ia = ifa2ia6(ifa);

		if (cmd == SIOCGLIFADDR) {
			int error;

			/* fill in the if_laddrreq structure */
			bcopy(&ia->ia_addr, &iflr->addr, ia->ia_addr.sin6_len);
			error = sa6_recoverscope(
			    (struct sockaddr_in6 *)&iflr->addr);
			if (error != 0)
				return (error);

			if ((ifp->if_flags & IFF_POINTOPOINT) != 0) {
				bcopy(&ia->ia_dstaddr, &iflr->dstaddr,
				    ia->ia_dstaddr.sin6_len);
				error = sa6_recoverscope(
				    (struct sockaddr_in6 *)&iflr->dstaddr);
				if (error != 0)
					return (error);
			} else
				bzero(&iflr->dstaddr, sizeof(iflr->dstaddr));

			iflr->prefixlen =
			    in6_mask2len(&ia->ia_prefixmask.sin6_addr, NULL);

			iflr->flags = ia->ia6_flags;	/* XXX */

			return 0;
		} else {
			struct in6_aliasreq ifra;

			/* fill in6_aliasreq and do ioctl(SIOCDIFADDR_IN6) */
			bzero(&ifra, sizeof(ifra));
			bcopy(iflr->iflr_name, ifra.ifra_name,
			    sizeof(ifra.ifra_name));

			bcopy(&ia->ia_addr, &ifra.ifra_addr,
			    ia->ia_addr.sin6_len);
			if ((ifp->if_flags & IFF_POINTOPOINT) != 0) {
				bcopy(&ia->ia_dstaddr, &ifra.ifra_dstaddr,
				    ia->ia_dstaddr.sin6_len);
			} else {
				bzero(&ifra.ifra_dstaddr,
				    sizeof(ifra.ifra_dstaddr));
			}
			bcopy(&ia->ia_prefixmask, &ifra.ifra_dstaddr,
			    ia->ia_prefixmask.sin6_len);

			ifra.ifra_flags = ia->ia6_flags;
			return in6_control(so, SIOCDIFADDR_IN6, (caddr_t)&ifra,
			    ifp, p);
		}
	    }
	}

	return EOPNOTSUPP;	/* just for safety */
}

/*
 * Initialize an interface's intetnet6 address
 * and routing table entry.
 */
static int
in6_ifinit(ifp, ia, sin6, newhost)
	struct ifnet *ifp;
	struct in6_ifaddr *ia;
	struct sockaddr_in6 *sin6;
	int newhost;
{
	int	error = 0, plen, ifacount = 0;
	int	s = splnet();
	struct ifaddr *ifa;

	/*
	 * Give the interface a chance to initialize
	 * if this is its first address,
	 * and to validate the address if necessary.
	 */
	for (ifa = ifp->if_addrlist.tqh_first; ifa;
	     ifa = ifa->ifa_list.tqe_next)
	{
		if (ifa->ifa_addr == NULL)
			continue;	/* just for safety */
		if (ifa->ifa_addr->sa_family != AF_INET6)
			continue;
		ifacount++;
	}

	ia->ia_addr = *sin6;

	if (ifacount <= 1 && ifp->if_ioctl &&
	    (error = (*ifp->if_ioctl)(ifp, SIOCSIFADDR, (caddr_t)ia))) {
		splx(s);
		return (error);
	}
	splx(s);

	ia->ia_ifa.ifa_metric = ifp->if_metric;

	/* we could do in(6)_socktrim here, but just omit it at this moment. */

	/*
	 * Special case:
	 * If the destination address is specified for a point-to-point
	 * interface, install a route to the destination as an interface
	 * direct route.
	 */
	plen = in6_mask2len(&ia->ia_prefixmask.sin6_addr, NULL); /* XXX */
	if (plen == 128 && ia->ia_dstaddr.sin6_family == AF_INET6) {
		if ((error = rtinit(&(ia->ia_ifa), (int)RTM_ADD,
				    RTF_UP | RTF_HOST)) != 0)
			return (error);
		ia->ia_flags |= IFA_ROUTE;
	}

	/* Add ownaddr as loopback rtentry, if necessary (ex. on p2p link). */
	if (newhost) {
		/* set the rtrequest function to create llinfo */
		ia->ia_ifa.ifa_rtrequest = nd6_rtrequest;
		in6_ifaddloop(&(ia->ia_ifa));
	}

	if (ifp->if_flags & IFF_MULTICAST)
		in6_restoremkludge(ia, ifp);

	return (error);
}

/*
 * Find an IPv6 interface link-local address specific to an interface.
 */
struct in6_ifaddr *
in6ifa_ifpforlinklocal(ifp, ignoreflags)
	struct ifnet *ifp;
	int ignoreflags;
{
	struct ifaddr *ifa;

	for (ifa = ifp->if_addrlist.tqh_first; ifa; ifa = ifa->ifa_list.tqe_next)
	{
		if (ifa->ifa_addr == NULL)
			continue;	/* just for safety */
		if (ifa->ifa_addr->sa_family != AF_INET6)
			continue;
		if (IN6_IS_ADDR_LINKLOCAL(IFA_IN6(ifa))) {
			if ((((struct in6_ifaddr *)ifa)->ia6_flags &
			     ignoreflags) != 0)
				continue;
			break;
		}
	}

	return ((struct in6_ifaddr *)ifa);
}


/*
 * find the internet address corresponding to a given interface and address.
 */
struct in6_ifaddr *
in6ifa_ifpwithaddr(ifp, addr)
	struct ifnet *ifp;
	struct in6_addr *addr;
{
	struct ifaddr *ifa;

	for (ifa = ifp->if_addrlist.tqh_first; ifa; ifa = ifa->ifa_list.tqe_next)
	{
		if (ifa->ifa_addr == NULL)
			continue;	/* just for safety */
		if (ifa->ifa_addr->sa_family != AF_INET6)
			continue;
		if (IN6_ARE_ADDR_EQUAL(addr, IFA_IN6(ifa)))
			break;
	}

	return ((struct in6_ifaddr *)ifa);
}

/*
 * Convert IP6 address to printable (loggable) representation.
 */
static int ip6round = 0;
char *
ip6_sprintf(addr)
	const struct in6_addr *addr;
{
	static char ip6buf[8][48];
	int i;
	char *cp;
	const u_int16_t *a = (const u_int16_t *)addr;
	const u_int8_t *d;
	int dcolon = 0;

	ip6round = (ip6round + 1) & 7;
	cp = ip6buf[ip6round];

	for (i = 0; i < 8; i++) {
		if (dcolon == 1) {
			if (*a == 0) {
				if (i == 7)
					*cp++ = ':';
				a++;
				continue;
			} else
				dcolon = 2;
		}
		if (*a == 0) {
			if (dcolon == 0 && *(a + 1) == 0) {
				if (i == 0)
					*cp++ = ':';
				*cp++ = ':';
				dcolon = 1;
			} else {
				*cp++ = '0';
				*cp++ = ':';
			}
			a++;
			continue;
		}
		d = (const u_char *)a;
		*cp++ = hexdigits[*d >> 4];
		*cp++ = hexdigits[*d++ & 0xf];
		*cp++ = hexdigits[*d >> 4];
		*cp++ = hexdigits[*d & 0xf];
		*cp++ = ':';
		a++;
	}
	*--cp = 0;
	return (ip6buf[ip6round]);
}

/*
 * Determine if an address is on a local network.
 */
int
in6_localaddr(in6)
	struct in6_addr *in6;
{
	struct in6_ifaddr *ia;

	if (IN6_IS_ADDR_LOOPBACK(in6) || IN6_IS_ADDR_LINKLOCAL(in6))
		return (1);

	for (ia = in6_ifaddr; ia; ia = ia->ia_next)
		if (IN6_ARE_MASKED_ADDR_EQUAL(in6, &ia->ia_addr.sin6_addr,
					      &ia->ia_prefixmask.sin6_addr))
			return (1);

	return (0);
}

int
in6_is_addr_deprecated(sa6)
	struct sockaddr_in6 *sa6;
{
	struct in6_ifaddr *ia;

	for (ia = in6_ifaddr; ia; ia = ia->ia_next) {
		if (IN6_ARE_ADDR_EQUAL(&ia->ia_addr.sin6_addr,
		    &sa6->sin6_addr) &&
#ifdef SCOPEDROUTING
		    ia->ia_addr.sin6_scope_id == sa6->sin6_scope_id &&
#endif
		    (ia->ia6_flags & IN6_IFF_DEPRECATED) != 0)
			return (1); /* true */

		/* XXX: do we still have to go thru the rest of the list? */
	}

	return (0);		/* false */
}

/*
 * return length of part which dst and src are equal
 * hard coding...
 */
int
in6_matchlen(src, dst)
struct in6_addr *src, *dst;
{
	int match = 0;
	u_char *s = (u_char *)src, *d = (u_char *)dst;
	u_char *lim = s + 16, r;

	while (s < lim)
		if ((r = (*d++ ^ *s++)) != 0) {
			while (r < 128) {
				match++;
				r <<= 1;
			}
			break;
		} else
			match += 8;
	return match;
}

/* XXX: to be scope conscious */
int
in6_are_prefix_equal(p1, p2, len)
	struct in6_addr *p1, *p2;
	int len;
{
	int bytelen, bitlen;

	/* sanity check */
	if (len < 0 || len > 128) {
		log(LOG_ERR, "in6_are_prefix_equal: invalid prefix length(%d)\n",
		    len);
		return (0);
	}

	bytelen = len / 8;
	bitlen = len % 8;

	if (bcmp(&p1->s6_addr, &p2->s6_addr, bytelen))
		return (0);
	if (bitlen != 0 &&
	    p1->s6_addr[bytelen] >> (8 - bitlen) !=
	    p2->s6_addr[bytelen] >> (8 - bitlen))
		return (0);

	return (1);
}

void
in6_prefixlen2mask(maskp, len)
	struct in6_addr *maskp;
	int len;
{
	static const u_char maskarray[8] = {0x80, 0xc0, 0xe0, 0xf0, 0xf8, 0xfc, 0xfe, 0xff};
	int bytelen, bitlen, i;

	/* sanity check */
	if (len < 0 || len > 128) {
		log(LOG_ERR, "in6_prefixlen2mask: invalid prefix length(%d)\n",
		    len);
		return;
	}

	bzero(maskp, sizeof(*maskp));
	bytelen = len / 8;
	bitlen = len % 8;
	for (i = 0; i < bytelen; i++)
		maskp->s6_addr[i] = 0xff;
	if (bitlen)
		maskp->s6_addr[bytelen] = maskarray[bitlen - 1];
}

/*
 * return the best address out of the same scope. if no address was
 * found, return the first valid address from designated IF.
 */
struct in6_ifaddr *
in6_ifawithifp(ifp, dst)
	struct ifnet *ifp;
	struct in6_addr *dst;
{
	int dst_scope =	in6_addrscope(dst), blen = -1, tlen;
	struct ifaddr *ifa;
	struct in6_ifaddr *besta = 0;
	struct in6_ifaddr *dep[2];	/* last-resort: deprecated */

	dep[0] = dep[1] = NULL;

	/*
	 * We first look for addresses in the same scope.
	 * If there is one, return it.
	 * If two or more, return one which matches the dst longest.
	 * If none, return one of global addresses assigned other ifs.
	 */
	for (ifa = ifp->if_addrlist.tqh_first; ifa; ifa = ifa->ifa_list.tqe_next)
	{
		if (ifa->ifa_addr->sa_family != AF_INET6)
			continue;
		if (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_ANYCAST)
			continue; /* XXX: is there any case to allow anycast? */
		if (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_NOTREADY)
			continue; /* don't use this interface */
		if (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_DETACHED)
			continue;
		if (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_DEPRECATED) {
			if (ip6_use_deprecated)
				dep[0] = (struct in6_ifaddr *)ifa;
			continue;
		}

		if (dst_scope == in6_addrscope(IFA_IN6(ifa))) {
			/*
			 * call in6_matchlen() as few as possible
			 */
			if (besta) {
				if (blen == -1)
					blen = in6_matchlen(&besta->ia_addr.sin6_addr, dst);
				tlen = in6_matchlen(IFA_IN6(ifa), dst);
				if (tlen > blen) {
					blen = tlen;
					besta = (struct in6_ifaddr *)ifa;
				}
			} else
				besta = (struct in6_ifaddr *)ifa;
		}
	}
	if (besta)
		return (besta);

	for (ifa = ifp->if_addrlist.tqh_first; ifa; ifa = ifa->ifa_list.tqe_next)
	{
		if (ifa->ifa_addr->sa_family != AF_INET6)
			continue;
		if (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_ANYCAST)
			continue; /* XXX: is there any case to allow anycast? */
		if (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_NOTREADY)
			continue; /* don't use this interface */
		if (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_DETACHED)
			continue;
		if (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_DEPRECATED) {
			if (ip6_use_deprecated)
				dep[1] = (struct in6_ifaddr *)ifa;
			continue;
		}

		return (struct in6_ifaddr *)ifa;
	}

	/* use the last-resort values, that are, deprecated addresses */
	if (dep[0])
		return dep[0];
	if (dep[1])
		return dep[1];

	return NULL;
}

/*
 * perform DAD when interface becomes IFF_UP.
 */
void
in6_if_up(ifp)
	struct ifnet *ifp;
{
	struct ifaddr *ifa;
	struct in6_ifaddr *ia;

	for (ifa = ifp->if_addrlist.tqh_first; ifa; ifa = ifa->ifa_list.tqe_next)
	{
		if (ifa->ifa_addr->sa_family != AF_INET6)
			continue;
		ia = (struct in6_ifaddr *)ifa;
		if (ia->ia6_flags & IN6_IFF_TENTATIVE) {
			/*
			 * The TENTATIVE flag was likely set by hand
			 * beforehand, implicitly indicating the need for DAD.
			 * We may be able to skip the random delay in this
			 * case, but we impose delays just in case.
			 */
			nd6_dad_start(ifa,
			    arc4random() % (MAX_RTR_SOLICITATION_DELAY * hz));
		}
	}

	/*
	 * special cases, like 6to4, are handled in in6_ifattach
	 */
	in6_ifattach(ifp, NULL);
}

int
in6if_do_dad(ifp)
	struct ifnet *ifp;
{
	if ((ifp->if_flags & IFF_LOOPBACK) != 0)
		return (0);

	switch (ifp->if_type) {
	case IFT_FAITH:
		/*
		 * These interfaces do not have the IFF_LOOPBACK flag,
		 * but loop packets back.  We do not have to do DAD on such
		 * interfaces.  We should even omit it, because loop-backed
		 * NS would confuse the DAD procedure.
		 */
		return (0);
	default:
		/*
		 * Our DAD routine requires the interface up and running.
		 * However, some interfaces can be up before the RUNNING
		 * status.  Additionaly, users may try to assign addresses
		 * before the interface becomes up (or running).
		 * We simply skip DAD in such a case as a work around.
		 * XXX: we should rather mark "tentative" on such addresses,
		 * and do DAD after the interface becomes ready.
		 */
		if ((ifp->if_flags & (IFF_UP|IFF_RUNNING)) !=
		    (IFF_UP|IFF_RUNNING))
			return (0);

		return (1);
	}
}

/*
 * Calculate max IPv6 MTU through all the interfaces and store it
 * to in6_maxmtu.
 */
void
in6_setmaxmtu()
{
	unsigned long maxmtu = 0;
	struct ifnet *ifp;

	for (ifp = TAILQ_FIRST(&ifnet); ifp; ifp = TAILQ_NEXT(ifp, if_list))
	{
		/* this function can be called during ifnet initialization */
		if (!ifp->if_afdata[AF_INET6])
			continue;
		if ((ifp->if_flags & IFF_LOOPBACK) == 0 &&
		    IN6_LINKMTU(ifp) > maxmtu)
			maxmtu = IN6_LINKMTU(ifp);
	}
	if (maxmtu)	     /* update only when maxmtu is positive */
		in6_maxmtu = maxmtu;
}

/*
 * Provide the length of interface identifiers to be used for the link attached
 * to the given interface.  The length should be defined in "IPv6 over
 * xxx-link" document.  Note that address architecture might also define
 * the length for a particular set of address prefixes, regardless of the
 * link type.  As clarified in rfc2462bis, those two definitions should be
 * consistent, and those really are as of August 2004.
 */
int
in6_if2idlen(ifp)
	struct ifnet *ifp;
{
	switch (ifp->if_type) {
	case IFT_ETHER:		/* RFC2464 */
	case IFT_PROPVIRTUAL:	/* XXX: no RFC. treat it as ether */
	case IFT_L2VLAN:	/* ditto */
	case IFT_IEEE80211:	/* ditto */
	case IFT_FDDI:		/* RFC2467 */
	case IFT_ISO88025:	/* RFC2470 (IPv6 over Token Ring) */
	case IFT_PPP:		/* RFC2472 */
	case IFT_ARCNET:	/* RFC2497 */
	case IFT_FRELAY:	/* RFC2590 */
	case IFT_IEEE1394:	/* RFC3146 */
	case IFT_GIF:		/* draft-ietf-v6ops-mech-v2-07 */
	case IFT_LOOP:		/* XXX: is this really correct? */
		return 64;
	default:
		/*
		 * Unknown link type:
		 * It might be controversial to use the today's common constant
		 * of 64 for these cases unconditionally.  For full compliance,
		 * we should return an error in this case.  On the other hand,
		 * if we simply miss the standard for the link type or a new
		 * standard is defined for a new link type, the IFID length
		 * is very likely to be the common constant.  As a compromise,
		 * we always use the constant, but make an explicit notice
		 * indicating the "unknown" case.
		 */
		printf("in6_if2idlen: unknown link type (%d)\n", ifp->if_type);
		return 64;
	}
}

void *
in6_domifattach(ifp)
	struct ifnet *ifp;
{
	struct in6_ifextra *ext;

	ext = (struct in6_ifextra *)malloc(sizeof(*ext), M_IFADDR, M_WAITOK);
	bzero(ext, sizeof(*ext));

	ext->in6_ifstat = (struct in6_ifstat *)malloc(sizeof(struct in6_ifstat),
	    M_IFADDR, M_WAITOK);
	bzero(ext->in6_ifstat, sizeof(*ext->in6_ifstat));

	ext->icmp6_ifstat =
	    (struct icmp6_ifstat *)malloc(sizeof(struct icmp6_ifstat),
	    M_IFADDR, M_WAITOK);
	bzero(ext->icmp6_ifstat, sizeof(*ext->icmp6_ifstat));

	ext->nd_ifinfo = nd6_ifattach(ifp);
	ext->scope6_id = scope6_ifattach(ifp);
	return ext;
}

void
in6_domifdetach(ifp, aux)
	struct ifnet *ifp;
	void *aux;
{
	struct in6_ifextra *ext = (struct in6_ifextra *)aux;

	nd6_ifdetach(ext->nd_ifinfo);
	free(ext->in6_ifstat, M_IFADDR);
	free(ext->icmp6_ifstat, M_IFADDR);
	scope6_ifdetach(ext->scope6_id);
	free(ext, M_IFADDR);
}