This commit was generated by cvs2svn to compensate for changes in r170349,

[FreeBSD/FreeBSD.git] / sys / netinet6 / in6.c

/*      $FreeBSD$       */
/*      $KAME: in6.c,v 1.259 2002/01/21 11:37:50 keiichi 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.
 * 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.
 *
 *      @(#)in.c        8.2 (Berkeley) 11/15/93
 */

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

#include <sys/param.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/priv.h>
#include <sys/proc.h>
#include <sys/time.h>
#include <sys/kernel.h>
#include <sys/syslog.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 <netinet/if_ether.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/in_pcb.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 <netinet6/in6_pcb.h>

MALLOC_DEFINE(M_IP6MADDR, "in6_multi", "internet multicast address");

/*
 * Definitions of some costant 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 thread *));
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 *));

struct in6_multihead in6_multihead;     /* XXX BSS initialization */
int     (*faithprefix_p)(struct in6_addr *);

/*
 * 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 all1_sa;
        struct rtentry *nrt = NULL;
        int e;
        char ip6buf[INET6_ADDRSTRLEN];

        bzero(&all1_sa, sizeof(all1_sa));
        all1_sa.sin6_family = AF_INET6;
        all1_sa.sin6_len = sizeof(struct sockaddr_in6);
        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) {
                /* XXX need more descriptive message */

                log(LOG_ERR, "in6_ifloop_request: "
                    "%s operation failed for %s (errno=%d)\n",
                    cmd == RTM_ADD ? "ADD" : "DELETE",
                    ip6_sprintf(ip6buf,
                            &((struct in6_ifaddr *)ifa)->ia_addr.sin6_addr), e);
        }

        /*
         * 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_LOCK(nrt);
                /*
                 * 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 && ifa != nrt->rt_ifa) {
                        IFAFREE(nrt->rt_ifa);
                        IFAREF(ifa);
                        nrt->rt_ifa = ifa;
                }

                rt_newaddrmsg(cmd, ifa, e, nrt);
                if (cmd == RTM_DELETE)
                        RTFREE_LOCKED(nrt);
                else {
                        /* the cmd must be RTM_ADD here */
                        RT_REMREF(nrt);
                        RT_UNLOCK(nrt);
                }
        }
}

/*
 * 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;
        int need_loop;

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

/*
 * 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, 0);
                if (rt != NULL) {
                        if ((rt->rt_flags & RTF_HOST) != 0 &&
                            (rt->rt_ifp->if_flags & IFF_LOOPBACK) != 0) {
                                RTFREE_LOCKED(rt);
                                in6_ifloop_request(RTM_DELETE, ifa);
                        } else
                                RT_UNLOCK(rt);
                }
        }
}

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, td)
        struct  socket *so;
        u_long cmd;
        caddr_t data;
        struct ifnet *ifp;
        struct thread *td;
{
        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;

        switch (cmd) {
        case SIOCGETSGCNT_IN6:
        case SIOCGETMIFCNT_IN6:
                return (mrt6_ioctl ? mrt6_ioctl(cmd, data) : EOPNOTSUPP);
        }

        switch(cmd) {
        case SIOCAADDRCTL_POLICY:
        case SIOCDADDRCTL_POLICY:
                if (td != NULL) {
                        error = priv_check(td, PRIV_NETINET_ADDRCTRL6);
                        if (error)
                                return (error);
                }
                return (in6_src_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:
                if (td != NULL) {
                        error = priv_check(td, PRIV_NETINET_ND6);
                        if (error)
                                return (error);
                }
                /* FALLTHROUGH */
        case OSIOCGIFINFO_IN6:
        case SIOCGIFINFO_IN6:
        case SIOCSIFINFO_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 SIOCSSCOPE6:
                if (td != NULL) {
                        error = priv_check(td, PRIV_NETINET_SCOPE6);
                        if (error)
                                return (error);
                }
                return (scope6_set(ifp,
                    (struct scope6_id *)ifr->ifr_ifru.ifru_scope_id));
        case SIOCGSCOPE6:
                return (scope6_get(ifp,
                    (struct scope6_id *)ifr->ifr_ifru.ifru_scope_id));
        case SIOCGSCOPE6DEF:
                return (scope6_get_default((struct scope6_id *)
                    ifr->ifr_ifru.ifru_scope_id));
        }

        switch (cmd) {
        case SIOCALIFADDR:
        case SIOCDLIFADDR:
                /*
                 * XXXRW: Is this checked at another layer?  What priv to use
                 * here?
                 */
                if (td != NULL) {
                        error = suser(td);
                        if (error)
                                return (error);
                }
                /* FALLTHROUGH */
        case SIOCGLIFADDR:
                return in6_lifaddr_ioctl(so, cmd, data, ifp, td);
        }

        /*
         * 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) {
                int error = 0;

                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.
                 */
                /* we decided to obsolete this command (20000704) */
                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);

                /*
                 * XXXRW: Is this checked at another layer?  What priv to use
                 * here?
                 */
                if (td != NULL) {
                        error = suser(td);
                        if (error)
                                return (error);
                }

                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 (td != NULL) {
                        error = priv_check(td, PRIV_NETINET_ALIFETIME6);
                        if (error)
                                return (error);
                }
                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_second < time_second) {
                        return EINVAL;
                }
                if (lt->ia6t_pltime != ND6_INFINITE_LIFETIME &&
                    lt->ia6t_pltime + time_second < time_second) {
                        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) &
                            ~((time_t)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) &
                            ~((time_t)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_second + 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_second + ia->ia6_lifetime.ia6t_pltime;
                } else
                        ia->ia6_lifetime.ia6t_preferred = 0;
                break;

        case SIOCAIFADDR_IN6:
        {
                int i, error = 0;
                struct nd_prefixctl pr0;
                struct nd_prefix *pr;

                /*
                 * 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();
                if (error == 0 && ia)
                        EVENTHANDLER_INVOKE(ifaddr_event, ifp);
                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);
                EVENTHANDLER_INVOKE(ifaddr_event, ifp);
                break;
        }

        default:
                if (ifp == NULL || ifp->if_ioctl == 0)
                        return (EOPNOTSUPP);
                return ((*ifp->if_ioctl)(ifp, cmd, data));
        }

        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 delay;
        char ip6buf[INET6_ADDRSTRLEN];

        /* 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) {
                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"));
                        return (EINVAL);
                }
        }
        /* 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(ip6buf, &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 */
                IFA_LOCK_INIT(&ia->ia_ifa);
                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_second;
                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;

                ia->ia_ifa.ifa_refcnt = 1;
                TAILQ_INSERT_TAIL(&ifp->if_addrlist, &ia->ia_ifa, ifa_list);
        }

        /* update timestamp */
        ia->ia6_updatetime = time_second;

        /* 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(ip6buf, &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)) {
                int e;

                if ((ia->ia_flags & IFA_ROUTE) != 0 &&
                    (e = 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(ip6buf, &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_second + 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_second + 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_second;
        }
        /*
         * 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 */
        in6m_sol = NULL;
        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_addr32[0] = IPV6_ADDR_INT32_MLL;
                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;
                }
                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]
                         */
                        delay = arc4random() %
                            (MAX_RTR_SOLICITATION_DELAY * hz);
                }
                imm = in6_joingroup(ifp, &llsol, &error, delay);
                if (imm == NULL) {
                        nd6log((LOG_WARNING,
                            "in6_update_ifa: addmulti failed for "
                            "%s on %s (errno=%d)\n",
                            ip6_sprintf(ip6buf, &llsol), if_name(ifp),
                            error));
                        in6_purgeaddr((struct ifaddr *)ia);
                        return (error);
                }
                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;
#define MLTMASK_LEN  4  /* mltmask's masklen (=32bit=4octet) */

                /*
                 * 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, 0UL);
                if (rt) {
                        if (memcmp(&mltaddr.sin6_addr,
                            &((struct sockaddr_in6 *)rt_key(rt))->sin6_addr,
                            MLTMASK_LEN)) {
                                RTFREE_LOCKED(rt);
                                rt = NULL;
                        }
                }
                if (!rt) {
                        /* XXX: we need RTF_CLONING to fake nd6_rtrequest */
                        error = rtrequest(RTM_ADD, (struct sockaddr *)&mltaddr,
                            (struct sockaddr *)&ia->ia_addr,
                            (struct sockaddr *)&mltmask, RTF_UP | RTF_CLONING,
                            (struct rtentry **)0);
                        if (error)
                                goto cleanup;
                } else
                        RTFREE_LOCKED(rt);

                /*
                 * 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, 0UL);
                if (rt) {
                        /* XXX: only works in !SCOPEDROUTING case. */
                        if (memcmp(&mltaddr.sin6_addr,
                            &((struct sockaddr_in6 *)rt_key(rt))->sin6_addr,
                            MLTMASK_LEN)) {
                                RTFREE_LOCKED(rt);
                                rt = NULL;
                        }
                }
                if (!rt) {
                        error = rtrequest(RTM_ADD, (struct sockaddr *)&mltaddr,
                            (struct sockaddr *)&ia->ia_addr,
                            (struct sockaddr *)&mltmask, RTF_UP | RTF_CLONING,
                            (struct rtentry **)0);
                        if (error)
                                goto cleanup;
                } else {
                        RTFREE_LOCKED(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(ip6buf, &mltaddr.sin6_addr),
                            if_name(ifp), error));
                        goto cleanup;
                }
                LIST_INSERT_HEAD(&ia->ia6_memberships, imm, i6mm_chain);

                /*
                 * join node information group address
                 */
#define hostnamelen     strlen(hostname)
                delay = 0;
                if ((flags & IN6_IFAUPDATE_DADDELAY)) {
                        /*
                         * The spec doesn't say anything about delay for this
                         * group, but the same logic should apply.
                         */
                        delay = arc4random() %
                            (MAX_RTR_SOLICITATION_DELAY * hz);
                }
                if (in6_nigroup(ifp, hostname, hostnamelen, &mltaddr.sin6_addr)
                    == 0) {
                        imm = in6_joingroup(ifp, &mltaddr.sin6_addr, &error,
                            delay); /* XXX jinmei */
                        if (!imm) {
                                nd6log((LOG_WARNING, "in6_update_ifa: "
                                    "addmulti failed for %s on %s "
                                    "(errno=%d)\n",
                                    ip6_sprintf(ip6buf, &mltaddr.sin6_addr),
                                    if_name(ifp), error));
                                /* XXX not very fatal, go on... */
                        } else {
                                LIST_INSERT_HEAD(&ia->ia6_memberships,
                                    imm, i6mm_chain);
                        }
                }
#undef hostnamelen

                /*
                 * 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, 0UL);
                if (rt) {
                        if (memcmp(&mltaddr.sin6_addr,
                            &((struct sockaddr_in6 *)rt_key(rt))->sin6_addr,
                            MLTMASK_LEN)) {
                                RTFREE_LOCKED(rt);
                                rt = NULL;
                        }
                }
                if (!rt) {
                        error = rtrequest(RTM_ADD, (struct sockaddr *)&mltaddr,
                            (struct sockaddr *)&ia->ia_addr,
                            (struct sockaddr *)&mltmask, RTF_UP | RTF_CLONING,
                            (struct rtentry **)0);
                        if (error)
                                goto cleanup;
                } else
                        RTFREE_LOCKED(rt);

                /* XXX: again, do we really need the route? */
                rt = rtalloc1((struct sockaddr *)&mltaddr, 0, 0UL);
                if (rt) {
                        if (memcmp(&mltaddr.sin6_addr,
                            &((struct sockaddr_in6 *)rt_key(rt))->sin6_addr,
                            MLTMASK_LEN)) {
                                RTFREE_LOCKED(rt);
                                rt = NULL;
                        }
                }
                if (!rt) {
                        error = rtrequest(RTM_ADD, (struct sockaddr *)&mltaddr,
                            (struct sockaddr *)&ia->ia_addr,
                            (struct sockaddr *)&mltmask, RTF_UP | RTF_CLONING,
                            (struct rtentry **)0);
                        if (error)
                                goto cleanup;
                } else {
                        RTFREE_LOCKED(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(ip6buf, &mltaddr.sin6_addr),
                            if_name(ifp), error));
                        goto cleanup;
                }
                LIST_INSERT_HEAD(&ia->ia6_memberships, imm, i6mm_chain);
#undef  MLTMASK_LEN
        }

        /*
         * 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;

                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)
                                delay = 0;
                        else {
                                delay =
                                    (arc4random() % (maxdelay - mindelay)) +
                                    mindelay;
                        }
                }
                nd6_dad_start((struct ifaddr *)ia, 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;
        char ip6buf[INET6_ADDRSTRLEN];
        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(ip6buf, &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);

        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");
                }
        }

        /*
         * 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)) {
                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, td)
        struct socket *so;
        u_long cmd;
        caddr_t data;
        struct ifnet *ifp;
        struct thread *td;
{
        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 *hostid = NULL;
                int prefixlen;

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

                        /*
                         * hostid is to fill in the hostid part of the
                         * address.  hostid points to the first link-local
                         * address attached to the interface.
                         */
                        ifa = (struct ifaddr *)in6ifa_ifpforlinklocal(ifp, 0);
                        if (!ifa)
                                return EADDRNOTAVAIL;
                        hostid = 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 (hostid) {
                        /* fill in hostid part */
                        ifra.ifra_addr.sin6_addr.s6_addr32[2] =
                            hostid->s6_addr32[2];
                        ifra.ifra_addr.sin6_addr.s6_addr32[3] =
                            hostid->s6_addr32[3];
                }

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

                TAILQ_FOREACH(ifa, &ifp->if_addrlist, ifa_list) {
                        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, td);
                }
            }
        }

        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 = splimp();
        struct ifaddr *ifa;

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

        ia->ia_addr = *sin6;

        if (ifacount <= 1 && ifp->if_ioctl) {
                IFF_LOCKGIANT(ifp);
                error = (*ifp->if_ioctl)(ifp, SIOCSIFADDR, (caddr_t)ia);
                IFF_UNLOCKGIANT(ifp);
                if (error) {
                        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. */

        if (newhost) {
                /*
                 * set the rtrequest function to create llinfo.  It also
                 * adjust outgoing interface of the route for the local
                 * address when called via in6_ifaddloop() below.
                 */
                ia->ia_ifa.ifa_rtrequest = nd6_rtrequest;
        }

        /*
         * Special case:
         * If a new destination address is specified for a point-to-point
         * interface, install a route to the destination as an interface
         * direct route.  In addition, if the link is expected to have neighbor
         * cache entries, specify RTF_LLINFO so that a cache entry for the
         * destination address will be created.
         * created
         * XXX: the logic below rejects assigning multiple addresses on a p2p
         * interface that share the same destination.
         */
        plen = in6_mask2len(&ia->ia_prefixmask.sin6_addr, NULL); /* XXX */
        if (!(ia->ia_flags & IFA_ROUTE) && plen == 128 &&
            ia->ia_dstaddr.sin6_family == AF_INET6) {
                int rtflags = RTF_UP | RTF_HOST;
                struct rtentry *rt = NULL, **rtp = NULL;

                if (nd6_need_cache(ifp) != 0) {
                        rtflags |= RTF_LLINFO;
                        rtp = &rt;
                }

                error = rtrequest(RTM_ADD, (struct sockaddr *)&ia->ia_dstaddr,
                    (struct sockaddr *)&ia->ia_addr,
                    (struct sockaddr *)&ia->ia_prefixmask,
                    ia->ia_flags | rtflags, rtp);
                if (error != 0)
                        return (error);
                if (rt != NULL) {
                        struct llinfo_nd6 *ln;

                        RT_LOCK(rt);
                        ln = (struct llinfo_nd6 *)rt->rt_llinfo;
                        if (ln != NULL) {
                                /*
                                 * Set the state to STALE because we don't
                                 * have to perform address resolution on this
                                 * link.
                                 */
                                ln->ln_state = ND6_LLINFO_STALE;
                        }
                        RT_REMREF(rt);
                        RT_UNLOCK(rt);
                }
                ia->ia_flags |= IFA_ROUTE;
        }
        if (plen < 128) {
                /*
                 * The RTF_CLONING flag is necessary for in6_is_ifloop_auto().
                 */
                ia->ia_ifa.ifa_flags |= RTF_CLONING;
        }

        /* Add ownaddr as loopback rtentry, if necessary (ex. on p2p link). */
        if (newhost)
                in6_ifaddloop(&(ia->ia_ifa));

        return (error);
}

struct in6_multi_mship *
in6_joingroup(ifp, addr, errorp, delay)
        struct ifnet *ifp;
        struct in6_addr *addr;
        int *errorp;
        int delay;
{
        struct in6_multi_mship *imm;

        imm = malloc(sizeof(*imm), M_IP6MADDR, M_NOWAIT);
        if (!imm) {
                *errorp = ENOBUFS;
                return NULL;
        }
        imm->i6mm_maddr = in6_addmulti(addr, ifp, errorp, delay);
        if (!imm->i6mm_maddr) {
                /* *errorp is alrady set */
                free(imm, M_IP6MADDR);
                return NULL;
        }
        return imm;
}

int
in6_leavegroup(imm)
        struct in6_multi_mship *imm;
{

        if (imm->i6mm_maddr)
                in6_delmulti(imm->i6mm_maddr);
        free(imm,  M_IP6MADDR);
        return 0;
}

/*
 * 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;

        TAILQ_FOREACH(ifa, &ifp->if_addrlist, ifa_list) {
                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;

        TAILQ_FOREACH(ifa, &ifp->if_addrlist, ifa_list) {
                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. Caller
 * has to make sure that ip6buf is at least INET6_ADDRSTRLEN long.
 */
static char digits[] = "0123456789abcdef";
char *
ip6_sprintf(char *ip6buf, const struct in6_addr *addr)
{
        int i;
        char *cp;
        const u_int16_t *a = (const u_int16_t *)addr;
        const u_int8_t *d;
        int dcolon = 0, zero = 0;

        cp = ip6buf;

        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;
                /* Try to eliminate leading zeros in printout like in :0001. */
                zero = 1;
                *cp = digits[*d >> 4];
                if (*cp != '0') {
                        zero = 0;
                        cp++;
                }
                *cp = digits[*d++ & 0xf];
                if (zero == 0 || (*cp != '0')) {
                        zero = 0;
                        cp++;
                }
                *cp = digits[*d >> 4];
                if (zero == 0 || (*cp != '0')) {
                        zero = 0;
                        cp++;
                }
                *cp++ = digits[*d & 0xf];
                *cp++ = ':';
                a++;
        }
        *--cp = '\0';
        return (ip6buf);
}

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) &&
                    (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 (0 > len || 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;
{
        u_char maskarray[8] = {0x80, 0xc0, 0xe0, 0xf0, 0xf8, 0xfc, 0xfe, 0xff};
        int bytelen, bitlen, i;

        /* sanity check */
        if (0 > len || 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.
         */
        TAILQ_FOREACH(ifa, &ifp->if_addrlist, ifa_list) {
                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);

        TAILQ_FOREACH(ifa, &ifp->if_addrlist, ifa_list) {
                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;

        TAILQ_FOREACH(ifa, &ifp->if_addrlist, ifa_list) {
                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) {
#ifdef IFT_DUMMY
        case IFT_DUMMY:
#endif
        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) &&
                    (ifp->if_drv_flags & IFF_DRV_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;

        IFNET_RLOCK();
        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);
        }
        IFNET_RUNLOCK();
        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 */
#ifdef IFT_PROPVIRTUAL
        case IFT_PROPVIRTUAL:   /* XXX: no RFC. treat it as ether */
#endif
#ifdef IFT_L2VLAN
        case IFT_L2VLAN:        /* ditto */
#endif
#ifdef IFT_IEEE80211
        case IFT_IEEE80211:     /* ditto */
#endif
#ifdef IFT_MIP
        case IFT_MIP:   /* ditto */
#endif
                return (64);
        case IFT_FDDI:          /* RFC2467 */
                return (64);
        case IFT_ISO88025:      /* RFC2470 (IPv6 over Token Ring) */
                return (64);
        case IFT_PPP:           /* RFC2472 */
                return (64);
        case IFT_ARCNET:        /* RFC2497 */
                return (64);
        case IFT_FRELAY:        /* RFC2590 */
                return (64);
        case IFT_IEEE1394:      /* RFC3146 */
                return (64);
        case IFT_GIF:
                return (64);    /* draft-ietf-v6ops-mech-v2-07 */
        case IFT_LOOP:
                return (64);    /* XXX: is this really correct? */
        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;

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

/*
 * Convert sockaddr_in6 to sockaddr_in.  Original sockaddr_in6 must be
 * v4 mapped addr or v4 compat addr
 */
void
in6_sin6_2_sin(struct sockaddr_in *sin, struct sockaddr_in6 *sin6)
{
        bzero(sin, sizeof(*sin));
        sin->sin_len = sizeof(struct sockaddr_in);
        sin->sin_family = AF_INET;
        sin->sin_port = sin6->sin6_port;
        sin->sin_addr.s_addr = sin6->sin6_addr.s6_addr32[3];
}

/* Convert sockaddr_in to sockaddr_in6 in v4 mapped addr format. */
void
in6_sin_2_v4mapsin6(struct sockaddr_in *sin, struct sockaddr_in6 *sin6)
{
        bzero(sin6, sizeof(*sin6));
        sin6->sin6_len = sizeof(struct sockaddr_in6);
        sin6->sin6_family = AF_INET6;
        sin6->sin6_port = sin->sin_port;
        sin6->sin6_addr.s6_addr32[0] = 0;
        sin6->sin6_addr.s6_addr32[1] = 0;
        sin6->sin6_addr.s6_addr32[2] = IPV6_ADDR_INT32_SMP;
        sin6->sin6_addr.s6_addr32[3] = sin->sin_addr.s_addr;
}

/* Convert sockaddr_in6 into sockaddr_in. */
void
in6_sin6_2_sin_in_sock(struct sockaddr *nam)
{
        struct sockaddr_in *sin_p;
        struct sockaddr_in6 sin6;

        /*
         * Save original sockaddr_in6 addr and convert it
         * to sockaddr_in.
         */
        sin6 = *(struct sockaddr_in6 *)nam;
        sin_p = (struct sockaddr_in *)nam;
        in6_sin6_2_sin(sin_p, &sin6);
}

/* Convert sockaddr_in into sockaddr_in6 in v4 mapped addr format. */
void
in6_sin_2_v4mapsin6_in_sock(struct sockaddr **nam)
{
        struct sockaddr_in *sin_p;
        struct sockaddr_in6 *sin6_p;

        MALLOC(sin6_p, struct sockaddr_in6 *, sizeof *sin6_p, M_SONAME,
               M_WAITOK);
        sin_p = (struct sockaddr_in *)*nam;
        in6_sin_2_v4mapsin6(sin_p, sin6_p);
        FREE(*nam, M_SONAME);
        *nam = (struct sockaddr *)sin6_p;
}