xnu-123.5.tar.gz

[apple/xnu.git] / bsd / netinet6 / nd6_rtr.c

/*      $KAME: nd6_rtr.c,v 1.30 2000/03/21 11:37:31 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.
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/sockio.h>
#include <sys/time.h>
#include <sys/kernel.h>
#include <sys/errno.h>
#if !(defined(__FreeBSD__) && __FreeBSD__ >= 3)
#include <sys/ioctl.h>
#endif
#include <sys/syslog.h>

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

#include <netinet/in.h>
#include <netinet6/in6_var.h>
#include <netinet/ip6.h>
#include <netinet6/ip6_var.h>
#include <netinet6/nd6.h>
#include <netinet/icmp6.h>

#if MIP6
#include <netinet6/mip6.h>
#endif

#include <net/net_osdep.h>

#define SDL(s)  ((struct sockaddr_dl *)s)

static struct nd_defrouter *defrtrlist_update __P((struct nd_defrouter *));
static int prelist_add __P((struct nd_prefix *, struct nd_defrouter *));
/* static struct nd_prefix *prefix_lookup __P((struct nd_prefix *)); XXXYYY */
static struct in6_ifaddr *in6_ifadd __P((struct ifnet *, struct in6_addr *,
                          struct in6_addr *, int));
/*static struct nd_pfxrouter *pfxrtr_lookup __P((struct nd_prefix *,
  struct nd_defrouter *)); XXXYYYY */
static void pfxrtr_add __P((struct nd_prefix *, struct nd_defrouter *));
static void pfxrtr_del __P((struct nd_pfxrouter *));
/*static struct nd_pfxrouter *find_pfxlist_reachable_router __P((struct nd_prefix *));  XXXYYY */
static void nd6_detach_prefix __P((struct nd_prefix *));
static void nd6_attach_prefix __P((struct nd_prefix *));
/* static void defrouter_addifreq __P((struct ifnet *)); XXXYYY */

static void in6_init_address_ltimes __P((struct nd_prefix *ndpr,
                                         struct in6_addrlifetime *lt6,
                                         int update_vltime));

static int rt6_deleteroute __P((struct radix_node *, void *));

extern int nd6_recalc_reachtm_interval;

struct ifnet *nd6_defifp;
int nd6_defifindex;


#if MIP6
void (*mip6_select_defrtr_hook)(void) = NULL;
struct nd_prefix * (*mip6_get_home_prefix_hook)(void) = NULL;
void (*mip6_prelist_update_hook)(struct nd_prefix *pr,
                                 struct nd_defrouter *dr) = NULL;
void (*mip6_probe_pfxrtrs_hook)(void) = NULL;
void (*mip6_store_advint_hook)(struct nd_opt_advint *ai,
                               struct nd_defrouter *dr) = NULL;
int (*mip6_get_md_state_hook)(void) = 0;
void (*mip6_minus_a_case_hook)(struct nd_prefix *) = NULL;
#endif /* MIP6 */

/*
 * Receive Router Solicitation Message - just for routers.
 * Router solicitation/advertisement is mostly managed by userland program
 * (rtadvd) so here we have no function like nd6_ra_output().
 *
 * Based on RFC 2461
 */
void
nd6_rs_input(m, off, icmp6len)
        struct  mbuf *m;
        int off, icmp6len;
{
        struct ifnet *ifp = m->m_pkthdr.rcvif;
        struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
        struct nd_router_solicit *nd_rs;
        struct in6_addr saddr6 = ip6->ip6_src;
#if 0
        struct in6_addr daddr6 = ip6->ip6_dst;
#endif
        char *lladdr = NULL;
        int lladdrlen = 0;
#if 0
        struct sockaddr_dl *sdl = (struct sockaddr_dl *)NULL;
        struct llinfo_nd6 *ln = (struct llinfo_nd6 *)NULL;
        struct rtentry *rt = NULL;
        int is_newentry;
#endif
        union nd_opts ndopts;

        /* If I'm not a router, ignore it. */
        if (ip6_accept_rtadv != 0 || ip6_forwarding != 1)
                goto freeit;

        /* Sanity checks */
        if (ip6->ip6_hlim != 255) {
                log(LOG_ERR,
                    "nd6_rs_input: invalid hlim %d\n", ip6->ip6_hlim);
                goto freeit;
        }

        /*
         * Don't update the neighbor cache, if src = ::.
         * This indicates that the src has no IP address assigned yet.
         */
        if (IN6_IS_ADDR_UNSPECIFIED(&saddr6))
                goto freeit;

#ifndef PULLDOWN_TEST
        IP6_EXTHDR_CHECK(m, off, icmp6len,);
        nd_rs = (struct nd_router_solicit *)((caddr_t)ip6 + off);
#else
        IP6_EXTHDR_GET(nd_rs, struct nd_router_solicit *, m, off, icmp6len);
        if (nd_rs == NULL) {
                icmp6stat.icp6s_tooshort++;
                return;
        }
#endif

        icmp6len -= sizeof(*nd_rs);
        nd6_option_init(nd_rs + 1, icmp6len, &ndopts);
        if (nd6_options(&ndopts) < 0) {
                log(LOG_INFO, "nd6_rs_input: invalid ND option, ignored\n");
                goto freeit;
        }

        if (ndopts.nd_opts_src_lladdr) {
                lladdr = (char *)(ndopts.nd_opts_src_lladdr + 1);
                lladdrlen = ndopts.nd_opts_src_lladdr->nd_opt_len << 3;
        }

        if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
                log(LOG_INFO,
                    "nd6_rs_input: lladdrlen mismatch for %s "
                    "(if %d, RS packet %d)\n",
                        ip6_sprintf(&saddr6), ifp->if_addrlen, lladdrlen - 2);
        }

        nd6_cache_lladdr(ifp, &saddr6, lladdr, lladdrlen, ND_ROUTER_SOLICIT, 0);

 freeit:
        m_freem(m);
}

/*
 * Receive Router Advertisement Message.
 *
 * Based on RFC 2461
 * TODO: on-link bit on prefix information
 * TODO: ND_RA_FLAG_{OTHER,MANAGED} processing
 */
void
nd6_ra_input(m, off, icmp6len)
        struct  mbuf *m;
        int off, icmp6len;
{
        struct ifnet *ifp = m->m_pkthdr.rcvif;
        struct nd_ifinfo *ndi = &nd_ifinfo[ifp->if_index];
        struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
        struct nd_router_advert *nd_ra;
        struct in6_addr saddr6 = ip6->ip6_src;
#if 0
        struct in6_addr daddr6 = ip6->ip6_dst;
        int flags; /* = nd_ra->nd_ra_flags_reserved; */
        int is_managed = ((flags & ND_RA_FLAG_MANAGED) != 0);
        int is_other = ((flags & ND_RA_FLAG_OTHER) != 0);
#endif
        union nd_opts ndopts;
        struct nd_defrouter *dr;

        if (ip6_accept_rtadv == 0)
                goto freeit;

        if (ip6->ip6_hlim != 255) {
                log(LOG_ERR,
                    "nd6_ra_input: invalid hlim %d\n", ip6->ip6_hlim);
                goto freeit;
        }

        if (!IN6_IS_ADDR_LINKLOCAL(&saddr6)) {
                log(LOG_ERR,
                    "nd6_ra_input: src %s is not link-local\n",
                    ip6_sprintf(&saddr6));
                goto freeit;
        }

#ifndef PULLDOWN_TEST
        IP6_EXTHDR_CHECK(m, off, icmp6len,);
        nd_ra = (struct nd_router_advert *)((caddr_t)ip6 + off);
#else
        IP6_EXTHDR_GET(nd_ra, struct nd_router_advert *, m, off, icmp6len);
        if (nd_ra == NULL) {
                icmp6stat.icp6s_tooshort++;
                return;
        }
#endif

        icmp6len -= sizeof(*nd_ra);
        nd6_option_init(nd_ra + 1, icmp6len, &ndopts);
        if (nd6_options(&ndopts) < 0) {
                log(LOG_INFO, "nd6_ra_input: invalid ND option, ignored\n");
                goto freeit;
        }

    {
        struct nd_defrouter dr0;
        u_int32_t advreachable = nd_ra->nd_ra_reachable;
#if !(defined(__FreeBSD__) && __FreeBSD__ >= 3) && !defined (__APPLE__)
        long time_second = time.tv_sec;
#endif

        dr0.rtaddr = saddr6;
        dr0.flags  = nd_ra->nd_ra_flags_reserved;
        dr0.rtlifetime = ntohs(nd_ra->nd_ra_router_lifetime);
        dr0.expire = time_second + dr0.rtlifetime;
        dr0.ifp = ifp;
        dr0.advint = 0;         /* Mobile IPv6 */
        dr0.advint_expire = 0;  /* Mobile IPv6 */
        dr0.advints_lost = 0;   /* Mobile IPv6 */
        /* unspecified or not? (RFC 2461 6.3.4) */
        if (advreachable) {
                NTOHL(advreachable);
                if (advreachable <= MAX_REACHABLE_TIME &&
                    ndi->basereachable != advreachable) {
                        ndi->basereachable = advreachable;
                        ndi->reachable = ND_COMPUTE_RTIME(ndi->basereachable);
                        ndi->recalctm = nd6_recalc_reachtm_interval; /* reset */
                }
        }
        if (nd_ra->nd_ra_retransmit)
                ndi->retrans = ntohl(nd_ra->nd_ra_retransmit);
        if (nd_ra->nd_ra_curhoplimit)
                ndi->chlim = nd_ra->nd_ra_curhoplimit;
        dr = defrtrlist_update(&dr0);
    }

        /*
         * prefix
         */
        if (ndopts.nd_opts_pi) {
                struct nd_opt_hdr *pt;
                struct nd_opt_prefix_info *pi;
                struct nd_prefix pr;

                for (pt = (struct nd_opt_hdr *)ndopts.nd_opts_pi;
                     pt <= (struct nd_opt_hdr *)ndopts.nd_opts_pi_end;
                     pt = (struct nd_opt_hdr *)((caddr_t)pt +
                                                (pt->nd_opt_len << 3))) {
                        if (pt->nd_opt_type != ND_OPT_PREFIX_INFORMATION)
                                continue;
                        pi = (struct nd_opt_prefix_info *)pt;

                        if (pi->nd_opt_pi_len != 4) {
                                log(LOG_INFO, "nd6_ra_input: invalid option "
                                        "len %d for prefix information option, "
                                        "ignored\n", pi->nd_opt_pi_len);
                                continue;
                        }

                        if (128 < pi->nd_opt_pi_prefix_len) {
                                log(LOG_INFO, "nd6_ra_input: invalid prefix "
                                        "len %d for prefix information option, "
                                        "ignored\n", pi->nd_opt_pi_prefix_len);
                                continue;
                        }

                        if (IN6_IS_ADDR_MULTICAST(&pi->nd_opt_pi_prefix)
                         || IN6_IS_ADDR_LINKLOCAL(&pi->nd_opt_pi_prefix)) {
                                log(LOG_INFO, "nd6_ra_input: invalid prefix "
                                        "%s, ignored\n",
                                        ip6_sprintf(&pi->nd_opt_pi_prefix));
                                continue;
                        }

                        /* aggregatable unicast address, rfc2374 */
                        if ((pi->nd_opt_pi_prefix.s6_addr8[0] & 0xe0) == 0x20
                         && pi->nd_opt_pi_prefix_len != 64) {
                                log(LOG_INFO, "nd6_ra_input: invalid prefixlen "
                                        "%d for rfc2374 prefix %s, ignored\n",
                                        pi->nd_opt_pi_prefix_len,
                                        ip6_sprintf(&pi->nd_opt_pi_prefix));
                                continue;
                        }

                        bzero(&pr, sizeof(pr));
                        pr.ndpr_prefix.sin6_family = AF_INET6;
                        pr.ndpr_prefix.sin6_len = sizeof(pr.ndpr_prefix);
                        pr.ndpr_prefix.sin6_addr = pi->nd_opt_pi_prefix;
                        pr.ndpr_ifp = (struct ifnet *)m->m_pkthdr.rcvif;

                        pr.ndpr_raf_onlink = (pi->nd_opt_pi_flags_reserved &
                                              ND_OPT_PI_FLAG_ONLINK) ? 1 : 0;
                        pr.ndpr_raf_auto = (pi->nd_opt_pi_flags_reserved &
                                            ND_OPT_PI_FLAG_AUTO) ? 1 : 0;
                        pr.ndpr_plen = pi->nd_opt_pi_prefix_len;
                        pr.ndpr_vltime = ntohl(pi->nd_opt_pi_valid_time);
                        pr.ndpr_pltime =
                                ntohl(pi->nd_opt_pi_preferred_time);

                        if (in6_init_prefix_ltimes(&pr))
                                continue; /* prefix lifetime init failed */

                        (void)prelist_update(&pr, dr, m);
                }
        }

        /*
         * MTU
         */
        if (ndopts.nd_opts_mtu && ndopts.nd_opts_mtu->nd_opt_mtu_len == 1) {
                u_int32_t mtu = ntohl(ndopts.nd_opts_mtu->nd_opt_mtu_mtu);

                /* lower bound */
                if (mtu < IPV6_MMTU) {
                        log(LOG_INFO, "nd6_ra_input: bogus mtu option "
                            "mtu=%d sent from %s, ignoring\n",
                            mtu, ip6_sprintf(&ip6->ip6_src));
                        goto skip;
                }

                /* upper bound */
                if (ndi->maxmtu) {
                        if (mtu <= ndi->maxmtu) {
                                int change = (ndi->linkmtu != mtu);

                                ndi->linkmtu = mtu;
                                if (change) /* in6_maxmtu may change */
                                        in6_setmaxmtu();
                        } else {
                                log(LOG_INFO, "nd6_ra_input: bogus mtu "
                                    "mtu=%d sent from %s; "
                                    "exceeds maxmtu %d, ignoring\n",
                                    mtu, ip6_sprintf(&ip6->ip6_src),
                                    ndi->maxmtu);
                        }
                } else {
                        log(LOG_INFO, "nd6_ra_input: mtu option "
                            "mtu=%d sent from %s; maxmtu unknown, "
                            "ignoring\n",
                            mtu, ip6_sprintf(&ip6->ip6_src));
                }
        }

 skip:
        
        /*
         * Src linkaddress
         */
    {
        char *lladdr = NULL;
        int lladdrlen = 0;
        
        if (ndopts.nd_opts_src_lladdr) {
                lladdr = (char *)(ndopts.nd_opts_src_lladdr + 1);
                lladdrlen = ndopts.nd_opts_src_lladdr->nd_opt_len << 3;
        }

        if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
                log(LOG_INFO,
                    "nd6_ra_input: lladdrlen mismatch for %s "
                    "(if %d, RA packet %d)\n",
                        ip6_sprintf(&saddr6), ifp->if_addrlen, lladdrlen - 2);
        }

        nd6_cache_lladdr(ifp, &saddr6, lladdr, lladdrlen, ND_ROUTER_ADVERT, 0);

        /*
         * Installing a link-layer address might change the state of the
         * router's neighbor cache, which might also affect our on-link
         * detection of adveritsed prefixes.
         */
        pfxlist_onlink_check();
    }

#if MIP6
        if (mip6_store_advint_hook) {
                if (ndopts.nd_opts_adv)
                        (*mip6_store_advint_hook)(ndopts.nd_opts_adv, dr);
        }
#endif

freeit:
        m_freem(m);
}

/*
 * default router list proccessing sub routines
 */
void
defrouter_addreq(new)
        struct nd_defrouter *new;
{
        struct sockaddr_in6 def, mask, gate;
        int s;

        Bzero(&def, sizeof(def));
        Bzero(&mask, sizeof(mask));
        Bzero(&gate, sizeof(gate));

        def.sin6_len = mask.sin6_len = gate.sin6_len
                = sizeof(struct sockaddr_in6);
        def.sin6_family = mask.sin6_family = gate.sin6_family = AF_INET6;
        gate.sin6_addr = new->rtaddr;

#ifdef __NetBSD__
        s = splsoftnet();
#else
        s = splnet();
#endif
        (void)rtrequest(RTM_ADD, (struct sockaddr *)&def,
                (struct sockaddr *)&gate, (struct sockaddr *)&mask,
                RTF_GATEWAY, NULL);
        splx(s);
        return;
}

/* Add a route to a given interface as default */
void
defrouter_addifreq(ifp)
        struct ifnet *ifp;
{
        struct sockaddr_in6 def, mask;
        struct ifaddr *ifa;
        int error, flags;

        bzero(&def, sizeof(def));
        bzero(&mask, sizeof(mask));

        def.sin6_len = mask.sin6_len = sizeof(struct sockaddr_in6);
        def.sin6_family = mask.sin6_family = AF_INET6;

        /*
         * Search for an ifaddr beloging to the specified interface.
         * XXX: An IPv6 address are required to be assigned on the interface.
         */
        if ((ifa = ifaof_ifpforaddr((struct sockaddr *)&def, ifp)) == NULL) {
                log(LOG_ERR,    /* better error? */
                    "defrouter_addifreq: failed to find an ifaddr "
                    "to install a route to interface %s\n",
                    if_name(ifp));
                return;
        }

        flags = ifa->ifa_flags;
        if ((ifp->if_flags & IFF_POINTOPOINT) != 0)
                flags &= ~RTF_CLONING;
        if ((error = rtrequest(RTM_ADD, (struct sockaddr *)&def,
                               ifa->ifa_addr, (struct sockaddr *)&mask,
                               flags, NULL)) != 0) {
                log(LOG_ERR,
                    "defrouter_addifreq: failed to install a route to "
                    "interface %s (errno = %d)\n",
                    if_name(ifp), error);
        }
}

struct nd_defrouter *
defrouter_lookup(addr, ifp)
        struct in6_addr *addr;
        struct ifnet *ifp;
{
        struct nd_defrouter *dr;

        for (dr = TAILQ_FIRST(&nd_defrouter); dr;
             dr = TAILQ_NEXT(dr, dr_entry)) {
                if (dr->ifp == ifp && IN6_ARE_ADDR_EQUAL(addr, &dr->rtaddr))
                        return(dr);
        }

        return(NULL);           /* search failed */
}

void
defrouter_delreq(dr, dofree)
        struct nd_defrouter *dr;
        int dofree;
{
        struct sockaddr_in6 def, mask, gate;

        Bzero(&def, sizeof(def));
        Bzero(&mask, sizeof(mask));
        Bzero(&gate, sizeof(gate));

        def.sin6_len = mask.sin6_len = gate.sin6_len
                = sizeof(struct sockaddr_in6);
        def.sin6_family = mask.sin6_family = gate.sin6_family = AF_INET6;
        gate.sin6_addr = dr->rtaddr;

        rtrequest(RTM_DELETE, (struct sockaddr *)&def,
                  (struct sockaddr *)&gate,
                  (struct sockaddr *)&mask,
                  RTF_GATEWAY, (struct rtentry **)0);

        if (dofree)             /* XXX: necessary? */
                _FREE(dr, M_IP6NDP);
}

void
defrtrlist_del(dr)
        struct nd_defrouter *dr;
{
        struct nd_defrouter *deldr = NULL;
        struct nd_prefix *pr;

        /*
         * Flush all the routing table entries that use the router
         * as a next hop.
         */
        if (!ip6_forwarding && ip6_accept_rtadv) {
                /* above is a good condition? */
                rt6_flush(&dr->rtaddr, dr->ifp);
        }

        if (dr == TAILQ_FIRST(&nd_defrouter))
                deldr = dr;     /* The router is primary. */

        TAILQ_REMOVE(&nd_defrouter, dr, dr_entry);

        /*
         * Also delete all the pointers to the router in each prefix lists.
         */
        for (pr = nd_prefix.lh_first; pr; pr = pr->ndpr_next) {
                struct nd_pfxrouter *pfxrtr;
                if ((pfxrtr = pfxrtr_lookup(pr, dr)) != NULL)
                        pfxrtr_del(pfxrtr);
        }
        pfxlist_onlink_check();

        /*
         * If the router is the primary one, choose a new one.
         * Note that defrouter_select() will remove the current gateway
         * from the routing table.
         */
        if (deldr)
                defrouter_select();

        _FREE(dr, M_IP6NDP);
}

/*
 * Default Router Selection according to Section 6.3.6 of RFC 2461:
 * 1) Routers that are reachable or probably reachable should be
 *    preferred.
 * 2) When no routers on the list are known to be reachable or
 *    probably reachable, routers SHOULD be selected in a round-robin
 *    fashion.
 * 3) If the Default Router List is empty, assume that all
 *    destinations are on-link.
 */
void
defrouter_select()
{
#ifdef __NetBSD__
        int s = splsoftnet();
#else
        int s = splnet();
#endif
        struct nd_defrouter *dr, anydr;
        struct rtentry *rt = NULL;
        struct llinfo_nd6 *ln = NULL;

#if MIP6
        /* Mobile IPv6 alternative routine */
        if (mip6_select_defrtr_hook) {
                (*mip6_select_defrtr_hook)();    /* XXXYYY Temporary? */
                splx(s);
                return;
        }
        /* End of Mobile IPv6 */
#endif /* MIP6 */

        /*
         * Search for a (probably) reachable router from the list.
         */
        for (dr = TAILQ_FIRST(&nd_defrouter); dr;
             dr = TAILQ_NEXT(dr, dr_entry)) {
                if ((rt = nd6_lookup(&dr->rtaddr, 0, dr->ifp)) &&
                    (ln = (struct llinfo_nd6 *)rt->rt_llinfo) &&
                    ND6_IS_LLINFO_PROBREACH(ln)) {
                        /* Got it, and move it to the head */
                        TAILQ_REMOVE(&nd_defrouter, dr, dr_entry);
                        TAILQ_INSERT_HEAD(&nd_defrouter, dr, dr_entry);
                        break;
                }
        }

        if ((dr = TAILQ_FIRST(&nd_defrouter))) {
                /*
                 * De-install the previous default gateway and install
                 * a new one.
                 * Note that if there is no reachable router in the list,
                 * the head entry will be used anyway.
                 * XXX: do we have to check the current routing table entry?
                 */
                bzero(&anydr, sizeof(anydr));
                defrouter_delreq(&anydr, 0);
                defrouter_addreq(dr);
        }
        else {
                /*
                 * The Default Router List is empty, so install the default
                 * route to an inteface.
                 * XXX: The specification does not say this mechanism should
                 * be restricted to hosts, but this would be not useful
                 * (even harmful) for routers.
                 */
                if (!ip6_forwarding) {
                        /*
                         * De-install the current default route
                         * in advance.
                         */
                        bzero(&anydr, sizeof(anydr));
                        defrouter_delreq(&anydr, 0);
                        if (nd6_defifp) {
                                /*
                                 * Install a route to the default interface
                                 * as default route.
                                 */
                                defrouter_addifreq(nd6_defifp);
                        }
#if ND6_DEBUG
                        else    /* noisy log? */
                                log(LOG_INFO, "defrouter_select: "
                                    "there's no default router and no default"
                                    " interface\n");
#endif
                }
        }

        splx(s);
        return;
}

static struct nd_defrouter *
defrtrlist_update(new)
        struct nd_defrouter *new;
{
        struct nd_defrouter *dr, *n;
#ifdef __NetBSD__
        int s = splsoftnet();
#else
        int s = splnet();
#endif

        if ((dr = defrouter_lookup(&new->rtaddr, new->ifp)) != NULL) {
                /* entry exists */
                if (new->rtlifetime == 0) {
                        defrtrlist_del(dr);
                        dr = NULL;
                } else {
                        /* override */
                        dr->flags = new->flags; /* xxx flag check */
                        dr->rtlifetime = new->rtlifetime;
                        dr->expire = new->expire;
                }
                splx(s);
                return(dr);
        }

        /* entry does not exist */
        if (new->rtlifetime == 0) {
                splx(s);
                return(NULL);
        }

        n = (struct nd_defrouter *)_MALLOC(sizeof(*n), M_IP6NDP, M_NOWAIT);
        if (n == NULL) {
                splx(s);
                return(NULL);
        }
        bzero(n, sizeof(*n));
        *n = *new;

        /*
         * Insert the new router at the end of the Default Router List.
         * If there is no other router, install it anyway. Otherwise,
         * just continue to use the current default router.
         */
        TAILQ_INSERT_TAIL(&nd_defrouter, n, dr_entry);
        if (TAILQ_FIRST(&nd_defrouter) == n)
                defrouter_select();
        splx(s);
                
        return(n);
}

struct nd_pfxrouter *
pfxrtr_lookup(pr, dr)
        struct nd_prefix *pr;
        struct nd_defrouter *dr;
{
        struct nd_pfxrouter *search;
        
        for (search = pr->ndpr_advrtrs.lh_first; search; search = search->pfr_next) {
                if (search->router == dr)
                        break;
        }

        return(search);
}

static void
pfxrtr_add(pr, dr)
        struct nd_prefix *pr;
        struct nd_defrouter *dr;
{
        struct nd_pfxrouter *new;

        new = (struct nd_pfxrouter *)_MALLOC(sizeof(*new), M_IP6NDP, M_NOWAIT);
        if (new == NULL)
                return;
        bzero(new, sizeof(*new));
        new->router = dr;

        LIST_INSERT_HEAD(&pr->ndpr_advrtrs, new, pfr_entry);

        pfxlist_onlink_check();
}

static void
pfxrtr_del(pfr)
        struct nd_pfxrouter *pfr;
{
        LIST_REMOVE(pfr, pfr_entry);
        _FREE(pfr, M_IP6NDP);
}

struct nd_prefix *
prefix_lookup(pr)
        struct nd_prefix *pr;
{
        struct nd_prefix *search;

        for (search = nd_prefix.lh_first; search; search = search->ndpr_next) {
                if (pr->ndpr_ifp == search->ndpr_ifp &&
                    pr->ndpr_plen == search->ndpr_plen &&
                    in6_are_prefix_equal(&pr->ndpr_prefix.sin6_addr,
                                         &search->ndpr_prefix.sin6_addr,
                                         pr->ndpr_plen)
                    ) {
                        break;
                }
        }

        return(search);
}

static int
prelist_add(pr, dr)
        struct nd_prefix *pr;
        struct nd_defrouter *dr;
{
        struct nd_prefix *new;
        int i, s;

        new = (struct nd_prefix *)_MALLOC(sizeof(*new), M_IP6NDP, M_NOWAIT);
        if (new == NULL)
                return ENOMEM;
        bzero(new, sizeof(*new));
        *new = *pr;

        /* initilization */
        new->ndpr_statef_onlink = pr->ndpr_statef_onlink;
        LIST_INIT(&new->ndpr_advrtrs);
        in6_prefixlen2mask(&new->ndpr_mask, new->ndpr_plen);
        /* make prefix in the canonical form */
        for (i = 0; i < 4; i++)
                new->ndpr_prefix.sin6_addr.s6_addr32[i] &=
                        new->ndpr_mask.s6_addr32[i];

        /* xxx ND_OPT_PI_FLAG_ONLINK processing */

#ifdef __NetBSD__
        s = splsoftnet();
#else
        s = splnet();
#endif
        /* link ndpr_entry to nd_prefix list */
        LIST_INSERT_HEAD(&nd_prefix, new, ndpr_entry);
        splx(s);

        if (dr) {
                pfxrtr_add(new, dr);
#if MIP6
                if (mip6_get_md_state_hook) {
                        /*
                         * If we are in UNDEFINED state and a router appears,
                         * select that router and change state.
                         * This case takes care of transitions from UNDEFINED
                         * to FOREIGN when the prefix is not known from before.
                         */
                        if ((*mip6_get_md_state_hook)() == MIP6_MD_UNDEFINED) {
                                if (mip6_select_defrtr_hook)
                                        (*mip6_select_defrtr_hook)();
                        }
                }
#endif /* MIP6 */
        }

        return 0;
}

void
prelist_remove(pr)
        struct nd_prefix *pr;
{
        struct nd_pfxrouter *pfr, *next;
        int s;

#ifdef __NetBSD__
        s = splsoftnet();
#else
        s = splnet();
#endif
        /* unlink ndpr_entry from nd_prefix list */
        LIST_REMOVE(pr, ndpr_entry);
        splx(s);

        /* free list of routers that adversed the prefix */
        for (pfr = pr->ndpr_advrtrs.lh_first; pfr; pfr = next) {
                next = pfr->pfr_next;

                _FREE(pfr, M_IP6NDP);
        }
        _FREE(pr, M_IP6NDP);

        pfxlist_onlink_check();
}

/*
 * NOTE: We set address lifetime to keep
 *      address lifetime <= prefix lifetime
 * invariant.  This is to simplify on-link determination code.
 * If onlink determination is udated, this routine may have to be updated too.
 */
int
prelist_update(new, dr, m)
        struct nd_prefix *new;
        struct nd_defrouter *dr; /* may be NULL */
        struct mbuf *m;
{
        struct in6_ifaddr *ia6 = NULL;
        struct nd_prefix *pr;
#ifdef __NetBSD__
        int s = splsoftnet();
#else
        int s = splnet();
#endif
        int error = 0;
        int auth;
        struct in6_addrlifetime *lt6;
        u_char onlink;  /* Mobile IPv6 */

        auth = 0;
        if (m) {
                /*
                 * Authenticity for NA consists authentication for
                 * both IP header and IP datagrams, doesn't it ?
                 */
#if defined(M_AUTHIPHDR) && defined(M_AUTHIPDGM)
                auth = (m->m_flags & M_AUTHIPHDR
                     && m->m_flags & M_AUTHIPDGM) ? 1 : 0;
#endif
        }

        if ((pr = prefix_lookup(new)) != NULL) {
                if (pr->ndpr_ifp != new->ndpr_ifp) {
                        error = EADDRNOTAVAIL;
                        goto end;
                }

#if MIP6
                if (mip6_get_home_prefix_hook) {
                        /*
                         * The home prefix should be kept away from updates.
                         * XXXYYY Tunneled RA? New Home Prefix? Unless
                         * configured, the code below will be executed.
                         */
                        if (pr == (*mip6_get_home_prefix_hook)())
                                goto noautoconf1;
                }
#endif /* MIP6 */

                /* update prefix information */
                pr->ndpr_flags = new->ndpr_flags;
                pr->ndpr_vltime = new->ndpr_vltime;
                pr->ndpr_pltime = new->ndpr_pltime;
                pr->ndpr_preferred = new->ndpr_preferred;
                pr->ndpr_expire = new->ndpr_expire;

                /*
                 * RFC 2462 5.5.3 (d) or (e)
                 * We got a prefix which we have seen in the past.
                 */
                if (!new->ndpr_raf_auto)
                        goto noautoconf1;

                if (IN6_IS_ADDR_UNSPECIFIED(&pr->ndpr_addr))
                        ia6 = NULL;
                else
                        ia6 = in6ifa_ifpwithaddr(pr->ndpr_ifp, &pr->ndpr_addr);

                if (ia6 == NULL) {
                        /*
                         * Special case:
                         * (1) We have seen the prefix advertised before, but
                         * we have never performed autoconfig for this prefix.
                         * This is because Autonomous bit was 0 previously, or
                         * autoconfig failed due to some other reasons.
                         * (2) We have seen the prefix advertised before and
                         * we have performed autoconfig in the past, but
                         * we seem to have no interface address right now.
                         * This is because the interface address have expired.
                         *
                         * This prefix is fresh, with respect to autoconfig
                         * process.
                         *
                         * Add an address based on RFC 2462 5.5.3 (d).
                         */
                        ia6 = in6_ifadd(pr->ndpr_ifp,
                                &pr->ndpr_prefix.sin6_addr, &pr->ndpr_addr,
                                new->ndpr_plen);
                        if (!ia6) {
                                error = EADDRNOTAVAIL;
                                log(LOG_ERR, "prelist_update: failed to add a "
                                    "new address\n");
                                goto noautoconf1;
                        }

                        lt6 = &ia6->ia6_lifetime;

                        /* address lifetime <= prefix lifetime */
                        lt6->ia6t_vltime = new->ndpr_vltime;
                        lt6->ia6t_pltime = new->ndpr_pltime;
                        in6_init_address_ltimes(new, lt6, 1);
                } else {
#define TWOHOUR         (120*60)
                        /*
                         * We have seen the prefix before, and we have added
                         * interface address in the past.  We still have
                         * the interface address assigned.
                         *
                         * update address lifetime based on RFC 2462
                         * 5.5.3 (e).
                         */
                        int update = 0;

                        lt6 = &ia6->ia6_lifetime;

#if 0   /* RFC 2462 5.5.3 (e) */
                        lt6->ia6t_pltime = new->ndpr_pltime;
                        if (TWOHOUR < new->ndpr_vltime
                         || lt6pr->nd < new->ndpr_vltime) {
                                lt6->ia6t_vltime = new->ndpr_vltime;
                                update++;
                        } else if (auth
                                && lt6->ia6t_vltime <= TWOHOUR0
                                && new->ndpr_vltime <= lt6->ia6t_vltime) {
                                lt6->ia6t_vltime = new->ndpr_vltime;
                                update++;
                        } else {
                                lt6->ia6t_vltime = TWOHOUR;
                                update++;
                        }

                        /* 2 hour rule is not imposed for pref lifetime */
                        new->ndpr_apltime = new->ndpr_pltime;
                        lt6->ia6t_pltime = new->ndpr_pltime;
#else   /* update from Jim Bound, (ipng 6712) */
                        if (TWOHOUR < new->ndpr_vltime
                         || lt6->ia6t_vltime < new->ndpr_vltime) {
                                lt6->ia6t_vltime = new->ndpr_vltime;
                                update++;
                        } else if (auth) {
                                lt6->ia6t_vltime = new->ndpr_vltime;
                                update++;
                        }

                        /* jim bound rule is not imposed for pref lifetime */
                        lt6->ia6t_pltime = new->ndpr_pltime;
#endif
                        in6_init_address_ltimes(new, lt6, update);
                }

 noautoconf1:

#if 0
                /* address lifetime expire processing, RFC 2462 5.5.4. */
                if (pr->ndpr_preferred && pr->ndpr_preferred < time_second) {
                        struct in6_ifaddr *ia6;

                        ia6 = in6ifa_ifpwithaddr(pr->ndpr_ifp, &pr->ndpr_addr);
                        if (ia6)
                                ia6->ia6_flags &= ~IN6_IFF_DEPRECATED;
                }
#endif

                onlink = pr->ndpr_statef_onlink;     /* Mobile IPv6 */

                if (dr && pfxrtr_lookup(pr, dr) == NULL)
                        pfxrtr_add(pr, dr);

#if MIP6
                if (mip6_prelist_update_hook) {
                        /*
                         * Check for home prefix. It can't be a fresh prefix
                         * (since it's static), so check here.
                         */
                        (*mip6_prelist_update_hook)(pr, dr);
                }

                if (mip6_probe_pfxrtrs_hook) {
                        /*
                         * If this prefix previously was detached, maybe we
                         * have moved.
                         */
                        if (!onlink)
                                (*mip6_probe_pfxrtrs_hook)();
                }
#endif /* MIP6 */

        } else {
                int error_tmp;

                if (new->ndpr_vltime == 0) goto end;

                bzero(&new->ndpr_addr, sizeof(struct in6_addr));

                /*
                 * RFC 2462 5.5.3 (d)
                 * We got a fresh prefix.  Perform some sanity checks
                 * and add an interface address by appending interface ID
                 * to the advertised prefix.
                 */
                if (!new->ndpr_raf_auto)
                        goto noautoconf2;

                ia6 = in6_ifadd(new->ndpr_ifp, &new->ndpr_prefix.sin6_addr,
                          &new->ndpr_addr, new->ndpr_plen);
                if (!ia6) {
                        error = EADDRNOTAVAIL;
                        log(LOG_ERR, "prelist_update: "
                                "failed to add a new address\n");
                        goto noautoconf2;
                }
                /* set onlink bit if an interface route is configured */
                new->ndpr_statef_onlink = (ia6->ia_flags & IFA_ROUTE) ? 1 : 0;

                lt6 = &ia6->ia6_lifetime;

                /* address lifetime <= prefix lifetime */
                lt6->ia6t_vltime = new->ndpr_vltime;
                lt6->ia6t_pltime = new->ndpr_pltime;
                in6_init_address_ltimes(new, lt6, 1);

 noautoconf2:
                error_tmp = prelist_add(new, dr);
                error = error_tmp ? error_tmp : error;

#if MIP6
                if (mip6_probe_pfxrtrs_hook) {
                        /* This is a new prefix, maybe we have moved. */
                        (*mip6_probe_pfxrtrs_hook)();
                }

                if (mip6_minus_a_case_hook) {
                        /*
                         * If we are still looking for an autoconfigured home
                         * address when we are in "minus a" case, here's a new
                         * prefix and hopefully we can use the address derived
                         *from that.
                         */
                        if (ia6)
                                (*mip6_minus_a_case_hook)(new);
                }
#endif /* MIP6 */

        }

 end:
        splx(s);
        return error;
}

/*
 * A supplement function used in the on-link detection below;
 * detect if a given prefix has a (probably) reachable advertising router.
 * XXX: lengthy function name...
 */
struct nd_pfxrouter *
find_pfxlist_reachable_router(pr)
        struct nd_prefix *pr;
{
        struct nd_pfxrouter *pfxrtr;
        struct rtentry *rt;
        struct llinfo_nd6 *ln;

        for (pfxrtr = LIST_FIRST(&pr->ndpr_advrtrs); pfxrtr;
             pfxrtr = LIST_NEXT(pfxrtr, pfr_entry)) {
                if ((rt = nd6_lookup(&pfxrtr->router->rtaddr, 0,
                                     pfxrtr->router->ifp)) &&
                    (ln = (struct llinfo_nd6 *)rt->rt_llinfo) &&
                    ND6_IS_LLINFO_PROBREACH(ln))
                        break;  /* found */
        }

        return(pfxrtr);

}

/*
 * Check if each prefix in the prefix list has at least one available router
 * that advertised the prefix (A router is "available" if its neighbor cache
 * entry has reachable or probably reachable).
 * If the check fails, the prefix may be off-link, because, for example,
 * we have moved from the network but the lifetime of the prefix has not
 * been expired yet. So we should not use the prefix if there is another
 * prefix that has an available router.
 * But if there is no prefix that has an available router, we still regards
 * all the prefixes as on-link. This is because we can't tell if all the
 * routers are simply dead or if we really moved from the network and there
 * is no router around us.
 */
void
pfxlist_onlink_check()
{
        struct nd_prefix *pr;

        /*
         * Check if there is a prefix that has a reachable advertising
         * router.
         */
        for (pr = nd_prefix.lh_first; pr; pr = pr->ndpr_next) {
                if (find_pfxlist_reachable_router(pr))
                        break;
        }

        if (pr) {
                /*
                 * There is at least one prefix that has a reachable router.
                 * First, detach prefixes which has no reachable advertising
                 * router and then attach other prefixes.
                 * The order is important since an attached prefix and a
                 * detached prefix may have a same interface route.
                 */
                for (pr = nd_prefix.lh_first; pr; pr = pr->ndpr_next) {
                        if (find_pfxlist_reachable_router(pr) == NULL &&
                            pr->ndpr_statef_onlink) {
                                pr->ndpr_statef_onlink = 0;
                                nd6_detach_prefix(pr);
                        }
                }
                for (pr = nd_prefix.lh_first; pr; pr = pr->ndpr_next) {
                        if (find_pfxlist_reachable_router(pr) &&
                            pr->ndpr_statef_onlink == 0)
                                nd6_attach_prefix(pr);
                }
        }
        else {
                /* there is no prefix that has a reachable router */
                for (pr = nd_prefix.lh_first; pr; pr = pr->ndpr_next)
                        if (pr->ndpr_statef_onlink == 0)
                                nd6_attach_prefix(pr);
        }
}

static void
nd6_detach_prefix(pr)
        struct nd_prefix *pr;
{
        struct in6_ifaddr *ia6;
        struct sockaddr_in6 sa6, mask6;

        /*
         * Delete the interface route associated with the prefix.
         */
        bzero(&sa6, sizeof(sa6));
        sa6.sin6_family = AF_INET6;
        sa6.sin6_len = sizeof(sa6);
        bcopy(&pr->ndpr_prefix.sin6_addr, &sa6.sin6_addr,
              sizeof(struct in6_addr));
        bzero(&mask6, sizeof(mask6));
        mask6.sin6_family = AF_INET6;
        mask6.sin6_len = sizeof(sa6);
        bcopy(&pr->ndpr_mask, &mask6.sin6_addr, sizeof(struct in6_addr));
        {
                int e;

                e = rtrequest(RTM_DELETE, (struct sockaddr *)&sa6, NULL,
                              (struct sockaddr *)&mask6, 0, NULL);
                if (e) {
                        log(LOG_ERR,
                            "nd6_detach_prefix: failed to delete route: "
                            "%s/%d (errno = %d)\n",
                            ip6_sprintf(&sa6.sin6_addr),
                            pr->ndpr_plen,
                            e);
                }
        }

        /*
         * Mark the address derived from the prefix detached so that
         * it won't be used as a source address for a new connection.
         */
        if (IN6_IS_ADDR_UNSPECIFIED(&pr->ndpr_addr))
                ia6 = NULL;
        else
                ia6 = in6ifa_ifpwithaddr(pr->ndpr_ifp, &pr->ndpr_addr);
        if (ia6)
#if MIP6
                if (mip6_get_home_prefix_hook)
                        if (pr != (*mip6_get_home_prefix_hook)())
                                ia6->ia6_flags |= IN6_IFF_DETACHED;
#else
                ia6->ia6_flags |= IN6_IFF_DETACHED;
#endif
}

static void
nd6_attach_prefix(pr)
        struct nd_prefix *pr;
{
        struct ifaddr *ifa;
        struct in6_ifaddr *ia6;

        /*
         * Add the interface route associated with the prefix(if necessary)
         * Should we consider if the L bit is set in pr->ndpr_flags?
         */
        ifa = ifaof_ifpforaddr((struct sockaddr *)&pr->ndpr_prefix,
                               pr->ndpr_ifp);
        if (ifa == NULL) {
                log(LOG_ERR,
                    "nd6_attach_prefix: failed to find any ifaddr"
                    " to add route for a prefix(%s/%d)\n",
                    ip6_sprintf(&pr->ndpr_addr), pr->ndpr_plen);
        }
        else {
                int e;
                struct sockaddr_in6 mask6;

                bzero(&mask6, sizeof(mask6));
                mask6.sin6_family = AF_INET6;
                mask6.sin6_len = sizeof(mask6);
                mask6.sin6_addr = pr->ndpr_mask;
                e = rtrequest(RTM_ADD, (struct sockaddr *)&pr->ndpr_prefix,
                              ifa->ifa_addr, (struct sockaddr *)&mask6,
                              ifa->ifa_flags, NULL);
                if (e == 0)
                        pr->ndpr_statef_onlink = 1;
                else {
                        log(LOG_ERR,
                            "nd6_attach_prefix: failed to add route for"
                            " a prefix(%s/%d), errno = %d\n",
                            ip6_sprintf(&pr->ndpr_addr), pr->ndpr_plen, e);
                }
        }

        /*
         * Now the address derived from the prefix can be used as a source
         * for a new connection, so clear the detached flag.
         */
        if (IN6_IS_ADDR_UNSPECIFIED(&pr->ndpr_addr))
                ia6 = NULL;
        else
                ia6 = in6ifa_ifpwithaddr(pr->ndpr_ifp, &pr->ndpr_addr);
        if (ia6) {
                ia6->ia6_flags &= ~IN6_IFF_DETACHED;
                if (pr->ndpr_statef_onlink)
                        ia6->ia_flags |= IFA_ROUTE;
        }
}

static struct in6_ifaddr *
in6_ifadd(ifp, in6, addr, prefixlen)
        struct ifnet *ifp;
        struct in6_addr *in6;
        struct in6_addr *addr;
        int prefixlen;  /* prefix len of the new prefix in "in6" */
{
        struct ifaddr *ifa;
        struct in6_ifaddr *ia, *ib, *oia;
        int s, error;
        struct in6_addr mask;

        in6_len2mask(&mask, prefixlen);

        /* find link-local address (will be interface ID) */
        ifa = (struct ifaddr *)in6ifa_ifpforlinklocal(ifp, 0);/* 0 is OK? */
        if (ifa)
                ib = (struct in6_ifaddr *)ifa;
        else
                return NULL;

#if 0 /* don't care link local addr state, and always do DAD */
        /* if link-local address is not eligible, do not autoconfigure. */
        if (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_NOTREADY) {
                printf("in6_ifadd: link-local address not ready\n");
                return NULL;
        }
#endif

        /* prefixlen + ifidlen must be equal to 128 */
        if (prefixlen != in6_mask2len(&ib->ia_prefixmask.sin6_addr)) {
                log(LOG_ERR, "in6_ifadd: wrong prefixlen for %s"
                        "(prefix=%d ifid=%d)\n", if_name(ifp),
                        prefixlen,
                        128 - in6_mask2len(&ib->ia_prefixmask.sin6_addr));
                return NULL;
        }

        /* make ifaddr */
        ia = (struct in6_ifaddr *)_MALLOC(sizeof(*ia), M_IFADDR, M_DONTWAIT);
        if (ia == NULL) {
                printf("ENOBUFS in in6_ifadd %d\n", __LINE__);
                return NULL;
        }

        bzero((caddr_t)ia, sizeof(*ia));
        ia->ia_ifa.ifa_addr = (struct sockaddr *)&ia->ia_addr;
        if (ifp->if_flags & IFF_POINTOPOINT)
                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;

        /* link to in6_ifaddr */
        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++;

        /* link to if_addrlist */
#if defined(__bsdi__) || (defined(__FreeBSD__) && __FreeBSD__ < 3)
        if ((ifa = ifp->if_addrlist) != NULL) {
                for ( ; ifa->ifa_next; ifa = ifa->ifa_next)
                        continue;
                ifa->ifa_next = (struct ifaddr *)ia;
        }
#else
        if (ifp->if_addrlist.tqh_first != NULL) {
                TAILQ_INSERT_TAIL(&ifp->if_addrlist, (struct ifaddr *)ia,
                        ifa_list);
                ia->ia_ifa.ifa_refcnt++;
        }
#endif
#if 0
        else {
                /*
                 * this should not be the case because there is at least one
                 * link-local address(see the beginning of the function).
                 */
                TAILQ_INIT(&ifp->if_addrlist);
        }
#endif

        /* new address */
        ia->ia_addr.sin6_len = sizeof(struct sockaddr_in6);
        ia->ia_addr.sin6_family = AF_INET6;
        /* prefix */
        bcopy(in6, &ia->ia_addr.sin6_addr, sizeof(ia->ia_addr.sin6_addr));
        ia->ia_addr.sin6_addr.s6_addr32[0] &= mask.s6_addr32[0];
        ia->ia_addr.sin6_addr.s6_addr32[1] &= mask.s6_addr32[1];
        ia->ia_addr.sin6_addr.s6_addr32[2] &= mask.s6_addr32[2];
        ia->ia_addr.sin6_addr.s6_addr32[3] &= mask.s6_addr32[3];
        /* interface ID */
        ia->ia_addr.sin6_addr.s6_addr32[0]
                |= (ib->ia_addr.sin6_addr.s6_addr32[0] & ~mask.s6_addr32[0]);
        ia->ia_addr.sin6_addr.s6_addr32[1]
                |= (ib->ia_addr.sin6_addr.s6_addr32[1] & ~mask.s6_addr32[1]);
        ia->ia_addr.sin6_addr.s6_addr32[2]
                |= (ib->ia_addr.sin6_addr.s6_addr32[2] & ~mask.s6_addr32[2]);
        ia->ia_addr.sin6_addr.s6_addr32[3]
                |= (ib->ia_addr.sin6_addr.s6_addr32[3] & ~mask.s6_addr32[3]);

        /* new prefix */
        ia->ia_prefixmask.sin6_len = sizeof(struct sockaddr_in6);
        ia->ia_prefixmask.sin6_family = AF_INET6;
        bcopy(&mask, &ia->ia_prefixmask.sin6_addr,
                sizeof(ia->ia_prefixmask.sin6_addr));

        /* same routine */
        ia->ia_ifa.ifa_rtrequest =
                (ifp->if_type == IFT_PPP) ? nd6_p2p_rtrequest : nd6_rtrequest;
        ia->ia_ifa.ifa_flags |= RTF_CLONING;
        ia->ia_ifa.ifa_metric = ifp->if_metric;

        /* add interface route */
        if ((error = rtinit(&(ia->ia_ifa), (int)RTM_ADD, RTF_UP|RTF_CLONING))) {
                log(LOG_NOTICE, "in6_ifadd: failed to add an interface route "
                    "for %s/%d on %s, errno = %d\n",
                    ip6_sprintf(&ia->ia_addr.sin6_addr), prefixlen,
                    if_name(ifp), error);
        }
        else
                ia->ia_flags |= IFA_ROUTE;

        *addr = ia->ia_addr.sin6_addr;

        if (ifp->if_flags & IFF_MULTICAST) {
                int error;      /* not used */
                struct in6_addr sol6;

#if !(defined(__FreeBSD__) && __FreeBSD__ >= 3) && !defined (__APPLE__)
                /* Restore saved multicast addresses(if any). */
                in6_restoremkludge(ia, ifp);
#endif

                /* join solicited node multicast address */
                bzero(&sol6, sizeof(sol6));
                sol6.s6_addr16[0] = htons(0xff02);
                sol6.s6_addr16[1] = htons(ifp->if_index);
                sol6.s6_addr32[1] = 0;
                sol6.s6_addr32[2] = htonl(1);
                sol6.s6_addr32[3] = ia->ia_addr.sin6_addr.s6_addr32[3];
                sol6.s6_addr8[12] = 0xff;
                (void)in6_addmulti(&sol6, ifp, &error);
        }

        ia->ia6_flags |= IN6_IFF_TENTATIVE;

        /*
         * To make the interface up. Only AF_INET6 in ia is used...
         */
        s = splimp();
        error = dlil_ioctl(PF_INET6, ifp, SIOCSIFADDR, (caddr_t)ia);
        if (error == EOPNOTSUPP)
                error = 0;
        if (error) {

                splx(s);
                return NULL;
        }
        splx(s);

        /* Perform DAD, if needed. */
        nd6_dad_start((struct ifaddr *)ia, NULL);

        return ia;
}

int
in6_ifdel(ifp, in6)
        struct ifnet *ifp;
        struct in6_addr *in6;
{
#if defined(__bsdi__) || (defined(__FreeBSD__) && __FreeBSD__ < 3)
        struct ifaddr *ifa;
#endif
        struct in6_ifaddr *ia = (struct in6_ifaddr *)NULL;
        struct in6_ifaddr *oia = (struct in6_ifaddr *)NULL;

        if (!ifp)
                return -1;

        ia = in6ifa_ifpwithaddr(ifp, in6);
        if (!ia)
                return -1;

        if (ifp->if_flags & IFF_MULTICAST) {
                /*
                 * delete solicited multicast addr for deleting host id
                 */
                struct in6_multi *in6m;
                struct in6_addr llsol;
                bzero(&llsol, sizeof(struct in6_addr));
                llsol.s6_addr16[0] = htons(0xff02);
                llsol.s6_addr16[1] = htons(ifp->if_index);
                llsol.s6_addr32[1] = 0;
                llsol.s6_addr32[2] = htonl(1);
                llsol.s6_addr32[3] =
                                ia->ia_addr.sin6_addr.s6_addr32[3];
                llsol.s6_addr8[12] = 0xff;

                IN6_LOOKUP_MULTI(llsol, ifp, in6m);
                if (in6m)
                        in6_delmulti(in6m);
        }

        if (ia->ia_flags & IFA_ROUTE) {
                rtinit(&(ia->ia_ifa), (int)RTM_DELETE, 0);
                ia->ia_flags &= ~IFA_ROUTE;
        }

#if defined(__bsdi__) || (defined(__FreeBSD__) && __FreeBSD__ < 3)
        if ((ifa = ifp->if_addrlist) == (struct ifaddr *)ia) {
                ifp->if_addrlist = ifa->ifa_next;
        } else {
                while (ifa->ifa_next &&
                      (ifa->ifa_next != (struct ifaddr *)ia))
                        ifa = ifa->ifa_next;
                if (ifa->ifa_next)
                        ifa->ifa_next = ((struct ifaddr *)ia)->ifa_next;
                else
                        return -1;
        }
#else
        TAILQ_REMOVE(&ifp->if_addrlist, (struct ifaddr *)ia, ifa_list);
#endif
        IFAFREE(&ia->ia_ifa);

        /* lladdr is never deleted */
        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
                        return -1;
        }

#if !(defined(__FreeBSD__) && __FreeBSD__ >= 3) && !defined (__APPLE__)
        in6_savemkludge(oia);
#endif
        IFAFREE((&oia->ia_ifa));
/* xxx
        rtrequest(RTM_DELETE,
                  (struct sockaddr *)&ia->ia_addr,
                  (struct sockaddr *)0
                  (struct sockaddr *)&ia->ia_prefixmask,
                  RTF_UP|RTF_CLONING,
                  (struct rtentry **)0);
*/
        return 0;
}

int
in6_init_prefix_ltimes(struct nd_prefix *ndpr)
{
#if !(defined(__FreeBSD__) && __FreeBSD__ >= 3) && !defined (__APPLE__)
        long time_second = time.tv_sec;
#endif

        /* check if preferred lifetime > valid lifetime */
        if (ndpr->ndpr_pltime > ndpr->ndpr_vltime) {
                log(LOG_INFO, "in6_init_prefix_ltimes: preferred lifetime"
                    "(%d) is greater than valid lifetime(%d)\n",
                    (u_int)ndpr->ndpr_pltime, (u_int)ndpr->ndpr_vltime);
                return (EINVAL);
        }
        if (ndpr->ndpr_pltime == ND6_INFINITE_LIFETIME)
                ndpr->ndpr_preferred = 0;
        else
                ndpr->ndpr_preferred = time_second + ndpr->ndpr_pltime;
        if (ndpr->ndpr_vltime == ND6_INFINITE_LIFETIME)
                ndpr->ndpr_expire = 0;
        else
                ndpr->ndpr_expire = time_second + ndpr->ndpr_vltime;

        return 0;
}

static void
in6_init_address_ltimes(struct nd_prefix *new,
                        struct in6_addrlifetime *lt6,
                        int update_vltime)
{
#if !(defined(__FreeBSD__) && __FreeBSD__ >= 3) && !defined (__APPLE__)
        long time_second = time.tv_sec;
#endif

        /* Valid lifetime must not be updated unless explicitly specified. */
        if (update_vltime) {
                /* init ia6t_expire */
                if (lt6->ia6t_vltime == ND6_INFINITE_LIFETIME)
                        lt6->ia6t_expire = 0;
                else {
                        lt6->ia6t_expire = time_second;
                        lt6->ia6t_expire += lt6->ia6t_vltime;
                }
                /* Ensure addr lifetime <= prefix lifetime. */
                if (new->ndpr_expire && lt6->ia6t_expire &&
                    new->ndpr_expire < lt6->ia6t_expire)
                        lt6->ia6t_expire = new->ndpr_expire;
        }

        /* init ia6t_preferred */
        if (lt6->ia6t_pltime == ND6_INFINITE_LIFETIME)
                lt6->ia6t_preferred = 0;
        else {
                lt6->ia6t_preferred = time_second;
                lt6->ia6t_preferred += lt6->ia6t_pltime;
        }
         /* Ensure addr lifetime <= prefix lifetime. */
        if (new->ndpr_preferred && lt6->ia6t_preferred
            && new->ndpr_preferred < lt6->ia6t_preferred)
                lt6->ia6t_preferred = new->ndpr_preferred;
}

/*
 * Delete all the routing table entries that use the specified gateway.
 * XXX: this function causes search through all entries of routing table, so
 * it shouldn't be called when acting as a router.
 */
void
rt6_flush(gateway, ifp)
    struct in6_addr *gateway;
    struct ifnet *ifp;
{
        struct radix_node_head *rnh = rt_tables[AF_INET6];
#ifdef __NetBSD__
        int s = splsoftnet();
#else
        int s = splnet();
#endif

        /* We'll care only link-local addresses */
        if (!IN6_IS_ADDR_LINKLOCAL(gateway)) {
                splx(s);
                return;
        }
        /* XXX: hack for KAME's link-local address kludge */
        gateway->s6_addr16[1] = htons(ifp->if_index);

        rnh->rnh_walktree(rnh, rt6_deleteroute, (void *)gateway);
        splx(s);
}

static int
rt6_deleteroute(rn, arg)
        struct radix_node *rn;
        void *arg;
{
#define SIN6(s) ((struct sockaddr_in6 *)s)
        struct rtentry *rt = (struct rtentry *)rn;
        struct in6_addr *gate = (struct in6_addr *)arg;

        if (rt->rt_gateway == NULL || rt->rt_gateway->sa_family != AF_INET6)
                return(0);

        if (!IN6_ARE_ADDR_EQUAL(gate, &SIN6(rt->rt_gateway)->sin6_addr))
                return(0);

        /*
         * We delete only host route. This means, in particular, we don't
         * delete default route.
         */
        if ((rt->rt_flags & RTF_HOST) == 0)
                return(0);

        return(rtrequest(RTM_DELETE, rt_key(rt),
                         rt->rt_gateway, rt_mask(rt), rt->rt_flags, 0));
#undef SIN6
}

int
nd6_setdefaultiface(ifindex)
        int ifindex;
{
        int error = 0;

        if (ifindex < 0 || if_index < ifindex)
                return(EINVAL);

        if (nd6_defifindex != ifindex) {
                nd6_defifindex = ifindex;
                if (nd6_defifindex > 0)
                        nd6_defifp = ifindex2ifnet[nd6_defifindex];
                else
                        nd6_defifp = NULL;

                /*
                 * If the Default Router List is empty, install a route
                 * to the specified interface as default or remove the default
                 * route when the default interface becomes canceled.
                 * The check for the queue is actually redundant, but
                 * we do this here to avoid re-install the default route
                 * if the list is NOT empty.
                 */
                if (TAILQ_FIRST(&nd_defrouter) == NULL)
                        defrouter_select();
        }

        return(error);
}