FreeBSD/Linux Kernel Cross Reference
sys/netinet6/in6.c

     /*      $NetBSD: in6.c,v 1.91.4.1 2008/10/03 10:43:48 jdc Exp $ */
     /*      $KAME: in6.c,v 1.198 2001/07/18 09:12:38 itojun Exp $   */
     
     /*
      * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
      * All rights reserved.
      *
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
     * are met:
     * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     * 3. Neither the name of the project nor the names of its contributors
     *    may be used to endorse or promote products derived from this software
     *    without specific prior written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     */
    
    /*
     * Copyright (c) 1982, 1986, 1991, 1993
     *      The Regents of the University of California.  All rights reserved.
     *
     * Redistribution and use in source and binary forms, with or without
     * modification, are permitted provided that the following conditions
     * are met:
     * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     * 3. Neither the name of the University nor the names of its contributors
     *    may be used to endorse or promote products derived from this software
     *    without specific prior written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     *
     *      @(#)in.c        8.2 (Berkeley) 11/15/93
     */
    
    #include <sys/cdefs.h>
    __KERNEL_RCSID(0, "$NetBSD: in6.c,v 1.91.4.1 2008/10/03 10:43:48 jdc Exp $");
    
    #include "opt_inet.h"
    #include "opt_pfil_hooks.h"
    
    #include <sys/param.h>
    #include <sys/ioctl.h>
    #include <sys/errno.h>
    #include <sys/malloc.h>
    #include <sys/socket.h>
    #include <sys/socketvar.h>
    #include <sys/sockio.h>
    #include <sys/systm.h>
    #include <sys/proc.h>
    #include <sys/time.h>
    #include <sys/kernel.h>
    #include <sys/syslog.h>
    
    #include <net/if.h>
    #include <net/if_types.h>
    #include <net/route.h>
    #include <net/if_dl.h>
    
    #include <netinet/in.h>
    #include <netinet/in_var.h>
    #include <net/if_ether.h>
    
    #include <netinet/ip6.h>
    #include <netinet6/ip6_var.h>
    #include <netinet6/nd6.h>
    #include <netinet6/mld6_var.h>
    #include <netinet6/ip6_mroute.h>
    #include <netinet6/in6_ifattach.h>
    
    #include <net/net_osdep.h>
   
   #ifdef PFIL_HOOKS
   #include <net/pfil.h>
   #endif
   
   MALLOC_DEFINE(M_IP6OPT, "ip6_options", "IPv6 options");
   
   /* enable backward compatibility code for obsoleted ioctls */
   #define COMPAT_IN6IFIOCTL
   
   /*
    * Definitions of some constant IP6 addresses.
    */
   const struct in6_addr in6addr_any = IN6ADDR_ANY_INIT;
   const struct in6_addr in6addr_loopback = IN6ADDR_LOOPBACK_INIT;
   const struct in6_addr in6addr_nodelocal_allnodes =
           IN6ADDR_NODELOCAL_ALLNODES_INIT;
   const struct in6_addr in6addr_linklocal_allnodes =
           IN6ADDR_LINKLOCAL_ALLNODES_INIT;
   const struct in6_addr in6addr_linklocal_allrouters =
           IN6ADDR_LINKLOCAL_ALLROUTERS_INIT;
   
   const struct in6_addr in6mask0 = IN6MASK0;
   const struct in6_addr in6mask32 = IN6MASK32;
   const struct in6_addr in6mask64 = IN6MASK64;
   const struct in6_addr in6mask96 = IN6MASK96;
   const struct in6_addr in6mask128 = IN6MASK128;
   
   const struct sockaddr_in6 sa6_any = {sizeof(sa6_any), AF_INET6,
                                        0, 0, IN6ADDR_ANY_INIT, 0};
   
   static int in6_lifaddr_ioctl __P((struct socket *, u_long, caddr_t,
           struct ifnet *, struct proc *));
   static int in6_ifinit __P((struct ifnet *, struct in6_ifaddr *,
           struct sockaddr_in6 *, int));
   static void in6_unlink_ifa __P((struct in6_ifaddr *, struct ifnet *));
   
   /*
    * This structure is used to keep track of in6_multi chains which belong to
    * deleted interface addresses.
    */
   static LIST_HEAD(, multi6_kludge) in6_mk; /* XXX BSS initialization */
   
   struct multi6_kludge {
           LIST_ENTRY(multi6_kludge) mk_entry;
           struct ifnet *mk_ifp;
           struct in6_multihead mk_head;
   };
   
   /*
    * Subroutine for in6_ifaddloop() and in6_ifremloop().
    * This routine does actual work.
    */
   static void
   in6_ifloop_request(int cmd, struct ifaddr *ifa)
   {
           struct sockaddr_in6 lo_sa;
           struct sockaddr_in6 all1_sa;
           struct rtentry *nrt = NULL;
           int e;
   
           bzero(&lo_sa, sizeof(lo_sa));
           bzero(&all1_sa, sizeof(all1_sa));
           lo_sa.sin6_family = all1_sa.sin6_family = AF_INET6;
           lo_sa.sin6_len = all1_sa.sin6_len = sizeof(struct sockaddr_in6);
           lo_sa.sin6_addr = in6addr_loopback;
           all1_sa.sin6_addr = in6mask128;
   
           /*
            * We specify the address itself as the gateway, and set the
            * RTF_LLINFO flag, so that the corresponding host route would have
            * the flag, and thus applications that assume traditional behavior
            * would be happy.  Note that we assume the caller of the function
            * (probably implicitly) set nd6_rtrequest() to ifa->ifa_rtrequest,
            * which changes the outgoing interface to the loopback interface.
            */
           e = rtrequest(cmd, ifa->ifa_addr, ifa->ifa_addr,
               (struct sockaddr *)&all1_sa, RTF_UP|RTF_HOST|RTF_LLINFO, &nrt);
           if (e != 0) {
                   log(LOG_ERR, "in6_ifloop_request: "
                       "%s operation failed for %s (errno=%d)\n",
                       cmd == RTM_ADD ? "ADD" : "DELETE",
                       ip6_sprintf(&((struct in6_ifaddr *)ifa)->ia_addr.sin6_addr),
                       e);
           }
   
           /*
            * Make sure rt_ifa be equal to IFA, the second argument of the
            * function.
            * We need this because when we refer to rt_ifa->ia6_flags in
            * ip6_input, we assume that the rt_ifa points to the address instead
            * of the loopback address.
            */
           if (cmd == RTM_ADD && nrt && ifa != nrt->rt_ifa) {
                   IFAFREE(nrt->rt_ifa);
                   IFAREF(ifa);
                   nrt->rt_ifa = ifa;
           }
   
           /*
            * Report the addition/removal of the address to the routing socket.
            * XXX: since we called rtinit for a p2p interface with a destination,
            *      we end up reporting twice in such a case.  Should we rather
            *      omit the second report?
            */
           if (nrt) {
                   rt_newaddrmsg(cmd, ifa, e, nrt);
                   if (cmd == RTM_DELETE) {
                           if (nrt->rt_refcnt <= 0) {
                                   /* XXX: we should free the entry ourselves. */
                                   nrt->rt_refcnt++;
                                   rtfree(nrt);
                           }
                   } else {
                           /* the cmd must be RTM_ADD here */
                           nrt->rt_refcnt--;
                   }
           }
   }
   
   /*
    * Add ownaddr as loopback rtentry.  We previously add the route only if
    * necessary (ex. on a p2p link).  However, since we now manage addresses
    * separately from prefixes, we should always add the route.  We can't
    * rely on the cloning mechanism from the corresponding interface route
    * any more.
    */
   static void
   in6_ifaddloop(struct ifaddr *ifa)
   {
           struct rtentry *rt;
   
           /* If there is no loopback entry, allocate one. */
           rt = rtalloc1(ifa->ifa_addr, 0);
           if (rt == NULL || (rt->rt_flags & RTF_HOST) == 0 ||
               (rt->rt_ifp->if_flags & IFF_LOOPBACK) == 0)
                   in6_ifloop_request(RTM_ADD, ifa);
           if (rt)
                   rt->rt_refcnt--;
   }
   
   /*
    * Remove loopback rtentry of ownaddr generated by in6_ifaddloop(),
    * if it exists.
    */
   static void
   in6_ifremloop(struct ifaddr *ifa)
   {
           struct in6_ifaddr *ia;
           struct rtentry *rt;
           int ia_count = 0;
   
           /*
            * Some of BSD variants do not remove cloned routes
            * from an interface direct route, when removing the direct route
            * (see comments in net/net_osdep.h).  Even for variants that do remove
            * cloned routes, they could fail to remove the cloned routes when
            * we handle multple addresses that share a common prefix.
            * So, we should remove the route corresponding to the deleted address.
            */
   
           /*
            * Delete the entry only if exact one ifa exists.  More than one ifa
            * can exist if we assign a same single address to multiple
            * (probably p2p) interfaces.
            * XXX: we should avoid such a configuration in IPv6...
            */
           for (ia = in6_ifaddr; ia; ia = ia->ia_next) {
                   if (IN6_ARE_ADDR_EQUAL(IFA_IN6(ifa), &ia->ia_addr.sin6_addr)) {
                           ia_count++;
                           if (ia_count > 1)
                                   break;
                   }
           }
   
           if (ia_count == 1) {
                   /*
                    * Before deleting, check if a corresponding loopbacked host
                    * route surely exists.  With this check, we can avoid to
                    * delete an interface direct route whose destination is same
                    * as the address being removed.  This can happen when removing
                    * a subnet-router anycast address on an interface attahced
                    * to a shared medium.
                    */
                   rt = rtalloc1(ifa->ifa_addr, 0);
                   if (rt != NULL && (rt->rt_flags & RTF_HOST) != 0 &&
                       (rt->rt_ifp->if_flags & IFF_LOOPBACK) != 0) {
                           rt->rt_refcnt--;
                           in6_ifloop_request(RTM_DELETE, ifa);
                   }
           }
   }
   
   int
   in6_mask2len(mask, lim0)
           struct in6_addr *mask;
           u_char *lim0;
   {
           int x = 0, y;
           u_char *lim = lim0, *p;
   
           /* ignore the scope_id part */
           if (lim0 == NULL || lim0 - (u_char *)mask > sizeof(*mask))
                   lim = (u_char *)mask + sizeof(*mask);
           for (p = (u_char *)mask; p < lim; x++, p++) {
                   if (*p != 0xff)
                           break;
           }
           y = 0;
           if (p < lim) {
                   for (y = 0; y < 8; y++) {
                           if ((*p & (0x80 >> y)) == 0)
                                   break;
                   }
           }
   
           /*
            * when the limit pointer is given, do a stricter check on the
            * remaining bits.
            */
           if (p < lim) {
                   if (y != 0 && (*p & (0x00ff >> y)) != 0)
                           return (-1);
                   for (p = p + 1; p < lim; p++)
                           if (*p != 0)
                                   return (-1);
           }
   
           return x * 8 + y;
   }
   
   #define ifa2ia6(ifa)    ((struct in6_ifaddr *)(ifa))
   #define ia62ifa(ia6)    (&((ia6)->ia_ifa))
   
   int
   in6_control(so, cmd, data, ifp, p)
           struct  socket *so;
           u_long cmd;
           caddr_t data;
           struct ifnet *ifp;
           struct proc *p;
   {
           struct  in6_ifreq *ifr = (struct in6_ifreq *)data;
           struct  in6_ifaddr *ia = NULL;
           struct  in6_aliasreq *ifra = (struct in6_aliasreq *)data;
           struct sockaddr_in6 *sa6;
           int privileged;
   
           privileged = 0;
           if (p && !suser(p->p_ucred, &p->p_acflag))
                   privileged++;
   
           switch (cmd) {
           case SIOCGETSGCNT_IN6:
           case SIOCGETMIFCNT_IN6:
                   return (mrt6_ioctl(cmd, data));
           }
   
           if (ifp == NULL)
                   return (EOPNOTSUPP);
   
           switch (cmd) {
           case SIOCSNDFLUSH_IN6:
           case SIOCSPFXFLUSH_IN6:
           case SIOCSRTRFLUSH_IN6:
           case SIOCSDEFIFACE_IN6:
           case SIOCSIFINFO_FLAGS:
                   if (!privileged)
                           return (EPERM);
                   /* FALLTHROUGH */
           case OSIOCGIFINFO_IN6:
           case SIOCGIFINFO_IN6:
           case SIOCGDRLST_IN6:
           case SIOCGPRLST_IN6:
           case SIOCGNBRINFO_IN6:
           case SIOCGDEFIFACE_IN6:
                   return (nd6_ioctl(cmd, data, ifp));
           }
   
           switch (cmd) {
           case SIOCSIFPREFIX_IN6:
           case SIOCDIFPREFIX_IN6:
           case SIOCAIFPREFIX_IN6:
           case SIOCCIFPREFIX_IN6:
           case SIOCSGIFPREFIX_IN6:
           case SIOCGIFPREFIX_IN6:
                   log(LOG_NOTICE,
                       "prefix ioctls are now invalidated. "
                       "please use ifconfig.\n");
                   return (EOPNOTSUPP);
           }
   
           switch (cmd) {
           case SIOCALIFADDR:
           case SIOCDLIFADDR:
                   if (!privileged)
                           return (EPERM);
                   /* FALLTHROUGH */
           case SIOCGLIFADDR:
                   return in6_lifaddr_ioctl(so, cmd, data, ifp, p);
           }
   
           /*
            * Find address for this interface, if it exists.
            *
            * In netinet code, we have checked ifra_addr in SIOCSIF*ADDR operation
            * only, and used the first interface address as the target of other
            * operations (without checking ifra_addr).  This was because netinet
            * code/API assumed at most 1 interface address per interface.
            * Since IPv6 allows a node to assign multiple addresses
            * on a single interface, we almost always look and check the
            * presence of ifra_addr, and reject invalid ones here.
            * It also decreases duplicated code among SIOC*_IN6 operations.
            */
           switch (cmd) {
           case SIOCAIFADDR_IN6:
           case SIOCSIFPHYADDR_IN6:
                   sa6 = &ifra->ifra_addr;
                   break;
           case SIOCSIFADDR_IN6:
           case SIOCGIFADDR_IN6:
           case SIOCSIFDSTADDR_IN6:
           case SIOCSIFNETMASK_IN6:
           case SIOCGIFDSTADDR_IN6:
           case SIOCGIFNETMASK_IN6:
           case SIOCDIFADDR_IN6:
           case SIOCGIFPSRCADDR_IN6:
           case SIOCGIFPDSTADDR_IN6:
           case SIOCGIFAFLAG_IN6:
           case SIOCSNDFLUSH_IN6:
           case SIOCSPFXFLUSH_IN6:
           case SIOCSRTRFLUSH_IN6:
           case SIOCGIFALIFETIME_IN6:
           case SIOCSIFALIFETIME_IN6:
           case SIOCGIFSTAT_IN6:
           case SIOCGIFSTAT_ICMP6:
                   sa6 = &ifr->ifr_addr;
                   break;
           default:
                   sa6 = NULL;
                   break;
           }
           if (sa6 && sa6->sin6_family == AF_INET6) {
                   if (IN6_IS_ADDR_LINKLOCAL(&sa6->sin6_addr)) {
                           if (sa6->sin6_addr.s6_addr16[1] == 0) {
                                   /* link ID is not embedded by the user */
                                   sa6->sin6_addr.s6_addr16[1] =
                                       htons(ifp->if_index);
                           } else if (sa6->sin6_addr.s6_addr16[1] !=
                               htons(ifp->if_index)) {
                                   return (EINVAL);        /* link ID contradicts */
                           }
                           if (sa6->sin6_scope_id) {
                                   if (sa6->sin6_scope_id !=
                                       (u_int32_t)ifp->if_index)
                                           return (EINVAL);
                                   sa6->sin6_scope_id = 0; /* XXX: good way? */
                           }
                   }
                   ia = in6ifa_ifpwithaddr(ifp, &sa6->sin6_addr);
           } else
                   ia = NULL;
   
           switch (cmd) {
           case SIOCSIFADDR_IN6:
           case SIOCSIFDSTADDR_IN6:
           case SIOCSIFNETMASK_IN6:
                   /*
                    * Since IPv6 allows a node to assign multiple addresses
                    * on a single interface, SIOCSIFxxx ioctls are deprecated.
                    */
                   return (EINVAL);
   
           case SIOCDIFADDR_IN6:
                   /*
                    * for IPv4, we look for existing in_ifaddr here to allow
                    * "ifconfig if0 delete" to remove the first IPv4 address on
                    * the interface.  For IPv6, as the spec allows multiple
                    * interface address from the day one, we consider "remove the
                    * first one" semantics to be not preferable.
                    */
                   if (ia == NULL)
                           return (EADDRNOTAVAIL);
                   /* FALLTHROUGH */
           case SIOCAIFADDR_IN6:
                   /*
                    * We always require users to specify a valid IPv6 address for
                    * the corresponding operation.
                    */
                   if (ifra->ifra_addr.sin6_family != AF_INET6 ||
                       ifra->ifra_addr.sin6_len != sizeof(struct sockaddr_in6))
                           return (EAFNOSUPPORT);
                   if (!privileged)
                           return (EPERM);
   
                   break;
   
           case SIOCGIFADDR_IN6:
                   /* This interface is basically deprecated. use SIOCGIFCONF. */
                   /* FALLTHROUGH */
           case SIOCGIFAFLAG_IN6:
           case SIOCGIFNETMASK_IN6:
           case SIOCGIFDSTADDR_IN6:
           case SIOCGIFALIFETIME_IN6:
                   /* must think again about its semantics */
                   if (ia == NULL)
                           return (EADDRNOTAVAIL);
                   break;
           case SIOCSIFALIFETIME_IN6:
               {
                   struct in6_addrlifetime *lt;
   
                   if (!privileged)
                           return (EPERM);
                   if (ia == NULL)
                           return (EADDRNOTAVAIL);
                   /* sanity for overflow - beware unsigned */
                   lt = &ifr->ifr_ifru.ifru_lifetime;
                   if (lt->ia6t_vltime != ND6_INFINITE_LIFETIME
                    && lt->ia6t_vltime + time.tv_sec < time.tv_sec) {
                           return EINVAL;
                   }
                   if (lt->ia6t_pltime != ND6_INFINITE_LIFETIME
                    && lt->ia6t_pltime + time.tv_sec < time.tv_sec) {
                           return EINVAL;
                   }
                   break;
               }
           }
   
           switch (cmd) {
   
           case SIOCGIFADDR_IN6:
                   ifr->ifr_addr = ia->ia_addr;
                   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;
                   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_stat,
                       sizeof(ifr->ifr_ifru.ifru_icmp6stat));
                   ifr->ifr_ifru.ifru_icmp6stat =
                       *((struct in6_ifextra *)ifp->if_afdata[AF_INET6])->icmp6_ifstat;
                   break;
   
           case SIOCGIFALIFETIME_IN6:
                   ifr->ifr_ifru.ifru_lifetime = ia->ia6_lifetime;
                   if (ia->ia6_lifetime.ia6t_vltime != ND6_INFINITE_LIFETIME) {
                           time_t maxexpire;
                           struct in6_addrlifetime *retlt =
                               &ifr->ifr_ifru.ifru_lifetime;
   
                           /*
                            * XXX: adjust expiration time assuming time_t is
                            * signed.
                            */
                           maxexpire = (-1) &
                               ~(1 << ((sizeof(maxexpire) * 8) - 1));
                           if (ia->ia6_lifetime.ia6t_vltime <
                               maxexpire - ia->ia6_updatetime) {
                                   retlt->ia6t_expire = ia->ia6_updatetime +
                                       ia->ia6_lifetime.ia6t_vltime;
                           } else
                                   retlt->ia6t_expire = maxexpire;
                   }
                   if (ia->ia6_lifetime.ia6t_pltime != ND6_INFINITE_LIFETIME) {
                           time_t maxexpire;
                           struct in6_addrlifetime *retlt =
                               &ifr->ifr_ifru.ifru_lifetime;
   
                           /*
                            * XXX: adjust expiration time assuming time_t is
                            * signed.
                            */
                           maxexpire = (-1) &
                               ~(1 << ((sizeof(maxexpire) * 8) - 1));
                           if (ia->ia6_lifetime.ia6t_pltime <
                               maxexpire - ia->ia6_updatetime) {
                                   retlt->ia6t_preferred = ia->ia6_updatetime +
                                       ia->ia6_lifetime.ia6t_pltime;
                           } else
                                   retlt->ia6t_preferred = maxexpire;
                   }
                   break;
   
           case SIOCSIFALIFETIME_IN6:
                   ia->ia6_lifetime = ifr->ifr_ifru.ifru_lifetime;
                   /* for sanity */
                   if (ia->ia6_lifetime.ia6t_vltime != ND6_INFINITE_LIFETIME) {
                           ia->ia6_lifetime.ia6t_expire =
                                   time.tv_sec + ia->ia6_lifetime.ia6t_vltime;
                   } else
                           ia->ia6_lifetime.ia6t_expire = 0;
                   if (ia->ia6_lifetime.ia6t_pltime != ND6_INFINITE_LIFETIME) {
                           ia->ia6_lifetime.ia6t_preferred =
                                   time.tv_sec + ia->ia6_lifetime.ia6t_pltime;
                   } else
                           ia->ia6_lifetime.ia6t_preferred = 0;
                   break;
   
           case SIOCAIFADDR_IN6:
           {
                   int i, error = 0;
                   struct nd_prefix pr0, *pr;
   
                   /* reject read-only flags */
                   if ((ifra->ifra_flags & IN6_IFF_DUPLICATED) != 0 ||
                       (ifra->ifra_flags & IN6_IFF_DETACHED) != 0 ||
                       (ifra->ifra_flags & IN6_IFF_NODAD) != 0 ||
                       (ifra->ifra_flags & IN6_IFF_AUTOCONF) != 0) {
                           return (EINVAL);
                   }
                   /*
                    * first, make or update the interface address structure,
                    * and link it to the list.
                    */
                   if ((error = in6_update_ifa(ifp, ifra, ia)) != 0)
                           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;
                   pr0.ndpr_mask = ifra->ifra_prefixmask.sin6_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++;
                   }
   
                   /*
                    * this might affect the status of autoconfigured addresses,
                    * that is, this address might make other addresses detached.
                    */
                   pfxlist_onlink_check();
   
   #ifdef PFIL_HOOKS
                   (void)pfil_run_hooks(&if_pfil, (struct mbuf **)SIOCAIFADDR_IN6,
                       ifp, PFIL_IFADDR);
   #endif
   
                   break;
           }
   
           case SIOCDIFADDR_IN6:
           {
                   int i = 0, purgeprefix = 0;
                   struct nd_prefix pr0, *pr = NULL;
   
                   /*
                    * 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.
                    */
                   bzero(&pr0, sizeof(pr0));
                   pr0.ndpr_ifp = ifp;
                   pr0.ndpr_plen = in6_mask2len(&ia->ia_prefixmask.sin6_addr,
                       NULL);
                   if (pr0.ndpr_plen == 128)
                           goto purgeaddr;
                   pr0.ndpr_prefix = ia->ia_addr;
                   pr0.ndpr_mask = ia->ia_prefixmask.sin6_addr;
                   for (i = 0; i < 4; i++) {
                           pr0.ndpr_prefix.sin6_addr.s6_addr32[i] &=
                               ia->ia_prefixmask.sin6_addr.s6_addr32[i];
                   }
                   if ((pr = nd6_prefix_lookup(&pr0)) != NULL &&
                       pr == ia->ia6_ndpr) {
                           pr->ndpr_refcnt--;
                           if (pr->ndpr_refcnt == 0)
                                   purgeprefix = 1;
                   }
   
             purgeaddr:
                   in6_purgeaddr(&ia->ia_ifa);
                   if (pr && purgeprefix)
                           prelist_remove(pr);
   #ifdef PFIL_HOOKS
                   (void)pfil_run_hooks(&if_pfil, (struct mbuf **)SIOCDIFADDR_IN6,
                       ifp, PFIL_IFADDR);
   #endif
                   break;
           }
   
           default:
                   if (ifp == NULL || ifp->if_ioctl == 0)
                           return (EOPNOTSUPP);
                   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)
           struct ifnet *ifp;
           struct in6_aliasreq *ifra;
           struct in6_ifaddr *ia;
   {
           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 rtentry *rt;
   
           /* 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)) {
                   /* link-local index check: should be a separate function? */
                   if (IN6_IS_ADDR_LINKLOCAL(&dst6.sin6_addr)) {
                           if (dst6.sin6_addr.s6_addr16[1] == 0) {
                                   /*
                                    * interface ID is not embedded by
                                    * the user
                                    */
                                   dst6.sin6_addr.s6_addr16[1] =
                                       htons(ifp->if_index);
                           } else if (dst6.sin6_addr.s6_addr16[1] !=
                               htons(ifp->if_index)) {
                                   return (EINVAL);        /* ifid contradicts */
                           }
                   }
           }
           /*
            * The destination address can be specified only for a p2p or a
            * loopback interface.  If specified, the corresponding prefix length
            * must be 128.
            */
           if (ifra->ifra_dstaddr.sin6_family == AF_INET6) {
   #ifdef FORCE_P2PPLEN
                   int i;
   #endif
   
                   if ((ifp->if_flags & (IFF_POINTOPOINT|IFF_LOOPBACK)) == 0) {
                           /* XXX: noisy message */
                           nd6log((LOG_INFO, "in6_update_ifa: a destination can "
                               "be specified for a p2p or a loopback IF only\n"));
                           return (EINVAL);
                   }
                   if (plen != 128) {
                           nd6log((LOG_INFO, "in6_update_ifa: prefixlen should "
                               "be 128 when dstaddr is specified\n"));
   #ifdef FORCE_P2PPLEN
                           /*
                            * To be compatible with old configurations,
                            * such as ifconfig gif0 inet6 2001::1 2001::2
                            * prefixlen 126, we override the specified
                            * prefixmask as if the prefix length was 128.
                            */
                           ifra->ifra_prefixmask.sin6_len =
                               sizeof(struct sockaddr_in6);
                           for (i = 0; i < 4; i++)
                                   ifra->ifra_prefixmask.sin6_addr.s6_addr32[i] =
                                       0xffffffff;
                           plen = 128;
   #else
                           return (EINVAL);
   #endif
                   }
           }
           /* lifetime consistency check */
           lt = &ifra->ifra_lifetime;
           if (lt->ia6t_pltime > lt->ia6t_vltime)
                   return (EINVAL);
           if (lt->ia6t_vltime == 0) {
                   /*
                    * the following log might be noisy, but this is a typical
                    * configuration mistake or a tool's bug.
                    */
                   nd6log((LOG_INFO,
                       "in6_update_ifa: valid lifetime is 0 for %s\n",
                       ip6_sprintf(&ifra->ifra_addr.sin6_addr)));
   
                   if (ia == NULL)
                           return (0); /* there's nothing to do */
           }
   
           /*
            * If this is a new address, allocate a new ifaddr and link it
            * into chains.
            */
           if (ia == NULL) {
                   hostIsNew = 1;
                   /*
                    * When in6_update_ifa() is called in a process of a received
                    * RA, it is called under an interrupt context.  So, we should
                    * call malloc with M_NOWAIT.
                    */
                   ia = (struct in6_ifaddr *) malloc(sizeof(*ia), M_IFADDR,
                       M_NOWAIT);
                   if (ia == NULL)
                           return (ENOBUFS);
                   bzero((caddr_t)ia, sizeof(*ia));
                   LIST_INIT(&ia->ia6_memberships);
                   /* Initialize the address and masks, and put time stamp */
                   ia->ia_ifa.ifa_addr = (struct sockaddr *)&ia->ia_addr;
                   ia->ia_addr.sin6_family = AF_INET6;
                   ia->ia_addr.sin6_len = sizeof(ia->ia_addr);
                   ia->ia6_createtime = ia->ia6_updatetime = time.tv_sec;
                   if ((ifp->if_flags & (IFF_POINTOPOINT | IFF_LOOPBACK)) != 0) {
                           /*
                            * XXX: some functions expect that ifa_dstaddr is not
                            * NULL for p2p interfaces.
                            */
                           ia->ia_ifa.ifa_dstaddr =
                               (struct sockaddr *)&ia->ia_dstaddr;
                   } else {
                           ia->ia_ifa.ifa_dstaddr = NULL;
                   }
                   ia->ia_ifa.ifa_netmask =
                       (struct sockaddr *)&ia->ia_prefixmask;
   
                   ia->ia_ifp = ifp;
                   if ((oia = in6_ifaddr) != NULL) {
                           for ( ; oia->ia_next; oia = oia->ia_next)
                                   continue;
                           oia->ia_next = ia;
                   } else
                           in6_ifaddr = ia;
                   /* gain a refcnt for the link from in6_ifaddr */
                   IFAREF(&ia->ia_ifa);
   
                   TAILQ_INSERT_TAIL(&ifp->if_addrlist, &ia->ia_ifa,
                                     ifa_list);
                   /* gain another refcnt for the link from if_addrlist */
                   IFAREF(&ia->ia_ifa);
           }
   
           /* set prefix mask */
           if (ifra->ifra_prefixmask.sin6_len) {
                   /*
                    * We prohibit changing the prefix length of an existing
                    * address, because
                    * + such an operation should be rare in IPv6, and
                    * + the operation would confuse prefix management.
                    */
                   if (ia->ia_prefixmask.sin6_len &&
                       in6_mask2len(&ia->ia_prefixmask.sin6_addr, NULL) != plen) {
                           nd6log((LOG_INFO, "in6_update_ifa: the prefix length of an"
                               " existing (%s) address should not be changed\n",
                               ip6_sprintf(&ia->ia_addr.sin6_addr)));
                           error = EINVAL;
                           goto unlink;
                   }
                   ia->ia_prefixmask = ifra->ifra_prefixmask;
           }
   
           /*
            * If a new destination address is specified, scrub the old one and
            * install the new destination.  Note that the interface must be
            * p2p or loopback (see the check above.)
            */
           if (dst6.sin6_family == AF_INET6 &&
               !IN6_ARE_ADDR_EQUAL(&dst6.sin6_addr, &ia->ia_dstaddr.sin6_addr)) {
                   if ((ia->ia_flags & IFA_ROUTE) != 0 &&
                       rtinit(&(ia->ia_ifa), (int)RTM_DELETE, RTF_HOST) != 0) {
                           nd6log((LOG_ERR, "in6_update_ifa: failed to remove "
                               "a route to the old destination: %s\n",
                               ip6_sprintf(&ia->ia_addr.sin6_addr)));
                           /* proceed anyway... */
                   } else
                           ia->ia_flags &= ~IFA_ROUTE;
                  ia->ia_dstaddr = dst6;
          }
  
          /*
           * Set lifetimes.  We do not refer to ia6t_expire and ia6t_preferred
           * to see if the address is deprecated or invalidated, but initialize
           * these members for applications.
           */
          ia->ia6_lifetime = ifra->ifra_lifetime;
          if (ia->ia6_lifetime.ia6t_vltime != ND6_INFINITE_LIFETIME) {
                  ia->ia6_lifetime.ia6t_expire =
                      time.tv_sec + ia->ia6_lifetime.ia6t_vltime;
          } else
                  ia->ia6_lifetime.ia6t_expire = 0;
          if (ia->ia6_lifetime.ia6t_pltime != ND6_INFINITE_LIFETIME) {
                  ia->ia6_lifetime.ia6t_preferred =
                      time.tv_sec + ia->ia6_lifetime.ia6t_pltime;
          } else
                  ia->ia6_lifetime.ia6t_preferred = 0;
  
          /* reset the interface and routing table appropriately. */
          if ((error = in6_ifinit(ifp, ia, &ifra->ifra_addr, hostIsNew)) != 0)
                  goto unlink;
  
          /*
           * configure address flags.
           */
          ia->ia6_flags = ifra->ifra_flags;
          /*
           * backward compatibility - if IN6_IFF_DEPRECATED is set from the
           * userland, make it deprecated.
           */
          if ((ifra->ifra_flags & IN6_IFF_DEPRECATED) != 0) {
                  ia->ia6_lifetime.ia6t_pltime = 0;
                  ia->ia6_lifetime.ia6t_preferred = time.tv_sec;
          }
          /*
           * Make the address tentative before joining multicast addresses,
           * so that corresponding MLD responses would not have a tentative
           * source address.
           */
          ia->ia6_flags &= ~IN6_IFF_DUPLICATED;   /* safety */
          if (hostIsNew && in6if_do_dad(ifp))
                  ia->ia6_flags |= IN6_IFF_TENTATIVE;
  
          /*
           * We are done if we have simply modified an existing address.
           */
          if (!hostIsNew)
                  return (error);
  
          /*
           * Beyond this point, we should call in6_purgeaddr upon an error,
           * not just go to unlink.
           */
  
          /* join necessary multiast groups */
          if ((ifp->if_flags & IFF_MULTICAST) != 0) {
                  struct sockaddr_in6 mltaddr, mltmask;
  #ifndef SCOPEDROUTING
                  u_int32_t zoneid = 0;
  #endif
  
                  /* join solicited multicast addr for new host id */
                  struct sockaddr_in6 llsol;
  
                  bzero(&llsol, sizeof(llsol));
                  llsol.sin6_family = AF_INET6;
                  llsol.sin6_len = sizeof(llsol);
                  llsol.sin6_addr.s6_addr16[0] = htons(0xff02);
                  llsol.sin6_addr.s6_addr16[1] = htons(ifp->if_index);
                  llsol.sin6_addr.s6_addr32[1] = 0;
                  llsol.sin6_addr.s6_addr32[2] = htonl(1);
                  llsol.sin6_addr.s6_addr32[3] =
                      ifra->ifra_addr.sin6_addr.s6_addr32[3];
                  llsol.sin6_addr.s6_addr8[12] = 0xff;
                  imm = in6_joingroup(ifp, &llsol.sin6_addr, &error);
                  if (!imm) {
                          nd6log((LOG_ERR,
                              "in6_update_ifa: addmulti "
                              "failed for %s on %s (errno=%d)\n",
                              ip6_sprintf(&llsol.sin6_addr),
                              if_name(ifp), error));
                          goto cleanup;
                  }
                  LIST_INSERT_HEAD(&ia->ia6_memberships, imm, i6mm_chain);
  
                  bzero(&mltmask, sizeof(mltmask));
                  mltmask.sin6_len = sizeof(struct sockaddr_in6);
                  mltmask.sin6_family = AF_INET6;
                  mltmask.sin6_addr = in6mask32;
  
                  /*
                   * join link-local all-nodes address
                   */
                  bzero(&mltaddr, sizeof(mltaddr));
                  mltaddr.sin6_len = sizeof(struct sockaddr_in6);
                  mltaddr.sin6_family = AF_INET6;
                  mltaddr.sin6_addr = in6addr_linklocal_allnodes;
                  mltaddr.sin6_addr.s6_addr16[1] = htons(ifp->if_index);
  
                  /*
                   * XXX: do we really need this automatic routes?
                   * We should probably reconsider this stuff.  Most applications
                   * actually do not need the routes, since they usually specify
                   * the outgoing interface.
                   */
                  rt = rtalloc1((struct sockaddr *)&mltaddr, 0);
                  if (rt) {
                          /*
                           * 32bit came from "mltmask"
                           * XXX: only works in !SCOPEDROUTING case.
                           */
                          if (memcmp(&mltaddr.sin6_addr,
                              &((struct sockaddr_in6 *)rt_key(rt))->sin6_addr,
                              32 / 8)) {
                                  RTFREE(rt);
                                  rt = NULL;
                          }
                  }
                  if (!rt) {
                          struct rt_addrinfo info;
  
                          bzero(&info, sizeof(info));
                          info.rti_info[RTAX_DST] = (struct sockaddr *)&mltaddr;
                          info.rti_info[RTAX_GATEWAY] =
                              (struct sockaddr *)&ia->ia_addr;
                          info.rti_info[RTAX_NETMASK] =
                              (struct sockaddr *)&mltmask;
                          info.rti_info[RTAX_IFA] =
                              (struct sockaddr *)&ia->ia_addr;
                          /* XXX: we need RTF_CLONING to fake nd6_rtrequest */
                          info.rti_flags = RTF_UP | RTF_CLONING;
                          error = rtrequest1(RTM_ADD, &info, NULL);
                          if (error)
                                  goto cleanup;
                  } else {
                          RTFREE(rt);
                  }
  #ifndef SCOPEDROUTING
                  mltaddr.sin6_scope_id = zoneid; /* XXX */
  #endif
                  imm = in6_joingroup(ifp, &mltaddr.sin6_addr, &error);
                  if (!imm) {
                          nd6log((LOG_WARNING,
                              "in6_update_ifa: addmulti failed for "
                              "%s on %s (errno=%d)\n",
                              ip6_sprintf(&mltaddr.sin6_addr),
                              if_name(ifp), error));
                          goto cleanup;
                  }
                  LIST_INSERT_HEAD(&ia->ia6_memberships, imm, i6mm_chain);
  
                  /*
                   * join node information group address
                   */
                  if (in6_nigroup(ifp, hostname, hostnamelen, &mltaddr) == 0) {
                          imm = in6_joingroup(ifp, &mltaddr.sin6_addr, &error);
                          if (!imm) {
                                  nd6log((LOG_WARNING, "in6_update_ifa: "
                                      "addmulti failed for %s on %s (errno=%d)\n",
                                      ip6_sprintf(&mltaddr.sin6_addr),
                                      if_name(ifp), error));
                                  /* XXX not very fatal, go on... */
                          } else {
                                  LIST_INSERT_HEAD(&ia->ia6_memberships,
                                      imm, i6mm_chain);
                          }
                  }
  
                  if (ifp->if_flags & IFF_LOOPBACK) {
                          /*
                           * join node-local all-nodes address, on loopback.
                           * (ff01::1%ifN, and ff01::%ifN/32)
                           */
                          mltaddr.sin6_addr = in6addr_nodelocal_allnodes;
  
                          /* XXX: again, do we really need the route? */
                          rt = rtalloc1((struct sockaddr *)&mltaddr, 0);
                          if (rt) {
                                  /* 32bit came from "mltmask" */
                                  if (memcmp(&mltaddr.sin6_addr,
                                      &((struct sockaddr_in6 *)rt_key(rt))->sin6_addr,
                                      32 / 8)) {
                                          RTFREE(rt);
                                          rt = NULL;
                                  }
                          }
                          if (!rt) {
                                  struct rt_addrinfo info;
  
                                  bzero(&info, sizeof(info));
                                  info.rti_info[RTAX_DST] = (struct sockaddr *)&mltaddr;
                                  info.rti_info[RTAX_GATEWAY] =
                                      (struct sockaddr *)&ia->ia_addr;
                                  info.rti_info[RTAX_NETMASK] =
                                      (struct sockaddr *)&mltmask;
                                  info.rti_info[RTAX_IFA] =
                                      (struct sockaddr *)&ia->ia_addr;
                                  info.rti_flags = RTF_UP | RTF_CLONING;
                                  error = rtrequest1(RTM_ADD, &info, NULL);
                                  if (error)
                                          goto cleanup;
                          } else {
                                  RTFREE(rt);
                          }
                          imm = in6_joingroup(ifp, &mltaddr.sin6_addr, &error);
                          if (!imm) {
                                  nd6log((LOG_WARNING, "in6_update_ifa: "
                                      "addmulti failed for %s on %s (errno=%d)\n",
                                      ip6_sprintf(&mltaddr.sin6_addr),
                                      if_name(ifp), error));
                                  goto cleanup;
                          }
                          LIST_INSERT_HEAD(&ia->ia6_memberships, imm, i6mm_chain);
                  }
          }
  
          /*
           * 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)
          {
                  nd6_dad_start((struct ifaddr *)ia, NULL);
          }
  
          return (error);
  
    unlink:
          /*
           * XXX: if a change of an existing address failed, keep the entry
           * anyway.
           */
          if (hostIsNew)
                  in6_unlink_ifa(ia, ifp);
          return (error);
  
    cleanup:
          in6_purgeaddr(&ia->ia_ifa);
          return error;
  }
  
  void
  in6_purgeaddr(ifa)
          struct ifaddr *ifa;
  {
          struct ifnet *ifp = ifa->ifa_ifp;
          struct in6_ifaddr *ia = (struct in6_ifaddr *) ifa;
          struct in6_multi_mship *imm;
  
          /* stop DAD processing */
          nd6_dad_stop(ifa);
  
          /*
           * delete route to the destination of the address being purged.
           * The interface must be p2p or loopback in this case.
           */
          if ((ia->ia_flags & IFA_ROUTE) != 0 && ia->ia_dstaddr.sin6_len != 0) {
                  int e;
  
                  if ((e = rtinit(&(ia->ia_ifa), (int)RTM_DELETE, RTF_HOST))
                      != 0) {
                          log(LOG_ERR, "in6_purgeaddr: failed to remove "
                              "a route to the p2p destination: %s on %s, "
                              "errno=%d\n",
                              ip6_sprintf(&ia->ia_addr.sin6_addr), if_name(ifp),
                              e);
                          /* proceed anyway... */
                  } else
                          ia->ia_flags &= ~IFA_ROUTE;
          }
  
          /* Remove ownaddr's loopback rtentry, if it exists. */
          in6_ifremloop(&(ia->ia_ifa));
  
          /*
           * leave from multicast groups we have joined for the interface
           */
          while ((imm = ia->ia6_memberships.lh_first) != NULL) {
                  LIST_REMOVE(imm, i6mm_chain);
                  in6_leavegroup(imm);
          }
  
          in6_unlink_ifa(ia, ifp);
  }
  
  static void
  in6_unlink_ifa(ia, ifp)
          struct in6_ifaddr *ia;
          struct ifnet *ifp;
  {
          struct in6_ifaddr *oia;
          int     s = splnet();
  
          TAILQ_REMOVE(&ifp->if_addrlist, &ia->ia_ifa, ifa_list);
          /* release a refcnt for the link from if_addrlist */
          IFAFREE(&ia->ia_ifa);
  
          oia = ia;
          if (oia == (ia = in6_ifaddr))
                  in6_ifaddr = ia->ia_next;
          else {
                  while (ia->ia_next && (ia->ia_next != oia))
                          ia = ia->ia_next;
                  if (ia->ia_next)
                          ia->ia_next = oia->ia_next;
                  else {
                          /* search failed */
                          printf("Couldn't unlink in6_ifaddr from in6_ifaddr\n");
                  }
          }
  
          if (oia->ia6_multiaddrs.lh_first != NULL) {
                  /*
                   * XXX thorpej@NetBSD.org -- if the interface is going
                   * XXX away, don't save the multicast entries, delete them!
                   */
                  if (oia->ia_ifa.ifa_ifp->if_output == if_nulloutput) {
                          struct in6_multi *in6m;
  
                          while ((in6m =
                              LIST_FIRST(&oia->ia6_multiaddrs)) != NULL)
                                  in6_delmulti(in6m);
                  } else
                          in6_savemkludge(oia);
          }
  
          /*
           * When an autoconfigured address is being removed, release the
           * reference to the base prefix.  Also, since the release might
           * affect the status of other (detached) addresses, call
           * pfxlist_onlink_check().
           */
          if ((oia->ia6_flags & IN6_IFF_AUTOCONF) != 0) {
                  if (oia->ia6_ndpr == NULL) {
                          log(LOG_NOTICE, "in6_unlink_ifa: autoconf'ed address "
                              "%p has no prefix\n", oia);
                  } else {
                          oia->ia6_ndpr->ndpr_refcnt--;
                          oia->ia6_flags &= ~IN6_IFF_AUTOCONF;
                          oia->ia6_ndpr = NULL;
                  }
  
                  pfxlist_onlink_check();
          }
  
          /*
           * release another refcnt for the link from in6_ifaddr.
           * Note that we should decrement the refcnt at least once for all *BSD.
           */
          IFAFREE(&oia->ia_ifa);
  
          splx(s);
  }
  
  void
  in6_purgeif(ifp)
          struct ifnet *ifp;
  {
          struct ifaddr *ifa, *nifa;
  
          for (ifa = TAILQ_FIRST(&ifp->if_addrlist); ifa != NULL; ifa = nifa)
          {
                  nifa = TAILQ_NEXT(ifa, ifa_list);
                  if (ifa->ifa_addr->sa_family != AF_INET6)
                          continue;
                  in6_purgeaddr(ifa);
          }
  
          in6_ifdetach(ifp);
  }
  
  /*
   * SIOC[GAD]LIFADDR.
   *      SIOCGLIFADDR: get first address. (?)
   *      SIOCGLIFADDR with IFLR_PREFIX:
   *              get first address that matches the specified prefix.
   *      SIOCALIFADDR: add the specified address.
   *      SIOCALIFADDR with IFLR_PREFIX:
   *              add the specified prefix, filling hostid part from
   *              the first link-local address.  prefixlen must be <= 64.
   *      SIOCDLIFADDR: delete the specified address.
   *      SIOCDLIFADDR with IFLR_PREFIX:
   *              delete the first address that matches the specified prefix.
   * return values:
   *      EINVAL on invalid parameters
   *      EADDRNOTAVAIL on prefix match failed/specified address not found
   *      other values may be returned from in6_ioctl()
   *
   * NOTE: SIOCALIFADDR(with IFLR_PREFIX set) allows prefixlen less than 64.
   * this is to accomodate address naming scheme other than RFC2374,
   * in the future.
   * RFC2373 defines interface id to be 64bit, but it allows non-RFC2374
   * address encoding scheme. (see figure on page 8)
   */
  static int
  in6_lifaddr_ioctl(so, cmd, data, ifp, p)
          struct socket *so;
          u_long cmd;
          caddr_t data;
          struct ifnet *ifp;
          struct proc *p;
  {
          struct if_laddrreq *iflr = (struct if_laddrreq *)data;
          struct ifaddr *ifa;
          struct sockaddr *sa;
  
          /* sanity checks */
          if (!data || !ifp) {
                  panic("invalid argument to in6_lifaddr_ioctl");
                  /* NOTREACHED */
          }
  
          switch (cmd) {
          case SIOCGLIFADDR:
                  /* address must be specified on GET with IFLR_PREFIX */
                  if ((iflr->flags & IFLR_PREFIX) == 0)
                          break;
                  /* FALLTHROUGH */
          case SIOCALIFADDR:
          case SIOCDLIFADDR:
                  /* address must be specified on ADD and DELETE */
                  sa = (struct sockaddr *)&iflr->addr;
                  if (sa->sa_family != AF_INET6)
                          return EINVAL;
                  if (sa->sa_len != sizeof(struct sockaddr_in6))
                          return EINVAL;
                  /* XXX need improvement */
                  sa = (struct sockaddr *)&iflr->dstaddr;
                  if (sa->sa_family && sa->sa_family != AF_INET6)
                          return EINVAL;
                  if (sa->sa_len && sa->sa_len != sizeof(struct sockaddr_in6))
                          return EINVAL;
                  break;
          default: /* shouldn't happen */
  #if 0
                  panic("invalid cmd to in6_lifaddr_ioctl");
                  /* NOTREACHED */
  #else
                  return EOPNOTSUPP;
  #endif
          }
          if (sizeof(struct in6_addr) * 8 < iflr->prefixlen)
                  return EINVAL;
  
          switch (cmd) {
          case SIOCALIFADDR:
              {
                  struct in6_aliasreq ifra;
                  struct in6_addr *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, p);
              }
          case SIOCGLIFADDR:
          case SIOCDLIFADDR:
              {
                  struct in6_ifaddr *ia;
                  struct in6_addr mask, candidate, match;
                  struct sockaddr_in6 *sin6;
                  int cmp;
  
                  bzero(&mask, sizeof(mask));
                  if (iflr->flags & IFLR_PREFIX) {
                          /* lookup a prefix rather than address. */
                          in6_prefixlen2mask(&mask, iflr->prefixlen);
  
                          sin6 = (struct sockaddr_in6 *)&iflr->addr;
                          bcopy(&sin6->sin6_addr, &match, sizeof(match));
                          match.s6_addr32[0] &= mask.s6_addr32[0];
                          match.s6_addr32[1] &= mask.s6_addr32[1];
                          match.s6_addr32[2] &= mask.s6_addr32[2];
                          match.s6_addr32[3] &= mask.s6_addr32[3];
  
                          /* if you set extra bits, that's wrong */
                          if (bcmp(&match, &sin6->sin6_addr, sizeof(match)))
                                  return EINVAL;
  
                          cmp = 1;
                  } else {
                          if (cmd == SIOCGLIFADDR) {
                                  /* on getting an address, take the 1st match */
                                  cmp = 0;        /* XXX */
                          } else {
                                  /* on deleting an address, do exact match */
                                  in6_prefixlen2mask(&mask, 128);
                                  sin6 = (struct sockaddr_in6 *)&iflr->addr;
                                  bcopy(&sin6->sin6_addr, &match, sizeof(match));
  
                                  cmp = 1;
                          }
                  }
  
                  for (ifa = ifp->if_addrlist.tqh_first;
                       ifa;
                       ifa = ifa->ifa_list.tqe_next)
                  {
                          if (ifa->ifa_addr->sa_family != AF_INET6)
                                  continue;
                          if (!cmp)
                                  break;
  
                          bcopy(IFA_IN6(ifa), &candidate, sizeof(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) {
                          /* fill in the if_laddrreq structure */
                          bcopy(&ia->ia_addr, &iflr->addr, ia->ia_addr.sin6_len);
                          if ((ifp->if_flags & IFF_POINTOPOINT) != 0) {
                                  bcopy(&ia->ia_dstaddr, &iflr->dstaddr,
                                      ia->ia_dstaddr.sin6_len);
                          } else
                                  bzero(&iflr->dstaddr, sizeof(iflr->dstaddr));
  
                          iflr->prefixlen =
                              in6_mask2len(&ia->ia_prefixmask.sin6_addr, NULL);
  
                          iflr->flags = ia->ia6_flags;    /* XXX */
  
                          return 0;
                  } else {
                          struct in6_aliasreq ifra;
  
                          /* fill in6_aliasreq and do ioctl(SIOCDIFADDR_IN6) */
                          bzero(&ifra, sizeof(ifra));
                          bcopy(iflr->iflr_name, ifra.ifra_name,
                              sizeof(ifra.ifra_name));
  
                          bcopy(&ia->ia_addr, &ifra.ifra_addr,
                              ia->ia_addr.sin6_len);
                          if ((ifp->if_flags & IFF_POINTOPOINT) != 0) {
                                  bcopy(&ia->ia_dstaddr, &ifra.ifra_dstaddr,
                                      ia->ia_dstaddr.sin6_len);
                          } else {
                                  bzero(&ifra.ifra_dstaddr,
                                      sizeof(ifra.ifra_dstaddr));
                          }
                          bcopy(&ia->ia_prefixmask, &ifra.ifra_dstaddr,
                              ia->ia_prefixmask.sin6_len);
  
                          ifra.ifra_flags = ia->ia6_flags;
                          return in6_control(so, SIOCDIFADDR_IN6, (caddr_t)&ifra,
                              ifp, p);
                  }
              }
          }
  
          return EOPNOTSUPP;      /* just for safety */
  }
  
  /*
   * Initialize an interface's intetnet6 address
   * and routing table entry.
   */
  static int
  in6_ifinit(ifp, ia, sin6, newhost)
          struct ifnet *ifp;
          struct in6_ifaddr *ia;
          struct sockaddr_in6 *sin6;
          int newhost;
  {
          int     error = 0, plen, ifacount = 0;
          int     s = splnet();
          struct ifaddr *ifa;
  
          /*
           * Give the interface a chance to initialize
           * if this is its first address,
           * and to validate the address if necessary.
           */
          for (ifa = ifp->if_addrlist.tqh_first; ifa;
               ifa = ifa->ifa_list.tqe_next)
          {
                  if (ifa->ifa_addr == NULL)
                          continue;       /* just for safety */
                  if (ifa->ifa_addr->sa_family != AF_INET6)
                          continue;
                  ifacount++;
          }
  
          ia->ia_addr = *sin6;
  
          if (ifacount <= 1 && ifp->if_ioctl &&
              (error = (*ifp->if_ioctl)(ifp, SIOCSIFADDR, (caddr_t)ia))) {
                  splx(s);
                  return (error);
          }
          splx(s);
  
          ia->ia_ifa.ifa_metric = ifp->if_metric;
  
          /* we could do in(6)_socktrim here, but just omit it at this moment. */
  
          /*
           * Special case:
           * If the destination address is specified for a point-to-point
           * interface, install a route to the destination as an interface
           * direct route.
           */
          plen = in6_mask2len(&ia->ia_prefixmask.sin6_addr, NULL); /* XXX */
          if (plen == 128 && ia->ia_dstaddr.sin6_family == AF_INET6) {
                  if ((error = rtinit(&(ia->ia_ifa), (int)RTM_ADD,
                                      RTF_UP | RTF_HOST)) != 0)
                          return (error);
                  ia->ia_flags |= IFA_ROUTE;
          }
  
          /* Add ownaddr as loopback rtentry, if necessary (ex. on p2p link). */
          if (newhost) {
                  /* set the rtrequest function to create llinfo */
                  ia->ia_ifa.ifa_rtrequest = nd6_rtrequest;
                  in6_ifaddloop(&(ia->ia_ifa));
          }
  
          if (ifp->if_flags & IFF_MULTICAST)
                  in6_restoremkludge(ia, ifp);
  
          return (error);
  }
  
  /*
   * Multicast address kludge:
   * If there were any multicast addresses attached to this interface address,
   * either move them to another address on this interface, or save them until
   * such time as this interface is reconfigured for IPv6.
   */
  void
  in6_savemkludge(oia)
          struct in6_ifaddr *oia;
  {
          struct in6_ifaddr *ia;
          struct in6_multi *in6m, *next;
  
          IFP_TO_IA6(oia->ia_ifp, ia);
          if (ia) {       /* there is another address */
                  for (in6m = oia->ia6_multiaddrs.lh_first; in6m; in6m = next){
                          next = in6m->in6m_entry.le_next;
                          IFAFREE(&in6m->in6m_ia->ia_ifa);
                          IFAREF(&ia->ia_ifa);
                          in6m->in6m_ia = ia;
                          LIST_INSERT_HEAD(&ia->ia6_multiaddrs, in6m, in6m_entry);
                  }
          } else {        /* last address on this if deleted, save */
                  struct multi6_kludge *mk;
  
                  for (mk = in6_mk.lh_first; mk; mk = mk->mk_entry.le_next) {
                          if (mk->mk_ifp == oia->ia_ifp)
                                  break;
                  }
                  if (mk == NULL) /* this should not happen! */
                          panic("in6_savemkludge: no kludge space");
  
                  for (in6m = oia->ia6_multiaddrs.lh_first; in6m; in6m = next){
                          next = in6m->in6m_entry.le_next;
                          IFAFREE(&in6m->in6m_ia->ia_ifa); /* release reference */
                          in6m->in6m_ia = NULL;
                          LIST_INSERT_HEAD(&mk->mk_head, in6m, in6m_entry);
                  }
          }
  }
  
  /*
   * Continuation of multicast address hack:
   * If there was a multicast group list previously saved for this interface,
   * then we re-attach it to the first address configured on the i/f.
   */
  void
  in6_restoremkludge(ia, ifp)
          struct in6_ifaddr *ia;
          struct ifnet *ifp;
  {
          struct multi6_kludge *mk;
  
          for (mk = in6_mk.lh_first; mk; mk = mk->mk_entry.le_next) {
                  if (mk->mk_ifp == ifp) {
                          struct in6_multi *in6m, *next;
  
                          for (in6m = mk->mk_head.lh_first; in6m; in6m = next) {
                                  next = in6m->in6m_entry.le_next;
                                  in6m->in6m_ia = ia;
                                  IFAREF(&ia->ia_ifa);
                                  LIST_INSERT_HEAD(&ia->ia6_multiaddrs,
                                      in6m, in6m_entry);
                          }
                          LIST_INIT(&mk->mk_head);
                          break;
                  }
          }
  }
  
  /*
   * Allocate space for the kludge at interface initialization time.
   * Formerly, we dynamically allocated the space in in6_savemkludge() with
   * malloc(M_WAITOK).  However, it was wrong since the function could be called
   * under an interrupt context (software timer on address lifetime expiration).
   * Also, we cannot just give up allocating the strucutre, since the group
   * membership structure is very complex and we need to keep it anyway.
   * Of course, this function MUST NOT be called under an interrupt context.
   * Specifically, it is expected to be called only from in6_ifattach(), though
   * it is a global function.
   */
  void
  in6_createmkludge(ifp)
          struct ifnet *ifp;
  {
          struct multi6_kludge *mk;
  
          for (mk = in6_mk.lh_first; mk; mk = mk->mk_entry.le_next) {
                  /* If we've already had one, do not allocate. */
                  if (mk->mk_ifp == ifp)
                          return;
          }
  
          mk = malloc(sizeof(*mk), M_IPMADDR, M_WAITOK);
  
          bzero(mk, sizeof(*mk));
          LIST_INIT(&mk->mk_head);
          mk->mk_ifp = ifp;
          LIST_INSERT_HEAD(&in6_mk, mk, mk_entry);
  }
  
  void
  in6_purgemkludge(ifp)
          struct ifnet *ifp;
  {
          struct multi6_kludge *mk;
          struct in6_multi *in6m;
  
          for (mk = in6_mk.lh_first; mk; mk = mk->mk_entry.le_next) {
                  if (mk->mk_ifp != ifp)
                          continue;
  
                  /* leave from all multicast groups joined */
                  while ((in6m = LIST_FIRST(&mk->mk_head)) != NULL)
                          in6_delmulti(in6m);
                  LIST_REMOVE(mk, mk_entry);
                  free(mk, M_IPMADDR);
                  break;
          }
  }
  
  /*
   * Add an address to the list of IP6 multicast addresses for a
   * given interface.
   */
  struct  in6_multi *
  in6_addmulti(maddr6, ifp, errorp)
          struct in6_addr *maddr6;
          struct ifnet *ifp;
          int *errorp;
  {
          struct  in6_ifaddr *ia;
          struct  in6_ifreq ifr;
          struct  in6_multi *in6m;
          int     s = splsoftnet();
  
          *errorp = 0;
          /*
           * See if address already in list.
           */
          IN6_LOOKUP_MULTI(*maddr6, ifp, in6m);
          if (in6m != NULL) {
                  /*
                   * Found it; just increment the refrence count.
                   */
                  in6m->in6m_refcount++;
          } else {
                  /*
                   * New address; allocate a new multicast record
                   * and link it into the interface's multicast list.
                   */
                  in6m = (struct in6_multi *)
                          malloc(sizeof(*in6m), M_IPMADDR, M_NOWAIT);
                  if (in6m == NULL) {
                          splx(s);
                          *errorp = ENOBUFS;
                          return (NULL);
                  }
                  in6m->in6m_addr = *maddr6;
                  in6m->in6m_ifp = ifp;
                  in6m->in6m_refcount = 1;
                  IFP_TO_IA6(ifp, ia);
                  if (ia == NULL) {
                          free(in6m, M_IPMADDR);
                          splx(s);
                          *errorp = EADDRNOTAVAIL; /* appropriate? */
                          return (NULL);
                  }
                  in6m->in6m_ia = ia;
                  IFAREF(&ia->ia_ifa); /* gain a reference */
                  LIST_INSERT_HEAD(&ia->ia6_multiaddrs, in6m, in6m_entry);
  
                  /*
                   * Ask the network driver to update its multicast reception
                   * filter appropriately for the new address.
                   */
                  bzero(&ifr.ifr_addr, sizeof(struct sockaddr_in6));
                  ifr.ifr_addr.sin6_len = sizeof(struct sockaddr_in6);
                  ifr.ifr_addr.sin6_family = AF_INET6;
                  ifr.ifr_addr.sin6_addr = *maddr6;
                  if (ifp->if_ioctl == NULL)
                          *errorp = ENXIO; /* XXX: appropriate? */
                  else
                          *errorp = (*ifp->if_ioctl)(ifp, SIOCADDMULTI,
                              (caddr_t)&ifr);
                  if (*errorp) {
                          LIST_REMOVE(in6m, in6m_entry);
                          free(in6m, M_IPMADDR);
                          IFAFREE(&ia->ia_ifa);
                          splx(s);
                          return (NULL);
                  }
                  /*
                   * Let MLD6 know that we have joined a new IP6 multicast
                   * group.
                   */
                  mld6_start_listening(in6m);
          }
          splx(s);
          return (in6m);
  }
  
  /*
   * Delete a multicast address record.
   */
  void
  in6_delmulti(in6m)
          struct in6_multi *in6m;
  {
          struct  in6_ifreq ifr;
          struct  in6_ifaddr *ia;
          int     s = splsoftnet();
  
          if (--in6m->in6m_refcount == 0) {
                  /*
                   * No remaining claims to this record; let MLD6 know
                   * that we are leaving the multicast group.
                   */
                  mld6_stop_listening(in6m);
  
                  /*
                   * Unlink from list.
                   */
                  LIST_REMOVE(in6m, in6m_entry);
                  if (in6m->in6m_ia) {
                          IFAFREE(&in6m->in6m_ia->ia_ifa); /* release reference */
                  }
                  /*
                   * Delete all references of this multicasting group from
                   * the membership arrays
                   */
                  for (ia = in6_ifaddr; ia; ia = ia->ia_next) {
                          struct in6_multi_mship *imm;
                          LIST_FOREACH(imm, &ia->ia6_memberships,
                              i6mm_chain) {
                                  if (imm->i6mm_maddr == in6m)
                                          imm->i6mm_maddr = NULL;
                          }
                  }
  
                  /*
                   * Notify the network driver to update its multicast
                   * reception filter.
                   */
                  bzero(&ifr.ifr_addr, sizeof(struct sockaddr_in6));
                  ifr.ifr_addr.sin6_len = sizeof(struct sockaddr_in6);
                  ifr.ifr_addr.sin6_family = AF_INET6;
                  ifr.ifr_addr.sin6_addr = in6m->in6m_addr;
                  (*in6m->in6m_ifp->if_ioctl)(in6m->in6m_ifp,
                                              SIOCDELMULTI, (caddr_t)&ifr);
                  free(in6m, M_IPMADDR);
          }
          splx(s);
  }
  
  struct in6_multi_mship *
  in6_joingroup(ifp, addr, errorp)
          struct ifnet *ifp;
          struct in6_addr *addr;
          int *errorp;
  {
          struct in6_multi_mship *imm;
  
          imm = malloc(sizeof(*imm), M_IPMADDR, M_NOWAIT);
          if (!imm) {
                  *errorp = ENOBUFS;
                  return NULL;
          }
          imm->i6mm_maddr = in6_addmulti(addr, ifp, errorp);
          if (!imm->i6mm_maddr) {
                  /* *errorp is alrady set */
                  free(imm, M_IPMADDR);
                  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_IPMADDR);
          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;
  
          for (ifa = ifp->if_addrlist.tqh_first; ifa; ifa = ifa->ifa_list.tqe_next)
          {
                  if (ifa->ifa_addr == NULL)
                          continue;       /* just for safety */
                  if (ifa->ifa_addr->sa_family != AF_INET6)
                          continue;
                  if (IN6_IS_ADDR_LINKLOCAL(IFA_IN6(ifa))) {
                          if ((((struct in6_ifaddr *)ifa)->ia6_flags &
                               ignoreflags) != 0)
                                  continue;
                          break;
                  }
          }
  
          return ((struct in6_ifaddr *)ifa);
  }
  
  
  /*
   * find the internet address corresponding to a given interface and address.
   */
  struct in6_ifaddr *
  in6ifa_ifpwithaddr(ifp, addr)
          struct ifnet *ifp;
          struct in6_addr *addr;
  {
          struct ifaddr *ifa;
  
          for (ifa = ifp->if_addrlist.tqh_first; ifa; ifa = ifa->ifa_list.tqe_next)
          {
                  if (ifa->ifa_addr == NULL)
                          continue;       /* just for safety */
                  if (ifa->ifa_addr->sa_family != AF_INET6)
                          continue;
                  if (IN6_ARE_ADDR_EQUAL(addr, IFA_IN6(ifa)))
                          break;
          }
  
          return ((struct in6_ifaddr *)ifa);
  }
  
  /*
   * find the internet address on a given interface corresponding to a neighbor's
   * address.
   */
  struct in6_ifaddr *
  in6ifa_ifplocaladdr(const struct ifnet *ifp, const struct in6_addr *addr)
  {
          struct ifaddr *ifa;
          struct in6_ifaddr *ia;
  
          IFADDR_FOREACH(ifa, ifp) {
                  if (ifa->ifa_addr == NULL)
                          continue;       /* just for safety */
                  if (ifa->ifa_addr->sa_family != AF_INET6)
                          continue;
                  ia = (struct in6_ifaddr *)ifa;
                  if (IN6_ARE_MASKED_ADDR_EQUAL(addr,
                                  &ia->ia_addr.sin6_addr,
                                  &ia->ia_prefixmask.sin6_addr))
                          return ia;
          }
  
          return NULL;
  }
  
  /*
   * Convert IP6 address to printable (loggable) representation.
   */
  static char digits[] = "0123456789abcdef";
  static int ip6round = 0;
  char *
  ip6_sprintf(addr)
          const struct in6_addr *addr;
  {
          static char ip6buf[8][48];
          int i;
          char *cp;
          const u_int16_t *a = (const u_int16_t *)addr;
          const u_int8_t *d;
          int dcolon = 0;
  
          ip6round = (ip6round + 1) & 7;
          cp = ip6buf[ip6round];
  
          for (i = 0; i < 8; i++) {
                  if (dcolon == 1) {
                          if (*a == 0) {
                                  if (i == 7)
                                          *cp++ = ':';
                                  a++;
                                  continue;
                          } else
                                  dcolon = 2;
                  }
                  if (*a == 0) {
                          if (dcolon == 0 && *(a + 1) == 0) {
                                  if (i == 0)
                                          *cp++ = ':';
                                  *cp++ = ':';
                                  dcolon = 1;
                          } else {
                                  *cp++ = '';
                                  *cp++ = ':';
                          }
                          a++;
                          continue;
                  }
                  d = (const u_char *)a;
                  *cp++ = digits[*d >> 4];
                  *cp++ = digits[*d++ & 0xf];
                  *cp++ = digits[*d >> 4];
                  *cp++ = digits[*d & 0xf];
                  *cp++ = ':';
                  a++;
          }
          *--cp = 0;
          return (ip6buf[ip6round]);
  }
  
  /*
   * Determine if an address is on a local network.
   */
  int
  in6_localaddr(in6)
          struct in6_addr *in6;
  {
          struct in6_ifaddr *ia;
  
          if (IN6_IS_ADDR_LOOPBACK(in6) || IN6_IS_ADDR_LINKLOCAL(in6))
                  return (1);
  
          for (ia = in6_ifaddr; ia; ia = ia->ia_next)
                  if (IN6_ARE_MASKED_ADDR_EQUAL(in6, &ia->ia_addr.sin6_addr,
                                                &ia->ia_prefixmask.sin6_addr))
                          return (1);
  
          return (0);
  }
  
  /*
   * Get a scope of the address. Node-local, link-local, site-local or global.
   */
  int
  in6_addrscope (addr)
  struct in6_addr *addr;
  {
          int scope;
  
          if (addr->s6_addr8[0] == 0xfe) {
                  scope = addr->s6_addr8[1] & 0xc0;
  
                  switch (scope) {
                  case 0x80:
                          return IPV6_ADDR_SCOPE_LINKLOCAL;
                  case 0xc0:
                          return IPV6_ADDR_SCOPE_SITELOCAL;
                  default:
                          return IPV6_ADDR_SCOPE_GLOBAL; /* just in case */
                  }
          }
  
  
          if (addr->s6_addr8[0] == 0xff) {
                  scope = addr->s6_addr8[1] & 0x0f;
  
                  /*
                   * due to other scope such as reserved,
                   * return scope doesn't work.
                   */
                  switch (scope) {
                  case IPV6_ADDR_SCOPE_NODELOCAL:
                          return IPV6_ADDR_SCOPE_NODELOCAL;
                  case IPV6_ADDR_SCOPE_LINKLOCAL:
                          return IPV6_ADDR_SCOPE_LINKLOCAL;
                  case IPV6_ADDR_SCOPE_SITELOCAL:
                          return IPV6_ADDR_SCOPE_SITELOCAL;
                  default:
                          return IPV6_ADDR_SCOPE_GLOBAL;
                  }
          }
  
          if (bcmp(&in6addr_loopback, addr, sizeof(*addr) - 1) == 0) {
                  if (addr->s6_addr8[15] == 1) /* loopback */
                          return IPV6_ADDR_SCOPE_NODELOCAL;
                  if (addr->s6_addr8[15] == 0) /* unspecified */
                          return IPV6_ADDR_SCOPE_LINKLOCAL;
          }
  
          return IPV6_ADDR_SCOPE_GLOBAL;
  }
  
  int
  in6_addr2scopeid(ifp, addr)
          struct ifnet *ifp;      /* must not be NULL */
          struct in6_addr *addr;  /* must not be NULL */
  {
          int scope = in6_addrscope(addr);
  
          switch (scope) {
          case IPV6_ADDR_SCOPE_NODELOCAL:
                  return (-1);    /* XXX: is this an appropriate value? */
  
          case IPV6_ADDR_SCOPE_LINKLOCAL:
                  /* XXX: we do not distinguish between a link and an I/F. */
                  return (ifp->if_index);
  
          case IPV6_ADDR_SCOPE_SITELOCAL:
                  return (0);     /* XXX: invalid. */
  
          default:
                  return (0);     /* XXX: treat as global. */
          }
  }
  
  int
  in6_is_addr_deprecated(sa6)
          struct sockaddr_in6 *sa6;
  {
          struct in6_ifaddr *ia;
  
          for (ia = in6_ifaddr; ia; ia = ia->ia_next) {
                  if (IN6_ARE_ADDR_EQUAL(&ia->ia_addr.sin6_addr,
                      &sa6->sin6_addr) &&
  #ifdef SCOPEDROUTING
                      ia->ia_addr.sin6_scope_id == sa6->sin6_scope_id &&
  #endif
                      (ia->ia6_flags & IN6_IFF_DEPRECATED) != 0)
                          return (1); /* true */
  
                  /* XXX: do we still have to go thru the rest of the list? */
          }
  
          return (0);             /* false */
  }
  
  /*
   * return length of part which dst and src are equal
   * hard coding...
   */
  int
  in6_matchlen(src, dst)
  struct in6_addr *src, *dst;
  {
          int match = 0;
          u_char *s = (u_char *)src, *d = (u_char *)dst;
          u_char *lim = s + 16, r;
  
          while (s < lim)
                  if ((r = (*d++ ^ *s++)) != 0) {
                          while (r < 128) {
                                  match++;
                                  r <<= 1;
                          }
                          break;
                  } else
                          match += 8;
          return match;
  }
  
  /* XXX: to be scope conscious */
  int
  in6_are_prefix_equal(p1, p2, len)
          struct in6_addr *p1, *p2;
          int len;
  {
          int bytelen, bitlen;
  
          /* sanity check */
          if (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;
  {
          static const 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
   */
  struct in6_ifaddr *
  in6_ifawithscope(oifp, dst)
          struct ifnet *oifp;
          struct in6_addr *dst;
  {
          int dst_scope = in6_addrscope(dst), src_scope, best_scope = 0;
          int blen = -1;
          struct ifaddr *ifa;
          struct ifnet *ifp;
          struct in6_ifaddr *ifa_best = NULL;
  
          if (oifp == NULL) {
                  printf("in6_ifawithscope: output interface is not specified\n");
                  return (NULL);
          }
  
          /*
           * We search for all addresses on all interfaces from the beginning.
           * Comparing an interface with the outgoing interface will be done
           * only at the final stage of tiebreaking.
           */
          for (ifp = TAILQ_FIRST(&ifnet); ifp; ifp = TAILQ_NEXT(ifp, if_list))
          {
                  /*
                   * We can never take an address that breaks the scope zone
                   * of the destination.
                   */
                  if (in6_addr2scopeid(ifp, dst) != in6_addr2scopeid(oifp, dst))
                          continue;
  
                  for (ifa = ifp->if_addrlist.tqh_first; ifa;
                       ifa = ifa->ifa_list.tqe_next)
                  {
                          int tlen = -1, dscopecmp, bscopecmp, matchcmp;
  
                          if (ifa->ifa_addr->sa_family != AF_INET6)
                                  continue;
  
                          src_scope = in6_addrscope(IFA_IN6(ifa));
  
  #ifdef ADDRSELECT_DEBUG         /* should be removed after stabilization */
                          dscopecmp = IN6_ARE_SCOPE_CMP(src_scope, dst_scope);
                          printf("in6_ifawithscope: dst=%s bestaddr=%s, "
                                 "newaddr=%s, scope=%x, dcmp=%d, bcmp=%d, "
                                 "matchlen=%d, flgs=%x\n",
                                 ip6_sprintf(dst),
                                 ifa_best ? ip6_sprintf(&ifa_best->ia_addr.sin6_addr) : "none",
                                 ip6_sprintf(IFA_IN6(ifa)), src_scope,
                                 dscopecmp,
                                 ifa_best ? IN6_ARE_SCOPE_CMP(src_scope, best_scope) : -1,
                                 in6_matchlen(IFA_IN6(ifa), dst),
                                 ((struct in6_ifaddr *)ifa)->ia6_flags);
  #endif
  
                          /*
                           * Don't use an address before completing DAD
                           * nor a duplicated address.
                           */
                          if (((struct in6_ifaddr *)ifa)->ia6_flags &
                              IN6_IFF_NOTREADY)
                                  continue;
  
                          /* XXX: is there any case to allow anycasts? */
                          if (((struct in6_ifaddr *)ifa)->ia6_flags &
                              IN6_IFF_ANYCAST)
                                  continue;
  
                          if (((struct in6_ifaddr *)ifa)->ia6_flags &
                              IN6_IFF_DETACHED)
                                  continue;
  
                          /*
                           * If this is the first address we find,
                           * keep it anyway.
                           */
                          if (ifa_best == NULL)
                                  goto replace;
  
                          /*
                           * ifa_best is never NULL beyond this line except
                           * within the block labeled "replace".
                           */
  
                          /*
                           * If ifa_best has a smaller scope than dst and
                           * the current address has a larger one than
                           * (or equal to) dst, always replace ifa_best.
                           * Also, if the current address has a smaller scope
                           * than dst, ignore it unless ifa_best also has a
                           * smaller scope.
                           */
                          if (IN6_ARE_SCOPE_CMP(best_scope, dst_scope) < 0 &&
                              IN6_ARE_SCOPE_CMP(src_scope, dst_scope) >= 0)
                                  goto replace;
                          if (IN6_ARE_SCOPE_CMP(src_scope, dst_scope) < 0 &&
                              IN6_ARE_SCOPE_CMP(best_scope, dst_scope) >= 0)
                                  continue;
  
                          /*
                           * A deprecated address SHOULD NOT be used in new
                           * communications if an alternate (non-deprecated)
                           * address is available and has sufficient scope.
                           * RFC 2462, Section 5.5.4.
                           */
                          if (((struct in6_ifaddr *)ifa)->ia6_flags &
                              IN6_IFF_DEPRECATED) {
                                  /*
                                   * Ignore any deprecated addresses if
                                   * specified by configuration.
                                   */
                                  if (!ip6_use_deprecated)
                                          continue;
  
                                  /*
                                   * If we have already found a non-deprecated
                                   * candidate, just ignore deprecated addresses.
                                   */
                                  if ((ifa_best->ia6_flags & IN6_IFF_DEPRECATED)
                                      == 0)
                                          continue;
                          }
  
                          /*
                           * A non-deprecated address is always preferred
                           * to a deprecated one regardless of scopes and
                           * address matching.
                           */
                          if ((ifa_best->ia6_flags & IN6_IFF_DEPRECATED) &&
                              (((struct in6_ifaddr *)ifa)->ia6_flags &
                               IN6_IFF_DEPRECATED) == 0)
                                  goto replace;
  
                          /*
                           * At this point, we have two cases:
                           * 1. we are looking at a non-deprecated address,
                           *    and ifa_best is also non-deprecated.
                           * 2. we are looking at a deprecated address,
                           *    and ifa_best is also deprecated.
                           * Also, we do not have to consider a case where
                           * the scope of if_best is larger(smaller) than dst and
                           * the scope of the current address is smaller(larger)
                           * than dst. Such a case has already been covered.
                           * Tiebreaking is done according to the following
                           * items:
                           * - the scope comparison between the address and
                           *   dst (dscopecmp)
                           * - the scope comparison between the address and
                           *   ifa_best (bscopecmp)
                           * - if the address match dst longer than ifa_best
                           *   (matchcmp)
                           * - if the address is on the outgoing I/F (outI/F)
                           *
                           * Roughly speaking, the selection policy is
                           * - the most important item is scope. The same scope
                           *   is best. Then search for a larger scope.
                           *   Smaller scopes are the last resort.
                           * - A deprecated address is chosen only when we have
                           *   no address that has an enough scope, but is
                           *   prefered to any addresses of smaller scopes.
                           * - Longest address match against dst is considered
                           *   only for addresses that has the same scope of dst.
                           * - If there is no other reasons to choose one,
                           *   addresses on the outgoing I/F are preferred.
                           *
                           * The precise decision table is as follows:
                           * dscopecmp bscopecmp matchcmp outI/F | replace?
                           *    !equal     equal      N/A    Yes |      Yes (1)
                           *    !equal     equal      N/A     No |       No (2)
                           *    larger    larger      N/A    N/A |       No (3)
                           *    larger   smaller      N/A    N/A |      Yes (4)
                           *   smaller    larger      N/A    N/A |      Yes (5)
                           *   smaller   smaller      N/A    N/A |       No (6)
                           *     equal   smaller      N/A    N/A |      Yes (7)
                           *     equal    larger       (already done)
                           *     equal     equal   larger    N/A |      Yes (8)
                           *     equal     equal  smaller    N/A |       No (9)
                           *     equal     equal    equal    Yes |      Yes (a)
                           *     eaual     eqaul    equal     No |       No (b)
                           */
                          dscopecmp = IN6_ARE_SCOPE_CMP(src_scope, dst_scope);
                          bscopecmp = IN6_ARE_SCOPE_CMP(src_scope, best_scope);
  
                          if (dscopecmp && bscopecmp == 0) {
                                  if (oifp == ifp) /* (1) */
                                          goto replace;
                                  continue; /* (2) */
                          }
                          if (dscopecmp > 0) {
                                  if (bscopecmp > 0) /* (3) */
                                          continue;
                                  goto replace; /* (4) */
                          }
                          if (dscopecmp < 0) {
                                  if (bscopecmp > 0) /* (5) */
                                          goto replace;
                                  continue; /* (6) */
                          }
  
                          /* now dscopecmp must be 0 */
                          if (bscopecmp < 0)
                                  goto replace; /* (7) */
  
                          /*
                           * At last both dscopecmp and bscopecmp must be 0.
                           * We need address matching against dst for
                           * tiebreaking.
                           */
                          tlen = in6_matchlen(IFA_IN6(ifa), dst);
                          matchcmp = tlen - blen;
                          if (matchcmp > 0) /* (8) */
                                  goto replace;
                          if (matchcmp < 0) /* (9) */
                                  continue;
                          if (oifp == ifp) /* (a) */
                                  goto replace;
                          continue; /* (b) */
  
                    replace:
                          ifa_best = (struct in6_ifaddr *)ifa;
                          blen = tlen >= 0 ? tlen :
                                  in6_matchlen(IFA_IN6(ifa), dst);
                          best_scope = in6_addrscope(&ifa_best->ia_addr.sin6_addr);
                  }
          }
  
          /* count statistics for future improvements */
          if (ifa_best == NULL)
                  ip6stat.ip6s_sources_none++;
          else {
                  if (oifp == ifa_best->ia_ifp)
                          ip6stat.ip6s_sources_sameif[best_scope]++;
                  else
                          ip6stat.ip6s_sources_otherif[best_scope]++;
  
                  if (best_scope == dst_scope)
                          ip6stat.ip6s_sources_samescope[best_scope]++;
                  else
                          ip6stat.ip6s_sources_otherscope[best_scope]++;
  
                  if ((ifa_best->ia6_flags & IN6_IFF_DEPRECATED) != 0)
                          ip6stat.ip6s_sources_deprecated[best_scope]++;
          }
  
          return (ifa_best);
  }
  
  /*
   * return the best address out of the same scope. if no address was
   * found, return the first valid address from designated IF.
   */
  struct in6_ifaddr *
  in6_ifawithifp(ifp, dst)
          struct ifnet *ifp;
          struct in6_addr *dst;
  {
          int dst_scope = in6_addrscope(dst), blen = -1, tlen;
          struct ifaddr *ifa;
          struct in6_ifaddr *besta = 0;
          struct in6_ifaddr *dep[2];      /* last-resort: deprecated */
  
          dep[0] = dep[1] = NULL;
  
          /*
           * We first look for addresses in the same scope.
           * If there is one, return it.
           * If two or more, return one which matches the dst longest.
           * If none, return one of global addresses assigned other ifs.
           */
          for (ifa = ifp->if_addrlist.tqh_first; ifa; ifa = ifa->ifa_list.tqe_next)
          {
                  if (ifa->ifa_addr->sa_family != AF_INET6)
                          continue;
                  if (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_ANYCAST)
                          continue; /* XXX: is there any case to allow anycast? */
                  if (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_NOTREADY)
                          continue; /* don't use this interface */
                  if (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_DETACHED)
                          continue;
                  if (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_DEPRECATED) {
                          if (ip6_use_deprecated)
                                  dep[0] = (struct in6_ifaddr *)ifa;
                          continue;
                  }
  
                  if (dst_scope == in6_addrscope(IFA_IN6(ifa))) {
                          /*
                           * call in6_matchlen() as few as possible
                           */
                          if (besta) {
                                  if (blen == -1)
                                          blen = in6_matchlen(&besta->ia_addr.sin6_addr, dst);
                                  tlen = in6_matchlen(IFA_IN6(ifa), dst);
                                  if (tlen > blen) {
                                          blen = tlen;
                                          besta = (struct in6_ifaddr *)ifa;
                                  }
                          } else
                                  besta = (struct in6_ifaddr *)ifa;
                  }
          }
          if (besta)
                  return (besta);
  
          for (ifa = ifp->if_addrlist.tqh_first; ifa; ifa = ifa->ifa_list.tqe_next)
          {
                  if (ifa->ifa_addr->sa_family != AF_INET6)
                          continue;
                  if (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_ANYCAST)
                          continue; /* XXX: is there any case to allow anycast? */
                  if (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_NOTREADY)
                          continue; /* don't use this interface */
                  if (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_DETACHED)
                          continue;
                  if (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_DEPRECATED) {
                          if (ip6_use_deprecated)
                                  dep[1] = (struct in6_ifaddr *)ifa;
                          continue;
                  }
  
                  return (struct in6_ifaddr *)ifa;
          }
  
          /* use the last-resort values, that are, deprecated addresses */
          if (dep[0])
                  return dep[0];
          if (dep[1])
                  return dep[1];
  
          return NULL;
  }
  
  /*
   * perform DAD when interface becomes IFF_UP.
   */
  void
  in6_if_up(ifp)
          struct ifnet *ifp;
  {
          struct ifaddr *ifa;
          struct in6_ifaddr *ia;
          int dad_delay;          /* delay ticks before DAD output */
  
          /*
           * special cases, like 6to4, are handled in in6_ifattach
           */
          in6_ifattach(ifp, NULL);
  
          dad_delay = 0;
          for (ifa = ifp->if_addrlist.tqh_first; ifa; ifa = ifa->ifa_list.tqe_next)
          {
                  if (ifa->ifa_addr->sa_family != AF_INET6)
                          continue;
                  ia = (struct in6_ifaddr *)ifa;
                  if (ia->ia6_flags & IN6_IFF_TENTATIVE)
                          nd6_dad_start(ifa, &dad_delay);
          }
  }
  
  int
  in6if_do_dad(ifp)
          struct ifnet *ifp;
  {
          if ((ifp->if_flags & IFF_LOOPBACK) != 0)
                  return (0);
  
          switch (ifp->if_type) {
          case IFT_FAITH:
                  /*
                   * These interfaces do not have the IFF_LOOPBACK flag,
                   * but loop packets back.  We do not have to do DAD on such
                   * interfaces.  We should even omit it, because loop-backed
                   * NS would confuse the DAD procedure.
                   */
                  return (0);
          default:
                  /*
                   * Our DAD routine requires the interface up and running.
                   * However, some interfaces can be up before the RUNNING
                   * status.  Additionaly, users may try to assign addresses
                   * before the interface becomes up (or running).
                   * We simply skip DAD in such a case as a work around.
                   * XXX: we should rather mark "tentative" on such addresses,
                   * and do DAD after the interface becomes ready.
                   */
                  if ((ifp->if_flags & (IFF_UP|IFF_RUNNING)) !=
                      (IFF_UP|IFF_RUNNING))
                          return (0);
  
                  return (1);
          }
  }
  
  /*
   * Calculate max IPv6 MTU through all the interfaces and store it
   * to in6_maxmtu.
   */
  void
  in6_setmaxmtu()
  {
          unsigned long maxmtu = 0;
          struct ifnet *ifp;
  
          for (ifp = TAILQ_FIRST(&ifnet); ifp; ifp = TAILQ_NEXT(ifp, if_list))
          {
                  /* this function can be called during ifnet initialization */
                  if (!ifp->if_afdata[AF_INET6])
                          continue;
                  if ((ifp->if_flags & IFF_LOOPBACK) == 0 &&
                      IN6_LINKMTU(ifp) > maxmtu)
                          maxmtu = IN6_LINKMTU(ifp);
          }
          if (maxmtu)          /* update only when maxmtu is positive */
                  in6_maxmtu = maxmtu;
  }
  
  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);
          return ext;
  }
  
  void
  in6_domifdetach(ifp, aux)
          struct ifnet *ifp;
          void *aux;
  {
          struct in6_ifextra *ext = (struct in6_ifextra *)aux;
  
          nd6_ifdetach(ext->nd_ifinfo);
          free(ext->in6_ifstat, M_IFADDR);
          free(ext->icmp6_ifstat, M_IFADDR);
          free(ext, M_IFADDR);
  }

Cache object: 527fde2e7526083af16761068ba8cfa7