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[netbsd-mini2440.git] / sys / netinet6 / in6_ifattach.c

/*      $NetBSD: in6_ifattach.c,v 1.82 2009/07/30 17:28:36 dyoung Exp $ */
/*      $KAME: in6_ifattach.c,v 1.124 2001/07/18 08:32:51 jinmei Exp $  */

/*
 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the project nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: in6_ifattach.c,v 1.84 2009/08/13 09:04:03 cegger Exp $");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kmem.h>
#include <sys/malloc.h>
#include <sys/socket.h>
#include <sys/sockio.h>
#include <sys/kernel.h>
#include <sys/syslog.h>
#include <sys/md5.h>
#include <sys/socketvar.h>

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

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

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

#include <net/net_osdep.h>

unsigned long in6_maxmtu = 0;

int ip6_auto_linklocal = 1;     /* enable by default */

callout_t in6_tmpaddrtimer_ch;


#if 0
static int get_hostid_ifid(struct ifnet *, struct in6_addr *);
#endif
static int get_rand_ifid(struct ifnet *, struct in6_addr *);
static int generate_tmp_ifid(u_int8_t *, const u_int8_t *, u_int8_t *);
static int get_ifid(struct ifnet *, struct ifnet *, struct in6_addr *);
static int in6_ifattach_linklocal(struct ifnet *, struct ifnet *);
static int in6_ifattach_loopback(struct ifnet *);

#define EUI64_GBIT      0x01
#define EUI64_UBIT      0x02
#define EUI64_TO_IFID(in6)      do {(in6)->s6_addr[8] ^= EUI64_UBIT; } while (/*CONSTCOND*/ 0)
#define EUI64_GROUP(in6)        ((in6)->s6_addr[8] & EUI64_GBIT)
#define EUI64_INDIVIDUAL(in6)   (!EUI64_GROUP(in6))
#define EUI64_LOCAL(in6)        ((in6)->s6_addr[8] & EUI64_UBIT)
#define EUI64_UNIVERSAL(in6)    (!EUI64_LOCAL(in6))

#define IFID_LOCAL(in6)         (!EUI64_LOCAL(in6))
#define IFID_UNIVERSAL(in6)     (!EUI64_UNIVERSAL(in6))

#define GEN_TEMPID_RETRY_MAX 5

#if 0
/*
 * Generate a last-resort interface identifier from hostid.
 * works only for certain architectures (like sparc).
 * also, using hostid itself may constitute a privacy threat, much worse
 * than MAC addresses (hostids are used for software licensing).
 * maybe we should use MD5(hostid) instead.
 *
 * in6 - upper 64bits are preserved
 */
static int
get_hostid_ifid(struct ifnet *ifp, struct in6_addr *in6)
{
        int off, len;
        static const uint8_t allzero[8] = { 0, 0, 0, 0, 0, 0, 0, 0 };
        static const uint8_t allone[8] =
            { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };

        if (!hostid)
                return -1;

        /* get up to 8 bytes from the hostid field - should we get */
        len = (sizeof(hostid) > 8) ? 8 : sizeof(hostid);
        off = sizeof(*in6) - len;
        memcpy(&in6->s6_addr[off], &hostid, len);

        /* make sure we do not return anything bogus */
        if (memcmp(&in6->s6_addr[8], allzero, sizeof(allzero)))
                return -1;
        if (memcmp(&in6->s6_addr[8], allone, sizeof(allone)))
                return -1;

        /* make sure to set "u" bit to local, and "g" bit to individual. */
        in6->s6_addr[8] &= ~EUI64_GBIT; /* g bit to "individual" */
        in6->s6_addr[8] |= EUI64_UBIT;  /* u bit to "local" */

        /* convert EUI64 into IPv6 interface identifier */
        EUI64_TO_IFID(in6);

        return 0;
}
#endif

/*
 * Generate a last-resort interface identifier, when the machine has no
 * IEEE802/EUI64 address sources.
 * The goal here is to get an interface identifier that is
 * (1) random enough and (2) does not change across reboot.
 * We currently use MD5(hostname) for it.
 */
static int
get_rand_ifid(struct ifnet *ifp,
        struct in6_addr *in6)   /* upper 64bits are preserved */
{
        MD5_CTX ctxt;
        u_int8_t digest[16];

#if 0
        /* we need at least several letters as seed for ifid */
        if (hostnamelen < 3)
                return -1;
#endif

        /* generate 8 bytes of pseudo-random value. */
        memset(&ctxt, 0, sizeof(ctxt));
        MD5Init(&ctxt);
        MD5Update(&ctxt, (u_char *)hostname, hostnamelen);
        MD5Final(digest, &ctxt);

        /* assumes sizeof(digest) > sizeof(ifid) */
        memcpy(&in6->s6_addr[8], digest, 8);

        /* make sure to set "u" bit to local, and "g" bit to individual. */
        in6->s6_addr[8] &= ~EUI64_GBIT; /* g bit to "individual" */
        in6->s6_addr[8] |= EUI64_UBIT;  /* u bit to "local" */

        /* convert EUI64 into IPv6 interface identifier */
        EUI64_TO_IFID(in6);

        return 0;
}

static int
generate_tmp_ifid(u_int8_t *seed0, const u_int8_t *seed1, u_int8_t *ret)
{
        MD5_CTX ctxt;
        u_int8_t seed[16], digest[16], nullbuf[8];
        u_int32_t val32;
        /*
         * interface ID for subnet anycast addresses.
         * XXX: we assume the unicast address range that requires IDs
         * in EUI-64 format.
         */
        static const uint8_t anycast_id[8] = { 0xfd, 0xff, 0xff, 0xff,
            0xff, 0xff, 0xff, 0x80 };
        static const uint8_t isatap_id[4] = { 0x00, 0x00, 0x5e, 0xfe };
        int badid, retry = 0;

        /* If there's no hisotry, start with a random seed. */
        memset(nullbuf, 0, sizeof(nullbuf));
        if (memcmp(nullbuf, seed0, sizeof(nullbuf)) == 0) {
                int i;

                for (i = 0; i < 2; i++) {
                        val32 = arc4random();
                        memcpy(seed + sizeof(val32) * i, &val32, sizeof(val32));
                }
        } else
                memcpy(seed, seed0, 8);

        /* copy the right-most 64-bits of the given address */
        /* XXX assumption on the size of IFID */
        memcpy(&seed[8], seed1, 8);

  again:
        /* for debugging purposes only */
#if 0
        {
                int i;

                printf("generate_tmp_ifid: new randomized ID from: ");
                for (i = 0; i < 16; i++)
                        printf("%02x", seed[i]);
                printf(" ");
        }
#endif

        /* generate 16 bytes of pseudo-random value. */
        memset(&ctxt, 0, sizeof(ctxt));
        MD5Init(&ctxt);
        MD5Update(&ctxt, seed, sizeof(seed));
        MD5Final(digest, &ctxt);

        /*
         * draft-ietf-ipngwg-temp-addresses-v2-00.txt 3.2.1. (3)
         * Take the left-most 64-bits of the MD5 digest and set bit 6 (the
         * left-most bit is numbered 0) to zero.
         */
        memcpy(ret, digest, 8);
        ret[0] &= ~EUI64_UBIT;

        /*
         * Reject inappropriate identifiers according to
         * draft-ietf-ipngwg-temp-addresses-v2-00.txt 3.2.1. (4)
         * At this moment, we reject following cases:
         * - all 0 identifier
         * - identifiers that conflict with reserved subnet anycast addresses,
         *   which are defined in RFC 2526.
         * - identifiers that conflict with ISATAP addresses
         * - identifiers used in our own addresses
         */
        badid = 0;
        if (memcmp(nullbuf, ret, sizeof(nullbuf)) == 0)
                badid = 1;
        else if (memcmp(anycast_id, ret, 7) == 0 &&
            (anycast_id[7] & ret[7]) == anycast_id[7]) {
                badid = 1;
        } else if (memcmp(isatap_id, ret, sizeof(isatap_id)) == 0)
                badid = 1;
        else {
                struct in6_ifaddr *ia;

                for (ia = in6_ifaddr; ia; ia = ia->ia_next) {
                        if (!memcmp(&ia->ia_addr.sin6_addr.s6_addr[8], 
                            ret, 8)) {
                                badid = 1;
                                break;
                        }
                }
        }

        /*
         * In the event that an unacceptable identifier has been generated,
         * restart the process, using the right-most 64 bits of the MD5 digest
         * obtained in place of the history value.
         */
        if (badid) {
                /* for debugging purposes only */
#if 0
                {
                        int i;

                        printf("unacceptable random ID: ");
                        for (i = 0; i < 16; i++)
                                printf("%02x", digest[i]);
                        printf("\n");
                }
#endif

                if (++retry < GEN_TEMPID_RETRY_MAX) {
                        memcpy(seed, &digest[8], 8);
                        goto again;
                } else {
                        /*
                         * We're so unlucky.  Give up for now, and return
                         * all 0 IDs to tell the caller not to make a
                         * temporary address.
                         */
                        nd6log((LOG_NOTICE,
                            "generate_tmp_ifid: never found a good ID\n"));
                        memset(ret, 0, 8);
                }
        }

        /*
         * draft-ietf-ipngwg-temp-addresses-v2-00.txt 3.2.1. (6)
         * Take the rightmost 64-bits of the MD5 digest and save them in
         * stable storage as the history value to be used in the next
         * iteration of the algorithm.
         */
        memcpy(seed0, &digest[8], 8);

        /* for debugging purposes only */
#if 0
        {
                int i;

                printf("to: ");
                for (i = 0; i < 16; i++)
                        printf("%02x", digest[i]);
                printf("\n");
        }
#endif

        return 0;
}

/*
 * Get interface identifier for the specified interface.
 *
 * in6 - upper 64bits are preserved
 */
int
in6_get_hw_ifid(struct ifnet *ifp, struct in6_addr *in6)
{
        struct ifaddr *ifa;
        const struct sockaddr_dl *sdl = NULL, *tsdl;
        const char *addr;
        size_t addrlen;
        static u_int8_t allzero[8] = { 0, 0, 0, 0, 0, 0, 0, 0 };
        static u_int8_t allone[8] =
                { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };

        IFADDR_FOREACH(ifa, ifp) {
                if (ifa->ifa_addr->sa_family != AF_LINK)
                        continue;
                tsdl = satocsdl(ifa->ifa_addr);
                if (tsdl == NULL || tsdl->sdl_alen == 0)
                        continue;
                if (sdl == NULL || ifa == ifp->if_dl || ifa == ifp->if_hwdl)
                        sdl = tsdl;
                if (ifa == ifp->if_hwdl)
                        break;
        }

        if (sdl == NULL)
                return -1;

        addr = CLLADDR(sdl);
        addrlen = sdl->sdl_alen;

        switch (ifp->if_type) {
        case IFT_IEEE1394:
        case IFT_IEEE80211:
                /* IEEE1394 uses 16byte length address starting with EUI64 */
                if (addrlen > 8)
                        addrlen = 8;
                break;
        default:
                break;
        }

        /* get EUI64 */
        switch (ifp->if_type) {
        /* IEEE802/EUI64 cases - what others? */
        case IFT_ETHER:
        case IFT_FDDI:
        case IFT_ATM:
        case IFT_IEEE1394:
        case IFT_IEEE80211:
                /* look at IEEE802/EUI64 only */
                if (addrlen != 8 && addrlen != 6)
                        return -1;

                /*
                 * check for invalid MAC address - on bsdi, we see it a lot
                 * since wildboar configures all-zero MAC on pccard before
                 * card insertion.
                 */
                if (memcmp(addr, allzero, addrlen) == 0)
                        return -1;
                if (memcmp(addr, allone, addrlen) == 0)
                        return -1;

                /* make EUI64 address */
                if (addrlen == 8)
                        memcpy(&in6->s6_addr[8], addr, 8);
                else if (addrlen == 6) {
                        in6->s6_addr[8] = addr[0];
                        in6->s6_addr[9] = addr[1];
                        in6->s6_addr[10] = addr[2];
                        in6->s6_addr[11] = 0xff;
                        in6->s6_addr[12] = 0xfe;
                        in6->s6_addr[13] = addr[3];
                        in6->s6_addr[14] = addr[4];
                        in6->s6_addr[15] = addr[5];
                }
                break;

        case IFT_ARCNET:
                if (addrlen != 1)
                        return -1;
                if (!addr[0])
                        return -1;

                memset(&in6->s6_addr[8], 0, 8);
                in6->s6_addr[15] = addr[0];

                /*
                 * due to insufficient bitwidth, we mark it local.
                 */
                in6->s6_addr[8] &= ~EUI64_GBIT; /* g bit to "individual" */
                in6->s6_addr[8] |= EUI64_UBIT;  /* u bit to "local" */
                break;

        case IFT_GIF:
#ifdef IFT_STF
        case IFT_STF:
#endif
                /*
                 * RFC2893 says: "SHOULD use IPv4 address as ifid source".
                 * however, IPv4 address is not very suitable as unique
                 * identifier source (can be renumbered).
                 * we don't do this.
                 */
                return -1;

        default:
                return -1;
        }

        /* sanity check: g bit must not indicate "group" */
        if (EUI64_GROUP(in6))
                return -1;

        /* convert EUI64 into IPv6 interface identifier */
        EUI64_TO_IFID(in6);

        /*
         * sanity check: ifid must not be all zero, avoid conflict with
         * subnet router anycast
         */
        if ((in6->s6_addr[8] & ~(EUI64_GBIT | EUI64_UBIT)) == 0x00 &&
            memcmp(&in6->s6_addr[9], allzero, 7) == 0) {
                return -1;
        }

        return 0;
}

/*
 * Get interface identifier for the specified interface.  If it is not
 * available on ifp0, borrow interface identifier from other information
 * sources.
 *
 * altifp - secondary EUI64 source
 */
static int
get_ifid(struct ifnet *ifp0, struct ifnet *altifp, 
        struct in6_addr *in6)
{
        struct ifnet *ifp;

        /* first, try to get it from the interface itself */
        if (in6_get_hw_ifid(ifp0, in6) == 0) {
                nd6log((LOG_DEBUG, "%s: got interface identifier from itself\n",
                    if_name(ifp0)));
                goto success;
        }

        /* try secondary EUI64 source. this basically is for ATM PVC */
        if (altifp && in6_get_hw_ifid(altifp, in6) == 0) {
                nd6log((LOG_DEBUG, "%s: got interface identifier from %s\n",
                    if_name(ifp0), if_name(altifp)));
                goto success;
        }

        /* next, try to get it from some other hardware interface */
        TAILQ_FOREACH(ifp, &ifnet, if_list) {
                if (ifp == ifp0)
                        continue;
                if (in6_get_hw_ifid(ifp, in6) != 0)
                        continue;

                /*
                 * to borrow ifid from other interface, ifid needs to be
                 * globally unique
                 */
                if (IFID_UNIVERSAL(in6)) {
                        nd6log((LOG_DEBUG,
                            "%s: borrow interface identifier from %s\n",
                            if_name(ifp0), if_name(ifp)));
                        goto success;
                }
        }

#if 0
        /* get from hostid - only for certain architectures */
        if (get_hostid_ifid(ifp, in6) == 0) {
                nd6log((LOG_DEBUG,
                    "%s: interface identifier generated by hostid\n",
                    if_name(ifp0)));
                goto success;
        }
#endif

        /* last resort: get from random number source */
        if (get_rand_ifid(ifp, in6) == 0) {
                nd6log((LOG_DEBUG,
                    "%s: interface identifier generated by random number\n",
                    if_name(ifp0)));
                goto success;
        }

        printf("%s: failed to get interface identifier\n", if_name(ifp0));
        return -1;

success:
        nd6log((LOG_INFO, "%s: ifid: %02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x\n",
            if_name(ifp0), in6->s6_addr[8], in6->s6_addr[9], in6->s6_addr[10],
            in6->s6_addr[11], in6->s6_addr[12], in6->s6_addr[13],
            in6->s6_addr[14], in6->s6_addr[15]));
        return 0;
}

/*
 * altifp - secondary EUI64 source
 */

static int
in6_ifattach_linklocal(struct ifnet *ifp, struct ifnet *altifp)
{
        struct in6_ifaddr *ia;
        struct in6_aliasreq ifra;
        struct nd_prefixctl pr0;
        int i, error;

        /*
         * configure link-local address.
         */
        memset(&ifra, 0, sizeof(ifra));

        /*
         * in6_update_ifa() does not use ifra_name, but we accurately set it
         * for safety.
         */
        strncpy(ifra.ifra_name, if_name(ifp), sizeof(ifra.ifra_name));

        ifra.ifra_addr.sin6_family = AF_INET6;
        ifra.ifra_addr.sin6_len = sizeof(struct sockaddr_in6);
        ifra.ifra_addr.sin6_addr.s6_addr32[0] = htonl(0xfe800000);
        ifra.ifra_addr.sin6_addr.s6_addr32[1] = 0;
        if ((ifp->if_flags & IFF_LOOPBACK) != 0) {
                ifra.ifra_addr.sin6_addr.s6_addr32[2] = 0;
                ifra.ifra_addr.sin6_addr.s6_addr32[3] = htonl(1);
        } else {
                if (get_ifid(ifp, altifp, &ifra.ifra_addr.sin6_addr) != 0) {
                        nd6log((LOG_ERR,
                            "%s: no ifid available\n", if_name(ifp)));
                        return -1;
                }
        }
        if (in6_setscope(&ifra.ifra_addr.sin6_addr, ifp, NULL))
                return -1;

        sockaddr_in6_init(&ifra.ifra_prefixmask, &in6mask64, 0, 0, 0);
        /* link-local addresses should NEVER expire. */
        ifra.ifra_lifetime.ia6t_vltime = ND6_INFINITE_LIFETIME;
        ifra.ifra_lifetime.ia6t_pltime = ND6_INFINITE_LIFETIME;

        /*
         * Now call in6_update_ifa() to do a bunch of procedures to configure
         * a link-local address. We can set the 3rd argument to NULL, because
         * we know there's no other link-local address on the interface
         * and therefore we are adding one (instead of updating one).
         */
        if ((error = in6_update_ifa(ifp, &ifra, NULL,
            IN6_IFAUPDATE_DADDELAY)) != 0) {
                /*
                 * XXX: When the interface does not support IPv6, this call
                 * would fail in the SIOCINITIFADDR ioctl.  I believe the
                 * notification is rather confusing in this case, so just
                 * suppress it.  (jinmei@kame.net 20010130)
                 */
                if (error != EAFNOSUPPORT)
                        nd6log((LOG_NOTICE, "in6_ifattach_linklocal: failed to "
                            "configure a link-local address on %s "
                            "(errno=%d)\n",
                            if_name(ifp), error));
                return -1;
        }

        ia = in6ifa_ifpforlinklocal(ifp, 0); /* ia must not be NULL */
#ifdef DIAGNOSTIC
        if (!ia) {
                panic("ia == NULL in in6_ifattach_linklocal");
                /* NOTREACHED */
        }
#endif

        /*
         * Make the link-local prefix (fe80::/64%link) as on-link.
         * Since we'd like to manage prefixes separately from addresses,
         * we make an ND6 prefix structure for the link-local prefix,
         * and add it to the prefix list as a never-expire prefix.
         * XXX: this change might affect some existing code base...
         */
        memset(&pr0, 0, sizeof(pr0));
        pr0.ndpr_ifp = ifp;
        /* this should be 64 at this moment. */
        pr0.ndpr_plen = in6_mask2len(&ifra.ifra_prefixmask.sin6_addr, NULL);
        pr0.ndpr_prefix = ifra.ifra_addr;
        /* apply the mask for safety. (nd6_prelist_add will apply it again) */
        for (i = 0; i < 4; i++) {
                pr0.ndpr_prefix.sin6_addr.s6_addr32[i] &=
                    in6mask64.s6_addr32[i];
        }
        /*
         * Initialize parameters.  The link-local prefix must always be
         * on-link, and its lifetimes never expire.
         */
        pr0.ndpr_raf_onlink = 1;
        pr0.ndpr_raf_auto = 1;  /* probably meaningless */
        pr0.ndpr_vltime = ND6_INFINITE_LIFETIME;
        pr0.ndpr_pltime = ND6_INFINITE_LIFETIME;
        /*
         * Since there is no other link-local addresses, nd6_prefix_lookup()
         * probably returns NULL.  However, we cannot always expect the result.
         * For example, if we first remove the (only) existing link-local
         * address, and then reconfigure another one, the prefix is still
         * valid with referring to the old link-local address.
         */
        if (nd6_prefix_lookup(&pr0) == NULL) {
                if ((error = nd6_prelist_add(&pr0, NULL, NULL)) != 0)
                        return error;
        }

        return 0;
}

/*
 * ifp - mut be IFT_LOOP
 */

static int
in6_ifattach_loopback(struct ifnet *ifp)
{
        struct in6_aliasreq ifra;
        int error;

        memset(&ifra, 0, sizeof(ifra));

        /*
         * in6_update_ifa() does not use ifra_name, but we accurately set it
         * for safety.
         */
        strncpy(ifra.ifra_name, if_name(ifp), sizeof(ifra.ifra_name));

        sockaddr_in6_init(&ifra.ifra_prefixmask, &in6mask128, 0, 0, 0);

        /*
         * Always initialize ia_dstaddr (= broadcast address) to loopback
         * address.  Follows IPv4 practice - see in_ifinit().
         */
        sockaddr_in6_init(&ifra.ifra_dstaddr, &in6addr_loopback, 0, 0, 0);

        sockaddr_in6_init(&ifra.ifra_addr, &in6addr_loopback, 0, 0, 0);

        /* the loopback  address should NEVER expire. */
        ifra.ifra_lifetime.ia6t_vltime = ND6_INFINITE_LIFETIME;
        ifra.ifra_lifetime.ia6t_pltime = ND6_INFINITE_LIFETIME;

        /* we don't need to perform DAD on loopback interfaces. */
        ifra.ifra_flags |= IN6_IFF_NODAD;

        /*
         * We are sure that this is a newly assigned address, so we can set
         * NULL to the 3rd arg.
         */
        if ((error = in6_update_ifa(ifp, &ifra, NULL, 0)) != 0) {
                nd6log((LOG_ERR, "in6_ifattach_loopback: failed to configure "
                    "the loopback address on %s (errno=%d)\n",
                    if_name(ifp), error));
                return -1;
        }

        return 0;
}

/*
 * compute NI group address, based on the current hostname setting.
 * see draft-ietf-ipngwg-icmp-name-lookup-* (04 and later).
 *
 * when ifp == NULL, the caller is responsible for filling scopeid.
 */
int
in6_nigroup(struct ifnet *ifp, const char *name, int namelen, 
        struct sockaddr_in6 *sa6)
{
        const char *p;
        u_int8_t *q;
        MD5_CTX ctxt;
        u_int8_t digest[16];
        u_int8_t l;
        u_int8_t n[64]; /* a single label must not exceed 63 chars */

        if (!namelen || !name)
                return -1;

        p = name;
        while (p && *p && *p != '.' && p - name < namelen)
                p++;
        if (p - name > sizeof(n) - 1)
                return -1;      /* label too long */
        l = p - name;
        strncpy((char *)n, name, l);
        n[(int)l] = '\0';
        for (q = n; *q; q++) {
                if ('A' <= *q && *q <= 'Z')
                        *q = *q - 'A' + 'a';
        }

        /* generate 8 bytes of pseudo-random value. */
        memset(&ctxt, 0, sizeof(ctxt));
        MD5Init(&ctxt);
        MD5Update(&ctxt, &l, sizeof(l));
        MD5Update(&ctxt, n, l);
        MD5Final(digest, &ctxt);

        memset(sa6, 0, sizeof(*sa6));
        sa6->sin6_family = AF_INET6;
        sa6->sin6_len = sizeof(*sa6);
        sa6->sin6_addr.s6_addr16[0] = htons(0xff02);
        sa6->sin6_addr.s6_addr8[11] = 2;
        memcpy(&sa6->sin6_addr.s6_addr32[3], digest,
            sizeof(sa6->sin6_addr.s6_addr32[3]));
        if (in6_setscope(&sa6->sin6_addr, ifp, NULL))
                return -1; /* XXX: should not fail */

        return 0;
}

/*
 * XXX multiple loopback interface needs more care.  for instance,
 * nodelocal address needs to be configured onto only one of them.
 * XXX multiple link-local address case
 *
 * altifp - secondary EUI64 source
 */
void
in6_ifattach(struct ifnet *ifp, struct ifnet *altifp)
{
        struct in6_ifaddr *ia;
        struct in6_addr in6;

        /* some of the interfaces are inherently not IPv6 capable */
        switch (ifp->if_type) {
        case IFT_BRIDGE:
#ifdef IFT_PFLOG
        case IFT_PFLOG:
#endif
#ifdef IFT_PFSYNC
        case IFT_PFSYNC:
#endif
                return;
        }

        /*
         * if link mtu is too small, don't try to configure IPv6.
         * remember there could be some link-layer that has special
         * fragmentation logic.
         */
        if (ifp->if_mtu < IPV6_MMTU) {
                nd6log((LOG_INFO, "in6_ifattach: "
                    "%s has too small MTU, IPv6 not enabled\n",
                    if_name(ifp)));
                return;
        }

        /* create a multicast kludge storage (if we have not had one) */
        in6_createmkludge(ifp);

        /*
         * quirks based on interface type
         */
        switch (ifp->if_type) {
#ifdef IFT_STF
        case IFT_STF:
                /*
                 * 6to4 interface is a very special kind of beast.
                 * no multicast, no linklocal.  RFC2529 specifies how to make
                 * linklocals for 6to4 interface, but there's no use and
                 * it is rather harmful to have one.
                 */
                return;
#endif
        case IFT_CARP:
                return;
        default:
                break;
        }

        /*
         * usually, we require multicast capability to the interface
         */
        if ((ifp->if_flags & IFF_MULTICAST) == 0) {
                nd6log((LOG_INFO, "in6_ifattach: "
                    "%s is not multicast capable, IPv6 not enabled\n",
                    if_name(ifp)));
                return;
        }

        /*
         * assign loopback address for loopback interface.
         * XXX multiple loopback interface case.
         */
        if ((ifp->if_flags & IFF_LOOPBACK) != 0) {
                in6 = in6addr_loopback;
                if (in6ifa_ifpwithaddr(ifp, &in6) == NULL) {
                        if (in6_ifattach_loopback(ifp) != 0)
                                return;
                }
        }

        /*
         * assign a link-local address, if there's none.
         */
        if (ip6_auto_linklocal) {
                ia = in6ifa_ifpforlinklocal(ifp, 0);
                if (ia == NULL && in6_ifattach_linklocal(ifp, altifp) != 0) {
                        printf("%s: cannot assign link-local address\n",
                            ifp->if_xname);
                }
        }
}

/*
 * NOTE: in6_ifdetach() does not support loopback if at this moment.
 * We don't need this function in bsdi, because interfaces are never removed
 * from the ifnet list in bsdi.
 */
void
in6_ifdetach(struct ifnet *ifp)
{
        struct in6_ifaddr *ia, *oia;
        struct ifaddr *ifa, *next;
        struct rtentry *rt;
        short rtflags;
        struct in6_multi_mship *imm;

        /* remove ip6_mrouter stuff */
        ip6_mrouter_detach(ifp);

        /* remove neighbor management table */
        nd6_purge(ifp);

        /* XXX this code is duplicated in in6_purgeif() --dyoung */
        /* nuke any of IPv6 addresses we have */
        if_purgeaddrs(ifp, AF_INET6, in6_purgeaddr);

        /* XXX isn't this code is redundant, given the above? --dyoung */
        /* XXX doesn't this code replicate code in in6_purgeaddr() ? --dyoung */
        /* undo everything done by in6_ifattach(), just in case */
        for (ifa = IFADDR_FIRST(ifp); ifa != NULL; ifa = next) {
                next = IFADDR_NEXT(ifa);

                if (ifa->ifa_addr->sa_family != AF_INET6
                 || !IN6_IS_ADDR_LINKLOCAL(&satosin6(&ifa->ifa_addr)->sin6_addr)) {
                        continue;
                }

                ia = (struct in6_ifaddr *)ifa;

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

                /* remove from the routing table */
                if ((ia->ia_flags & IFA_ROUTE) &&
                    (rt = rtalloc1((struct sockaddr *)&ia->ia_addr, 0))) {
                        rtflags = rt->rt_flags;
                        rtfree(rt);
                        rtrequest(RTM_DELETE, (struct sockaddr *)&ia->ia_addr,
                            (struct sockaddr *)&ia->ia_addr,
                            (struct sockaddr *)&ia->ia_prefixmask,
                            rtflags, (struct rtentry **)0);
                }

                /* remove from the linked list */
                ifa_remove(ifp, &ia->ia_ifa);

                /* also remove from the IPv6 address chain(itojun&jinmei) */
                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 {
                                nd6log((LOG_ERR,
                                    "%s: didn't unlink in6ifaddr from list\n",
                                    if_name(ifp)));
                        }
                }

                IFAFREE(&oia->ia_ifa);
        }

        /* cleanup multicast address kludge table, if there is any */
        in6_purgemkludge(ifp);

        /*
         * remove neighbor management table.  we call it twice just to make
         * sure we nuke everything.  maybe we need just one call.
         * XXX: since the first call did not release addresses, some prefixes
         * might remain.  We should call nd6_purge() again to release the
         * prefixes after removing all addresses above.
         * (Or can we just delay calling nd6_purge until at this point?)
         */
        nd6_purge(ifp);
}

int
in6_get_tmpifid(struct ifnet *ifp, u_int8_t *retbuf, 
        const u_int8_t *baseid, int generate)
{
        u_int8_t nullbuf[8];
        struct nd_ifinfo *ndi = ND_IFINFO(ifp);

        memset(nullbuf, 0, sizeof(nullbuf));
        if (memcmp(ndi->randomid, nullbuf, sizeof(nullbuf)) == 0) {
                /* we've never created a random ID.  Create a new one. */
                generate = 1;
        }

        if (generate) {
                memcpy(ndi->randomseed1, baseid, sizeof(ndi->randomseed1));

                /* generate_tmp_ifid will update seedn and buf */
                (void)generate_tmp_ifid(ndi->randomseed0, ndi->randomseed1,
                    ndi->randomid);
        }
        memcpy(retbuf, ndi->randomid, 8);
        if (generate && memcmp(retbuf, nullbuf, sizeof(nullbuf)) == 0) {
                /* generate_tmp_ifid could not found a good ID. */
                return -1;
        }

        return 0;
}

void
in6_tmpaddrtimer(void *ignored_arg)
{
        struct nd_ifinfo *ndi;
        u_int8_t nullbuf[8];
        struct ifnet *ifp;

        mutex_enter(softnet_lock);
        KERNEL_LOCK(1, NULL);

        callout_reset(&in6_tmpaddrtimer_ch,
            (ip6_temp_preferred_lifetime - ip6_desync_factor -
            ip6_temp_regen_advance) * hz, in6_tmpaddrtimer, NULL);

        memset(nullbuf, 0, sizeof(nullbuf));
        TAILQ_FOREACH(ifp, &ifnet, if_list) {
                ndi = ND_IFINFO(ifp);
                if (memcmp(ndi->randomid, nullbuf, sizeof(nullbuf)) != 0) {
                        /*
                         * We've been generating a random ID on this interface.
                         * Create a new one.
                         */
                        (void)generate_tmp_ifid(ndi->randomseed0,
                            ndi->randomseed1, ndi->randomid);
                }
        }

        KERNEL_UNLOCK_ONE(NULL);
        mutex_exit(softnet_lock);
}