[apple/xnu.git] / bsd / netinet6 / in6_ifattach.c

/*
 * Copyright (c) 2003-2013 Apple Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 *
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 *
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 *
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */

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

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/sockio.h>
#include <sys/kernel.h>
#include <sys/syslog.h>
#include <libkern/crypto/sha1.h>
#include <libkern/OSAtomic.h>
#include <kern/lock.h>

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

#include <netinet/in.h>
#include <netinet/in_var.h>
#include <netinet/if_ether.h>
#include <netinet/in_pcb.h>
#include <netinet/icmp6.h>

#include <netinet/ip6.h>
#include <netinet6/ip6_var.h>
#include <netinet6/in6_var.h>
#include <netinet6/in6_pcb.h>
#include <netinet6/in6_ifattach.h>
#include <netinet6/ip6_var.h>
#include <netinet6/nd6.h>
#include <netinet6/scope6_var.h>

#include <net/net_osdep.h>
#include <dev/random/randomdev.h>

u_int32_t in6_maxmtu = 0;
extern lck_mtx_t *nd6_mutex;

#if IP6_AUTO_LINKLOCAL
int ip6_auto_linklocal = IP6_AUTO_LINKLOCAL;
#else
int ip6_auto_linklocal = 1;     /* enable by default */
#endif

extern struct inpcbinfo udbinfo;
extern struct inpcbinfo ripcbinfo;

static const unsigned int in6_extra_size = sizeof(struct in6_ifextra);
static const unsigned int in6_extra_bufsize = in6_extra_size + 
    sizeof(void *) + sizeof(uint64_t);

static int get_rand_iid(struct ifnet *, struct in6_addr *);
static int in6_generate_tmp_iid(u_int8_t *, const u_int8_t *, u_int8_t *);
static int in6_select_iid_from_all_hw(struct ifnet *, struct ifnet *,
    struct in6_addr *);
static int in6_ifattach_linklocal(struct ifnet *, struct in6_aliasreq *);
static int in6_ifattach_loopback(struct ifnet *);

/*
 * 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 SHA1(hostname) for it.
 *
 * in6 - upper 64bits are preserved
 */
static int
get_rand_iid(
        __unused struct ifnet *ifp,
        struct in6_addr *in6)   /* upper 64bits are preserved */
{
        SHA1_CTX ctxt;
        u_int8_t digest[SHA1_RESULTLEN];
        int hostnlen    = strlen(hostname);

        /* generate 8 bytes of pseudo-random value. */
        bzero(&ctxt, sizeof (ctxt));
        SHA1Init(&ctxt);
        SHA1Update(&ctxt, hostname, hostnlen);
        SHA1Final(digest, &ctxt);

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

        /* make sure to set "u" bit to local, and "g" bit to individual. */
        in6->s6_addr[8] &= ~ND6_EUI64_GBIT;     /* g bit to "individual" */
        in6->s6_addr[8] |= ND6_EUI64_UBIT;      /* u bit to "local" */

        /* convert EUI64 into IPv6 interface identifier */
        ND6_EUI64_TO_IFID(in6);

        return (0);
}

static int
in6_generate_tmp_iid(
        u_int8_t *seed0,
        const u_int8_t *seed1,
        u_int8_t *ret)
{
        SHA1_CTX ctxt;
        u_int8_t seed[16], nullbuf[8], digest[SHA1_RESULTLEN];
        u_int32_t val32;
        struct timeval tv;

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

                for (i = 0; i < 2; i++) {
                        getmicrotime(&tv);
                        val32 = RandomULong() ^ tv.tv_usec;
                        bcopy(&val32, seed + sizeof (val32) * i,
                            sizeof (val32));
                }
        } else {
                bcopy(seed0, seed, 8);
        }

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

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

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

        /* generate 16 bytes of pseudo-random value. */
        bzero(&ctxt, sizeof (ctxt));
        SHA1Init(&ctxt);
        SHA1Update(&ctxt, seed, sizeof (seed));
        SHA1Final(digest, &ctxt);

        /*
         * RFC 4941 3.2.1. (3)
         * Take the left-most 64-bits of the SHA1 digest and set bit 6 (the
         * left-most bit is numbered 0) to zero.
         */
        bcopy(digest, ret, 8);
        ret[0] &= ~ND6_EUI64_UBIT;

        /*
         * XXX: we'd like to ensure that the generated value is not zero
         * for simplicity.  If the caclculated digest happens to be zero,
         * use a random non-zero value as the last resort.
         */
        if (bcmp(nullbuf, ret, sizeof (nullbuf)) == 0) {
                nd6log((LOG_INFO,
                    "%s: computed SHA1 value is zero.\n", __func__));

                getmicrotime(&tv);
                val32 = random() ^ tv.tv_usec;
                val32 = 1 + (val32 % (0xffffffff - 1));
        }

        /*
         * RFC 4941 3.2.1. (4)
         * Take the next 64-bits of the SHA1 digest and save them in
         * stable storage as the history value to be used in the next
         * iteration of the algorithm.
         */
        bcopy(&digest[8], seed0, 8);

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

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

        return (0);
}

/*
 * Get interface identifier for the specified interface using the method in
 * Appendix A of RFC 4291.
 *
 * XXX assumes single sockaddr_dl (AF_LINK address) per an interface
 *
 * in6 - upper 64bits are preserved
 */
int
in6_iid_from_hw(struct ifnet *ifp, struct in6_addr *in6)
{
        struct ifaddr *ifa = NULL;
        struct sockaddr_dl *sdl;
        u_int8_t *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 };
        int err = -1;

        /* Why doesn't this code use ifnet_addrs? */
        ifnet_lock_shared(ifp);
        ifa = ifp->if_lladdr;
        sdl = (struct sockaddr_dl *)(void *)ifa->ifa_addr;
        if (sdl->sdl_alen == 0) {
                ifnet_lock_done(ifp);
                return (-1);
        }
        IFA_ADDREF(ifa);        /* for this routine */
        ifnet_lock_done(ifp);

        IFA_LOCK(ifa);
        addr = (u_int8_t *) LLADDR(sdl);
        addrlen = sdl->sdl_alen;

        /* get EUI64 */
        switch (ifp->if_type) {
        case IFT_ETHER:
        case IFT_FDDI:
        case IFT_ISO88025:
        case IFT_ATM:
        case IFT_IEEE1394:
        case IFT_L2VLAN:
        case IFT_IEEE8023ADLAG:
#if IFT_IEEE80211
        case IFT_IEEE80211:
#endif
        case IFT_BRIDGE:
                /* IEEE802/EUI64 cases - what others? */
                /* IEEE1394 uses 16byte length address starting with EUI64 */
                if (addrlen > 8)
                        addrlen = 8;

                /* look at IEEE802/EUI64 only */
                if (addrlen != 8 && addrlen != 6)
                        goto done;

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

                /* make EUI64 address */
                if (addrlen == 8)
                        bcopy(addr, &in6->s6_addr[8], 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)
                        goto done;
                if (!addr[0])
                        goto done;

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

                /*
                 * due to insufficient bitwidth, we mark it local.
                 */
                in6->s6_addr[8] &= ~ND6_EUI64_GBIT;     /* g to "individual" */
                in6->s6_addr[8] |= ND6_EUI64_UBIT;      /* u to "local" */
                break;

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

        case IFT_CELLULAR:
                goto done;

        default:
                goto done;
        }

        /* sanity check: g bit must not indicate "group" */
        if (ND6_EUI64_GROUP(in6))
                goto done;

        /* convert EUI64 into IPv6 interface identifier */
        ND6_EUI64_TO_IFID(in6);

        /*
         * sanity check: iid must not be all zero, avoid conflict with
         * subnet router anycast
         */
        if ((in6->s6_addr[8] & ~(ND6_EUI64_GBIT | ND6_EUI64_UBIT)) == 0x00 &&
            bcmp(&in6->s6_addr[9], allzero, 7) == 0) {
                goto done;
        }

        err = 0;        /* found */

done:
        /* This must not be the last reference to the lladdr */
        if (IFA_REMREF_LOCKED(ifa) == NULL) {
                panic("%s: unexpected (missing) refcnt ifa=%p", __func__, ifa);
                /* NOTREACHED */
        }
        IFA_UNLOCK(ifa);
        return (err);
}

/*
 * Get interface identifier for the specified interface using the method in
 * Appendix A of RFC 4291.  If it is not available on ifp0, borrow interface
 * identifier from other information sources.
 *
 * ifp     - primary EUI64 source
 * altifp  - secondary EUI64 source
 * in6     - IPv6 address to output IID
 */
static int
in6_select_iid_from_all_hw(
        struct ifnet *ifp0,
        struct ifnet *altifp,   /* secondary EUI64 source */
        struct in6_addr *in6)
{
        struct ifnet *ifp;

        /* first, try to get it from the interface itself */
        if (in6_iid_from_hw(ifp0, in6) == 0) {
                nd6log((LOG_DEBUG, "%s: IID derived from HW interface.\n",
                    if_name(ifp0)));
                goto success;
        }

        /* try secondary EUI64 source. this basically is for ATM PVC */
        if (altifp && in6_iid_from_hw(altifp, in6) == 0) {
                nd6log((LOG_DEBUG, "%s: IID from alterate HW interface %s.\n",
                    if_name(ifp0), if_name(altifp)));
                goto success;
        }

        /* next, try to get it from some other hardware interface */
        ifnet_head_lock_shared();
        TAILQ_FOREACH(ifp, &ifnet_head, if_list) {
                if (ifp == ifp0)
                        continue;
                if (in6_iid_from_hw(ifp, in6) != 0)
                        continue;

                /*
                 * to borrow IID from other interface, IID needs to be
                 * globally unique
                 */
                if (ND6_IFID_UNIVERSAL(in6)) {
                        nd6log((LOG_DEBUG, "%s: borrowed IID from %s\n",
                            if_name(ifp0), if_name(ifp)));
                        ifnet_head_done();
                        goto success;
                }
        }
        ifnet_head_done();

        /* last resort: get from random number source */
        if (get_rand_iid(ifp, in6) == 0) {
                nd6log((LOG_DEBUG, "%s: IID from PRNG.\n", if_name(ifp0)));
                goto success;
        }

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

success:
        nd6log((LOG_INFO, "%s: IID: "
                "%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);
}

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

        VERIFY(ifra != NULL);

        proto_plumb(PF_INET6, ifp);

        error = in6_update_ifa(ifp, ifra, IN6_IFAUPDATE_DADDELAY, &ia);
        if (error != 0) {
                /*
                 * XXX: When the interface does not support IPv6, this call
                 * would fail in the SIOCSIFADDR 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, "%s: failed to "
                            "configure a link-local address on %s "
                            "(errno=%d)\n",
                            __func__, if_name(ifp), error));
                return (EADDRNOTAVAIL);
        }
        VERIFY(ia != NULL);

        /*
         * Make the link-local prefix (fe80::%link/64) 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...
         */
        bzero(&pr0, sizeof (pr0));
        lck_mtx_init(&pr0.ndpr_lock, ifa_mtx_grp, ifa_mtx_attr);
        pr0.ndpr_ifp = ifp;
        /* this should be 64 at this moment. */
        pr0.ndpr_plen = in6_mask2len(&ifra->ifra_prefixmask.sin6_addr, NULL);
        pr0.ndpr_mask = ifra->ifra_prefixmask.sin6_addr;
        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;
        pr0.ndpr_stateflags |= NDPRF_STATIC;
        /*
         * 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 ((pr = nd6_prefix_lookup(&pr0)) == NULL) {
                if ((error = nd6_prelist_add(&pr0, NULL, &pr, TRUE)) != 0) {
                        IFA_REMREF(&ia->ia_ifa);
                        lck_mtx_destroy(&pr0.ndpr_lock, ifa_mtx_grp);
                        return (error);
                }
        }

        in6_post_msg(ifp, KEV_INET6_NEW_LL_ADDR, ia);
        IFA_REMREF(&ia->ia_ifa);

        /* Drop use count held above during lookup/add */
        if (pr != NULL)
                NDPR_REMREF(pr);

        lck_mtx_destroy(&pr0.ndpr_lock, ifa_mtx_grp);
        return (0);
}

static int
in6_ifattach_loopback(
        struct ifnet *ifp)      /* must be IFT_LOOP */
{
        struct in6_aliasreq ifra;
        struct in6_ifaddr *ia;
        int error;

        bzero(&ifra, 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_prefixmask.sin6_len = sizeof (struct sockaddr_in6);
        ifra.ifra_prefixmask.sin6_family = AF_INET6;
        ifra.ifra_prefixmask.sin6_addr = in6mask128;

        /*
         * Always initialize ia_dstaddr (= broadcast address) to loopback
         * address.  Follows IPv4 practice - see in_ifinit().
         */
        ifra.ifra_dstaddr.sin6_len = sizeof (struct sockaddr_in6);
        ifra.ifra_dstaddr.sin6_family = AF_INET6;
        ifra.ifra_dstaddr.sin6_addr = in6addr_loopback;

        ifra.ifra_addr.sin6_len = sizeof (struct sockaddr_in6);
        ifra.ifra_addr.sin6_family = AF_INET6;
        ifra.ifra_addr.sin6_addr = in6addr_loopback;

        /* 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;

        /* skip registration to the prefix list. XXX should be temporary. */
        ifra.ifra_flags |= IN6_IFF_NOPFX;

        /* add the new interface address */
        error = in6_update_ifa(ifp, &ifra, 0, &ia);
        if (error != 0) {
                nd6log((LOG_ERR,
                    "%s: failed to configure loopback address %s (error=%d)\n",
                    __func__, if_name(ifp), error));
                VERIFY(ia == NULL);
                return (EADDRNOTAVAIL);
        }

        VERIFY(ia != NULL);
        IFA_REMREF(&ia->ia_ifa);
        return (0);
}

/*
 * compute NI group address, based on the current hostname setting.
 * see RFC 4620.
 *
 * when ifp == NULL, the caller is responsible for filling scopeid.
 */
int
in6_nigroup(
        struct ifnet *ifp,
        const char *name,
        int namelen,
        struct in6_addr *in6)
{
        const char *p;
        u_char *q;
        SHA1_CTX ctxt;
        u_int8_t digest[SHA1_RESULTLEN];
        char l;
        char 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(n, name, l);
        n[(int)l] = '\0';
        for (q = (u_char *) n; *q; q++) {
                if ('A' <= *q && *q <= 'Z')
                        *q = *q - 'A' + 'a';
        }

        /* generate 16 bytes of pseudo-random value. */
        bzero(&ctxt, sizeof (ctxt));
        SHA1Init(&ctxt);
        SHA1Update(&ctxt, &l, sizeof (l));
        SHA1Update(&ctxt, n, l);
        SHA1Final(digest, &ctxt);

        bzero(in6, sizeof (*in6));
        in6->s6_addr16[0] = IPV6_ADDR_INT16_MLL;
        in6->s6_addr8[11] = 2;
        in6->s6_addr8[12] = 0xff;
        /* copy first 3 bytes of prefix into address */
        bcopy(digest, &in6->s6_addr8[13], 3);
        if (in6_setscope(in6, ifp, NULL))
                return (-1); /* XXX: should not fail */

        return (0);
}

int
in6_domifattach(struct ifnet *ifp)
{
        int error;

        VERIFY(ifp != NULL);

        error = proto_plumb(PF_INET6, ifp);
        if (error != 0) {
                if (error != EEXIST)
                        log(LOG_ERR, "%s: proto_plumb returned %d if=%s\n",
                            __func__, error, if_name(ifp));
        } else {
                error = in6_ifattach_prelim(ifp);
                if (error != 0) {
                        int errorx;

                        log(LOG_ERR,
                            "%s: in6_ifattach_prelim returned %d if=%s%d\n",
                            __func__, error, ifp->if_name, ifp->if_unit);

                        errorx = proto_unplumb(PF_INET6, ifp);
                        if (errorx != 0) /* XXX should not fail */
                                log(LOG_ERR,
                                    "%s: proto_unplumb returned %d if=%s%d\n",
                                    __func__, errorx, ifp->if_name,
                                    ifp->if_unit);
                }
        }

        return (error);
}

int
in6_ifattach_prelim(struct ifnet *ifp)
{
        struct in6_ifextra *ext;
        void **pbuf, *base;
        int error = 0;

        VERIFY(ifp != NULL);

        /* quirks based on interface type */
        switch (ifp->if_type) {
#if 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.
                 */
                goto skipmcast;
#endif
        default:
                break;
        }

        /*
         * IPv6 requires multicast capability at the interface.
         *   (previously, this was a silent error.)
         */
        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 (EINVAL);
        }

#if IFT_STF
skipmcast:
#endif

        if (ifp->if_inet6data == NULL) {
                ext = (struct in6_ifextra *)_MALLOC(in6_extra_size, M_IFADDR,
                    M_WAITOK|M_ZERO);
                if (!ext)
                        return (ENOMEM);
                base = (void *)P2ROUNDUP((intptr_t)ext + sizeof(uint64_t),
                    sizeof(uint64_t));
                VERIFY(((intptr_t)base + in6_extra_size) <= 
                    ((intptr_t)ext + in6_extra_bufsize));
                pbuf = (void **)((intptr_t)base - sizeof(void *));
                *pbuf = ext;
                ifp->if_inet6data = base;
                VERIFY(IS_P2ALIGNED(ifp->if_inet6data, sizeof(uint64_t)));
        } else {
                /*
                 * Since the structure is never freed, we need to zero out 
                 * some of its members. We avoid zeroing out the scope6
                 * structure on purpose because other threads might be
                 * using its contents.
                 */
                bzero(&IN6_IFEXTRA(ifp)->icmp6_ifstat,
                    sizeof(IN6_IFEXTRA(ifp)->icmp6_ifstat));
                bzero(&IN6_IFEXTRA(ifp)->in6_ifstat,
                    sizeof(IN6_IFEXTRA(ifp)->in6_ifstat));
        }

        /* initialize NDP variables */
        if ((error = nd6_ifattach(ifp)) != 0)
                return (error);

        scope6_ifattach(ifp);

        /* initialize loopback interface address */
        if ((ifp->if_flags & IFF_LOOPBACK) != 0) {
                error = in6_ifattach_loopback(ifp);
                if (error != 0) {
                        log(LOG_ERR, "%s: in6_ifattach_loopback returned %d\n",
                            __func__, error, ifp->if_name,
                            ifp->if_unit);
                        return (error);
                }
        }

        /* update dynamically. */
        if (in6_maxmtu < ifp->if_mtu)
                in6_maxmtu = ifp->if_mtu;

        VERIFY(error == 0);
        return (0);
}

int
in6_ifattach_aliasreq(struct ifnet *ifp, struct ifnet *altifp,
    struct in6_aliasreq *ifra0)
{
        int error;
        struct in6_ifaddr *ia6;
        struct in6_aliasreq ifra;

        error = in6_ifattach_prelim(ifp);
        if (error != 0)
                return (error);

        if (!ip6_auto_linklocal)
                return (0);

        /* assign a link-local address, only if there isn't one here already. */
        ia6 = in6ifa_ifpforlinklocal(ifp, 0);
        if (ia6 != NULL) {
                IFA_REMREF(&ia6->ia_ifa);
                return (0);
        }

        bzero(&ifra, 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));

        /* Initialize the IPv6 interface address in our in6_aliasreq block */
        if ((ifp->if_eflags & IFEF_NOAUTOIPV6LL) != 0 && ifra0 != NULL) {
                /* interface provided both addresses for us */
                struct sockaddr_in6 *sin6 = &ifra.ifra_addr;
                struct in6_addr *in6 = &sin6->sin6_addr;
                boolean_t ok = TRUE;

                bcopy(&ifra0->ifra_addr, sin6, sizeof (struct sockaddr_in6));

                if (sin6->sin6_family != AF_INET6 || sin6->sin6_port != 0)
                        ok = FALSE;
                if (ok && (in6->s6_addr16[0] != htons(0xfe80)))
                        ok = FALSE;
                if (ok) {
                        if (sin6->sin6_scope_id == 0 && in6->s6_addr16[1] == 0)
                                in6->s6_addr16[1] = htons(ifp->if_index);
                        else if (sin6->sin6_scope_id != 0 &&
                            sin6->sin6_scope_id != ifp->if_index)
                                ok = FALSE;
                        else if (in6->s6_addr16[1] != 0 &&
                            ntohs(in6->s6_addr16[1]) != ifp->if_index)
                                ok = FALSE;
                }
                if (ok && (in6->s6_addr32[1] != 0))
                        ok = FALSE;
                if (!ok)
                        return (EINVAL);
        } else {
                ifra.ifra_addr.sin6_family = AF_INET6;
                ifra.ifra_addr.sin6_len = sizeof (struct sockaddr_in6);
                ifra.ifra_addr.sin6_addr.s6_addr16[0] = htons(0xfe80);
                ifra.ifra_addr.sin6_addr.s6_addr16[1] = htons(ifp->if_index);
                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 (in6_select_iid_from_all_hw(ifp, altifp,
                            &ifra.ifra_addr.sin6_addr) != 0) {
                                nd6log((LOG_ERR, "%s: no IID available\n",
                                    if_name(ifp)));
                                return (EADDRNOTAVAIL);
                        }
                }
        }

        if (in6_setscope(&ifra.ifra_addr.sin6_addr, ifp, NULL))
                return (EADDRNOTAVAIL);

        /* Set the prefix mask */
        ifra.ifra_prefixmask.sin6_len = sizeof (struct sockaddr_in6);
        ifra.ifra_prefixmask.sin6_family = AF_INET6;
        ifra.ifra_prefixmask.sin6_addr = in6mask64;

        /* link-local addresses should NEVER expire. */
        ifra.ifra_lifetime.ia6t_vltime = ND6_INFINITE_LIFETIME;
        ifra.ifra_lifetime.ia6t_pltime = ND6_INFINITE_LIFETIME;

        /* Attach the link-local address */
        if (in6_ifattach_linklocal(ifp, &ifra) != 0) {
                nd6log((LOG_INFO,
                    "%s: %s could not attach link-local address.\n",
                    __func__, if_name(ifp)));
                /* NB: not an error */
        }

        return (0);
}

int
in6_ifattach_llstartreq(struct ifnet *ifp, struct in6_llstartreq *llsr)
{
        struct in6_aliasreq ifra;
        struct in6_ifaddr *ia6;
        struct nd_ifinfo *ndi;
        int error;

        VERIFY(llsr != NULL);

        error = in6_ifattach_prelim(ifp);
        if (error != 0)
                return (error);

        if (!ip6_auto_linklocal || (ifp->if_eflags & IFEF_NOAUTOIPV6LL) != 0)
                return (0);

        if (nd6_send_opstate == ND6_SEND_OPMODE_DISABLED)
                return (ENXIO);

        lck_rw_lock_shared(nd_if_rwlock);
        ndi = ND_IFINFO(ifp);
        VERIFY(ndi != NULL && ndi->initialized);
        if ((ndi->flags & ND6_IFF_INSECURE) != 0) {
                lck_rw_done(nd_if_rwlock);
                return (ENXIO);
        }
        lck_rw_done(nd_if_rwlock);

        /* assign a link-local address, only if there isn't one here already. */
        ia6 = in6ifa_ifpforlinklocal(ifp, 0);
        if (ia6 != NULL) {
                IFA_REMREF(&ia6->ia_ifa);
                return (0);
        }

        bzero(&ifra, sizeof (ifra));
        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_addr16[0] = htons(0xfe80);
        ifra.ifra_addr.sin6_addr.s6_addr16[1] = htons(ifp->if_index);
        ifra.ifra_addr.sin6_addr.s6_addr32[1] = 0;
        ifra.ifra_flags = IN6_IFF_SECURED;

        in6_cga_node_lock();
        if (in6_cga_generate(&llsr->llsr_cgaprep, 0,
            &ifra.ifra_addr.sin6_addr)) {
                in6_cga_node_unlock();
                return (EADDRNOTAVAIL);
        }
        in6_cga_node_unlock();

        if (in6_setscope(&ifra.ifra_addr.sin6_addr, ifp, NULL))
                return (EADDRNOTAVAIL);

        /* Set the prefix mask */
        ifra.ifra_prefixmask.sin6_len = sizeof (struct sockaddr_in6);
        ifra.ifra_prefixmask.sin6_family = AF_INET6;
        ifra.ifra_prefixmask.sin6_addr = in6mask64;

        /*
         * link-local addresses should NEVER expire, but cryptographic
         * ones may have finite preferred lifetime [if it's important to
         * keep them from being used by applications as persistent device
         * identifiers].
         */
        ifra.ifra_lifetime.ia6t_vltime = ND6_INFINITE_LIFETIME;
        ifra.ifra_lifetime.ia6t_pltime = llsr->llsr_lifetime.ia6t_pltime;

        /* Attach the link-local address */
        if (in6_ifattach_linklocal(ifp, &ifra) != 0) {
                /* NB: not an error */
                nd6log((LOG_INFO,
                    "%s: %s could not attach link-local address.\n",
                    __func__, if_name(ifp)));
        }

        VERIFY(error == 0);
        return (error);
}

/*
 * NOTE: in6_ifdetach() does not support loopback if at this moment.
 */
void
in6_ifdetach(struct ifnet *ifp)
{
        struct in6_ifaddr *ia, *oia;
        struct ifaddr *ifa;
        struct rtentry *rt;
        struct sockaddr_in6 sin6;
        struct in6_multi_mship *imm;
        int unlinked;

        lck_mtx_assert(nd6_mutex, LCK_MTX_ASSERT_NOTOWNED);

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

        /* nuke any of IPv6 addresses we have */
        lck_rw_lock_exclusive(&in6_ifaddr_rwlock);
        ia = in6_ifaddrs;
        while (ia != NULL) {
                if (ia->ia_ifa.ifa_ifp != ifp) {
                        ia = ia->ia_next;
                        continue;
                }
                IFA_ADDREF(&ia->ia_ifa);        /* for us */
                lck_rw_done(&in6_ifaddr_rwlock);
                in6_purgeaddr(&ia->ia_ifa);
                IFA_REMREF(&ia->ia_ifa);        /* for us */
                lck_rw_lock_exclusive(&in6_ifaddr_rwlock);
                /*
                 * Purging the address caused in6_ifaddr_rwlock
                 * to be dropped and reacquired;
                 * therefore search again from the beginning
                 * of in6_ifaddrs list.
                 */
                ia = in6_ifaddrs;
        }
        lck_rw_done(&in6_ifaddr_rwlock);

        ifnet_lock_exclusive(ifp);

        /* undo everything done by in6_ifattach(), just in case */
        ifa = TAILQ_FIRST(&ifp->if_addrlist);
        while (ifa != NULL) {
                IFA_LOCK(ifa);
                if (ifa->ifa_addr->sa_family != AF_INET6 ||
                    !IN6_IS_ADDR_LINKLOCAL(&satosin6(&ifa->ifa_addr)->
                    sin6_addr)) {
                        IFA_UNLOCK(ifa);
                        ifa = TAILQ_NEXT(ifa, ifa_list);
                        continue;
                }

                ia = (struct in6_ifaddr *)ifa;

                /* hold a reference for this routine */
                IFA_ADDREF_LOCKED(ifa);
                /* remove from the linked list */
                if_detach_ifa(ifp, ifa);
                IFA_UNLOCK(ifa);

                /*
                 * Leaving the multicast group(s) may involve freeing the
                 * link address multicast structure(s) for the interface,
                 * which is protected by ifnet lock.  To avoid violating
                 * lock ordering, we must drop ifnet lock before doing so.
                 * The ifa won't go away since we held a refcnt above.
                 */
                ifnet_lock_done(ifp);

                /*
                 * We have to do this work manually here instead of calling
                 * in6_purgeaddr() since in6_purgeaddr() uses the RTM_HOST flag.
                 */

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

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

                /* also remove from the IPv6 address chain(itojun&jinmei) */
                unlinked = 1;
                oia = ia;
                lck_rw_lock_exclusive(&in6_ifaddr_rwlock);
                if (oia == (ia = in6_ifaddrs)) {
                        in6_ifaddrs = 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)));
                                unlinked = 0;
                        }
                }
                lck_rw_done(&in6_ifaddr_rwlock);

                ifa = &oia->ia_ifa;
                /*
                 * release another refcnt for the link from in6_ifaddrs.
                 * Do this only if it's not already unlinked in the event
                 * that we lost the race, since in6_ifaddr_rwlock was
                 * momentarily dropped above.
                 */
                if (unlinked)
                        IFA_REMREF(ifa);
                /* release reference held for this routine */
                IFA_REMREF(ifa);

                /*
                 * This is suboptimal, but since we dropped ifnet lock above
                 * the list might have changed.  Repeat the search from the
                 * beginning until we find the first eligible IPv6 address.
                 */
                ifnet_lock_exclusive(ifp);
                ifa = TAILQ_FIRST(&ifp->if_addrlist);
        }
        ifnet_lock_done(ifp);

        /* invalidate route caches */
        routegenid_inet6_update();

        /*
         * 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);

        /* remove route to link-local allnodes multicast (ff02::1) */
        bzero(&sin6, sizeof (sin6));
        sin6.sin6_len = sizeof (struct sockaddr_in6);
        sin6.sin6_family = AF_INET6;
        sin6.sin6_addr = in6addr_linklocal_allnodes;
        sin6.sin6_addr.s6_addr16[1] = htons(ifp->if_index);
        rt = rtalloc1((struct sockaddr *)&sin6, 0, 0);
        if (rt != NULL) {
                RT_LOCK(rt);
                if (rt->rt_ifp == ifp) {
                        /*
                         * Prevent another thread from modifying rt_key,
                         * rt_gateway via rt_setgate() after the rt_lock
                         * is dropped by marking the route as defunct.
                         */
                        rt->rt_flags |= RTF_CONDEMNED;
                        RT_UNLOCK(rt);
                        (void) rtrequest(RTM_DELETE, rt_key(rt), rt->rt_gateway,
                            rt_mask(rt), rt->rt_flags, 0);
                } else {
                        RT_UNLOCK(rt);
                }
                rtfree(rt);
        }
}

void
in6_iid_mktmp(struct ifnet *ifp, u_int8_t *retbuf, const u_int8_t *baseid,
    int generate)
{
        u_int8_t nullbuf[8];
        struct nd_ifinfo *ndi;

        lck_rw_lock_shared(nd_if_rwlock);
        ndi = ND_IFINFO(ifp);
        VERIFY(ndi != NULL && ndi->initialized);
        lck_mtx_lock(&ndi->lock);
        bzero(nullbuf, sizeof (nullbuf));
        if (bcmp(ndi->randomid, nullbuf, sizeof (nullbuf)) == 0) {
                /* we've never created a random ID.  Create a new one. */
                generate = 1;
        }

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

                /* in6_generate_tmp_iid will update seedn and buf */
                (void) in6_generate_tmp_iid(ndi->randomseed0, ndi->randomseed1,
                    ndi->randomid);
        }

        bcopy(ndi->randomid, retbuf, 8);
        lck_mtx_unlock(&ndi->lock);
        lck_rw_done(nd_if_rwlock);
}

void
in6_tmpaddrtimer(void *arg)
{
#pragma unused(arg)
        int i;
        struct nd_ifinfo *ndi;
        u_int8_t nullbuf[8];

        timeout(in6_tmpaddrtimer, (caddr_t)0, (ip6_temp_preferred_lifetime -
            ip6_desync_factor - ip6_temp_regen_advance) * hz);

        lck_rw_lock_shared(nd_if_rwlock);
        bzero(nullbuf, sizeof (nullbuf));
        for (i = 1; i < if_index + 1; i++) {
                if (!nd_ifinfo || i >= nd_ifinfo_indexlim)
                        break;
                ndi = &nd_ifinfo[i];
                if (!ndi->initialized)
                        continue;
                lck_mtx_lock(&ndi->lock);
                if (bcmp(ndi->randomid, nullbuf, sizeof (nullbuf)) != 0) {
                        /*
                         * We've been generating a random ID on this interface.
                         * Create a new one.
                         */
                        (void) in6_generate_tmp_iid(ndi->randomseed0,
                            ndi->randomseed1, ndi->randomid);
                }
                lck_mtx_unlock(&ndi->lock);
        }
        lck_rw_done(nd_if_rwlock);
}