xnu-7195.101.1.tar.gz

[apple/xnu.git] / bsd / netinet6 / in6.c

/*
 * Copyright (c) 2003-2020 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.
 */

/*
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *      @(#)in.c        8.2 (Berkeley) 11/15/93
 */


#include <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/time.h>
#include <sys/kernel.h>
#include <sys/syslog.h>
#include <sys/kern_event.h>
#include <sys/mcache.h>
#include <sys/protosw.h>
#include <sys/sysctl.h>

#include <kern/locks.h>
#include <kern/zalloc.h>
#include <kern/clock.h>
#include <libkern/OSAtomic.h>
#include <machine/machine_routines.h>
#include <mach/boolean.h>

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

#include <netinet/in.h>
#include <netinet/in_var.h>
#include <netinet/if_ether.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/in_pcb.h>
#include <netinet/icmp6.h>
#include <netinet/tcp.h>
#include <netinet/tcp_seq.h>
#include <netinet/tcp_var.h>

#include <netinet6/nd6.h>
#include <netinet/ip6.h>
#include <netinet6/ip6_var.h>
#include <netinet6/mld6_var.h>
#include <netinet6/in6_ifattach.h>
#include <netinet6/scope6_var.h>
#include <netinet6/in6_var.h>
#include <netinet6/in6_pcb.h>

#include <net/net_osdep.h>

#include <net/dlil.h>
#include <net/if_llatbl.h>

#if PF
#include <net/pfvar.h>
#endif /* PF */

/*
 * Definitions of some costant IP6 addresses.
 */
const struct in6_addr in6addr_any = IN6ADDR_ANY_INIT;
const struct in6_addr in6addr_loopback = IN6ADDR_LOOPBACK_INIT;
const struct in6_addr in6addr_nodelocal_allnodes =
    IN6ADDR_NODELOCAL_ALLNODES_INIT;
const struct in6_addr in6addr_linklocal_allnodes =
    IN6ADDR_LINKLOCAL_ALLNODES_INIT;
const struct in6_addr in6addr_linklocal_allrouters =
    IN6ADDR_LINKLOCAL_ALLROUTERS_INIT;
const struct in6_addr in6addr_linklocal_allv2routers =
    IN6ADDR_LINKLOCAL_ALLV2ROUTERS_INIT;
const struct in6_addr in6addr_multicast_prefix =
    IN6ADDR_MULTICAST_PREFIX;

const struct in6_addr in6mask0 = IN6MASK0;
const struct in6_addr in6mask7 = IN6MASK7;
const struct in6_addr in6mask8 = IN6MASK8;
const struct in6_addr in6mask16 = IN6MASK16;
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 = {
        .sin6_len = sizeof(sa6_any),
        .sin6_family = AF_INET6,
        .sin6_port = 0,
        .sin6_flowinfo = 0,
        .sin6_addr = IN6ADDR_ANY_INIT,
        .sin6_scope_id = 0
};

static int in6ctl_associd(struct socket *, u_long, caddr_t);
static int in6ctl_connid(struct socket *, u_long, caddr_t);
static int in6ctl_conninfo(struct socket *, u_long, caddr_t);
static int in6ctl_llstart(struct ifnet *, u_long, caddr_t);
static int in6ctl_llstop(struct ifnet *);
static int in6ctl_cgastart(struct ifnet *, u_long, caddr_t);
static int in6ctl_gifaddr(struct ifnet *, struct in6_ifaddr *, u_long,
    struct in6_ifreq *);
static int in6ctl_gifstat(struct ifnet *, u_long, struct in6_ifreq *);
static int in6ctl_alifetime(struct in6_ifaddr *, u_long, struct in6_ifreq *,
    boolean_t);
static int in6ctl_aifaddr(struct ifnet *, struct in6_aliasreq *);
static void in6ctl_difaddr(struct ifnet *, struct in6_ifaddr *);
static int in6_autoconf(struct ifnet *, int);
static int in6_setrouter(struct ifnet *, ipv6_router_mode_t);
static int in6_ifinit(struct ifnet *, struct in6_ifaddr *, int);
static int in6_ifaupdate_aux(struct in6_ifaddr *, struct ifnet *, int);
static void in6_unlink_ifa(struct in6_ifaddr *, struct ifnet *);
static struct in6_ifaddr *in6_ifaddr_alloc(zalloc_flags_t);
static void in6_ifaddr_attached(struct ifaddr *);
static void in6_ifaddr_detached(struct ifaddr *);
static void in6_ifaddr_free(struct ifaddr *);
static void in6_ifaddr_trace(struct ifaddr *, int);
#if defined(__LP64__)
static void in6_cgareq_32_to_64(const struct in6_cgareq_32 *,
    struct in6_cgareq_64 *);
#else
static void in6_cgareq_64_to_32(const struct in6_cgareq_64 *,
    struct in6_cgareq_32 *);
#endif
static struct in6_aliasreq *in6_aliasreq_to_native(void *, int,
    struct in6_aliasreq *);
static int in6_to_kamescope(struct sockaddr_in6 *, struct ifnet *);
static int in6_getassocids(struct socket *, uint32_t *, user_addr_t);
static int in6_getconnids(struct socket *, sae_associd_t, uint32_t *,
    user_addr_t);

static void in6_if_up_dad_start(struct ifnet *);

#define IA6_HASH_INIT(ia) {                                      \
        (ia)->ia6_hash.tqe_next = (void *)(uintptr_t)-1;         \
        (ia)->ia6_hash.tqe_prev = (void *)(uintptr_t)-1;         \
}

#define IA6_IS_HASHED(ia)                                        \
        (!((ia)->ia6_hash.tqe_next == (void *)(uintptr_t)-1 ||   \
        (ia)->ia6_hash.tqe_prev == (void *)(uintptr_t)-1))

static void in6_iahash_remove(struct in6_ifaddr *);
static void in6_iahash_insert(struct in6_ifaddr *);
static void in6_iahash_insert_ptp(struct in6_ifaddr *);

extern lck_mtx_t *nd6_mutex;

#define IN6IFA_TRACE_HIST_SIZE  32      /* size of trace history */

/* For gdb */
__private_extern__ unsigned int in6ifa_trace_hist_size = IN6IFA_TRACE_HIST_SIZE;

struct in6_ifaddr_dbg {
        struct in6_ifaddr       in6ifa;                 /* in6_ifaddr */
        struct in6_ifaddr       in6ifa_old;             /* saved in6_ifaddr */
        u_int16_t               in6ifa_refhold_cnt;     /* # of IFA_ADDREF */
        u_int16_t               in6ifa_refrele_cnt;     /* # of IFA_REMREF */
        /*
         * Alloc and free callers.
         */
        ctrace_t                in6ifa_alloc;
        ctrace_t                in6ifa_free;
        /*
         * Circular lists of IFA_ADDREF and IFA_REMREF callers.
         */
        ctrace_t                in6ifa_refhold[IN6IFA_TRACE_HIST_SIZE];
        ctrace_t                in6ifa_refrele[IN6IFA_TRACE_HIST_SIZE];
        /*
         * Trash list linkage
         */
        TAILQ_ENTRY(in6_ifaddr_dbg) in6ifa_trash_link;
};

/* List of trash in6_ifaddr entries protected by in6ifa_trash_lock */
static TAILQ_HEAD(, in6_ifaddr_dbg) in6ifa_trash_head;
static decl_lck_mtx_data(, in6ifa_trash_lock);

#if DEBUG
static unsigned int in6ifa_debug = 1;           /* debugging (enabled) */
#else
static unsigned int in6ifa_debug;               /* debugging (disabled) */
#endif /* !DEBUG */
static struct zone *in6ifa_zone;                /* zone for in6_ifaddr */
#define IN6IFA_ZONE_NAME        "in6_ifaddr"    /* zone name */

struct eventhandler_lists_ctxt in6_evhdlr_ctxt;
struct eventhandler_lists_ctxt in6_clat46_evhdlr_ctxt;
/*
 * Subroutine for in6_ifaddloop() and in6_ifremloop().
 * This routine does actual work.
 */
static void
in6_ifloop_request(int cmd, struct ifaddr *ifa)
{
        struct sockaddr_in6 all1_sa;
        struct rtentry *nrt = NULL;
        int e;

        bzero(&all1_sa, sizeof(all1_sa));
        all1_sa.sin6_family = AF_INET6;
        all1_sa.sin6_len = sizeof(struct sockaddr_in6);
        all1_sa.sin6_addr = in6mask128;

        /*
         * We specify the address itself as the gateway, and set the
         * RTF_LLINFO flag, so that the corresponding host route would have
         * the flag, and thus applications that assume traditional behavior
         * would be happy.  Note that we assume the caller of the function
         * (probably implicitly) set nd6_rtrequest() to ifa->ifa_rtrequest,
         * which changes the outgoing interface to the loopback interface.
         * ifa_addr for INET6 is set once during init; no need to hold lock.
         */
        lck_mtx_lock(rnh_lock);
        e = rtrequest_locked(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);
        }

        if (nrt != NULL) {
                RT_LOCK(nrt);
        }
        /*
         * Make sure rt_ifa be equal to IFA, the second argument of the
         * function.
         * We need this because when we refer to rt_ifa->ia6_flags in
         * ip6_input, we assume that the rt_ifa points to the address instead
         * of the loopback address.
         */
        if (cmd == RTM_ADD && nrt && ifa != nrt->rt_ifa) {
                rtsetifa(nrt, 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 != NULL) {
                rt_newaddrmsg(cmd, ifa, e, nrt);
                if (cmd == RTM_DELETE) {
                        RT_UNLOCK(nrt);
                        rtfree_locked(nrt);
                } else {
                        /* the cmd must be RTM_ADD here */
                        RT_REMREF_LOCKED(nrt);
                        RT_UNLOCK(nrt);
                }
        }
        lck_mtx_unlock(rnh_lock);
}

/*
 * 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.  ifa_addr for
         * INET6 is set once during init; no need to hold lock.
         */
        rt = rtalloc1(ifa->ifa_addr, 0, 0);
        if (rt != NULL) {
                RT_LOCK(rt);
        }
        if (rt == NULL || (rt->rt_flags & RTF_HOST) == 0 ||
            (rt->rt_ifp->if_flags & IFF_LOOPBACK) == 0) {
                if (rt != NULL) {
                        RT_REMREF_LOCKED(rt);
                        RT_UNLOCK(rt);
                }
                in6_ifloop_request(RTM_ADD, ifa);
        } else if (rt != NULL) {
                RT_REMREF_LOCKED(rt);
                RT_UNLOCK(rt);
        }
}

/*
 * 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
         * regardless of the result of in6_is_ifloop_auto().
         */

        /*
         * 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...
         */
        lck_rw_lock_exclusive(&in6_ifaddr_rwlock);
        TAILQ_FOREACH(ia, IN6ADDR_HASH(IFA_IN6(ifa)), ia6_hash) {
                IFA_LOCK(&ia->ia_ifa);
                if (IN6_ARE_ADDR_EQUAL(IFA_IN6(ifa), &ia->ia_addr.sin6_addr)) {
                        ia_count++;
                        if (ia_count > 1) {
                                IFA_UNLOCK(&ia->ia_ifa);
                                break;
                        }
                }
                IFA_UNLOCK(&ia->ia_ifa);
        }
        lck_rw_done(&in6_ifaddr_rwlock);

        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.  ifa_addr for INET6 is set once during
                 * init; no need to hold lock.
                 */
                rt = rtalloc1(ifa->ifa_addr, 0, 0);
                if (rt != NULL) {
                        RT_LOCK(rt);
                        if ((rt->rt_flags & RTF_HOST) != 0 &&
                            (rt->rt_ifp->if_flags & IFF_LOOPBACK) != 0) {
                                RT_REMREF_LOCKED(rt);
                                RT_UNLOCK(rt);
                                in6_ifloop_request(RTM_DELETE, ifa);
                        } else {
                                RT_UNLOCK(rt);
                        }
                }
        }
}


int
in6_mask2len(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;
}

void
in6_len2mask(struct in6_addr *mask, int len)
{
        int i;

        bzero(mask, sizeof(*mask));
        for (i = 0; i < len / 8; i++) {
                mask->s6_addr8[i] = 0xff;
        }
        if (len % 8) {
                mask->s6_addr8[i] = (0xff00 >> (len % 8)) & 0xff;
        }
}

void
in6_aliasreq_64_to_32(struct in6_aliasreq_64 *src, struct in6_aliasreq_32 *dst)
{
        bzero(dst, sizeof(*dst));
        bcopy(src->ifra_name, dst->ifra_name, sizeof(dst->ifra_name));
        dst->ifra_addr = src->ifra_addr;
        dst->ifra_dstaddr = src->ifra_dstaddr;
        dst->ifra_prefixmask = src->ifra_prefixmask;
        dst->ifra_flags = src->ifra_flags;
        dst->ifra_lifetime.ia6t_expire = (u_int32_t)src->ifra_lifetime.ia6t_expire;
        dst->ifra_lifetime.ia6t_preferred = (u_int32_t)src->ifra_lifetime.ia6t_preferred;
        dst->ifra_lifetime.ia6t_vltime = src->ifra_lifetime.ia6t_vltime;
        dst->ifra_lifetime.ia6t_pltime = src->ifra_lifetime.ia6t_pltime;
}

void
in6_aliasreq_32_to_64(struct in6_aliasreq_32 *src, struct in6_aliasreq_64 *dst)
{
        bzero(dst, sizeof(*dst));
        bcopy(src->ifra_name, dst->ifra_name, sizeof(dst->ifra_name));
        dst->ifra_addr = src->ifra_addr;
        dst->ifra_dstaddr = src->ifra_dstaddr;
        dst->ifra_prefixmask = src->ifra_prefixmask;
        dst->ifra_flags = src->ifra_flags;
        dst->ifra_lifetime.ia6t_expire = src->ifra_lifetime.ia6t_expire;
        dst->ifra_lifetime.ia6t_preferred = src->ifra_lifetime.ia6t_preferred;
        dst->ifra_lifetime.ia6t_vltime = src->ifra_lifetime.ia6t_vltime;
        dst->ifra_lifetime.ia6t_pltime = src->ifra_lifetime.ia6t_pltime;
}

#if defined(__LP64__)
static void
in6_cgareq_32_to_64(const struct in6_cgareq_32 *src,
    struct in6_cgareq_64 *dst)
{
        bzero(dst, sizeof(*dst));
        bcopy(src->cgar_name, dst->cgar_name, sizeof(dst->cgar_name));
        dst->cgar_flags = src->cgar_flags;
        bcopy(src->cgar_cgaprep.cga_modifier.octets,
            dst->cgar_cgaprep.cga_modifier.octets,
            sizeof(dst->cgar_cgaprep.cga_modifier.octets));
        dst->cgar_cgaprep.cga_security_level =
            src->cgar_cgaprep.cga_security_level;
        dst->cgar_lifetime.ia6t_expire = src->cgar_lifetime.ia6t_expire;
        dst->cgar_lifetime.ia6t_preferred = src->cgar_lifetime.ia6t_preferred;
        dst->cgar_lifetime.ia6t_vltime = src->cgar_lifetime.ia6t_vltime;
        dst->cgar_lifetime.ia6t_pltime = src->cgar_lifetime.ia6t_pltime;
        dst->cgar_collision_count = src->cgar_collision_count;
}
#endif

#if !defined(__LP64__)
static void
in6_cgareq_64_to_32(const struct in6_cgareq_64 *src,
    struct in6_cgareq_32 *dst)
{
        bzero(dst, sizeof(*dst));
        bcopy(src->cgar_name, dst->cgar_name, sizeof(dst->cgar_name));
        dst->cgar_flags = src->cgar_flags;
        bcopy(src->cgar_cgaprep.cga_modifier.octets,
            dst->cgar_cgaprep.cga_modifier.octets,
            sizeof(dst->cgar_cgaprep.cga_modifier.octets));
        dst->cgar_cgaprep.cga_security_level =
            src->cgar_cgaprep.cga_security_level;
        dst->cgar_lifetime.ia6t_expire = src->cgar_lifetime.ia6t_expire;
        dst->cgar_lifetime.ia6t_preferred = src->cgar_lifetime.ia6t_preferred;
        dst->cgar_lifetime.ia6t_vltime = src->cgar_lifetime.ia6t_vltime;
        dst->cgar_lifetime.ia6t_pltime = src->cgar_lifetime.ia6t_pltime;
        dst->cgar_collision_count = src->cgar_collision_count;
}
#endif

static struct in6_aliasreq *
in6_aliasreq_to_native(void *data, int data_is_64, struct in6_aliasreq *dst)
{
#if defined(__LP64__)
        if (data_is_64) {
                bcopy(data, dst, sizeof(*dst));
        } else {
                in6_aliasreq_32_to_64((struct in6_aliasreq_32 *)data,
                    (struct in6_aliasreq_64 *)dst);
        }
#else
        if (data_is_64) {
                in6_aliasreq_64_to_32((struct in6_aliasreq_64 *)data,
                    (struct in6_aliasreq_32 *)dst);
        } else {
                bcopy(data, dst, sizeof(*dst));
        }
#endif /* __LP64__ */
        return dst;
}

void
in6_cgareq_copy_from_user(const void *user_data, int user_is_64,
    struct in6_cgareq *cgareq)
{
#if defined(__LP64__)
        if (user_is_64) {
                bcopy(user_data, cgareq, sizeof(*cgareq));
        } else {
                in6_cgareq_32_to_64((const struct in6_cgareq_32 *)user_data,
                    (struct in6_cgareq_64 *)cgareq);
        }
#else
        if (user_is_64) {
                in6_cgareq_64_to_32((const struct in6_cgareq_64 *)user_data,
                    (struct in6_cgareq_32 *)cgareq);
        } else {
                bcopy(user_data, cgareq, sizeof(*cgareq));
        }
#endif /* __LP64__ */
}

static __attribute__((noinline)) int
in6ctl_associd(struct socket *so, u_long cmd, caddr_t data)
{
        int error = 0;
        union {
                struct so_aidreq32 a32;
                struct so_aidreq64 a64;
        } u;

        VERIFY(so != NULL);

        switch (cmd) {
        case SIOCGASSOCIDS32: {         /* struct so_aidreq32 */
                bcopy(data, &u.a32, sizeof(u.a32));
                error = in6_getassocids(so, &u.a32.sar_cnt, u.a32.sar_aidp);
                if (error == 0) {
                        bcopy(&u.a32, data, sizeof(u.a32));
                }
                break;
        }

        case SIOCGASSOCIDS64: {         /* struct so_aidreq64 */
                bcopy(data, &u.a64, sizeof(u.a64));
                error = in6_getassocids(so, &u.a64.sar_cnt, u.a64.sar_aidp);
                if (error == 0) {
                        bcopy(&u.a64, data, sizeof(u.a64));
                }
                break;
        }

        default:
                VERIFY(0);
                /* NOTREACHED */
        }

        return error;
}

static __attribute__((noinline)) int
in6ctl_connid(struct socket *so, u_long cmd, caddr_t data)
{
        int error = 0;
        union {
                struct so_cidreq32 c32;
                struct so_cidreq64 c64;
        } u;

        VERIFY(so != NULL);

        switch (cmd) {
        case SIOCGCONNIDS32: {          /* struct so_cidreq32 */
                bcopy(data, &u.c32, sizeof(u.c32));
                error = in6_getconnids(so, u.c32.scr_aid, &u.c32.scr_cnt,
                    u.c32.scr_cidp);
                if (error == 0) {
                        bcopy(&u.c32, data, sizeof(u.c32));
                }
                break;
        }

        case SIOCGCONNIDS64: {          /* struct so_cidreq64 */
                bcopy(data, &u.c64, sizeof(u.c64));
                error = in6_getconnids(so, u.c64.scr_aid, &u.c64.scr_cnt,
                    u.c64.scr_cidp);
                if (error == 0) {
                        bcopy(&u.c64, data, sizeof(u.c64));
                }
                break;
        }

        default:
                VERIFY(0);
                /* NOTREACHED */
        }

        return error;
}

static __attribute__((noinline)) int
in6ctl_conninfo(struct socket *so, u_long cmd, caddr_t data)
{
        int error = 0;
        union {
                struct so_cinforeq32 ci32;
                struct so_cinforeq64 ci64;
        } u;

        VERIFY(so != NULL);

        switch (cmd) {
        case SIOCGCONNINFO32: {         /* struct so_cinforeq32 */
                bcopy(data, &u.ci32, sizeof(u.ci32));
                error = in6_getconninfo(so, u.ci32.scir_cid, &u.ci32.scir_flags,
                    &u.ci32.scir_ifindex, &u.ci32.scir_error, u.ci32.scir_src,
                    &u.ci32.scir_src_len, u.ci32.scir_dst, &u.ci32.scir_dst_len,
                    &u.ci32.scir_aux_type, u.ci32.scir_aux_data,
                    &u.ci32.scir_aux_len);
                if (error == 0) {
                        bcopy(&u.ci32, data, sizeof(u.ci32));
                }
                break;
        }

        case SIOCGCONNINFO64: {         /* struct so_cinforeq64 */
                bcopy(data, &u.ci64, sizeof(u.ci64));
                error = in6_getconninfo(so, u.ci64.scir_cid, &u.ci64.scir_flags,
                    &u.ci64.scir_ifindex, &u.ci64.scir_error, u.ci64.scir_src,
                    &u.ci64.scir_src_len, u.ci64.scir_dst, &u.ci64.scir_dst_len,
                    &u.ci64.scir_aux_type, u.ci64.scir_aux_data,
                    &u.ci64.scir_aux_len);
                if (error == 0) {
                        bcopy(&u.ci64, data, sizeof(u.ci64));
                }
                break;
        }

        default:
                VERIFY(0);
                /* NOTREACHED */
        }

        return error;
}

static __attribute__((noinline)) int
in6ctl_llstart(struct ifnet *ifp, u_long cmd, caddr_t data)
{
        struct in6_aliasreq sifra, *ifra = NULL;
        boolean_t is64;
        int error = 0;

        VERIFY(ifp != NULL);

        switch (cmd) {
        case SIOCLL_START_32:           /* struct in6_aliasreq_32 */
        case SIOCLL_START_64:           /* struct in6_aliasreq_64 */
                is64 = (cmd == SIOCLL_START_64);
                /*
                 * Convert user ifra to the kernel form, when appropriate.
                 * This allows the conversion between different data models
                 * to be centralized, so that it can be passed around to other
                 * routines that are expecting the kernel form.
                 */
                ifra = in6_aliasreq_to_native(data, is64, &sifra);

                /*
                 * NOTE: All the interface specific DLIL attachements should
                 * be done here.  They are currently done in in6_ifattach_aux()
                 * for the interfaces that need it.
                 */
                if (ifra->ifra_addr.sin6_family == AF_INET6 &&
                    /* Only check ifra_dstaddr if valid */
                    (ifra->ifra_dstaddr.sin6_len == 0 ||
                    ifra->ifra_dstaddr.sin6_family == AF_INET6)) {
                        /* some interfaces may provide LinkLocal addresses */
                        error = in6_ifattach_aliasreq(ifp, NULL, ifra);
                } else {
                        error = in6_ifattach_aliasreq(ifp, NULL, NULL);
                }
                if (error == 0) {
                        in6_if_up_dad_start(ifp);
                }
                break;

        default:
                VERIFY(0);
                /* NOTREACHED */
        }

        return error;
}

static __attribute__((noinline)) int
in6ctl_llstop(struct ifnet *ifp)
{
        struct in6_ifaddr *ia;
        struct nd_prefix pr0, *pr;

        VERIFY(ifp != NULL);

        /* Remove link local addresses from interface */
        lck_rw_lock_exclusive(&in6_ifaddr_rwlock);
        boolean_t from_begining = TRUE;
        while (from_begining) {
                from_begining = FALSE;
                TAILQ_FOREACH(ia, &in6_ifaddrhead, ia6_link) {
                        if (ia->ia_ifa.ifa_ifp != ifp) {
                                continue;
                        }
                        IFA_LOCK(&ia->ia_ifa);
                        if (IN6_IS_ADDR_LINKLOCAL(&ia->ia_addr.sin6_addr)) {
                                IFA_ADDREF_LOCKED(&ia->ia_ifa); /* for us */
                                IFA_UNLOCK(&ia->ia_ifa);
                                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.
                                 */
                                from_begining = TRUE;
                                break;
                        }
                        IFA_UNLOCK(&ia->ia_ifa);
                }
        }
        lck_rw_done(&in6_ifaddr_rwlock);

        /* Delete the link local prefix */
        bzero(&pr0, sizeof(pr0));
        pr0.ndpr_plen = 64;
        pr0.ndpr_ifp = ifp;
        pr0.ndpr_prefix.sin6_addr.s6_addr16[0] = IPV6_ADDR_INT16_ULL;
        (void)in6_setscope(&pr0.ndpr_prefix.sin6_addr, ifp, NULL);
        pr = nd6_prefix_lookup(&pr0, ND6_PREFIX_EXPIRY_UNSPEC);
        if (pr) {
                lck_mtx_lock(nd6_mutex);
                NDPR_LOCK(pr);
                prelist_remove(pr);
                NDPR_UNLOCK(pr);
                NDPR_REMREF(pr); /* Drop the reference from lookup */
                lck_mtx_unlock(nd6_mutex);
        }

        return 0;
}

/*
 * This routine configures secure link local address
 */
static __attribute__((noinline)) int
in6ctl_cgastart(struct ifnet *ifp, u_long cmd, caddr_t data)
{
        struct in6_cgareq llcgasr;
        int is64, error = 0;

        VERIFY(ifp != NULL);

        switch (cmd) {
        case SIOCLL_CGASTART_32:        /* struct in6_cgareq_32 */
        case SIOCLL_CGASTART_64:        /* struct in6_cgareq_64 */
                is64 = (cmd == SIOCLL_CGASTART_64);
                /*
                 * Convert user cgareq to the kernel form, when appropriate.
                 * This allows the conversion between different data models
                 * to be centralized, so that it can be passed around to other
                 * routines that are expecting the kernel form.
                 */
                in6_cgareq_copy_from_user(data, is64, &llcgasr);

                /*
                 * NOTE: All the interface specific DLIL attachements
                 * should be done here.  They are currently done in
                 * in6_ifattach_cgareq() for the interfaces that
                 * need it.
                 */
                error = in6_ifattach_llcgareq(ifp, &llcgasr);
                if (error == 0) {
                        in6_if_up_dad_start(ifp);
                }
                break;

        default:
                VERIFY(0);
                /* NOTREACHED */
        }

        return error;
}

/*
 * Caller passes in the ioctl data pointer directly via "ifr", with the
 * expectation that this routine always uses bcopy() or other byte-aligned
 * memory accesses.
 */
static __attribute__((noinline)) int
in6ctl_gifaddr(struct ifnet *ifp, struct in6_ifaddr *ia, u_long cmd,
    struct in6_ifreq *ifr)
{
        struct sockaddr_in6 addr;
        int error = 0;

        VERIFY(ifp != NULL);

        if (ia == NULL) {
                return EADDRNOTAVAIL;
        }

        switch (cmd) {
        case SIOCGIFADDR_IN6:           /* struct in6_ifreq */
                IFA_LOCK(&ia->ia_ifa);
                bcopy(&ia->ia_addr, &addr, sizeof(addr));
                IFA_UNLOCK(&ia->ia_ifa);
                if ((error = sa6_recoverscope(&addr, TRUE)) != 0) {
                        break;
                }
                bcopy(&addr, &ifr->ifr_addr, sizeof(addr));
                break;

        case SIOCGIFDSTADDR_IN6:        /* struct in6_ifreq */
                if (!(ifp->if_flags & IFF_POINTOPOINT)) {
                        error = EINVAL;
                        break;
                }
                /*
                 * XXX: should we check if ifa_dstaddr is NULL and return
                 * an error?
                 */
                IFA_LOCK(&ia->ia_ifa);
                bcopy(&ia->ia_dstaddr, &addr, sizeof(addr));
                IFA_UNLOCK(&ia->ia_ifa);
                if ((error = sa6_recoverscope(&addr, TRUE)) != 0) {
                        break;
                }
                bcopy(&addr, &ifr->ifr_dstaddr, sizeof(addr));
                break;

        default:
                VERIFY(0);
                /* NOTREACHED */
        }

        return error;
}

/*
 * Caller passes in the ioctl data pointer directly via "ifr", with the
 * expectation that this routine always uses bcopy() or other byte-aligned
 * memory accesses.
 */
static __attribute__((noinline)) int
in6ctl_gifstat(struct ifnet *ifp, u_long cmd, struct in6_ifreq *ifr)
{
        int error = 0, index;

        VERIFY(ifp != NULL);
        index = ifp->if_index;

        switch (cmd) {
        case SIOCGIFSTAT_IN6:           /* struct in6_ifreq */
                /* N.B.: if_inet6data is never freed once set. */
                if (IN6_IFEXTRA(ifp) == NULL) {
                        /* return (EAFNOSUPPORT)? */
                        bzero(&ifr->ifr_ifru.ifru_stat,
                            sizeof(ifr->ifr_ifru.ifru_stat));
                } else {
                        bcopy(&IN6_IFEXTRA(ifp)->in6_ifstat,
                            &ifr->ifr_ifru.ifru_stat,
                            sizeof(ifr->ifr_ifru.ifru_stat));
                }
                break;

        case SIOCGIFSTAT_ICMP6:         /* struct in6_ifreq */
                /* N.B.: if_inet6data is never freed once set. */
                if (IN6_IFEXTRA(ifp) == NULL) {
                        /* return (EAFNOSUPPORT)? */
                        bzero(&ifr->ifr_ifru.ifru_icmp6stat,
                            sizeof(ifr->ifr_ifru.ifru_icmp6stat));
                } else {
                        bcopy(&IN6_IFEXTRA(ifp)->icmp6_ifstat,
                            &ifr->ifr_ifru.ifru_icmp6stat,
                            sizeof(ifr->ifr_ifru.ifru_icmp6stat));
                }
                break;

        default:
                VERIFY(0);
                /* NOTREACHED */
        }

        return error;
}

/*
 * Caller passes in the ioctl data pointer directly via "ifr", with the
 * expectation that this routine always uses bcopy() or other byte-aligned
 * memory accesses.
 */
static __attribute__((noinline)) int
in6ctl_alifetime(struct in6_ifaddr *ia, u_long cmd, struct in6_ifreq *ifr,
    boolean_t p64)
{
        uint64_t timenow = net_uptime();
        struct in6_addrlifetime ia6_lt;
        struct timeval caltime;
        int error = 0;

        if (ia == NULL) {
                return EADDRNOTAVAIL;
        }

        switch (cmd) {
        case SIOCGIFALIFETIME_IN6:      /* struct in6_ifreq */
                IFA_LOCK(&ia->ia_ifa);
                /* retrieve time as calendar time (last arg is 1) */
                in6ifa_getlifetime(ia, &ia6_lt, 1);
                if (p64) {
                        struct in6_addrlifetime_64 lt;

                        bzero(&lt, sizeof(lt));
                        lt.ia6t_expire = ia6_lt.ia6t_expire;
                        lt.ia6t_preferred = ia6_lt.ia6t_preferred;
                        lt.ia6t_vltime = ia6_lt.ia6t_vltime;
                        lt.ia6t_pltime = ia6_lt.ia6t_pltime;
                        bcopy(&lt, &ifr->ifr_ifru.ifru_lifetime, sizeof(ifr->ifr_ifru.ifru_lifetime));
                } else {
                        struct in6_addrlifetime_32 lt;

                        bzero(&lt, sizeof(lt));
                        lt.ia6t_expire = (uint32_t)ia6_lt.ia6t_expire;
                        lt.ia6t_preferred = (uint32_t)ia6_lt.ia6t_preferred;
                        lt.ia6t_vltime = (uint32_t)ia6_lt.ia6t_vltime;
                        lt.ia6t_pltime = (uint32_t)ia6_lt.ia6t_pltime;
                        bcopy(&lt, &ifr->ifr_ifru.ifru_lifetime, sizeof(ifr->ifr_ifru.ifru_lifetime));
                }
                IFA_UNLOCK(&ia->ia_ifa);
                break;

        case SIOCSIFALIFETIME_IN6:      /* struct in6_ifreq */
                getmicrotime(&caltime);

                /* sanity for overflow - beware unsigned */
                if (p64) {
                        struct in6_addrlifetime_64 lt;

                        bcopy(&ifr->ifr_ifru.ifru_lifetime, &lt, sizeof(lt));
                        if (lt.ia6t_vltime != ND6_INFINITE_LIFETIME &&
                            lt.ia6t_vltime + caltime.tv_sec < caltime.tv_sec) {
                                error = EINVAL;
                                break;
                        }
                        if (lt.ia6t_pltime != ND6_INFINITE_LIFETIME &&
                            lt.ia6t_pltime + caltime.tv_sec < caltime.tv_sec) {
                                error = EINVAL;
                                break;
                        }
                } else {
                        struct in6_addrlifetime_32 lt;

                        bcopy(&ifr->ifr_ifru.ifru_lifetime, &lt, sizeof(lt));
                        if (lt.ia6t_vltime != ND6_INFINITE_LIFETIME &&
                            lt.ia6t_vltime + caltime.tv_sec < caltime.tv_sec) {
                                error = EINVAL;
                                break;
                        }
                        if (lt.ia6t_pltime != ND6_INFINITE_LIFETIME &&
                            lt.ia6t_pltime + caltime.tv_sec < caltime.tv_sec) {
                                error = EINVAL;
                                break;
                        }
                }

                IFA_LOCK(&ia->ia_ifa);
                if (p64) {
                        struct in6_addrlifetime_64 lt;

                        bcopy(&ifr->ifr_ifru.ifru_lifetime, &lt, sizeof(lt));
                        ia6_lt.ia6t_expire = lt.ia6t_expire;
                        ia6_lt.ia6t_preferred = lt.ia6t_preferred;
                        ia6_lt.ia6t_vltime = lt.ia6t_vltime;
                        ia6_lt.ia6t_pltime = lt.ia6t_pltime;
                } else {
                        struct in6_addrlifetime_32 lt;

                        bcopy(&ifr->ifr_ifru.ifru_lifetime, &lt, sizeof(lt));
                        ia6_lt.ia6t_expire = (uint32_t)lt.ia6t_expire;
                        ia6_lt.ia6t_preferred = (uint32_t)lt.ia6t_preferred;
                        ia6_lt.ia6t_vltime = lt.ia6t_vltime;
                        ia6_lt.ia6t_pltime = lt.ia6t_pltime;
                }
                /* for sanity */
                if (ia6_lt.ia6t_vltime != ND6_INFINITE_LIFETIME) {
                        ia6_lt.ia6t_expire = timenow + ia6_lt.ia6t_vltime;
                } else {
                        ia6_lt.ia6t_expire = 0;
                }

                if (ia6_lt.ia6t_pltime != ND6_INFINITE_LIFETIME) {
                        ia6_lt.ia6t_preferred = timenow + ia6_lt.ia6t_pltime;
                } else {
                        ia6_lt.ia6t_preferred = 0;
                }

                in6ifa_setlifetime(ia, &ia6_lt);
                IFA_UNLOCK(&ia->ia_ifa);
                break;

        default:
                VERIFY(0);
                /* NOTREACHED */
        }

        return error;
}

static int
in6ctl_clat46start(struct ifnet *ifp)
{
        struct nd_prefix *pr = NULL;
        struct nd_prefix *next = NULL;
        struct in6_ifaddr *ia6 = NULL;
        int error = 0;

        if (ifp == lo_ifp) {
                return EINVAL;
        }
        /*
         * Traverse the list of prefixes and find the first non-linklocal
         * prefix on the interface.
         * For that found eligible prefix, configure a CLAT46 reserved address.
         */
        lck_mtx_lock(nd6_mutex);
        for (pr = nd_prefix.lh_first; pr; pr = next) {
                next = pr->ndpr_next;

                NDPR_LOCK(pr);
                if (pr->ndpr_ifp != ifp) {
                        NDPR_UNLOCK(pr);
                        continue;
                }

                if (IN6_IS_ADDR_LINKLOCAL(&pr->ndpr_prefix.sin6_addr)) {
                        NDPR_UNLOCK(pr);
                        continue; /* XXX */
                }

                if (pr->ndpr_raf_auto == 0) {
                        NDPR_UNLOCK(pr);
                        continue;
                }

                if (pr->ndpr_stateflags & NDPRF_DEFUNCT) {
                        NDPR_UNLOCK(pr);
                        continue;
                }

                if ((pr->ndpr_stateflags & NDPRF_CLAT46) == 0
                    && pr->ndpr_vltime != 0) {
                        NDPR_ADDREF(pr); /* Take reference for rest of the processing */
                        NDPR_UNLOCK(pr);
                        break;
                } else {
                        NDPR_UNLOCK(pr);
                        continue;
                }
        }
        lck_mtx_unlock(nd6_mutex);

        if (pr != NULL) {
                if ((ia6 = in6_pfx_newpersistaddr(pr, FALSE, &error,
                    TRUE, CLAT46_COLLISION_COUNT_OFFSET)) == NULL) {
                        nd6log0(error,
                            "Could not configure CLAT46 address on"
                            " interface %s.\n", ifp->if_xname);
                } else {
                        IFA_LOCK(&ia6->ia_ifa);
                        NDPR_LOCK(pr);
                        ia6->ia6_ndpr = pr;
                        NDPR_ADDREF(pr); /* for addr reference */
                        pr->ndpr_stateflags |= NDPRF_CLAT46;
                        pr->ndpr_addrcnt++;
                        VERIFY(pr->ndpr_addrcnt != 0);
                        NDPR_UNLOCK(pr);
                        IFA_UNLOCK(&ia6->ia_ifa);
                        IFA_REMREF(&ia6->ia_ifa);
                        ia6 = NULL;
                        /*
                         * A newly added address might affect the status
                         * of other addresses, so we check and update it.
                         * XXX: what if address duplication happens?
                         */
                        lck_mtx_lock(nd6_mutex);
                        pfxlist_onlink_check();
                        lck_mtx_unlock(nd6_mutex);
                }
                NDPR_REMREF(pr);
        }
        return error;
}

#define ifa2ia6(ifa)    ((struct in6_ifaddr *)(void *)(ifa))

/*
 * Generic INET6 control operations (ioctl's).
 *
 * ifp is NULL if not an interface-specific ioctl.
 *
 * Most of the routines called to handle the ioctls would end up being
 * tail-call optimized, which unfortunately causes this routine to
 * consume too much stack space; this is the reason for the "noinline"
 * attribute used on those routines.
 *
 * If called directly from within the networking stack (as opposed to via
 * pru_control), the socket parameter may be NULL.
 */
int
in6_control(struct socket *so, u_long cmd, caddr_t data, struct ifnet *ifp,
    struct proc *p)
{
        struct in6_ifreq *ifr = (struct in6_ifreq *)(void *)data;
        struct in6_aliasreq sifra, *ifra = NULL;
        struct in6_ifaddr *ia = NULL;
        struct sockaddr_in6 sin6, *sa6 = NULL;
        boolean_t privileged = (proc_suser(p) == 0);
        boolean_t p64 = proc_is64bit(p);
        boolean_t so_unlocked = FALSE;
        int intval, error = 0;

        /* In case it's NULL, make sure it came from the kernel */
        VERIFY(so != NULL || p == kernproc);

        /*
         * ioctls which don't require ifp, may require socket.
         */
        switch (cmd) {
        case SIOCAADDRCTL_POLICY:       /* struct in6_addrpolicy */
        case SIOCDADDRCTL_POLICY:       /* struct in6_addrpolicy */
                if (!privileged) {
                        return EPERM;
                }
                return in6_src_ioctl(cmd, data);
        /* NOTREACHED */

        case SIOCDRADD_IN6_32:          /* struct in6_defrouter_32 */
        case SIOCDRADD_IN6_64:          /* struct in6_defrouter_64 */
        case SIOCDRDEL_IN6_32:          /* struct in6_defrouter_32 */
        case SIOCDRDEL_IN6_64:          /* struct in6_defrouter_64 */
                if (!privileged) {
                        return EPERM;
                }
                return defrtrlist_ioctl(cmd, data);
        /* NOTREACHED */

        case SIOCGASSOCIDS32:           /* struct so_aidreq32 */
        case SIOCGASSOCIDS64:           /* struct so_aidreq64 */
                return in6ctl_associd(so, cmd, data);
        /* NOTREACHED */

        case SIOCGCONNIDS32:            /* struct so_cidreq32 */
        case SIOCGCONNIDS64:            /* struct so_cidreq64 */
                return in6ctl_connid(so, cmd, data);
        /* NOTREACHED */

        case SIOCGCONNINFO32:           /* struct so_cinforeq32 */
        case SIOCGCONNINFO64:           /* struct so_cinforeq64 */
                return in6ctl_conninfo(so, cmd, data);
                /* NOTREACHED */
        }

        /*
         * The rest of ioctls require ifp; reject if we don't have one;
         * return ENXIO to be consistent with ifioctl().
         */
        if (ifp == NULL) {
                return ENXIO;
        }

        /*
         * Unlock the socket since ifnet_ioctl() may be invoked by
         * one of the ioctl handlers below.  Socket will be re-locked
         * prior to returning.
         */
        if (so != NULL) {
                socket_unlock(so, 0);
                so_unlocked = TRUE;
        }

        /*
         * ioctls which require ifp but not interface address.
         */
        switch (cmd) {
        case SIOCAUTOCONF_START:        /* struct in6_ifreq */
                if (!privileged) {
                        error = EPERM;
                        goto done;
                }
                error = in6_autoconf(ifp, TRUE);
                goto done;

        case SIOCAUTOCONF_STOP:         /* struct in6_ifreq */
                if (!privileged) {
                        error = EPERM;
                        goto done;
                }
                error = in6_autoconf(ifp, FALSE);
                goto done;

        case SIOCLL_START_32:           /* struct in6_aliasreq_32 */
        case SIOCLL_START_64:           /* struct in6_aliasreq_64 */
                if (!privileged) {
                        error = EPERM;
                        goto done;
                }
                error = in6ctl_llstart(ifp, cmd, data);
                goto done;

        case SIOCLL_STOP:               /* struct in6_ifreq */
                if (!privileged) {
                        error = EPERM;
                        goto done;
                }
                error = in6ctl_llstop(ifp);
                goto done;

        case SIOCCLAT46_START:          /* struct in6_ifreq */
                if (!privileged) {
                        error = EPERM;
                        goto done;
                }
                error = in6ctl_clat46start(ifp);
                if (error == 0) {
                        if_set_eflags(ifp, IFEF_CLAT46);
                }
                goto done;

        case SIOCCLAT46_STOP:           /* struct in6_ifreq */
                if (!privileged) {
                        error = EPERM;
                        goto done;
                }

                /*
                 * Not much to be done here and it might not be needed
                 * It would usually be done when IPv6 configuration is being
                 * flushed.
                 * XXX Probably STOP equivalent is not needed here.
                 */
                if_clear_eflags(ifp, IFEF_CLAT46);
                goto done;
        case SIOCGETROUTERMODE_IN6:     /* struct in6_ifreq */
                intval = ifp->if_ipv6_router_mode;
                bcopy(&intval, &((struct in6_ifreq *)(void *)data)->ifr_intval,
                    sizeof(intval));
                goto done;
        case SIOCSETROUTERMODE_IN6:     /* struct in6_ifreq */
                if (!privileged) {
                        error = EPERM;
                        goto done;
                }
                bcopy(&((struct in6_ifreq *)(void *)data)->ifr_intval,
                    &intval, sizeof(intval));
                switch (intval) {
                case IPV6_ROUTER_MODE_DISABLED:
                case IPV6_ROUTER_MODE_EXCLUSIVE:
                case IPV6_ROUTER_MODE_HYBRID:
                        break;
                default:
                        error = EINVAL;
                        goto done;
                }
                error = in6_setrouter(ifp, (ipv6_router_mode_t)intval);
                goto done;

        case SIOCPROTOATTACH_IN6_32:    /* struct in6_aliasreq_32 */
        case SIOCPROTOATTACH_IN6_64:    /* struct in6_aliasreq_64 */
                if (!privileged) {
                        error = EPERM;
                        goto done;
                }
                error = in6_domifattach(ifp);
                goto done;

        case SIOCPROTODETACH_IN6:       /* struct in6_ifreq */
                if (!privileged) {
                        error = EPERM;
                        goto done;
                }
                /* Cleanup interface routes and addresses */
                in6_purgeif(ifp);

                if ((error = proto_unplumb(PF_INET6, ifp))) {
                        log(LOG_ERR, "SIOCPROTODETACH_IN6: %s error=%d\n",
                            if_name(ifp), error);
                }
                goto done;

        case SIOCSNDFLUSH_IN6:          /* struct in6_ifreq */
        case SIOCSPFXFLUSH_IN6:         /* struct in6_ifreq */
        case SIOCSRTRFLUSH_IN6:         /* struct in6_ifreq */
        case SIOCSDEFIFACE_IN6_32:      /* struct in6_ndifreq_32 */
        case SIOCSDEFIFACE_IN6_64:      /* struct in6_ndifreq_64 */
        case SIOCSIFINFO_FLAGS:         /* struct in6_ndireq */
        case SIOCGIFCGAPREP_IN6_32:     /* struct in6_cgareq_32 */
        case SIOCGIFCGAPREP_IN6_64:     /* struct in6_cgareq_64 */
        case SIOCSIFCGAPREP_IN6_32:     /* struct in6_cgareq_32 */
        case SIOCSIFCGAPREP_IN6_64:     /* struct in6_cgareq_32 */
                if (!privileged) {
                        error = EPERM;
                        goto done;
                }
                OS_FALLTHROUGH;
        case OSIOCGIFINFO_IN6:          /* struct in6_ondireq */
        case SIOCGIFINFO_IN6:           /* struct in6_ondireq */
        case SIOCGDRLST_IN6_32:         /* struct in6_drlist_32 */
        case SIOCGDRLST_IN6_64:         /* struct in6_drlist_64 */
        case SIOCGPRLST_IN6_32:         /* struct in6_prlist_32 */
        case SIOCGPRLST_IN6_64:         /* struct in6_prlist_64 */
        case SIOCGNBRINFO_IN6_32:       /* struct in6_nbrinfo_32 */
        case SIOCGNBRINFO_IN6_64:       /* struct in6_nbrinfo_64 */
        case SIOCGDEFIFACE_IN6_32:      /* struct in6_ndifreq_32 */
        case SIOCGDEFIFACE_IN6_64:      /* struct in6_ndifreq_64 */
                error = nd6_ioctl(cmd, data, ifp);
                goto done;

        case SIOCSIFPREFIX_IN6:         /* struct in6_prefixreq (deprecated) */
        case SIOCDIFPREFIX_IN6:         /* struct in6_prefixreq (deprecated) */
        case SIOCAIFPREFIX_IN6:         /* struct in6_rrenumreq (deprecated) */
        case SIOCCIFPREFIX_IN6:         /* struct in6_rrenumreq (deprecated) */
        case SIOCSGIFPREFIX_IN6:        /* struct in6_rrenumreq (deprecated) */
        case SIOCGIFPREFIX_IN6:         /* struct in6_prefixreq (deprecated) */
                log(LOG_NOTICE,
                    "prefix ioctls are now invalidated. "
                    "please use ifconfig.\n");
                error = EOPNOTSUPP;
                goto done;

        case SIOCSSCOPE6:               /* struct in6_ifreq (deprecated) */
        case SIOCGSCOPE6:               /* struct in6_ifreq (deprecated) */
        case SIOCGSCOPE6DEF:            /* struct in6_ifreq (deprecated) */
                error = EOPNOTSUPP;
                goto done;

        case SIOCLL_CGASTART_32:        /* struct in6_cgareq_32 */
        case SIOCLL_CGASTART_64:        /* struct in6_cgareq_64 */
                if (!privileged) {
                        error = EPERM;
                } else {
                        error = in6ctl_cgastart(ifp, cmd, data);
                }
                goto done;

        case SIOCGIFSTAT_IN6:           /* struct in6_ifreq */
        case SIOCGIFSTAT_ICMP6:         /* struct in6_ifreq */
                error = in6ctl_gifstat(ifp, cmd, ifr);
                goto done;
        }

        /*
         * ioctls which require interface address; obtain sockaddr_in6.
         */
        switch (cmd) {
        case SIOCSIFADDR_IN6:           /* struct in6_ifreq (deprecated) */
        case SIOCSIFDSTADDR_IN6:        /* struct in6_ifreq (deprecated) */
        case SIOCSIFNETMASK_IN6:        /* struct in6_ifreq (deprecated) */
                /*
                 * Since IPv6 allows a node to assign multiple addresses
                 * on a single interface, SIOCSIFxxx ioctls are deprecated.
                 */
                /* we decided to obsolete this command (20000704) */
                error = EOPNOTSUPP;
                goto done;

        case SIOCAIFADDR_IN6_32:        /* struct in6_aliasreq_32 */
        case SIOCAIFADDR_IN6_64:        /* struct in6_aliasreq_64 */
                if (!privileged) {
                        error = EPERM;
                        goto done;
                }
                /*
                 * Convert user ifra to the kernel form, when appropriate.
                 * This allows the conversion between different data models
                 * to be centralized, so that it can be passed around to other
                 * routines that are expecting the kernel form.
                 */
                ifra = in6_aliasreq_to_native(data,
                    (cmd == SIOCAIFADDR_IN6_64), &sifra);
                bcopy(&ifra->ifra_addr, &sin6, sizeof(sin6));
                sa6 = &sin6;
                break;

        case SIOCDIFADDR_IN6:           /* struct in6_ifreq */
        case SIOCSIFALIFETIME_IN6:      /* struct in6_ifreq */
                if (!privileged) {
                        error = EPERM;
                        goto done;
                }
                OS_FALLTHROUGH;
        case SIOCGIFADDR_IN6:           /* struct in6_ifreq */
        case SIOCGIFDSTADDR_IN6:        /* struct in6_ifreq */
        case SIOCGIFNETMASK_IN6:        /* struct in6_ifreq */
        case SIOCGIFAFLAG_IN6:          /* struct in6_ifreq */
        case SIOCGIFALIFETIME_IN6:      /* struct in6_ifreq */
                bcopy(&ifr->ifr_addr, &sin6, sizeof(sin6));
                sa6 = &sin6;
                break;
        case SIOCGIFDSTADDR:
        case SIOCSIFDSTADDR:
        case SIOCGIFBRDADDR:
        case SIOCSIFBRDADDR:
        case SIOCGIFNETMASK:
        case SIOCSIFNETMASK:
        case SIOCGIFADDR:
        case SIOCSIFADDR:
        case SIOCAIFADDR:
        case SIOCDIFADDR:
                /* Do not handle these AF_INET commands in AF_INET6 path */
                error = EINVAL;
                goto done;
        }

        /*
         * 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.
         */
        VERIFY(ia == NULL);
        if (sa6 != NULL && 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)) {
                                error = EINVAL; /* link ID contradicts */
                                goto done;
                        }
                        if (sa6->sin6_scope_id) {
                                if (sa6->sin6_scope_id !=
                                    (u_int32_t)ifp->if_index) {
                                        error = EINVAL;
                                        goto done;
                                }
                                sa6->sin6_scope_id = 0; /* XXX: good way? */
                        }
                }
                /*
                 * Any failures from this point on must take into account
                 * a non-NULL "ia" with an outstanding reference count, and
                 * therefore requires IFA_REMREF.  Jump to "done" label
                 * instead of calling return if "ia" is valid.
                 */
                ia = in6ifa_ifpwithaddr(ifp, &sa6->sin6_addr);
        }

        /*
         * SIOCDIFADDR_IN6/SIOCAIFADDR_IN6 specific tests.
         */
        switch (cmd) {
        case SIOCDIFADDR_IN6:           /* struct in6_ifreq */
                if (ia == NULL) {
                        error = EADDRNOTAVAIL;
                        goto done;
                }
                OS_FALLTHROUGH;
        case SIOCAIFADDR_IN6_32:        /* struct in6_aliasreq_32 */
        case SIOCAIFADDR_IN6_64:        /* struct in6_aliasreq_64 */
                VERIFY(sa6 != NULL);
                /*
                 * We always require users to specify a valid IPv6 address for
                 * the corresponding operation.  Use "sa6" instead of "ifra"
                 * since SIOCDIFADDR_IN6 falls thru above.
                 */
                if (sa6->sin6_family != AF_INET6 ||
                    sa6->sin6_len != sizeof(struct sockaddr_in6)) {
                        error = EAFNOSUPPORT;
                        goto done;
                }
                break;
        }

        /*
         * And finally process address-related ioctls.
         */
        switch (cmd) {
        case SIOCGIFADDR_IN6:           /* struct in6_ifreq */
        /* This interface is basically deprecated. use SIOCGIFCONF. */
        /* FALLTHRU */
        case SIOCGIFDSTADDR_IN6:        /* struct in6_ifreq */
                error = in6ctl_gifaddr(ifp, ia, cmd, ifr);
                break;

        case SIOCGIFNETMASK_IN6:        /* struct in6_ifreq */
                if (ia != NULL) {
                        IFA_LOCK(&ia->ia_ifa);
                        bcopy(&ia->ia_prefixmask, &ifr->ifr_addr,
                            sizeof(struct sockaddr_in6));
                        IFA_UNLOCK(&ia->ia_ifa);
                } else {
                        error = EADDRNOTAVAIL;
                }
                break;

        case SIOCGIFAFLAG_IN6:          /* struct in6_ifreq */
                if (ia != NULL) {
                        IFA_LOCK(&ia->ia_ifa);
                        bcopy(&ia->ia6_flags, &ifr->ifr_ifru.ifru_flags6,
                            sizeof(ifr->ifr_ifru.ifru_flags6));
                        IFA_UNLOCK(&ia->ia_ifa);
                } else {
                        error = EADDRNOTAVAIL;
                }
                break;

        case SIOCGIFALIFETIME_IN6:      /* struct in6_ifreq */
        case SIOCSIFALIFETIME_IN6:      /* struct in6_ifreq */
                error = in6ctl_alifetime(ia, cmd, ifr, p64);
                break;

        case SIOCAIFADDR_IN6_32:        /* struct in6_aliasreq_32 */
        case SIOCAIFADDR_IN6_64:        /* struct in6_aliasreq_64 */
                error = in6ctl_aifaddr(ifp, ifra);
                break;

        case SIOCDIFADDR_IN6:
                in6ctl_difaddr(ifp, ia);
                break;

        default:
                error = ifnet_ioctl(ifp, PF_INET6, cmd, data);
                break;
        }

done:
        if (ia != NULL) {
                IFA_REMREF(&ia->ia_ifa);
        }
        if (so_unlocked) {
                socket_lock(so, 0);
        }

        return error;
}

static __attribute__((noinline)) int
in6ctl_aifaddr(struct ifnet *ifp, struct in6_aliasreq *ifra)
{
        int i, error, addtmp;
        uint8_t plen;
        struct nd_prefix pr0, *pr;
        struct in6_ifaddr *ia;

        VERIFY(ifp != NULL && ifra != NULL);
        ia = NULL;

        /* Attempt to attach the protocol, in case it isn't attached */
        error = in6_domifattach(ifp);
        if (error == 0) {
                /* PF_INET6 wasn't previously attached */
                error = in6_ifattach_aliasreq(ifp, NULL, NULL);
                if (error != 0) {
                        goto done;
                }

                in6_if_up_dad_start(ifp);
        } else if (error != EEXIST) {
                goto done;
        }

        /*
         * First, make or update the interface address structure, and link it
         * to the list.
         */
        error = in6_update_ifa(ifp, ifra, 0, &ia);
        if (error != 0) {
                goto done;
        }
        VERIFY(ia != NULL);

        /* Now, make the prefix on-link on the interface. */
        plen = (uint8_t)in6_mask2len(&ifra->ifra_prefixmask.sin6_addr, NULL);
        if (plen == 128) {
                goto done;
        }

        /*
         * NOTE: 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_plen = plen;
        pr0.ndpr_ifp = ifp;
        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];
        }

        /*
         * 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);
        if (ifra->ifra_flags & (IN6_IFF_AUTOCONF | IN6_IFF_DYNAMIC)) {
                pr0.ndpr_vltime = ifra->ifra_lifetime.ia6t_vltime;
                pr0.ndpr_pltime = ifra->ifra_lifetime.ia6t_pltime;
        } else {
                pr0.ndpr_vltime = ND6_INFINITE_LIFETIME;
                pr0.ndpr_pltime = ND6_INFINITE_LIFETIME;
        }
        pr0.ndpr_stateflags |= NDPRF_STATIC;
        lck_mtx_init(&pr0.ndpr_lock, ifa_mtx_grp, ifa_mtx_attr);

        /* add the prefix if there's none. */
        if ((pr = nd6_prefix_lookup(&pr0, ND6_PREFIX_EXPIRY_NEVER)) == NULL) {
                /*
                 * nd6_prelist_add will install the corresponding interface
                 * route.
                 */
                error = nd6_prelist_add(&pr0, NULL, &pr, FALSE);
                if (error != 0) {
                        goto done;
                }

                if (pr == NULL) {
                        log(LOG_ERR, "%s: nd6_prelist_add okay, but"
                            " no prefix.\n", __func__);
                        error = EINVAL;
                        goto done;
                }
        }

        IFA_LOCK(&ia->ia_ifa);

        /* if this is a new autoconfed addr */
        addtmp = FALSE;
        if (ia->ia6_ndpr == NULL) {
                NDPR_LOCK(pr);
                ++pr->ndpr_addrcnt;
                VERIFY(pr->ndpr_addrcnt != 0);
                ia->ia6_ndpr = pr;
                NDPR_ADDREF(pr); /* for addr reference */

                /*
                 * If this is the first autoconf address from the prefix,
                 * create a temporary address as well (when specified).
                 */
                if ((ia->ia6_flags & IN6_IFF_AUTOCONF) != 0 &&
                    ip6_use_tempaddr &&
                    pr->ndpr_addrcnt == 1) {
                        addtmp = true;
                }
                NDPR_UNLOCK(pr);
        }

        IFA_UNLOCK(&ia->ia_ifa);

        if (addtmp) {
                int e;
                e = in6_tmpifadd(ia, 1);
                if (e != 0) {
                        log(LOG_NOTICE, "%s: failed to create a"
                            " temporary address, error=%d\n",
                            __func__, e);
                }
        }

        /*
         * This might affect the status of autoconfigured addresses, that is,
         * this address might make other addresses detached.
         */
        lck_mtx_lock(nd6_mutex);
        pfxlist_onlink_check();
        lck_mtx_unlock(nd6_mutex);

        /* Drop use count held above during lookup/add */
        NDPR_REMREF(pr);

done:
        if (ia != NULL) {
                IFA_REMREF(&ia->ia_ifa);
        }
        return error;
}

static __attribute__((noinline)) void
in6ctl_difaddr(struct ifnet *ifp, struct in6_ifaddr *ia)
{
        int i = 0;
        struct nd_prefix pr0, *pr;

        VERIFY(ifp != NULL && ia != 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.
         * Note that in6_purgeaddr() will decrement ndpr_addrcnt.
         */
        IFA_LOCK(&ia->ia_ifa);
        bzero(&pr0, sizeof(pr0));
        pr0.ndpr_ifp = ifp;
        pr0.ndpr_plen = (uint8_t)in6_mask2len(&ia->ia_prefixmask.sin6_addr, NULL);
        if (pr0.ndpr_plen == 128) {
                IFA_UNLOCK(&ia->ia_ifa);
                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];
        }
        IFA_UNLOCK(&ia->ia_ifa);

        if ((pr = nd6_prefix_lookup(&pr0, ND6_PREFIX_EXPIRY_UNSPEC)) != NULL) {
                IFA_LOCK(&ia->ia_ifa);
                NDPR_LOCK(pr);
                if (pr->ndpr_addrcnt == 1) {
                        /* XXX: just for expiration */
                        pr->ndpr_expire = 1;
                }
                NDPR_UNLOCK(pr);
                IFA_UNLOCK(&ia->ia_ifa);

                /* Drop use count held above during lookup */
                NDPR_REMREF(pr);
        }

purgeaddr:
        in6_purgeaddr(&ia->ia_ifa);
}

static __attribute__((noinline)) int
in6_autoconf(struct ifnet *ifp, int enable)
{
        int error = 0;

        VERIFY(ifp != NULL);

        if (ifp->if_flags & IFF_LOOPBACK) {
                return EINVAL;
        }

        if (enable) {
                /*
                 * An interface in IPv6 router mode implies that it
                 * is either configured with a static IP address or
                 * autoconfigured via a locally-generated RA.  Prevent
                 * SIOCAUTOCONF_START from being set in that mode.
                 */
                ifnet_lock_exclusive(ifp);
                if (ifp->if_ipv6_router_mode == IPV6_ROUTER_MODE_EXCLUSIVE) {
                        if_clear_eflags(ifp, IFEF_ACCEPT_RTADV);
                        error = EBUSY;
                } else {
                        if_set_eflags(ifp, IFEF_ACCEPT_RTADV);
                }
                ifnet_lock_done(ifp);
        } else {
                struct in6_ifaddr *ia = NULL;

                if_clear_eflags(ifp, IFEF_ACCEPT_RTADV);

                /* Remove autoconfigured address from interface */
                lck_rw_lock_exclusive(&in6_ifaddr_rwlock);
                boolean_t from_begining = TRUE;
                while (from_begining) {
                        from_begining = FALSE;
                        TAILQ_FOREACH(ia, &in6_ifaddrhead, ia6_link) {
                                if (ia->ia_ifa.ifa_ifp != ifp) {
                                        continue;
                                }
                                IFA_LOCK(&ia->ia_ifa);
                                if (ia->ia6_flags & IN6_IFF_AUTOCONF) {
                                        IFA_ADDREF_LOCKED(&ia->ia_ifa); /* for us */
                                        IFA_UNLOCK(&ia->ia_ifa);
                                        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.
                                         */
                                        from_begining = TRUE;
                                        break;
                                }
                                IFA_UNLOCK(&ia->ia_ifa);
                        }
                }
                lck_rw_done(&in6_ifaddr_rwlock);
        }
        return error;
}

/*
 * Handle SIOCSETROUTERMODE_IN6 to set the IPv6 router mode on the interface
 * Entering or exiting IPV6_ROUTER_MODE_EXCLUSIVE will result in the removal of
 * autoconfigured IPv6 addresses on the interface.
 */
static __attribute__((noinline)) int
in6_setrouter(struct ifnet *ifp, ipv6_router_mode_t mode)
{
        int                     error = 0;
        ipv6_router_mode_t      prev_mode;

        VERIFY(ifp != NULL);

        if (ifp->if_flags & IFF_LOOPBACK) {
                return ENODEV;
        }

        prev_mode = ifp->if_ipv6_router_mode;
        if (prev_mode == mode) {
                /* no mode change, there's nothing to do */
                return 0;
        }
        if (mode == IPV6_ROUTER_MODE_EXCLUSIVE) {
                struct nd_ifinfo *ndi = NULL;

                ndi = ND_IFINFO(ifp);
                if (ndi != NULL && ndi->initialized) {
                        lck_mtx_lock(&ndi->lock);
                        if (ndi->flags & ND6_IFF_PROXY_PREFIXES) {
                                /* No proxy if we are an advertising router */
                                ndi->flags &= ~ND6_IFF_PROXY_PREFIXES;
                                lck_mtx_unlock(&ndi->lock);
                                (void) nd6_if_prproxy(ifp, FALSE);
                        } else {
                                lck_mtx_unlock(&ndi->lock);
                        }
                }
        }

        ifp->if_ipv6_router_mode = mode;
        lck_mtx_lock(nd6_mutex);
        defrouter_select(ifp, NULL);
        lck_mtx_unlock(nd6_mutex);
        if_allmulti(ifp, (mode == IPV6_ROUTER_MODE_EXCLUSIVE));
        if (mode == IPV6_ROUTER_MODE_EXCLUSIVE ||
            (prev_mode == IPV6_ROUTER_MODE_EXCLUSIVE
            && mode == IPV6_ROUTER_MODE_DISABLED)) {
                error = in6_autoconf(ifp, FALSE);
        }
        return error;
}

static int
in6_to_kamescope(struct sockaddr_in6 *sin6, struct ifnet *ifp)
{
        struct sockaddr_in6 tmp;
        int error, id;

        VERIFY(sin6 != NULL);
        tmp = *sin6;

        error = in6_recoverscope(&tmp, &sin6->sin6_addr, ifp);
        if (error != 0) {
                return error;
        }

        id = in6_addr2scopeid(ifp, &tmp.sin6_addr);
        if (tmp.sin6_scope_id == 0) {
                tmp.sin6_scope_id = id;
        } else if (tmp.sin6_scope_id != id) {
                return EINVAL; /* scope ID mismatch. */
        }
        error = in6_embedscope(&tmp.sin6_addr, &tmp, NULL, NULL, NULL);
        if (error != 0) {
                return error;
        }

        tmp.sin6_scope_id = 0;
        *sin6 = tmp;
        return 0;
}

/*
 * When the address is being configured we should clear out certain flags
 * coming in from the caller.
 */
#define IN6_IFF_CLR_ADDR_FLAG_MASK      (~(IN6_IFF_DEPRECATED | IN6_IFF_DETACHED | IN6_IFF_DUPLICATED))

static int
in6_ifaupdate_aux(struct in6_ifaddr *ia, struct ifnet *ifp, int ifaupflags)
{
        struct sockaddr_in6 mltaddr, mltmask;
        struct in6_addr llsol;
        struct ifaddr *ifa;
        struct in6_multi *in6m_sol;
        struct in6_multi_mship *imm;
        struct rtentry *rt;
        int delay, error = 0;

        VERIFY(ifp != NULL && ia != NULL);
        ifa = &ia->ia_ifa;
        in6m_sol = NULL;

        nd6log2(debug, "%s - %s ifp %s ia6_flags 0x%x ifaupflags 0x%x\n",
            __func__,
            ip6_sprintf(&ia->ia_addr.sin6_addr),
            if_name(ia->ia_ifp),
            ia->ia6_flags,
            ifaupflags);

        /*
         * Just to be safe, always clear certain flags when address
         * is being configured
         */
        ia->ia6_flags &= IN6_IFF_CLR_ADDR_FLAG_MASK;

        /*
         * Mark the address as tentative before joining multicast addresses,
         * so that corresponding MLD responses would not have a tentative
         * source address.
         */
        if (in6if_do_dad(ifp)) {
                in6_ifaddr_set_dadprogress(ia);
                /*
                 * Do not delay sending neighbor solicitations when using optimistic
                 * duplicate address detection, c.f. RFC 4429.
                 */
                if (ia->ia6_flags & IN6_IFF_OPTIMISTIC) {
                        ifaupflags &= ~IN6_IFAUPDATE_DADDELAY;
                } else {
                        ifaupflags |= IN6_IFAUPDATE_DADDELAY;
                }
        } else {
                /*
                 * If the interface has been marked to not perform
                 * DAD, make sure to reset DAD in progress flags
                 * that may come in from the caller.
                 */
                ia->ia6_flags &= ~IN6_IFF_DADPROGRESS;
        }

        /* Join necessary multicast groups */
        if ((ifp->if_flags & IFF_MULTICAST) != 0) {
                /* join solicited multicast addr for new host id */
                bzero(&llsol, sizeof(struct in6_addr));
                llsol.s6_addr32[0] = IPV6_ADDR_INT32_MLL;
                llsol.s6_addr32[1] = 0;
                llsol.s6_addr32[2] = htonl(1);
                llsol.s6_addr32[3] = ia->ia_addr.sin6_addr.s6_addr32[3];
                llsol.s6_addr8[12] = 0xff;
                if ((error = in6_setscope(&llsol, ifp, NULL)) != 0) {
                        /* XXX: should not happen */
                        log(LOG_ERR, "%s: in6_setscope failed\n", __func__);
                        goto unwind;
                }
                delay = 0;
                if ((ifaupflags & IN6_IFAUPDATE_DADDELAY)) {
                        /*
                         * We need a random delay for DAD on the address
                         * being configured.  It also means delaying
                         * transmission of the corresponding MLD report to
                         * avoid report collision. [RFC 4862]
                         */
                        delay = random() % MAX_RTR_SOLICITATION_DELAY;
                }
                imm = in6_joingroup(ifp, &llsol, &error, delay);
                if (imm == NULL) {
                        nd6log(info,
                            "%s: addmulti failed for %s on %s (errno=%d)\n",
                            __func__, ip6_sprintf(&llsol), if_name(ifp),
                            error);
                        VERIFY(error != 0);
                        goto unwind;
                }
                in6m_sol = imm->i6mm_maddr;
                /* take a refcount for this routine */
                IN6M_ADDREF(in6m_sol);

                IFA_LOCK_SPIN(ifa);
                LIST_INSERT_HEAD(&ia->ia6_memberships, imm, i6mm_chain);
                IFA_UNLOCK(ifa);

                bzero(&mltmask, sizeof(mltmask));
                mltmask.sin6_len = sizeof(struct sockaddr_in6);
                mltmask.sin6_family = AF_INET6;
                mltmask.sin6_addr = in6mask32;
#define MLTMASK_LEN  4  /* mltmask's masklen (=32bit=4octet) */

                /*
                 * join link-local all-nodes address
                 */
                bzero(&mltaddr, sizeof(mltaddr));
                mltaddr.sin6_len = sizeof(struct sockaddr_in6);
                mltaddr.sin6_family = AF_INET6;
                mltaddr.sin6_addr = in6addr_linklocal_allnodes;
                if ((error = in6_setscope(&mltaddr.sin6_addr, ifp, NULL)) != 0) {
                        goto unwind; /* XXX: should not fail */
                }
                /*
                 * XXX: do we really need this automatic routes?
                 * We should probably reconsider this stuff.  Most applications
                 * actually do not need the routes, since they usually specify
                 * the outgoing interface.
                 */
                rt = rtalloc1_scoped((struct sockaddr *)&mltaddr, 0, 0UL,
                    ia->ia_ifp->if_index);
                if (rt) {
                        if (memcmp(&mltaddr.sin6_addr, &((struct sockaddr_in6 *)
                            (void *)rt_key(rt))->sin6_addr, MLTMASK_LEN)) {
                                rtfree(rt);
                                rt = NULL;
                        }
                }
                if (!rt) {
                        error = rtrequest_scoped(RTM_ADD,
                            (struct sockaddr *)&mltaddr,
                            (struct sockaddr *)&ia->ia_addr,
                            (struct sockaddr *)&mltmask, RTF_UP | RTF_CLONING,
                            NULL, ia->ia_ifp->if_index);
                        if (error) {
                                goto unwind;
                        }
                } else {
                        rtfree(rt);
                }

                imm = in6_joingroup(ifp, &mltaddr.sin6_addr, &error, 0);
                if (!imm) {
                        nd6log(info,
                            "%s: addmulti failed for %s on %s (errno=%d)\n",
                            __func__, ip6_sprintf(&mltaddr.sin6_addr),
                            if_name(ifp), error);
                        VERIFY(error != 0);
                        goto unwind;
                }
                IFA_LOCK_SPIN(ifa);
                LIST_INSERT_HEAD(&ia->ia6_memberships, imm, i6mm_chain);
                IFA_UNLOCK(ifa);

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

                /*
                 * join interface-local all-nodes address.
                 * (ff01::1%ifN, and ff01::%ifN/32)
                 */
                mltaddr.sin6_addr = in6addr_nodelocal_allnodes;
                if ((error = in6_setscope(&mltaddr.sin6_addr, ifp, NULL)) != 0) {
                        goto unwind; /* XXX: should not fail */
                }
                /* XXX: again, do we really need the route? */
                rt = rtalloc1_scoped((struct sockaddr *)&mltaddr, 0, 0UL,
                    ia->ia_ifp->if_index);
                if (rt) {
                        if (memcmp(&mltaddr.sin6_addr, &((struct sockaddr_in6 *)
                            (void *)rt_key(rt))->sin6_addr, MLTMASK_LEN)) {
                                rtfree(rt);
                                rt = NULL;
                        }
                }
                if (!rt) {
                        error = rtrequest_scoped(RTM_ADD,
                            (struct sockaddr *)&mltaddr,
                            (struct sockaddr *)&ia->ia_addr,
                            (struct sockaddr *)&mltmask, RTF_UP | RTF_CLONING,
                            NULL, ia->ia_ifp->if_index);
                        if (error) {
                                goto unwind;
                        }
                } else {
                        rtfree(rt);
                }

                imm = in6_joingroup(ifp, &mltaddr.sin6_addr, &error, 0);
                if (!imm) {
                        nd6log(info,
                            "%s: addmulti failed for %s on %s (errno=%d)\n",
                            __func__, ip6_sprintf(&mltaddr.sin6_addr),
                            if_name(ifp), error);
                        VERIFY(error != 0);
                        goto unwind;
                }
                IFA_LOCK(ifa);
                LIST_INSERT_HEAD(&ia->ia6_memberships, imm, i6mm_chain);
                IFA_UNLOCK(ifa);
#undef  MLTMASK_LEN

                /*
                 * create a ff00::/8 route
                 */
                bzero(&mltmask, sizeof(mltmask));
                mltmask.sin6_len = sizeof(struct sockaddr_in6);
                mltmask.sin6_family = AF_INET6;
                mltmask.sin6_addr = in6mask8;
#define MLTMASK_LEN_8_BITS  1  /* ff00::/8 mltmask's masklen (=8bit=1octet) */

                bzero(&mltaddr, sizeof(mltaddr));
                mltaddr.sin6_len = sizeof(struct sockaddr_in6);
                mltaddr.sin6_family = AF_INET6;
                mltaddr.sin6_addr = in6addr_multicast_prefix;

                rt = rtalloc1_scoped((struct sockaddr *)&mltaddr, 0, 0UL,
                    ia->ia_ifp->if_index);
                if (rt) {
                        if (memcmp(&mltaddr.sin6_addr, &((struct sockaddr_in6 *)
                            (void *)rt_key(rt))->sin6_addr, MLTMASK_LEN_8_BITS)) {
                                rtfree(rt);
                                rt = NULL;
                        }
                }
                if (!rt) {
                        error = rtrequest_scoped(RTM_ADD,
                            (struct sockaddr *)&mltaddr,
                            (struct sockaddr *)&ia->ia_addr,
                            (struct sockaddr *)&mltmask, RTF_UP | RTF_CLONING,
                            NULL, ia->ia_ifp->if_index);
                        if (error) {
                                goto unwind;
                        }
                } else {
                        rtfree(rt);
                }
        }
#undef  MLTMASK_LEN_8_BITS

        /* Ensure nd6_service() is scheduled as soon as it's convenient */
        ++nd6_sched_timeout_want;

        /*
         * Perform DAD, if:
         * * Interface is marked to perform DAD, AND
         * * Address is not marked to skip DAD, AND
         * * Address is in a pre-DAD state (Tentative or Optimistic)
         */
        IFA_LOCK_SPIN(ifa);
        if (in6if_do_dad(ifp) && (ia->ia6_flags & IN6_IFF_NODAD) == 0 &&
            (ia->ia6_flags & IN6_IFF_DADPROGRESS) != 0) {
                int mindelay, maxdelay;
                int *delayptr, delayval;

                IFA_UNLOCK(ifa);
                delayptr = NULL;
                /*
                 * Avoid the DAD delay if the caller wants us to skip it.
                 * This is not compliant with RFC 2461, but it's only being
                 * used for signalling and not for actual DAD.
                 */
                if ((ifaupflags & IN6_IFAUPDATE_DADDELAY) &&
                    !(ia->ia6_flags & IN6_IFF_SWIFTDAD)) {
                        /*
                         * We need to impose a delay before sending an NS
                         * for DAD.  Check if we also needed a delay for the
                         * corresponding MLD message.  If we did, the delay
                         * should be larger than the MLD delay (this could be
                         * relaxed a bit, but this simple logic is at least
                         * safe).
                         */
                        mindelay = 0;
                        if (in6m_sol != NULL) {
                                IN6M_LOCK(in6m_sol);
                                if (in6m_sol->in6m_state ==
                                    MLD_REPORTING_MEMBER) {
                                        mindelay = in6m_sol->in6m_timer;
                                }
                                IN6M_UNLOCK(in6m_sol);
                        }
                        maxdelay = MAX_RTR_SOLICITATION_DELAY * hz;
                        if (maxdelay - mindelay == 0) {
                                delayval = 0;
                        } else {
                                delayval =
                                    (random() % (maxdelay - mindelay)) +
                                    mindelay;
                        }
                        delayptr = &delayval;
                }

                nd6_dad_start((struct ifaddr *)ia, delayptr);
        } else {
                IFA_UNLOCK(ifa);
        }

        goto done;

unwind:
        VERIFY(error != 0);
        in6_purgeaddr(&ia->ia_ifa);

done:
        /* release reference held for this routine */
        if (in6m_sol != NULL) {
                IN6M_REMREF(in6m_sol);
        }
        return error;
}

/*
 * Request an IPv6 interface address.  If the address is new, then it will be
 * constructed and appended to the interface address chains.  The interface
 * address structure is optionally returned with a reference for the caller.
 */
int
in6_update_ifa(struct ifnet *ifp, struct in6_aliasreq *ifra, int ifaupflags,
    struct in6_ifaddr **iar)
{
        struct in6_addrlifetime ia6_lt;
        struct in6_ifaddr *ia;
        struct ifaddr *ifa;
        struct ifaddr *xifa;
        struct in6_addrlifetime *lt;
        uint64_t timenow;
        int plen, error;

        /* Sanity check parameters and initialize locals */
        VERIFY(ifp != NULL && ifra != NULL && iar != NULL);
        ia = NULL;
        ifa = NULL;
        error = 0;

        /*
         * 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)) {
                error = EAFNOSUPPORT;
                goto unwind;
        }

        /* Validate ifra_prefixmask.sin6_len is properly bounded. */
        if (ifra->ifra_prefixmask.sin6_len == 0 ||
            ifra->ifra_prefixmask.sin6_len > sizeof(struct sockaddr_in6)) {
                error = EINVAL;
                goto unwind;
        }

        /* Validate prefix length extracted from ifra_prefixmask structure. */
        plen = (uint8_t)in6_mask2len(&ifra->ifra_prefixmask.sin6_addr,
            (u_char *)&ifra->ifra_prefixmask + ifra->ifra_prefixmask.sin6_len);
        if (plen <= 0) {
                error = EINVAL;
                goto unwind;
        }

        /* Validate lifetimes */
        lt = &ifra->ifra_lifetime;
        if (lt->ia6t_pltime > lt->ia6t_vltime) {
                log(LOG_INFO,
                    "%s: pltime 0x%x > vltime 0x%x for %s\n", __func__,
                    lt->ia6t_pltime, lt->ia6t_vltime,
                    ip6_sprintf(&ifra->ifra_addr.sin6_addr));
                error = EINVAL;
                goto unwind;
        }
        if (lt->ia6t_vltime == 0) {
                /*
                 * the following log might be noisy, but this is a typical
                 * configuration mistake or a tool's bug.
                 */
                log(LOG_INFO, "%s: valid lifetime is 0 for %s\n", __func__,
                    ip6_sprintf(&ifra->ifra_addr.sin6_addr));
        }

        /*
         * Before we lock the ifnet structure, we first check to see if the
         * address already exists. If so, then we don't allocate and link a
         * new one here.
         */
        struct sockaddr_in6 lookup_address = ifra->ifra_addr;
        if (IN6_IS_ADDR_LINKLOCAL(&lookup_address.sin6_addr)) {
                if (lookup_address.sin6_addr.s6_addr16[1] == 0) {
                        /* link ID is not embedded by the user */
                        lookup_address.sin6_addr.s6_addr16[1] =
                            htons(ifp->if_index);
                } else if (lookup_address.sin6_addr.s6_addr16[1] !=
                    htons(ifp->if_index)) {
                        error = EINVAL; /* link ID contradicts */
                        goto done;
                }
                if (lookup_address.sin6_scope_id != 0 &&
                    lookup_address.sin6_scope_id !=
                    (u_int32_t)ifp->if_index) {
                        error = EINVAL;
                        goto done;
                }
        }

        ia = in6ifa_ifpwithaddr(ifp, &lookup_address.sin6_addr);
        if (ia != NULL) {
                ifa = &ia->ia_ifa;
        }

        /*
         * Validate destination address on interface types that require it.
         */
        if ((ifp->if_flags & (IFF_LOOPBACK | IFF_POINTOPOINT)) != 0) {
                switch (ifra->ifra_dstaddr.sin6_family) {
                case AF_INET6:
                        if (plen != 128) {
                                /* noisy message for diagnostic purposes */
                                log(LOG_INFO,
                                    "%s: prefix length < 128 with"
                                    " explicit dstaddr.\n", __func__);
                                error = EINVAL;
                                goto unwind;
                        }
                        break;

                case AF_UNSPEC:
                        break;

                default:
                        error = EAFNOSUPPORT;
                        goto unwind;
                }
        } else if (ifra->ifra_dstaddr.sin6_family != AF_UNSPEC) {
                log(LOG_INFO,
                    "%s: dstaddr valid only on p2p and loopback interfaces.\n",
                    __func__);
                error = EINVAL;
                goto unwind;
        }

        timenow = net_uptime();

        if (ia == NULL) {
                zalloc_flags_t how;

                /* Is this the first new IPv6 address for the interface? */
                ifaupflags |= IN6_IFAUPDATE_NEWADDR;

                /* Allocate memory for IPv6 interface address structure. */
                how = (ifaupflags & IN6_IFAUPDATE_NOWAIT) ? Z_NOWAIT : Z_WAITOK;
                ia = in6_ifaddr_alloc(how);
                if (ia == NULL) {
                        error = ENOBUFS;
                        goto unwind;
                }

                ifa = &ia->ia_ifa;

                /*
                 * Initialize interface address structure.
                 *
                 * Note well: none of these sockaddr_in6 structures contain a
                 * valid sin6_port, sin6_flowinfo or even a sin6_scope_id field.
                 * We still embed link-local scope identifiers at the end of an
                 * arbitrary fe80::/32 prefix, for historical reasons. Also, the
                 * ifa_dstaddr field is always non-NULL on point-to-point and
                 * loopback interfaces, and conventionally points to a socket
                 * address of AF_UNSPEC family when there is no destination.
                 *
                 * Please enjoy the dancing sea turtle.
                 */
                IFA_ADDREF(ifa); /* for this and optionally for caller */
                IA6_HASH_INIT(ia);
                ifa->ifa_addr = (struct sockaddr *)&ia->ia_addr;
                if (ifra->ifra_dstaddr.sin6_family == AF_INET6 ||
                    (ifp->if_flags & (IFF_POINTOPOINT | IFF_LOOPBACK)) != 0) {
                        ifa->ifa_dstaddr = (struct sockaddr *)&ia->ia_dstaddr;
                }
                ifa->ifa_netmask = (struct sockaddr *)&ia->ia_prefixmask;
                ifa->ifa_ifp = ifp;
                ifa->ifa_metric = ifp->if_metric;
                ifa->ifa_rtrequest = nd6_rtrequest;

                LIST_INIT(&ia->ia6_memberships);
                ia->ia_addr.sin6_family = AF_INET6;
                ia->ia_addr.sin6_len = sizeof(ia->ia_addr);
                ia->ia_addr.sin6_addr = ifra->ifra_addr.sin6_addr;
                ia->ia_prefixmask.sin6_family = AF_INET6;
                ia->ia_prefixmask.sin6_len = sizeof(ia->ia_prefixmask);
                ia->ia_prefixmask.sin6_addr = ifra->ifra_prefixmask.sin6_addr;
                error = in6_to_kamescope(&ia->ia_addr, ifp);
                if (error != 0) {
                        goto unwind;
                }
                if (ifa->ifa_dstaddr != NULL) {
                        ia->ia_dstaddr = ifra->ifra_dstaddr;
                        error = in6_to_kamescope(&ia->ia_dstaddr, ifp);
                        if (error != 0) {
                                goto unwind;
                        }
                }

                /* Append to address chains */
                ifnet_lock_exclusive(ifp);
                ifaupflags |= IN6_IFAUPDATE_1STADDR;
                TAILQ_FOREACH(xifa, &ifp->if_addrlist, ifa_list) {
                        IFA_LOCK_SPIN(xifa);
                        if (xifa->ifa_addr->sa_family != AF_INET6) {
                                IFA_UNLOCK(xifa);
                                ifaupflags &= ~IN6_IFAUPDATE_1STADDR;
                                break;
                        }
                        IFA_UNLOCK(xifa);
                }

                IFA_LOCK_SPIN(ifa);
                if_attach_ifa(ifp, ifa); /* holds reference for ifnet link */
                IFA_UNLOCK(ifa);
                ifnet_lock_done(ifp);

                lck_rw_lock_exclusive(&in6_ifaddr_rwlock);
                TAILQ_INSERT_TAIL(&in6_ifaddrhead, ia, ia6_link);
                IFA_ADDREF(ifa); /* hold for in6_ifaddrs link */
                lck_rw_done(&in6_ifaddr_rwlock);
        } else {
                ifa = &ia->ia_ifa;
                ifaupflags &= ~(IN6_IFAUPDATE_NEWADDR | IN6_IFAUPDATE_1STADDR);
        }

        VERIFY(ia != NULL && ifa == &ia->ia_ifa);
        IFA_LOCK(ifa);

        /*
         * 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_updatetime = ia->ia6_createtime = timenow;
        ia6_lt = *lt;
        if (ia6_lt.ia6t_vltime != ND6_INFINITE_LIFETIME) {
                ia6_lt.ia6t_expire = timenow + ia6_lt.ia6t_vltime;
        } else {
                ia6_lt.ia6t_expire = 0;
        }
        if (ia6_lt.ia6t_pltime != ND6_INFINITE_LIFETIME) {
                ia6_lt.ia6t_preferred = timenow + ia6_lt.ia6t_pltime;
        } else {
                ia6_lt.ia6t_preferred = 0;
        }
        in6ifa_setlifetime(ia, &ia6_lt);

        /*
         * Backward compatibility - if IN6_IFF_DEPRECATED is set from the
         * userland, make it deprecated.
         */
        if ((ia->ia6_flags & IN6_IFF_DEPRECATED) != 0) {
                ia->ia6_lifetime.ia6ti_pltime = 0;
                ia->ia6_lifetime.ia6ti_preferred = timenow;
        }

        /*
         * Update flag or prefix length
         */
        ia->ia_plen = plen;
        ia->ia6_flags = ifra->ifra_flags;

        /* Release locks (new address available to concurrent tasks) */
        IFA_UNLOCK(ifa);

        /* Further initialization of the interface address */
        error = in6_ifinit(ifp, ia, ifaupflags);
        if (error != 0) {
                goto unwind;
        }

        /* Finish updating the address while other tasks are working with it */
        error = in6_ifaupdate_aux(ia, ifp, ifaupflags);
        if (error != 0) {
                goto unwind;
        }

        /* Return success (optionally w/ address for caller). */
        VERIFY(error == 0);
        (void) ifnet_notify_address(ifp, AF_INET6);
        goto done;

unwind:
        VERIFY(error != 0);
        if (ia != NULL) {
                VERIFY(ifa == &ia->ia_ifa);
                IFA_REMREF(ifa);
                ia = NULL;
        }

done:
        *iar = ia;
        return error;
}

void
in6_purgeaddr(struct ifaddr *ifa)
{
        struct ifnet *ifp = ifa->ifa_ifp;
        struct in6_ifaddr *ia = (struct in6_ifaddr *)ifa;
        struct in6_multi_mship *imm;

        LCK_MTX_ASSERT(nd6_mutex, LCK_MTX_ASSERT_NOTOWNED);

        /* 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.
         */
        IFA_LOCK(ifa);
        if ((ia->ia_flags & IFA_ROUTE) && ia->ia_plen == 128) {
                int error, rtf;

                IFA_UNLOCK(ifa);
                rtf = (ia->ia_dstaddr.sin6_family == AF_INET6) ? RTF_HOST : 0;
                error = rtinit(&(ia->ia_ifa), RTM_DELETE, rtf);
                if (error != 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),
                            error);
                        /* proceed anyway... */
                }
                IFA_LOCK_SPIN(ifa);
                ia->ia_flags &= ~IFA_ROUTE;
        }
        IFA_UNLOCK(ifa);

        /* Remove ownaddr's loopback rtentry, if it exists. */
        in6_ifremloop(&(ia->ia_ifa));

        /*
         * 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);
        }
        IFA_UNLOCK(ifa);

        /* in6_unlink_ifa() will need exclusive access */
        in6_unlink_ifa(ia, ifp);
        in6_post_msg(ifp, KEV_INET6_ADDR_DELETED, ia, NULL);

        (void) ifnet_notify_address(ifp, AF_INET6);
}

static void
in6_unlink_ifa(struct in6_ifaddr *ia, struct ifnet *ifp)
{
        struct in6_ifaddr *nia;
        struct ifaddr *ifa;
        int unlinked;

        LCK_MTX_ASSERT(nd6_mutex, LCK_MTX_ASSERT_NOTOWNED);

        ifa = &ia->ia_ifa;
        IFA_ADDREF(ifa);

        ifnet_lock_exclusive(ifp);
        IFA_LOCK(ifa);
        if (ifa->ifa_debug & IFD_ATTACHED) {
                if_detach_ifa(ifp, ifa);
        }
        IFA_UNLOCK(ifa);
        ifnet_lock_done(ifp);

        unlinked = 0;
        lck_rw_lock_exclusive(&in6_ifaddr_rwlock);
        TAILQ_FOREACH(nia, &in6_ifaddrhead, ia6_link) {
                if (ia == nia) {
                        TAILQ_REMOVE(&in6_ifaddrhead, ia, ia6_link);
                        IFA_LOCK(ifa);
                        if (IA6_IS_HASHED(ia)) {
                                in6_iahash_remove(ia);
                        }
                        IFA_UNLOCK(ifa);
                        unlinked = 1;
                        break;
                }
        }

        /*
         * When IPv6 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().
         */
        IFA_LOCK(ifa);
        /*
         * Only log the below message for addresses other than
         * link local.
         * Only one LLA (auto-configured or statically) is allowed
         * on an interface.
         * LLA prefix, while added to the prefix list, is not
         * reference countedi (as it is the only one).
         * The prefix also never expires on its own as LLAs
         * have infinite lifetime.
         *
         * For now quiece down the log message for LLAs.
         */
        if (!IN6_IS_ADDR_LINKLOCAL(&ia->ia_addr.sin6_addr)) {
                if (ia->ia6_ndpr == NULL) {
                        log(LOG_NOTICE, "in6_unlink_ifa: IPv6 address "
                            "0x%llx has no prefix\n",
                            (uint64_t)VM_KERNEL_ADDRPERM(ia));
                } else {
                        struct nd_prefix *pr = ia->ia6_ndpr;
                        ia->ia6_flags &= ~IN6_IFF_AUTOCONF;
                        ia->ia6_ndpr = NULL;
                        NDPR_LOCK(pr);
                        VERIFY(pr->ndpr_addrcnt != 0);
                        pr->ndpr_addrcnt--;
                        if (ia->ia6_flags & IN6_IFF_CLAT46) {
                                pr->ndpr_stateflags &= ~NDPRF_CLAT46;
                        }
                        NDPR_UNLOCK(pr);
                        NDPR_REMREF(pr);        /* release addr reference */
                }
        }
        IFA_UNLOCK(ifa);
        lck_rw_done(&in6_ifaddr_rwlock);

        if ((ia->ia6_flags & IN6_IFF_AUTOCONF) != 0) {
                lck_mtx_lock(nd6_mutex);
                pfxlist_onlink_check();
                lck_mtx_unlock(nd6_mutex);
        }
        /*
         * 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);

        /* invalidate route caches */
        routegenid_inet6_update();
}

void
in6_purgeif(struct ifnet *ifp)
{
        struct in6_ifaddr *ia;

        if (ifp == NULL) {
                return;
        }

        LCK_MTX_ASSERT(nd6_mutex, LCK_MTX_ASSERT_NOTOWNED);

        lck_rw_lock_exclusive(&in6_ifaddr_rwlock);
        boolean_t from_begining = TRUE;
        while (from_begining) {
                from_begining = FALSE;
                TAILQ_FOREACH(ia, &in6_ifaddrhead, ia6_link) {
                        if (ia->ia_ifa.ifa_ifp != ifp) {
                                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 would have caused
                         * in6_ifaddr_rwlock to be dropped and reacquired;
                         * therefore search again from the beginning
                         * of in6_ifaddrs list.
                         */
                        from_begining = TRUE;
                        break;
                }
        }
        lck_rw_done(&in6_ifaddr_rwlock);

        in6_ifdetach(ifp);
}

/*
 * Initialize an interface's internet6 address and routing table entry.
 */
static int
in6_ifinit(struct ifnet *ifp, struct in6_ifaddr *ia, int ifaupflags)
{
        int error;
        struct ifaddr *ifa;

        error = 0;
        ifa = &ia->ia_ifa;

        lck_rw_lock_exclusive(&in6_ifaddr_rwlock);
        IFA_LOCK(&ia->ia_ifa);
        if (IA6_IS_HASHED(ia)) {
                in6_iahash_remove(ia);
        }
        if ((ifp->if_flags & IFF_POINTOPOINT)) {
                in6_iahash_insert_ptp(ia);
        } else {
                in6_iahash_insert(ia);
        }
        IFA_UNLOCK(&ia->ia_ifa);
        lck_rw_done(&in6_ifaddr_rwlock);

        /*
         * NOTE: SIOCSIFADDR is defined with struct ifreq as parameter,
         * but here we are sending it down to the interface with a pointer
         * to struct ifaddr, for legacy reasons.
         */
        if ((ifaupflags & IN6_IFAUPDATE_1STADDR) != 0) {
                error = ifnet_ioctl(ifp, PF_INET6, SIOCSIFADDR, ia);
                if (error != 0) {
                        if (error != EOPNOTSUPP) {
                                goto failed;
                        }
                        error = 0;
                }
        }

        IFA_LOCK(ifa);

        /*
         * 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.
         */
        if (!(ia->ia_flags & IFA_ROUTE) && ia->ia_plen == 128 &&
            ia->ia_dstaddr.sin6_family == AF_INET6) {
                IFA_UNLOCK(ifa);
                error = rtinit(ifa, RTM_ADD, RTF_UP | RTF_HOST);
                if (error != 0) {
                        goto failed;
                }
                IFA_LOCK(ifa);
                ia->ia_flags |= IFA_ROUTE;
        }
        IFA_LOCK_ASSERT_HELD(ifa);
        if (ia->ia_plen < 128) {
                /*
                 * The RTF_CLONING flag is necessary for in6_is_ifloop_auto().
                 */
                ia->ia_flags |= RTF_CLONING;
        }

        IFA_UNLOCK(ifa);

        /* Add ownaddr as loopback rtentry, if necessary (ex. on p2p link). */
        if ((ifaupflags & IN6_IFAUPDATE_NEWADDR) != 0) {
                in6_ifaddloop(ifa);
        }

        /* invalidate route caches */
        routegenid_inet6_update();

        VERIFY(error == 0);
        return 0;
failed:
        VERIFY(error != 0);
        lck_rw_lock_exclusive(&in6_ifaddr_rwlock);
        IFA_LOCK(&ia->ia_ifa);
        if (IA6_IS_HASHED(ia)) {
                in6_iahash_remove(ia);
        }
        IFA_UNLOCK(&ia->ia_ifa);
        lck_rw_done(&in6_ifaddr_rwlock);

        return error;
}

void
in6_purgeaddrs(struct ifnet *ifp)
{
        in6_purgeif(ifp);
}

/*
 * Find an IPv6 interface link-local address specific to an interface.
 */
struct in6_ifaddr *
in6ifa_ifpforlinklocal(struct ifnet *ifp, int ignoreflags)
{
        struct ifaddr *ifa;

        ifnet_lock_shared(ifp);
        TAILQ_FOREACH(ifa, &ifp->if_addrlist, ifa_list)
        {
                IFA_LOCK_SPIN(ifa);
                if (ifa->ifa_addr->sa_family != AF_INET6) {
                        IFA_UNLOCK(ifa);
                        continue;
                }
                if (IN6_IS_ADDR_LINKLOCAL(IFA_IN6(ifa))) {
                        if ((((struct in6_ifaddr *)ifa)->ia6_flags &
                            ignoreflags) != 0) {
                                IFA_UNLOCK(ifa);
                                continue;
                        }
                        IFA_ADDREF_LOCKED(ifa); /* for caller */
                        IFA_UNLOCK(ifa);
                        break;
                }
                IFA_UNLOCK(ifa);
        }
        ifnet_lock_done(ifp);

        return (struct in6_ifaddr *)ifa;
}

struct in6_ifaddr *
in6ifa_ifpwithflag(struct ifnet * ifp, int flag)
{
        struct ifaddr *ifa;

        ifnet_lock_shared(ifp);
        TAILQ_FOREACH(ifa, &ifp->if_addrlist, ifa_list)
        {
                IFA_LOCK_SPIN(ifa);
                if (ifa->ifa_addr->sa_family != AF_INET6) {
                        IFA_UNLOCK(ifa);
                        continue;
                }
                if ((((struct in6_ifaddr *)ifa)->ia6_flags & flag) == flag) {
                        IFA_ADDREF_LOCKED(ifa);
                        IFA_UNLOCK(ifa);
                        break;
                }
                IFA_UNLOCK(ifa);
        }
        ifnet_lock_done(ifp);

        return (struct in6_ifaddr *)ifa;
}

/*
 * find the internet address corresponding to a given interface and address.
 */
struct in6_ifaddr *
in6ifa_ifpwithaddr(struct ifnet *ifp, struct in6_addr *addr)
{
        struct ifaddr *ifa;

        ifnet_lock_shared(ifp);
        TAILQ_FOREACH(ifa, &ifp->if_addrlist, ifa_list)
        {
                IFA_LOCK_SPIN(ifa);
                if (ifa->ifa_addr->sa_family != AF_INET6) {
                        IFA_UNLOCK(ifa);
                        continue;
                }
                if (IN6_ARE_ADDR_EQUAL(addr, IFA_IN6(ifa))) {
                        IFA_ADDREF_LOCKED(ifa); /* for caller */
                        IFA_UNLOCK(ifa);
                        break;
                }
                IFA_UNLOCK(ifa);
        }
        ifnet_lock_done(ifp);

        return (struct in6_ifaddr *)ifa;
}

struct in6_ifaddr *
in6ifa_prproxyaddr(struct in6_addr *addr)
{
        struct in6_ifaddr *ia;

        lck_rw_lock_shared(&in6_ifaddr_rwlock);
        TAILQ_FOREACH(ia, IN6ADDR_HASH(addr), ia6_hash) {
                IFA_LOCK(&ia->ia_ifa);
                if (IN6_ARE_ADDR_EQUAL(addr, IFA_IN6(&ia->ia_ifa))) {
                        IFA_ADDREF_LOCKED(&ia->ia_ifa); /* for caller */
                        IFA_UNLOCK(&ia->ia_ifa);
                        break;
                }
                IFA_UNLOCK(&ia->ia_ifa);
        }
        lck_rw_done(&in6_ifaddr_rwlock);

        if (ia != NULL && !nd6_prproxy_ifaddr(ia)) {
                IFA_REMREF(&ia->ia_ifa);
                ia = NULL;
        }

        return ia;
}

void
in6ifa_getlifetime(struct in6_ifaddr *ia6, struct in6_addrlifetime *t_dst,
    int iscalendar)
{
        struct in6_addrlifetime_i *t_src = &ia6->ia6_lifetime;
        struct timeval caltime;

        t_dst->ia6t_vltime = t_src->ia6ti_vltime;
        t_dst->ia6t_pltime = t_src->ia6ti_pltime;
        t_dst->ia6t_expire = 0;
        t_dst->ia6t_preferred = 0;

        /* account for system time change */
        getmicrotime(&caltime);
        t_src->ia6ti_base_calendartime +=
            NET_CALCULATE_CLOCKSKEW(caltime,
            t_src->ia6ti_base_calendartime, net_uptime(),
            t_src->ia6ti_base_uptime);

        if (iscalendar) {
                if (t_src->ia6ti_expire != 0 &&
                    t_src->ia6ti_vltime != ND6_INFINITE_LIFETIME) {
                        t_dst->ia6t_expire = t_src->ia6ti_base_calendartime +
                            t_src->ia6ti_expire - t_src->ia6ti_base_uptime;
                }

                if (t_src->ia6ti_preferred != 0 &&
                    t_src->ia6ti_pltime != ND6_INFINITE_LIFETIME) {
                        t_dst->ia6t_preferred = t_src->ia6ti_base_calendartime +
                            t_src->ia6ti_preferred - t_src->ia6ti_base_uptime;
                }
        } else {
                if (t_src->ia6ti_expire != 0 &&
                    t_src->ia6ti_vltime != ND6_INFINITE_LIFETIME) {
                        t_dst->ia6t_expire = t_src->ia6ti_expire;
                }

                if (t_src->ia6ti_preferred != 0 &&
                    t_src->ia6ti_pltime != ND6_INFINITE_LIFETIME) {
                        t_dst->ia6t_preferred = t_src->ia6ti_preferred;
                }
        }
}

void
in6ifa_setlifetime(struct in6_ifaddr *ia6, struct in6_addrlifetime *t_src)
{
        struct in6_addrlifetime_i *t_dst = &ia6->ia6_lifetime;
        struct timeval caltime;

        /* account for system time change */
        getmicrotime(&caltime);
        t_dst->ia6ti_base_calendartime +=
            NET_CALCULATE_CLOCKSKEW(caltime,
            t_dst->ia6ti_base_calendartime, net_uptime(),
            t_dst->ia6ti_base_uptime);

        /* trust the caller for the values */
        t_dst->ia6ti_expire = t_src->ia6t_expire;
        t_dst->ia6ti_preferred = t_src->ia6t_preferred;
        t_dst->ia6ti_vltime = t_src->ia6t_vltime;
        t_dst->ia6ti_pltime = t_src->ia6t_pltime;
}

/*
 * Convert IP6 address to printable (loggable) representation.
 */
char *
ip6_sprintf(const struct in6_addr *addr)
{
        static const char digits[] = "0123456789abcdef";
        static int ip6round = 0;
        static char ip6buf[8][48];

        int i;
        char *cp;
        const u_short *a = (const u_short *)addr;
        const u_char *d;
        u_char n;
        int dcolon = 0;
        int zpad = 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++ = '0';
                                *cp++ = ':';
                        }
                        a++;
                        continue;
                }
                d = (const u_char *)a;
                zpad = 0;
                if ((n = *d >> 4) != 0) {
                        *cp++ = digits[n];
                        zpad = 1;
                }
                if ((n = *d++ & 0xf) != 0 || zpad) {
                        *cp++ = digits[n];
                        zpad = 1;
                }
                if ((n = *d >> 4) != 0 || zpad) {
                        *cp++ = digits[n];
                        zpad = 1;
                }
                if ((n = *d & 0xf) != 0 || zpad) {
                        *cp++ = digits[n];
                }
                *cp++ = ':';
                a++;
        }
        *--cp = 0;
        return ip6buf[ip6round];
}

int
in6addr_local(struct in6_addr *in6)
{
        struct rtentry *rt;
        struct sockaddr_in6 sin6;
        int local = 0;

        if (IN6_IS_ADDR_LOOPBACK(in6) || IN6_IS_SCOPE_LINKLOCAL(in6)) {
                return 1;
        }

        sin6.sin6_family = AF_INET6;
        sin6.sin6_len = sizeof(sin6);
        bcopy(in6, &sin6.sin6_addr, sizeof(*in6));
        rt = rtalloc1((struct sockaddr *)&sin6, 0, 0);

        if (rt != NULL) {
                RT_LOCK_SPIN(rt);
                if (rt->rt_gateway->sa_family == AF_LINK) {
                        local = 1;
                }
                RT_UNLOCK(rt);
                rtfree(rt);
        } else {
                local = in6_localaddr(in6);
        }
        return local;
}

int
in6_localaddr(struct in6_addr *in6)
{
        struct in6_ifaddr *ia;

        if (IN6_IS_ADDR_LOOPBACK(in6) || IN6_IS_ADDR_LINKLOCAL(in6) || IN6_IS_ADDR_MC_UNICAST_BASED_LINKLOCAL(in6)) {
                return 1;
        }

        lck_rw_lock_shared(&in6_ifaddr_rwlock);
        TAILQ_FOREACH(ia, &in6_ifaddrhead, ia6_link) {
                IFA_LOCK_SPIN(&ia->ia_ifa);
                if (IN6_ARE_MASKED_ADDR_EQUAL(in6, &ia->ia_addr.sin6_addr,
                    &ia->ia_prefixmask.sin6_addr)) {
                        IFA_UNLOCK(&ia->ia_ifa);
                        lck_rw_done(&in6_ifaddr_rwlock);
                        return 1;
                }
                IFA_UNLOCK(&ia->ia_ifa);
        }
        lck_rw_done(&in6_ifaddr_rwlock);
        return 0;
}

/*
 * return length of part which dst and src are equal
 * hard coding...
 */
int
in6_matchlen(struct in6_addr *src, struct in6_addr *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(struct in6_addr *p1, struct in6_addr *p2, int len)
{
        int bytelen, bitlen;

        /* sanity check */
        if (0 > len || len > 128) {
                log(LOG_ERR, "%s: invalid prefix length(%d)\n", __func__, 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(struct in6_addr *maskp, int len)
{
        u_char maskarray[8] = {0x80, 0xc0, 0xe0, 0xf0, 0xf8, 0xfc, 0xfe, 0xff};
        int bytelen, bitlen, i;

        /* sanity check */
        if (0 > len || len > 128) {
                log(LOG_ERR, "%s: invalid prefix length(%d)\n", __func__, 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(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) {
                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.
         */
        ifnet_head_lock_shared();
        TAILQ_FOREACH(ifp, &ifnet_head, 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;
                }

                ifnet_lock_shared(ifp);
                TAILQ_FOREACH(ifa, &ifp->if_addrlist, ifa_list) {
                        int tlen = -1, dscopecmp, bscopecmp, matchcmp;

                        IFA_LOCK(ifa);
                        if (ifa->ifa_addr->sa_family != AF_INET6) {
                                IFA_UNLOCK(ifa);
                                continue;
                        }
                        src_scope = in6_addrscope(IFA_IN6(ifa));

                        /*
                         * Don't use an address before completing DAD
                         * nor a duplicated address.
                         */
                        if (((struct in6_ifaddr *)ifa)->ia6_flags &
                            (IN6_IFF_NOTREADY | IN6_IFF_CLAT46)) {
                                IFA_UNLOCK(ifa);
                                continue;
                        }
                        /* XXX: is there any case to allow anycasts? */
                        if (((struct in6_ifaddr *)ifa)->ia6_flags &
                            IN6_IFF_ANYCAST) {
                                IFA_UNLOCK(ifa);
                                continue;
                        }
                        if (((struct in6_ifaddr *)ifa)->ia6_flags &
                            IN6_IFF_DETACHED) {
                                IFA_UNLOCK(ifa);
                                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.
                         * Consequently, after the two if-clause below,
                         * the followings must be satisfied:
                         * (scope(src) < scope(dst) &&
                         *  scope(best) < scope(dst))
                         *  OR
                         * (scope(best) >= scope(dst) &&
                         *  scope(src) >= scope(dst))
                         */
                        if (IN6_ARE_SCOPE_CMP(best_scope, dst_scope) < 0 &&
                            IN6_ARE_SCOPE_CMP(src_scope, dst_scope) >= 0) {
                                goto replace; /* (A) */
                        }
                        if (IN6_ARE_SCOPE_CMP(src_scope, dst_scope) < 0 &&
                            IN6_ARE_SCOPE_CMP(best_scope, dst_scope) >= 0) {
                                IFA_UNLOCK(ifa);
                                continue; /* (B) */
                        }
                        /*
                         * A deprecated address SHOULD NOT be used in new
                         * communications if an alternate (non-deprecated)
                         * address is available and has sufficient scope.
                         * RFC 4862, 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) {
                                        IFA_UNLOCK(ifa);
                                        continue;
                                }
                                /*
                                 * If we have already found a non-deprecated
                                 * candidate, just ignore deprecated addresses.
                                 */
                                if ((ifa_best->ia6_flags & IN6_IFF_DEPRECATED)
                                    == 0) {
                                        IFA_UNLOCK(ifa);
                                        continue;
                                }
                        }

                        /*
                         * A non-deprecated address is always preferred
                         * to a deprecated one regardless of scopes and
                         * address matching (Note invariants ensured by the
                         * conditions (A) and (B) above.)
                         */
                        if ((ifa_best->ia6_flags & IN6_IFF_DEPRECATED) &&
                            (((struct in6_ifaddr *)ifa)->ia6_flags &
                            IN6_IFF_DEPRECATED) == 0) {
                                goto replace;
                        }

                        /*
                         * When we use temporary addresses described in
                         * RFC 4941, we prefer temporary addresses to
                         * public autoconf addresses.  Again, note the
                         * invariants from (A) and (B).  Also note that we
                         * don't have any preference between static addresses
                         * and autoconf addresses (despite of whether or not
                         * the latter is temporary or public.)
                         */
                        if (ip6_use_tempaddr) {
                                struct in6_ifaddr *ifat;

                                ifat = (struct in6_ifaddr *)ifa;
                                if ((ifa_best->ia6_flags &
                                    (IN6_IFF_AUTOCONF | IN6_IFF_TEMPORARY))
                                    == IN6_IFF_AUTOCONF &&
                                    (ifat->ia6_flags &
                                    (IN6_IFF_AUTOCONF | IN6_IFF_TEMPORARY))
                                    == (IN6_IFF_AUTOCONF | IN6_IFF_TEMPORARY)) {
                                        goto replace;
                                }
                                if ((ifa_best->ia6_flags &
                                    (IN6_IFF_AUTOCONF | IN6_IFF_TEMPORARY))
                                    == (IN6_IFF_AUTOCONF | IN6_IFF_TEMPORARY) &&
                                    (ifat->ia6_flags &
                                    (IN6_IFF_AUTOCONF | IN6_IFF_TEMPORARY))
                                    == IN6_IFF_AUTOCONF) {
                                        IFA_UNLOCK(ifa);
                                        continue;
                                }
                        }

                        /*
                         * 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
                         *   (this must be already done above.)
                         * - addresses on the outgoing I/F are preferred to
                         *   ones on other interfaces if none of above
                         *   tiebreaks.  In the table below, the column "bI"
                         *   means if the best_ifa is on the outgoing
                         *   interface, and the column "sI" means if the ifa
                         *   is on the outgoing interface.
                         * - If there is no other reasons to choose one,
                         *   longest address match against dst is considered.
                         *
                         * The precise decision table is as follows:
                         * dscopecmp bscopecmp  match   bI oI | replace?
                         *   N/A       equal    N/A     Y   N |   No (1)
                         *   N/A       equal    N/A     N   Y |  Yes (2)
                         *   N/A       equal    larger   N/A  |  Yes (3)
                         *   N/A       equal    !larger  N/A  |   No (4)
                         *   larger    larger   N/A      N/A  |   No (5)
                         *   larger    smaller  N/A      N/A  |  Yes (6)
                         *   smaller   larger   N/A      N/A  |  Yes (7)
                         *   smaller   smaller  N/A      N/A  |   No (8)
                         *   equal     smaller  N/A      N/A  |  Yes (9)
                         *   equal     larger   (already done at A above)
                         */
                        dscopecmp = IN6_ARE_SCOPE_CMP(src_scope, dst_scope);
                        bscopecmp = IN6_ARE_SCOPE_CMP(src_scope, best_scope);

                        if (bscopecmp == 0) {
                                struct ifnet *bifp = ifa_best->ia_ifp;

                                if (bifp == oifp && ifp != oifp) { /* (1) */
                                        IFA_UNLOCK(ifa);
                                        continue;
                                }
                                if (bifp != oifp && ifp == oifp) { /* (2) */
                                        goto replace;
                                }

                                /*
                                 * Both bifp and ifp are on the outgoing
                                 * interface, or both two are on a different
                                 * interface from the outgoing I/F.
                                 * now we need address matching against dst
                                 * for tiebreaking.
                                 */
                                tlen = in6_matchlen(IFA_IN6(ifa), dst);
                                matchcmp = tlen - blen;
                                if (matchcmp > 0) { /* (3) */
                                        goto replace;
                                }
                                IFA_UNLOCK(ifa);
                                continue; /* (4) */
                        }
                        if (dscopecmp > 0) {
                                if (bscopecmp > 0) { /* (5) */
                                        IFA_UNLOCK(ifa);
                                        continue;
                                }
                                goto replace; /* (6) */
                        }
                        if (dscopecmp < 0) {
                                if (bscopecmp > 0) { /* (7) */
                                        goto replace;
                                }
                                IFA_UNLOCK(ifa);
                                continue; /* (8) */
                        }

                        /* now dscopecmp must be 0 */
                        if (bscopecmp < 0) {
                                goto replace; /* (9) */
                        }
replace:
                        IFA_ADDREF_LOCKED(ifa); /* for ifa_best */
                        blen = tlen >= 0 ? tlen :
                            in6_matchlen(IFA_IN6(ifa), dst);
                        best_scope =
                            in6_addrscope(&ifa2ia6(ifa)->ia_addr.sin6_addr);
                        IFA_UNLOCK(ifa);
                        if (ifa_best) {
                                IFA_REMREF(&ifa_best->ia_ifa);
                        }
                        ifa_best = (struct in6_ifaddr *)ifa;
                }
                ifnet_lock_done(ifp);
        }
        ifnet_head_done();

        /* count statistics for future improvements */
        if (ifa_best == NULL) {
                ip6stat.ip6s_sources_none++;
        } else {
                IFA_LOCK_SPIN(&ifa_best->ia_ifa);
                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]++;
                }
                IFA_UNLOCK(&ifa_best->ia_ifa);
        }

        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(struct ifnet *ifp, struct in6_addr *dst)
{
        int dst_scope = in6_addrscope(dst), blen = -1, tlen;
        struct ifaddr *ifa;
        struct in6_ifaddr *besta = NULL;
        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.
         */
        ifnet_lock_shared(ifp);
        TAILQ_FOREACH(ifa, &ifp->if_addrlist, ifa_list) {
                IFA_LOCK(ifa);
                if (ifa->ifa_addr->sa_family != AF_INET6) {
                        IFA_UNLOCK(ifa);
                        continue;
                }
                if (ifa2ia6(ifa)->ia6_flags & IN6_IFF_ANYCAST) {
                        IFA_UNLOCK(ifa);
                        continue; /* XXX: is there any case to allow anycast? */
                }
                if (ifa2ia6(ifa)->ia6_flags & (IN6_IFF_NOTREADY | IN6_IFF_CLAT46)) {
                        IFA_UNLOCK(ifa);
                        continue; /* don't use this interface */
                }
                if (ifa2ia6(ifa)->ia6_flags & IN6_IFF_DETACHED) {
                        IFA_UNLOCK(ifa);
                        continue;
                }
                if (ifa2ia6(ifa)->ia6_flags & IN6_IFF_DEPRECATED) {
                        if (ip6_use_deprecated) {
                                IFA_ADDREF_LOCKED(ifa); /* for dep[0] */
                                IFA_UNLOCK(ifa);
                                if (dep[0] != NULL) {
                                        IFA_REMREF(&dep[0]->ia_ifa);
                                }
                                dep[0] = (struct in6_ifaddr *)ifa;
                        } else {
                                IFA_UNLOCK(ifa);
                        }
                        continue;
                }

                if (dst_scope == in6_addrscope(IFA_IN6(ifa))) {
                        /*
                         * call in6_matchlen() as few as possible
                         */
                        if (besta) {
                                if (blen == -1) {
                                        IFA_UNLOCK(ifa);
                                        IFA_LOCK(&besta->ia_ifa);
                                        blen = in6_matchlen(
                                                &besta->ia_addr.sin6_addr, dst);
                                        IFA_UNLOCK(&besta->ia_ifa);
                                        IFA_LOCK(ifa);
                                }
                                tlen = in6_matchlen(IFA_IN6(ifa), dst);
                                if (tlen > blen) {
                                        blen = tlen;
                                        IFA_ADDREF_LOCKED(ifa); /* for besta */
                                        IFA_UNLOCK(ifa);
                                        IFA_REMREF(&besta->ia_ifa);
                                        besta = (struct in6_ifaddr *)ifa;
                                } else {
                                        IFA_UNLOCK(ifa);
                                }
                        } else {
                                besta = (struct in6_ifaddr *)ifa;
                                IFA_ADDREF_LOCKED(ifa); /* for besta */
                                IFA_UNLOCK(ifa);
                        }
                } else {
                        IFA_UNLOCK(ifa);
                }
        }
        if (besta) {
                ifnet_lock_done(ifp);
                if (dep[0] != NULL) {
                        IFA_REMREF(&dep[0]->ia_ifa);
                }
                return besta;
        }

        TAILQ_FOREACH(ifa, &ifp->if_addrlist, ifa_list) {
                IFA_LOCK(ifa);
                if (ifa->ifa_addr->sa_family != AF_INET6) {
                        IFA_UNLOCK(ifa);
                        continue;
                }
                if (ifa2ia6(ifa)->ia6_flags & IN6_IFF_ANYCAST) {
                        IFA_UNLOCK(ifa);
                        continue; /* XXX: is there any case to allow anycast? */
                }
                if (ifa2ia6(ifa)->ia6_flags & (IN6_IFF_NOTREADY | IN6_IFF_CLAT46)) {
                        IFA_UNLOCK(ifa);
                        continue; /* don't use this interface */
                }
                if (ifa2ia6(ifa)->ia6_flags & IN6_IFF_DETACHED) {
                        IFA_UNLOCK(ifa);
                        continue;
                }
                if (ifa2ia6(ifa)->ia6_flags & IN6_IFF_DEPRECATED) {
                        if (ip6_use_deprecated) {
                                IFA_ADDREF_LOCKED(ifa); /* for dep[1] */
                                IFA_UNLOCK(ifa);
                                if (dep[1] != NULL) {
                                        IFA_REMREF(&dep[1]->ia_ifa);
                                }
                                dep[1] = (struct in6_ifaddr *)ifa;
                        } else {
                                IFA_UNLOCK(ifa);
                        }
                        continue;
                }
                IFA_ADDREF_LOCKED(ifa); /* for caller */
                IFA_UNLOCK(ifa);
                ifnet_lock_done(ifp);
                if (dep[0] != NULL) {
                        IFA_REMREF(&dep[0]->ia_ifa);
                }
                if (dep[1] != NULL) {
                        IFA_REMREF(&dep[1]->ia_ifa);
                }
                return (struct in6_ifaddr *)ifa;
        }
        ifnet_lock_done(ifp);

        /* use the last-resort values, that are, deprecated addresses */
        if (dep[0]) {
                if (dep[1] != NULL) {
                        IFA_REMREF(&dep[1]->ia_ifa);
                }
                return dep[0];
        }
        if (dep[1]) {
                return dep[1];
        }

        return NULL;
}

/*
 * perform DAD when interface becomes IFF_UP.
 */
static void
in6_if_up_dad_start(struct ifnet *ifp)
{
        struct ifaddr *ifa;
        struct nd_ifinfo *ndi = NULL;

        ndi = ND_IFINFO(ifp);
        VERIFY((NULL != ndi) && (TRUE == ndi->initialized));
        if (!(ndi->flags & ND6_IFF_DAD)) {
                return;
        }

        /* start DAD on all the interface addresses */
        ifnet_lock_exclusive(ifp);
        TAILQ_FOREACH(ifa, &ifp->if_addrlist, ifa_list) {
                struct in6_ifaddr *ia6;

                IFA_LOCK_SPIN(ifa);
                if (ifa->ifa_addr->sa_family != AF_INET6) {
                        IFA_UNLOCK(ifa);
                        continue;
                }
                ia6 = (struct in6_ifaddr *)ifa;
                if (ia6->ia6_flags & IN6_IFF_DADPROGRESS) {
                        int delay = 0;  /* delay ticks before DAD output */
                        IFA_UNLOCK(ifa);
                        nd6_dad_start(ifa, &delay);
                } else {
                        IFA_UNLOCK(ifa);
                }
        }
        ifnet_lock_done(ifp);
}

int
in6if_do_dad(
        struct ifnet *ifp)
{
        struct nd_ifinfo *ndi = NULL;

        if ((ifp->if_flags & IFF_LOOPBACK) != 0) {
                return 0;
        }

        ndi = ND_IFINFO(ifp);
        VERIFY((NULL != ndi) && (TRUE == ndi->initialized));
        if (!(ndi->flags & ND6_IFF_DAD)) {
                return 0;
        }

        /*
         * If we are using the alternative neighbor discovery
         * interface on this interface, then skip DAD.
         *
         * Also, skip it for interfaces marked "local private"
         * for now, even when not marked as using the alternative
         * interface.  This is for historical reasons.
         */
        if (ifp->if_eflags &
            (IFEF_IPV6_ND6ALT | IFEF_LOCALNET_PRIVATE | IFEF_DIRECTLINK)) {
                return 0;
        }

        if (ifp->if_family == IFNET_FAMILY_IPSEC ||
            ifp->if_family == IFNET_FAMILY_UTUN) {
                /*
                 * Ignore DAD for tunneling virtual interfaces, which get
                 * their IPv6 address explicitly assigned.
                 */
                return 0;
        }

        switch (ifp->if_type) {
#if IFT_DUMMY
        case IFT_DUMMY:
#endif
        case IFT_FAITH:
                /*
                 * These interfaces do not have the IFF_LOOPBACK flag,
                 * but loop packets back.  We do not have to do DAD on such
                 * interfaces.  We should even omit it, because loop-backed
                 * NS would confuse the DAD procedure.
                 */
                return 0;
        default:
                /*
                 * Our DAD routine requires the interface up and running.
                 * However, some interfaces can be up before the RUNNING
                 * status.  Additionaly, users may try to assign addresses
                 * before the interface becomes up (or running).
                 * We simply skip DAD in such a case as a work around.
                 * XXX: we should rather mark "tentative" on such addresses,
                 * and do DAD after the interface becomes ready.
                 */
                if ((ifp->if_flags & (IFF_UP | 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(void)
{
        u_int32_t maxmtu = 0;
        struct ifnet *ifp;

        ifnet_head_lock_shared();
        TAILQ_FOREACH(ifp, &ifnet_head, if_list) {
                struct nd_ifinfo *ndi = NULL;

                if ((ndi = ND_IFINFO(ifp)) != NULL && !ndi->initialized) {
                        ndi = NULL;
                }
                if (ndi != NULL) {
                        lck_mtx_lock(&ndi->lock);
                }
                if ((ifp->if_flags & IFF_LOOPBACK) == 0 &&
                    IN6_LINKMTU(ifp) > maxmtu) {
                        maxmtu = IN6_LINKMTU(ifp);
                }
                if (ndi != NULL) {
                        lck_mtx_unlock(&ndi->lock);
                }
        }
        ifnet_head_done();
        if (maxmtu) {   /* update only when maxmtu is positive */
                in6_maxmtu = maxmtu;
        }
}
/*
 * Provide the length of interface identifiers to be used for the link attached
 * to the given interface.  The length should be defined in "IPv6 over
 * xxx-link" document.  Note that address architecture might also define
 * the length for a particular set of address prefixes, regardless of the
 * link type.  Also see RFC 4862 for additional background.
 */
int
in6_if2idlen(struct ifnet *ifp)
{
        switch (ifp->if_type) {
        case IFT_ETHER:         /* RFC2464 */
        case IFT_IEEE8023ADLAG: /* IEEE802.3ad Link Aggregate */
#ifdef IFT_PROPVIRTUAL
        case IFT_PROPVIRTUAL:   /* XXX: no RFC. treat it as ether */
#endif
#ifdef IFT_L2VLAN
        case IFT_L2VLAN:        /* ditto */
#endif
#ifdef IFT_IEEE80211
        case IFT_IEEE80211:     /* ditto */
#endif
#ifdef IFT_MIP
        case IFT_MIP:   /* ditto */
#endif
                return 64;
        case IFT_FDDI:          /* RFC2467 */
                return 64;
        case IFT_ISO88025:      /* RFC2470 (IPv6 over Token Ring) */
                return 64;
        case IFT_PPP:           /* RFC2472 */
                return 64;
        case IFT_ARCNET:        /* RFC2497 */
                return 64;
        case IFT_FRELAY:        /* RFC2590 */
                return 64;
        case IFT_IEEE1394:      /* RFC3146 */
                return 64;
        case IFT_GIF:
                return 64;    /* draft-ietf-v6ops-mech-v2-07 */
        case IFT_LOOP:
                return 64;    /* XXX: is this really correct? */
        case IFT_OTHER:
                return 64;    /* for utun interfaces */
        case IFT_CELLULAR:
                return 64;    /* Packet Data over Cellular */
        case IFT_BRIDGE:
                return 64;    /* Transparent bridge interface */
        case IFT_6LOWPAN:
                return 64;    /* 6LoWPAN */
        default:
                /*
                 * Unknown link type:
                 * It might be controversial to use the today's common constant
                 * of 64 for these cases unconditionally.  For full compliance,
                 * we should return an error in this case.  On the other hand,
                 * if we simply miss the standard for the link type or a new
                 * standard is defined for a new link type, the IFID length
                 * is very likely to be the common constant.  As a compromise,
                 * we always use the constant, but make an explicit notice
                 * indicating the "unknown" case.
                 */
                log(LOG_NOTICE, "%s: unknown link type (%d)\n", __func__,
                    ifp->if_type);
                return 64;
        }
}
/*
 * Convert sockaddr_in6 to sockaddr_in.  Original sockaddr_in6 must be
 * v4 mapped addr or v4 compat addr
 */
void
in6_sin6_2_sin(struct sockaddr_in *sin, struct sockaddr_in6 *sin6)
{
        bzero(sin, sizeof(*sin));
        sin->sin_len = sizeof(struct sockaddr_in);
        sin->sin_family = AF_INET;
        sin->sin_port = sin6->sin6_port;
        sin->sin_addr.s_addr = sin6->sin6_addr.s6_addr32[3];
}

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

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

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

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

        MALLOC(sin6_p, struct sockaddr_in6 *, sizeof(*sin6_p), M_SONAME,
            M_WAITOK);
        if (sin6_p == NULL) {
                return ENOBUFS;
        }
        sin_p = (struct sockaddr_in *)(void *)*nam;
        in6_sin_2_v4mapsin6(sin_p, sin6_p);
        FREE(*nam, M_SONAME);
        *nam = (struct sockaddr *)sin6_p;

        return 0;
}

/*
 * Posts in6_event_data message kernel events.
 *
 * To get the same size of kev_in6_data between ILP32 and LP64 data models
 * we are using a special version of the in6_addrlifetime structure that
 * uses only 32 bits fields to be compatible with Leopard, and that
 * are large enough to span 68 years.
 */
void
in6_post_msg(struct ifnet *ifp, u_int32_t event_code, struct in6_ifaddr *ifa,
    uint8_t *mac)
{
        struct kev_msg ev_msg;
        struct kev_in6_data in6_event_data;
        struct in6_addrlifetime ia6_lt;

        bzero(&in6_event_data, sizeof(struct kev_in6_data));
        bzero(&ev_msg, sizeof(struct kev_msg));
        ev_msg.vendor_code      = KEV_VENDOR_APPLE;
        ev_msg.kev_class        = KEV_NETWORK_CLASS;
        ev_msg.kev_subclass     = KEV_INET6_SUBCLASS;
        ev_msg.event_code       = event_code;

        if (ifa) {
                IFA_LOCK(&ifa->ia_ifa);
                in6_event_data.ia_addr          = ifa->ia_addr;
                in6_event_data.ia_net           = ifa->ia_net;
                in6_event_data.ia_dstaddr       = ifa->ia_dstaddr;
                in6_event_data.ia_prefixmask    = ifa->ia_prefixmask;
                in6_event_data.ia_plen          = ifa->ia_plen;
                in6_event_data.ia6_flags        = (u_int32_t)ifa->ia6_flags;

                /* retrieve time as calendar time (last arg is 1) */
                in6ifa_getlifetime(ifa, &ia6_lt, 1);
                in6_event_data.ia_lifetime.ia6t_expire = (u_int32_t)ia6_lt.ia6t_expire;
                in6_event_data.ia_lifetime.ia6t_preferred = (u_int32_t)ia6_lt.ia6t_preferred;
                in6_event_data.ia_lifetime.ia6t_vltime = ia6_lt.ia6t_vltime;
                in6_event_data.ia_lifetime.ia6t_pltime = ia6_lt.ia6t_pltime;
                IFA_UNLOCK(&ifa->ia_ifa);
        }

        if (ifp != NULL) {
                (void) strlcpy(&in6_event_data.link_data.if_name[0],
                    ifp->if_name, IFNAMSIZ);
                in6_event_data.link_data.if_family = ifp->if_family;
                in6_event_data.link_data.if_unit  = (u_int32_t)ifp->if_unit;
        }

        if (mac != NULL) {
                memcpy(&in6_event_data.ia_mac, mac,
                    sizeof(in6_event_data.ia_mac));
        }

        ev_msg.dv[0].data_ptr    = &in6_event_data;
        ev_msg.dv[0].data_length = sizeof(in6_event_data);
        ev_msg.dv[1].data_length = 0;

        dlil_post_complete_msg(NULL, &ev_msg);
}

/*
 * Called as part of ip6_init
 */
void
in6_ifaddr_init(void)
{
        in6_cga_init();
        in6_multi_init();

        PE_parse_boot_argn("ifa_debug", &in6ifa_debug, sizeof(in6ifa_debug));

        vm_size_t in6ifa_size = (in6ifa_debug == 0) ? sizeof(struct in6_ifaddr) :
            sizeof(struct in6_ifaddr_dbg);

        in6ifa_zone = zone_create(IN6IFA_ZONE_NAME, in6ifa_size, ZC_ZFREE_CLEARMEM);

        lck_mtx_init(&in6ifa_trash_lock, ifa_mtx_grp, ifa_mtx_attr);
        TAILQ_INIT(&in6ifa_trash_head);
}

static struct in6_ifaddr *
in6_ifaddr_alloc(zalloc_flags_t how)
{
        struct in6_ifaddr *in6ifa;

        in6ifa = zalloc_flags(in6ifa_zone, how | Z_ZERO);
        if (in6ifa != NULL) {
                in6ifa->ia_ifa.ifa_free = in6_ifaddr_free;
                in6ifa->ia_ifa.ifa_debug |= IFD_ALLOC;
                in6ifa->ia_ifa.ifa_del_wc = &in6ifa->ia_ifa.ifa_debug;
                in6ifa->ia_ifa.ifa_del_waiters = 0;
                ifa_lock_init(&in6ifa->ia_ifa);
                if (in6ifa_debug != 0) {
                        struct in6_ifaddr_dbg *in6ifa_dbg =
                            (struct in6_ifaddr_dbg *)in6ifa;
                        in6ifa->ia_ifa.ifa_debug |= IFD_DEBUG;
                        in6ifa->ia_ifa.ifa_trace = in6_ifaddr_trace;
                        in6ifa->ia_ifa.ifa_attached = in6_ifaddr_attached;
                        in6ifa->ia_ifa.ifa_detached = in6_ifaddr_detached;
                        ctrace_record(&in6ifa_dbg->in6ifa_alloc);
                }
        }

        return in6ifa;
}

static void
in6_ifaddr_free(struct ifaddr *ifa)
{
        IFA_LOCK_ASSERT_HELD(ifa);

        if (ifa->ifa_refcnt != 0) {
                panic("%s: ifa %p bad ref cnt", __func__, ifa);
                /* NOTREACHED */
        } else if (!(ifa->ifa_debug & IFD_ALLOC)) {
                panic("%s: ifa %p cannot be freed", __func__, ifa);
                /* NOTREACHED */
        }
        if (ifa->ifa_debug & IFD_DEBUG) {
                struct in6_ifaddr_dbg *in6ifa_dbg =
                    (struct in6_ifaddr_dbg *)ifa;
                ctrace_record(&in6ifa_dbg->in6ifa_free);
                bcopy(&in6ifa_dbg->in6ifa, &in6ifa_dbg->in6ifa_old,
                    sizeof(struct in6_ifaddr));
                if (ifa->ifa_debug & IFD_TRASHED) {
                        /* Become a regular mutex, just in case */
                        IFA_CONVERT_LOCK(ifa);
                        lck_mtx_lock(&in6ifa_trash_lock);
                        TAILQ_REMOVE(&in6ifa_trash_head, in6ifa_dbg,
                            in6ifa_trash_link);
                        lck_mtx_unlock(&in6ifa_trash_lock);
                        ifa->ifa_debug &= ~IFD_TRASHED;
                }
        }
        IFA_UNLOCK(ifa);
        ifa_lock_destroy(ifa);
        bzero(ifa, sizeof(struct in6_ifaddr));
        zfree(in6ifa_zone, ifa);
}

static void
in6_ifaddr_attached(struct ifaddr *ifa)
{
        struct in6_ifaddr_dbg *in6ifa_dbg = (struct in6_ifaddr_dbg *)ifa;

        IFA_LOCK_ASSERT_HELD(ifa);

        if (!(ifa->ifa_debug & IFD_DEBUG)) {
                panic("%s: ifa %p has no debug structure", __func__, ifa);
                /* NOTREACHED */
        }
        if (ifa->ifa_debug & IFD_TRASHED) {
                /* Become a regular mutex, just in case */
                IFA_CONVERT_LOCK(ifa);
                lck_mtx_lock(&in6ifa_trash_lock);
                TAILQ_REMOVE(&in6ifa_trash_head, in6ifa_dbg, in6ifa_trash_link);
                lck_mtx_unlock(&in6ifa_trash_lock);
                ifa->ifa_debug &= ~IFD_TRASHED;
        }
}

static void
in6_ifaddr_detached(struct ifaddr *ifa)
{
        struct in6_ifaddr_dbg *in6ifa_dbg = (struct in6_ifaddr_dbg *)ifa;

        IFA_LOCK_ASSERT_HELD(ifa);

        if (!(ifa->ifa_debug & IFD_DEBUG)) {
                panic("%s: ifa %p has no debug structure", __func__, ifa);
                /* NOTREACHED */
        } else if (ifa->ifa_debug & IFD_TRASHED) {
                panic("%s: ifa %p is already in trash list", __func__, ifa);
                /* NOTREACHED */
        }
        ifa->ifa_debug |= IFD_TRASHED;
        /* Become a regular mutex, just in case */
        IFA_CONVERT_LOCK(ifa);
        lck_mtx_lock(&in6ifa_trash_lock);
        TAILQ_INSERT_TAIL(&in6ifa_trash_head, in6ifa_dbg, in6ifa_trash_link);
        lck_mtx_unlock(&in6ifa_trash_lock);
}

static void
in6_ifaddr_trace(struct ifaddr *ifa, int refhold)
{
        struct in6_ifaddr_dbg *in6ifa_dbg = (struct in6_ifaddr_dbg *)ifa;
        ctrace_t *tr;
        u_int32_t idx;
        u_int16_t *cnt;

        if (!(ifa->ifa_debug & IFD_DEBUG)) {
                panic("%s: ifa %p has no debug structure", __func__, ifa);
                /* NOTREACHED */
        }
        if (refhold) {
                cnt = &in6ifa_dbg->in6ifa_refhold_cnt;
                tr = in6ifa_dbg->in6ifa_refhold;
        } else {
                cnt = &in6ifa_dbg->in6ifa_refrele_cnt;
                tr = in6ifa_dbg->in6ifa_refrele;
        }

        idx = atomic_add_16_ov(cnt, 1) % IN6IFA_TRACE_HIST_SIZE;
        ctrace_record(&tr[idx]);
}

/*
 * Handle SIOCGASSOCIDS ioctl for PF_INET6 domain.
 */
static int
in6_getassocids(struct socket *so, uint32_t *cnt, user_addr_t aidp)
{
        struct in6pcb *in6p = sotoin6pcb(so);
        sae_associd_t aid;

        if (in6p == NULL || in6p->inp_state == INPCB_STATE_DEAD) {
                return EINVAL;
        }

        /* IN6PCB has no concept of association */
        aid = SAE_ASSOCID_ANY;
        *cnt = 0;

        /* just asking how many there are? */
        if (aidp == USER_ADDR_NULL) {
                return 0;
        }

        return copyout(&aid, aidp, sizeof(aid));
}

/*
 * Handle SIOCGCONNIDS ioctl for PF_INET6 domain.
 */
static int
in6_getconnids(struct socket *so, sae_associd_t aid, uint32_t *cnt,
    user_addr_t cidp)
{
        struct in6pcb *in6p = sotoin6pcb(so);
        sae_connid_t cid;

        if (in6p == NULL || in6p->inp_state == INPCB_STATE_DEAD) {
                return EINVAL;
        }

        if (aid != SAE_ASSOCID_ANY && aid != SAE_ASSOCID_ALL) {
                return EINVAL;
        }

        /* if connected, return 1 connection count */
        *cnt = ((so->so_state & SS_ISCONNECTED) ? 1 : 0);

        /* just asking how many there are? */
        if (cidp == USER_ADDR_NULL) {
                return 0;
        }

        /* if IN6PCB is connected, assign it connid 1 */
        cid = ((*cnt != 0) ? 1 : SAE_CONNID_ANY);

        return copyout(&cid, cidp, sizeof(cid));
}

/*
 * Handle SIOCGCONNINFO ioctl for PF_INET6 domain.
 */
int
in6_getconninfo(struct socket *so, sae_connid_t cid, uint32_t *flags,
    uint32_t *ifindex, int32_t *soerror, user_addr_t src, socklen_t *src_len,
    user_addr_t dst, socklen_t *dst_len, uint32_t *aux_type,
    user_addr_t aux_data, uint32_t *aux_len)
{
        struct in6pcb *in6p = sotoin6pcb(so);
        struct sockaddr_in6 sin6;
        struct ifnet *ifp = NULL;
        int error = 0;
        u_int32_t copy_len = 0;

        /*
         * Don't test for INPCB_STATE_DEAD since this may be called
         * after SOF_PCBCLEARING is set, e.g. after tcp_close().
         */
        if (in6p == NULL) {
                error = EINVAL;
                goto out;
        }

        if (cid != SAE_CONNID_ANY && cid != SAE_CONNID_ALL && cid != 1) {
                error = EINVAL;
                goto out;
        }

        ifp = in6p->in6p_last_outifp;
        *ifindex = ((ifp != NULL) ? ifp->if_index : 0);
        *soerror = so->so_error;
        *flags = 0;
        if (so->so_state & SS_ISCONNECTED) {
                *flags |= (CIF_CONNECTED | CIF_PREFERRED);
        }
        if (in6p->in6p_flags & INP_BOUND_IF) {
                *flags |= CIF_BOUND_IF;
        }
        if (!(in6p->in6p_flags & INP_IN6ADDR_ANY)) {
                *flags |= CIF_BOUND_IP;
        }
        if (!(in6p->in6p_flags & INP_ANONPORT)) {
                *flags |= CIF_BOUND_PORT;
        }

        bzero(&sin6, sizeof(sin6));
        sin6.sin6_len = sizeof(sin6);
        sin6.sin6_family = AF_INET6;

        /* source address and port */
        sin6.sin6_port = in6p->in6p_lport;
        in6_recoverscope(&sin6, &in6p->in6p_laddr, NULL);
        if (*src_len == 0) {
                *src_len = sin6.sin6_len;
        } else {
                if (src != USER_ADDR_NULL) {
                        copy_len = min(*src_len, sizeof(sin6));
                        error = copyout(&sin6, src, copy_len);
                        if (error != 0) {
                                goto out;
                        }
                        *src_len = copy_len;
                }
        }

        /* destination address and port */
        sin6.sin6_port = in6p->in6p_fport;
        in6_recoverscope(&sin6, &in6p->in6p_faddr, NULL);
        if (*dst_len == 0) {
                *dst_len = sin6.sin6_len;
        } else {
                if (dst != USER_ADDR_NULL) {
                        copy_len = min(*dst_len, sizeof(sin6));
                        error = copyout(&sin6, dst, copy_len);
                        if (error != 0) {
                                goto out;
                        }
                        *dst_len = copy_len;
                }
        }

        if (SOCK_PROTO(so) == IPPROTO_TCP) {
                struct conninfo_tcp tcp_ci;

                *aux_type = CIAUX_TCP;
                if (*aux_len == 0) {
                        *aux_len = sizeof(tcp_ci);
                } else {
                        if (aux_data != USER_ADDR_NULL) {
                                copy_len = min(*aux_len, sizeof(tcp_ci));
                                bzero(&tcp_ci, sizeof(tcp_ci));
                                tcp_getconninfo(so, &tcp_ci);
                                error = copyout(&tcp_ci, aux_data, copy_len);
                                if (error != 0) {
                                        goto out;
                                }
                                *aux_len = copy_len;
                        }
                }
        } else {
                *aux_type = 0;
                *aux_len = 0;
        }

out:
        return error;
}

/*
 * 'u' group ioctls.
 *
 * The switch statement below does nothing at runtime, as it serves as a
 * compile time check to ensure that all of the socket 'u' ioctls (those
 * in the 'u' group going thru soo_ioctl) that are made available by the
 * networking stack is unique.  This works as long as this routine gets
 * updated each time a new interface ioctl gets added.
 *
 * Any failures at compile time indicates duplicated ioctl values.
 */
static __attribute__((unused)) void
in6ioctl_cassert(void)
{
        /*
         * This is equivalent to _CASSERT() and the compiler wouldn't
         * generate any instructions, thus for compile time only.
         */
        switch ((u_long)0) {
        case 0:

        /* bsd/netinet6/in6_var.h */
        case SIOCAADDRCTL_POLICY:
        case SIOCDADDRCTL_POLICY:
        case SIOCDRADD_IN6_32:
        case SIOCDRADD_IN6_64:
        case SIOCDRDEL_IN6_32:
        case SIOCDRDEL_IN6_64:
                ;
        }
}

struct in6_llentry {
        struct llentry          base;
};

#define        IN6_LLTBL_DEFAULT_HSIZE 32
#define        IN6_LLTBL_HASH(k, h) \
        ((((((((k) >> 8) ^ (k)) >> 8) ^ (k)) >> 8) ^ (k)) & ((h) - 1))

/*
 * Do actual deallocation of @lle.
 */
static void
in6_lltable_destroy_lle_unlocked(struct llentry *lle)
{
        LLE_LOCK_DESTROY(lle);
        LLE_REQ_DESTROY(lle);
        FREE(lle, M_LLTABLE);
}

/*
 * Called by LLE_FREE_LOCKED when number of references
 * drops to zero.
 */
static void
in6_lltable_destroy_lle(struct llentry *lle)
{
        LLE_WUNLOCK(lle);
        /* XXX TBD */
        //thread_call_free(lle->lle_timer);
        in6_lltable_destroy_lle_unlocked(lle);
}


static struct llentry *
in6_lltable_new(const struct in6_addr *addr6, uint16_t flags)
{
#pragma unused(flags)
        struct in6_llentry *lle;

        MALLOC(lle, struct in6_llentry *, sizeof(struct in6_llentry), M_LLTABLE, M_NOWAIT | M_ZERO);
        if (lle == NULL) {              /* NB: caller generates msg */
                return NULL;
        }

        lle->base.r_l3addr.addr6 = *addr6;
        lle->base.lle_refcnt = 1;
        lle->base.lle_free = in6_lltable_destroy_lle;
        LLE_LOCK_INIT(&lle->base);
        LLE_REQ_INIT(&lle->base);
#if 0
        /* XXX TBD */
        lle->base.lle_timer = thread_call_allocate(nd6_llinfo_timer, lle);

        if (lle->base.lle_timer == NULL) {
                printf("lle_timer thread call could not be allocated.\n");
                LLE_LOCK_DESTROY(&lle->base);
                LLE_REQ_DESTROY(&lle->base);
                FREE(lle, M_LLTABLE);
                return NULL;
        }
#endif
        return &lle->base;
}

static int
in6_lltable_match_prefix(const struct sockaddr *saddr,
    const struct sockaddr *smask, uint16_t flags, struct llentry *lle)
{
        const struct in6_addr *addr, *mask, *lle_addr;

        addr = &((const struct sockaddr_in6 *)(const void *)saddr)->sin6_addr;
        mask = &((const struct sockaddr_in6 *)(const void *)smask)->sin6_addr;
        lle_addr = &lle->r_l3addr.addr6;

        if (IN6_ARE_MASKED_ADDR_EQUAL(lle_addr, addr, mask) == 0) {
                return 0;
        }

        if (lle->la_flags & LLE_IFADDR) {
                /*
                 * Delete LLE_IFADDR records IFF address & flag matches.
                 * Note that addr is the interface address within prefix
                 * being matched.
                 */
                if (IN6_ARE_ADDR_EQUAL(addr, lle_addr) &&
                    (flags & LLE_STATIC) != 0) {
                        return 1;
                }
                return 0;
        }

        /* flags & LLE_STATIC means deleting both dynamic and static entries */
        if ((flags & LLE_STATIC) || !(lle->la_flags & LLE_STATIC)) {
                return 1;
        }

        return 0;
}

static void
in6_lltable_free_entry(struct lltable *llt, struct llentry *lle)
{
        struct ifnet *ifp;

        LLE_WLOCK_ASSERT(lle);
        KASSERT(llt != NULL, ("lltable is NULL"));

        /* Unlink entry from table */
        if ((lle->la_flags & LLE_LINKED) != 0) {
                ifp = llt->llt_ifp;
                if_afdata_wlock_assert(ifp, llt->llt_af);
                lltable_unlink_entry(llt, lle);
        }

#if 0
        /* XXX TBD */
        if (thread_call_cancel(lle->lle_timer) == TRUE) {
                LLE_REMREF(lle);
        }
#endif
        llentry_free(lle);
}

static int
in6_lltable_rtcheck(struct ifnet *ifp,
    uint16_t flags, const struct sockaddr *l3addr)
{
#pragma unused(flags)
        struct rtentry *rt;

        KASSERT(l3addr->sa_family == AF_INET6,
            ("sin_family %d", l3addr->sa_family));
        /* XXX rtalloc1 should take a const param */
        rt = rtalloc1(__DECONST(struct sockaddr *, l3addr), 0, 0);
        if (rt == NULL || (rt->rt_flags & RTF_GATEWAY) || rt->rt_ifp != ifp) {
                struct ifaddr *ifa;
                /*
                 * Create an ND6 cache for an IPv6 neighbor
                 * that is not covered by our own prefix.
                 */
                /* XXX ifaof_ifpforaddr should take a const param */
                ifa = ifaof_ifpforaddr(__DECONST(struct sockaddr *, l3addr), ifp);
                if (ifa != NULL) {
                        IFA_REMREF(ifa);
                        if (rt != NULL) {
                                rtfree(rt);
                        }
                        return 0;
                }
                log(LOG_INFO, "IPv6 address: \"%s\" is not on the network\n",
                    ip6_sprintf(&((const struct sockaddr_in6 *)(const void *)l3addr)->sin6_addr));
                if (rt != NULL) {
                        rtfree(rt);
                }
                return EINVAL;
        }
        rtfree(rt);
        return 0;
}

static inline uint32_t
in6_lltable_hash_dst(const struct in6_addr *dst, uint32_t hsize)
{
        return IN6_LLTBL_HASH(dst->s6_addr32[3], hsize);
}

static uint32_t
in6_lltable_hash(const struct llentry *lle, uint32_t hsize)
{
        return in6_lltable_hash_dst(&lle->r_l3addr.addr6, hsize);
}

static void
in6_lltable_fill_sa_entry(const struct llentry *lle, struct sockaddr *sa)
{
        struct sockaddr_in6 *sin6;

        sin6 = (struct sockaddr_in6 *)(void *)sa;
        bzero(sin6, sizeof(*sin6));
        sin6->sin6_family = AF_INET6;
        sin6->sin6_len = sizeof(*sin6);
        sin6->sin6_addr = lle->r_l3addr.addr6;
}

static inline struct llentry *
in6_lltable_find_dst(struct lltable *llt, const struct in6_addr *dst)
{
        struct llentry *lle;
        struct llentries *lleh;
        u_int hashidx;

        hashidx = in6_lltable_hash_dst(dst, llt->llt_hsize);
        lleh = &llt->lle_head[hashidx];
        LIST_FOREACH(lle, lleh, lle_next) {
                if (lle->la_flags & LLE_DELETED) {
                        continue;
                }
                if (IN6_ARE_ADDR_EQUAL(&lle->r_l3addr.addr6, dst)) {
                        break;
                }
        }

        return lle;
}

static void
in6_lltable_delete_entry(struct lltable *llt, struct llentry *lle)
{
#pragma unused(llt)
        lle->la_flags |= LLE_DELETED;
        EVENTHANDLER_INVOKE(NULL, lle_event, lle, LLENTRY_DELETED);
#ifdef DIAGNOSTIC
        log(LOG_INFO, "ifaddr cache = %p is deleted\n", lle);
#endif
        llentry_free(lle);
}

static struct llentry *
in6_lltable_alloc(struct lltable *llt, uint16_t flags,
    const struct sockaddr *l3addr)
{
        const struct sockaddr_in6 *sin6 = (const struct sockaddr_in6 *)(const void *)l3addr;
        struct ifnet *ifp = llt->llt_ifp;
        struct llentry *lle;

        KASSERT(l3addr->sa_family == AF_INET6,
            ("sin_family %d", l3addr->sa_family));

        /*
         * A route that covers the given address must have
         * been installed 1st because we are doing a resolution,
         * verify this.
         */
        if (!(flags & LLE_IFADDR) &&
            in6_lltable_rtcheck(ifp, flags, l3addr) != 0) {
                return NULL;
        }

        lle = in6_lltable_new(&sin6->sin6_addr, flags);
        if (lle == NULL) {
                log(LOG_INFO, "lla_lookup: new lle malloc failed\n");
                return NULL;
        }
        lle->la_flags = (uint16_t)flags;
        if ((flags & LLE_IFADDR) == LLE_IFADDR) {
                lltable_set_entry_addr(ifp, lle, LLADDR(SDL(ifp->if_lladdr->ifa_addr)));
                lle->la_flags |= LLE_STATIC;
        }

        if ((lle->la_flags & LLE_STATIC) != 0) {
                lle->ln_state = ND6_LLINFO_REACHABLE;
        }

        return lle;
}

static struct llentry *
in6_lltable_lookup(struct lltable *llt, uint16_t flags,
    const struct sockaddr *l3addr)
{
        const struct sockaddr_in6 *sin6 = (const struct sockaddr_in6 *)(const void *)l3addr;
        struct llentry *lle;

        IF_AFDATA_LOCK_ASSERT(llt->llt_ifp, llt->llt_af);
        KASSERT(l3addr->sa_family == AF_INET6,
            ("sin_family %d", l3addr->sa_family));

        lle = in6_lltable_find_dst(llt, &sin6->sin6_addr);

        if (lle == NULL) {
                return NULL;
        }

        KASSERT((flags & (LLE_UNLOCKED | LLE_EXCLUSIVE)) !=
            (LLE_UNLOCKED | LLE_EXCLUSIVE), ("wrong lle request flags: 0x%X",
            flags));

        if (flags & LLE_UNLOCKED) {
                return lle;
        }

        if (flags & LLE_EXCLUSIVE) {
                LLE_WLOCK(lle);
        } else {
                LLE_RLOCK(lle);
        }
        return lle;
}

static int
in6_lltable_dump_entry(struct lltable *llt, struct llentry *lle,
    struct sysctl_req *wr)
{
        struct ifnet *ifp = llt->llt_ifp;
        /* XXX stack use */
        struct {
                struct rt_msghdr        rtm;
                struct sockaddr_in6     sin6;
                /*
                 * ndp.c assumes that sdl is word aligned
                 */
#ifdef __LP64__
                uint32_t                pad;
#endif
                struct sockaddr_dl      sdl;
        } ndpc;
        struct sockaddr_dl *sdl;
        int error;

        bzero(&ndpc, sizeof(ndpc));
        /* skip deleted entries */
        if ((lle->la_flags & LLE_DELETED) == LLE_DELETED) {
                return 0;
        }
        /* Skip if jailed and not a valid IP of the prison. */
        lltable_fill_sa_entry(lle,
            (struct sockaddr *)&ndpc.sin6);
        /*
         * produce a msg made of:
         *  struct rt_msghdr;
         *  struct sockaddr_in6 (IPv6)
         *  struct sockaddr_dl;
         */
        ndpc.rtm.rtm_msglen = sizeof(ndpc);
        ndpc.rtm.rtm_version = RTM_VERSION;
        ndpc.rtm.rtm_type = RTM_GET;
        ndpc.rtm.rtm_flags = RTF_UP;
        ndpc.rtm.rtm_addrs = RTA_DST | RTA_GATEWAY;

        /* publish */
        if (lle->la_flags & LLE_PUB) {
                ndpc.rtm.rtm_flags |= RTF_ANNOUNCE;
        }
        sdl = &ndpc.sdl;
        sdl->sdl_family = AF_LINK;
        sdl->sdl_len = sizeof(*sdl);
        sdl->sdl_index = ifp->if_index;
        sdl->sdl_type = ifp->if_type;
        if ((lle->la_flags & LLE_VALID) == LLE_VALID) {
                sdl->sdl_alen = ifp->if_addrlen;
                bcopy(&lle->ll_addr, LLADDR(sdl), ifp->if_addrlen);
        } else {
                sdl->sdl_alen = 0;
                bzero(LLADDR(sdl), ifp->if_addrlen);
        }
        if (lle->la_expire != 0) {
                clock_sec_t secs;
                clock_usec_t usecs;

                clock_get_calendar_microtime(&secs, &usecs);
                ndpc.rtm.rtm_rmx.rmx_expire = (int32_t)(lle->la_expire +
                    lle->lle_remtime / hz +
                    secs - net_uptime());
        }
        ndpc.rtm.rtm_flags |= (RTF_HOST | RTF_LLDATA);
        if (lle->la_flags & LLE_STATIC) {
                ndpc.rtm.rtm_flags |= RTF_STATIC;
        }
        if (lle->la_flags & LLE_IFADDR) {
                ndpc.rtm.rtm_flags |= RTF_PINNED;
        }
        if (lle->ln_router != 0) {
                ndpc.rtm.rtm_flags |= RTF_GATEWAY;
        }
        ndpc.rtm.rtm_rmx.rmx_pksent = lle->la_asked;
        /* Store state in rmx_weight value */
        ndpc.rtm.rtm_rmx.rmx_state = lle->ln_state;
        ndpc.rtm.rtm_index = ifp->if_index;
        error = SYSCTL_OUT(wr, &ndpc, sizeof(ndpc));

        return error;
}

struct lltable *
in6_lltattach(struct ifnet *ifp)
{
        struct lltable *llt;

        llt = lltable_allocate_htbl(IN6_LLTBL_DEFAULT_HSIZE);
        llt->llt_af = AF_INET6;
        llt->llt_ifp = ifp;

        llt->llt_lookup = in6_lltable_lookup;
        llt->llt_alloc_entry = in6_lltable_alloc;
        llt->llt_delete_entry = in6_lltable_delete_entry;
        llt->llt_dump_entry = in6_lltable_dump_entry;
        llt->llt_hash = in6_lltable_hash;
        llt->llt_fill_sa_entry = in6_lltable_fill_sa_entry;
        llt->llt_free_entry = in6_lltable_free_entry;
        llt->llt_match_prefix = in6_lltable_match_prefix;
        lltable_link(llt);

        return llt;
}

void
in6_ip6_to_sockaddr(const struct in6_addr *ip6, u_int16_t port,
    struct sockaddr_in6 *sin6, u_int32_t maxlen)
{
        if (maxlen < sizeof(struct sockaddr_in6)) {
                return;
        }

        *sin6 = (struct sockaddr_in6) {
                .sin6_family = AF_INET6,
                .sin6_len = sizeof(*sin6),
                .sin6_port = port,
                .sin6_addr = *ip6,
        };

        if (IN6_IS_SCOPE_EMBED(&sin6->sin6_addr)) {
                sin6->sin6_scope_id = ntohs(sin6->sin6_addr.s6_addr16[1]);
                sin6->sin6_addr.s6_addr16[1] = 0;
        }
}

/* IPv6 events */
struct in6_event {
        in6_evhdlr_code_t in6_event_code;
        struct ifnet *in6_ifp;
        struct in6_addr in6_address;
        uint32_t val;
};

struct in6_event2kev in6_event2kev_array[IN6_EVENT_MAX] = {
        {
                .in6_event_code = IN6_ADDR_MARKED_DUPLICATED,
                .in6_event_kev_subclass = KEV_ND6_SUBCLASS,
                .in6_event_kev_code = KEV_ND6_DAD_FAILURE,
                .in6_event_str = "IN6_ADDR_MARKED_DUPLICATED",
        },
        {
                .in6_event_code = IN6_ADDR_MARKED_DETACHED,
                .in6_event_kev_subclass = KEV_ND6_SUBCLASS,
                .in6_event_kev_code = KEV_ND6_ADDR_DETACHED,
                .in6_event_str = "IN6_ADDR_MARKED_DETACHED",
        },
        {
                .in6_event_code = IN6_ADDR_MARKED_DEPRECATED,
                .in6_event_kev_subclass = KEV_ND6_SUBCLASS,
                .in6_event_kev_code = KEV_ND6_ADDR_DEPRECATED,
                .in6_event_str = "IN6_ADDR_MARKED_DEPRECATED",
        },
        {
                .in6_event_code = IN6_NDP_RTR_EXPIRY,
                .in6_event_kev_subclass = KEV_ND6_SUBCLASS,
                .in6_event_kev_code = KEV_ND6_RTR_EXPIRED,
                .in6_event_str = "IN6_NDP_RTR_EXPIRY",
        },
        {
                .in6_event_code = IN6_NDP_PFX_EXPIRY,
                .in6_event_kev_subclass = KEV_ND6_SUBCLASS,
                .in6_event_kev_code = KEV_ND6_PFX_EXPIRED,
                .in6_event_str = "IN6_NDP_PFX_EXPIRY",
        },
        {
                .in6_event_code = IN6_NDP_ADDR_EXPIRY,
                .in6_event_kev_subclass = KEV_ND6_SUBCLASS,
                .in6_event_kev_code = KEV_ND6_ADDR_EXPIRED,
                .in6_event_str = "IN6_NDP_ADDR_EXPIRY",
        },
};

void
in6_eventhdlr_callback(struct eventhandler_entry_arg arg0 __unused,
    in6_evhdlr_code_t in6_ev_code, struct ifnet *ifp,
    struct in6_addr *p_addr6, uint32_t val)
{
        struct kev_msg ev_msg;
        struct kev_nd6_event nd6_event;

        bzero(&ev_msg, sizeof(ev_msg));
        bzero(&nd6_event, sizeof(nd6_event));

        nd6log0(info, "%s Event %s received for %s\n",
            __func__, in6_event2kev_array[in6_ev_code].in6_event_str,
            ip6_sprintf(p_addr6));

        ev_msg.vendor_code      = KEV_VENDOR_APPLE;
        ev_msg.kev_class        = KEV_NETWORK_CLASS;
        ev_msg.kev_subclass     =
            in6_event2kev_array[in6_ev_code].in6_event_kev_subclass;
        ev_msg.event_code       =
            in6_event2kev_array[in6_ev_code].in6_event_kev_code;

        nd6_event.link_data.if_family = ifp->if_family;
        nd6_event.link_data.if_unit = ifp->if_unit;
        strlcpy(nd6_event.link_data.if_name, ifp->if_name,
            sizeof(nd6_event.link_data.if_name));

        VERIFY(p_addr6 != NULL);
        bcopy(p_addr6, &nd6_event.in6_address,
            sizeof(nd6_event.in6_address));
        nd6_event.val = val;

        ev_msg.dv[0].data_ptr = &nd6_event;
        ev_msg.dv[0].data_length = sizeof(nd6_event);

        kev_post_msg(&ev_msg);
}

static void
in6_event_callback(void *arg)
{
        struct in6_event *p_in6_ev = (struct in6_event *)arg;

        EVENTHANDLER_INVOKE(&in6_evhdlr_ctxt, in6_event,
            p_in6_ev->in6_event_code, p_in6_ev->in6_ifp,
            &p_in6_ev->in6_address, p_in6_ev->val);
}

struct in6_event_nwk_wq_entry {
        struct nwk_wq_entry nwk_wqe;
        struct in6_event in6_ev_arg;
};

void
in6_event_enqueue_nwk_wq_entry(in6_evhdlr_code_t in6_event_code,
    struct ifnet *ifp, struct in6_addr *p_addr6,
    uint32_t val)
{
        struct in6_event_nwk_wq_entry *p_in6_ev = NULL;

        MALLOC(p_in6_ev, struct in6_event_nwk_wq_entry *,
            sizeof(struct in6_event_nwk_wq_entry),
            M_NWKWQ, M_WAITOK | M_ZERO);

        p_in6_ev->nwk_wqe.func = in6_event_callback;
        p_in6_ev->nwk_wqe.is_arg_managed = TRUE;
        p_in6_ev->nwk_wqe.arg = &p_in6_ev->in6_ev_arg;

        p_in6_ev->in6_ev_arg.in6_event_code = in6_event_code;
        p_in6_ev->in6_ev_arg.in6_ifp = ifp;
        if (p_addr6 != NULL) {
                bcopy(p_addr6, &p_in6_ev->in6_ev_arg.in6_address,
                    sizeof(p_in6_ev->in6_ev_arg.in6_address));
        }
        p_in6_ev->in6_ev_arg.val = val;

        nwk_wq_enqueue((struct nwk_wq_entry*)p_in6_ev);
}

/*
 * Caller must hold in6_ifaddr_rwlock as writer.
 */
static void
in6_iahash_remove(struct in6_ifaddr *ia)
{
        LCK_RW_ASSERT(&in6_ifaddr_rwlock, LCK_RW_ASSERT_EXCLUSIVE);
        IFA_LOCK_ASSERT_HELD(&ia->ia_ifa);

        if (!IA6_IS_HASHED(ia)) {
                panic("%s: attempt to remove wrong ia %p from ipv6 hash table\n", __func__, ia);
                /* NOTREACHED */
        }
        TAILQ_REMOVE(IN6ADDR_HASH(&ia->ia_addr.sin6_addr), ia, ia6_hash);
        IA6_HASH_INIT(ia);
        if (IFA_REMREF_LOCKED(&ia->ia_ifa) == NULL) {
                panic("%s: unexpected (missing) refcnt ifa=%p", __func__,
                    &ia->ia_ifa);
                /* NOTREACHED */
        }
}

/*
 * Caller must hold in6_ifaddr_rwlock as writer.
 */
static void
in6_iahash_insert(struct in6_ifaddr *ia)
{
        LCK_RW_ASSERT(&in6_ifaddr_rwlock, LCK_RW_ASSERT_EXCLUSIVE);
        IFA_LOCK_ASSERT_HELD(&ia->ia_ifa);

        if (ia->ia_addr.sin6_family != AF_INET6) {
                panic("%s: attempt to insert wrong ia %p into hash table\n", __func__, ia);
                /* NOTREACHED */
        } else if (IA6_IS_HASHED(ia)) {
                panic("%s: attempt to double-insert ia %p into hash table\n", __func__, ia);
                /* NOTREACHED */
        }
        TAILQ_INSERT_HEAD(IN6ADDR_HASH(&ia->ia_addr.sin6_addr),
            ia, ia6_hash);
        IFA_ADDREF_LOCKED(&ia->ia_ifa);
}

/*
 * Some point to point interfaces that are tunnels borrow the address from
 * an underlying interface (e.g. VPN server). In order for source address
 * selection logic to find the underlying interface first, we add the address
 * of borrowing point to point interfaces at the end of the list.
 * (see rdar://6733789)
 *
 * Caller must hold in6_ifaddr_rwlock as writer.
 */
static void
in6_iahash_insert_ptp(struct in6_ifaddr *ia)
{
        struct in6_ifaddr *tmp_ifa;
        struct ifnet *tmp_ifp;

        LCK_RW_ASSERT(&in6_ifaddr_rwlock, LCK_RW_ASSERT_EXCLUSIVE);
        IFA_LOCK_ASSERT_HELD(&ia->ia_ifa);

        if (ia->ia_addr.sin6_family != AF_INET6) {
                panic("%s: attempt to insert wrong ia %p into hash table\n", __func__, ia);
                /* NOTREACHED */
        } else if (IA6_IS_HASHED(ia)) {
                panic("%s: attempt to double-insert ia %p into hash table\n", __func__, ia);
                /* NOTREACHED */
        }
        IFA_UNLOCK(&ia->ia_ifa);
        TAILQ_FOREACH(tmp_ifa, IN6ADDR_HASH(&ia->ia_addr.sin6_addr), ia6_hash) {
                IFA_LOCK(&tmp_ifa->ia_ifa);
                /* ia->ia_addr won't change, so check without lock */
                if (IN6_ARE_ADDR_EQUAL(&tmp_ifa->ia_addr.sin6_addr, &ia->ia_addr.sin6_addr)) {
                        IFA_UNLOCK(&tmp_ifa->ia_ifa);
                        break;
                }
                IFA_UNLOCK(&tmp_ifa->ia_ifa);
        }
        tmp_ifp = (tmp_ifa == NULL) ? NULL : tmp_ifa->ia_ifp;

        IFA_LOCK(&ia->ia_ifa);
        if (tmp_ifp == NULL) {
                TAILQ_INSERT_HEAD(IN6ADDR_HASH(&ia->ia_addr.sin6_addr),
                    ia, ia6_hash);
        } else {
                TAILQ_INSERT_TAIL(IN6ADDR_HASH(&ia->ia_addr.sin6_addr),
                    ia, ia6_hash);
        }
        IFA_ADDREF_LOCKED(&ia->ia_ifa);
}