xnu-3789.60.24.tar.gz

[apple/xnu.git] / bsd / netinet / in.c

/*
 * Copyright (c) 2000-2016 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) 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        8.4 (Berkeley) 1/9/95
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/sockio.h>
#include <sys/socketvar.h>
#include <sys/malloc.h>
#include <sys/proc.h>
#include <sys/socket.h>
#include <sys/kernel.h>
#include <sys/sysctl.h>
#include <sys/kern_event.h>
#include <sys/syslog.h>
#include <sys/mcache.h>
#include <sys/protosw.h>
#include <sys/file.h>

#include <kern/zalloc.h>
#include <pexpert/pexpert.h>

#include <net/if.h>
#include <net/if_types.h>
#include <net/route.h>
#include <net/kpi_protocol.h>
#include <net/dlil.h>
#if PF
#include <net/pfvar.h>
#endif /* PF */

#include <netinet/in.h>
#include <netinet/in_var.h>
#include <netinet/in_pcb.h>
#include <netinet/igmp_var.h>
#include <netinet/ip_var.h>
#include <netinet/tcp.h>
#include <netinet/tcp_timer.h>
#include <netinet/tcp_var.h>

static int inctl_associd(struct socket *, u_long, caddr_t);
static int inctl_connid(struct socket *, u_long, caddr_t);
static int inctl_conninfo(struct socket *, u_long, caddr_t);
static int inctl_autoaddr(struct ifnet *, struct ifreq *);
static int inctl_arpipll(struct ifnet *, struct ifreq *);
static int inctl_setrouter(struct ifnet *, struct ifreq *);
static int inctl_ifaddr(struct ifnet *, struct in_ifaddr *, u_long,
    struct ifreq *);
static int inctl_ifdstaddr(struct ifnet *, struct in_ifaddr *, u_long,
    struct ifreq *);
static int inctl_ifbrdaddr(struct ifnet *, struct in_ifaddr *, u_long,
    struct ifreq *);
static int inctl_ifnetmask(struct ifnet *, struct in_ifaddr *, u_long,
    struct ifreq *);

static void in_socktrim(struct sockaddr_in *);
static int in_ifinit(struct ifnet *, struct in_ifaddr *,
    struct sockaddr_in *, int);

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

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

static void in_iahash_remove(struct in_ifaddr *);
static void in_iahash_insert(struct in_ifaddr *);
static void in_iahash_insert_ptp(struct in_ifaddr *);
static struct in_ifaddr *in_ifaddr_alloc(int);
static void in_ifaddr_attached(struct ifaddr *);
static void in_ifaddr_detached(struct ifaddr *);
static void in_ifaddr_free(struct ifaddr *);
static void in_ifaddr_trace(struct ifaddr *, int);

static int in_getassocids(struct socket *, uint32_t *, user_addr_t);
static int in_getconnids(struct socket *, sae_associd_t, uint32_t *, user_addr_t);
static int in_getconninfo(struct socket *, sae_connid_t, uint32_t *,
    uint32_t *, int32_t *, user_addr_t, socklen_t *, user_addr_t, socklen_t *,
    uint32_t *, user_addr_t, uint32_t *);

static int subnetsarelocal = 0;
SYSCTL_INT(_net_inet_ip, OID_AUTO, subnets_are_local,
        CTLFLAG_RW | CTLFLAG_LOCKED, &subnetsarelocal, 0, "");

/* Track whether or not the SIOCARPIPLL ioctl has been called */
u_int32_t ipv4_ll_arp_aware = 0;

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

/* For gdb */
__private_extern__ unsigned int inifa_trace_hist_size = INIFA_TRACE_HIST_SIZE;

struct in_ifaddr_dbg {
        struct in_ifaddr        inifa;                  /* in_ifaddr */
        struct in_ifaddr        inifa_old;              /* saved in_ifaddr */
        u_int16_t               inifa_refhold_cnt;      /* # of IFA_ADDREF */
        u_int16_t               inifa_refrele_cnt;      /* # of IFA_REMREF */
        /*
         * Alloc and free callers.
         */
        ctrace_t                inifa_alloc;
        ctrace_t                inifa_free;
        /*
         * Circular lists of IFA_ADDREF and IFA_REMREF callers.
         */
        ctrace_t                inifa_refhold[INIFA_TRACE_HIST_SIZE];
        ctrace_t                inifa_refrele[INIFA_TRACE_HIST_SIZE];
        /*
         * Trash list linkage
         */
        TAILQ_ENTRY(in_ifaddr_dbg) inifa_trash_link;
};

/* List of trash in_ifaddr entries protected by inifa_trash_lock */
static TAILQ_HEAD(, in_ifaddr_dbg) inifa_trash_head;
static decl_lck_mtx_data(, inifa_trash_lock);

#if DEBUG
static unsigned int inifa_debug = 1;            /* debugging (enabled) */
#else
static unsigned int inifa_debug;                /* debugging (disabled) */
#endif /* !DEBUG */
static unsigned int inifa_size;                 /* size of zone element */
static struct zone *inifa_zone;                 /* zone for in_ifaddr */

#define INIFA_ZONE_MAX          64              /* maximum elements in zone */
#define INIFA_ZONE_NAME         "in_ifaddr"     /* zone name */

static const unsigned int in_extra_size = sizeof (struct in_ifextra);
static const unsigned int in_extra_bufsize = in_extra_size +
    sizeof (void *) + sizeof (uint64_t);

/*
 * Return 1 if the address is
 * - loopback
 * - unicast or multicast link local
 * - routed via a link level gateway
 * - belongs to a directly connected (sub)net
 */
int
inaddr_local(struct in_addr in)
{
        struct rtentry *rt;
        struct sockaddr_in sin;
        int local = 0;

        if (ntohl(in.s_addr) == INADDR_LOOPBACK ||
            IN_LINKLOCAL(ntohl(in.s_addr))) {
                local = 1;
        } else if (ntohl(in.s_addr) >= INADDR_UNSPEC_GROUP &&
            ntohl(in.s_addr) <= INADDR_MAX_LOCAL_GROUP) {
                        local = 1;
        } else {
                sin.sin_family = AF_INET;
                sin.sin_len = sizeof (sin);
                sin.sin_addr = in;
                rt = rtalloc1((struct sockaddr *)&sin, 0, 0);

                if (rt != NULL) {
                        RT_LOCK_SPIN(rt);
                        if (rt->rt_gateway->sa_family == AF_LINK ||
                            (rt->rt_ifp->if_flags & IFF_LOOPBACK))
                                local = 1;
                        RT_UNLOCK(rt);
                        rtfree(rt);
                } else {
                        local = in_localaddr(in);
                }
        }
        return (local);
}

/*
 * Return 1 if an internet address is for a ``local'' host
 * (one to which we have a connection).  If subnetsarelocal
 * is true, this includes other subnets of the local net,
 * otherwise, it includes the directly-connected (sub)nets.
 * The IPv4 link local prefix 169.254/16 is also included.
 */
int
in_localaddr(struct in_addr in)
{
        u_int32_t i = ntohl(in.s_addr);
        struct in_ifaddr *ia;

        if (IN_LINKLOCAL(i))
                return (1);

        if (subnetsarelocal) {
                lck_rw_lock_shared(in_ifaddr_rwlock);
                for (ia = in_ifaddrhead.tqh_first; ia != NULL;
                    ia = ia->ia_link.tqe_next) {
                        IFA_LOCK(&ia->ia_ifa);
                        if ((i & ia->ia_netmask) == ia->ia_net) {
                                IFA_UNLOCK(&ia->ia_ifa);
                                lck_rw_done(in_ifaddr_rwlock);
                                return (1);
                        }
                        IFA_UNLOCK(&ia->ia_ifa);
                }
                lck_rw_done(in_ifaddr_rwlock);
        } else {
                lck_rw_lock_shared(in_ifaddr_rwlock);
                for (ia = in_ifaddrhead.tqh_first; ia != NULL;
                    ia = ia->ia_link.tqe_next) {
                        IFA_LOCK(&ia->ia_ifa);
                        if ((i & ia->ia_subnetmask) == ia->ia_subnet) {
                                IFA_UNLOCK(&ia->ia_ifa);
                                lck_rw_done(in_ifaddr_rwlock);
                                return (1);
                        }
                        IFA_UNLOCK(&ia->ia_ifa);
                }
                lck_rw_done(in_ifaddr_rwlock);
        }
        return (0);
}

/*
 * Determine whether an IP address is in a reserved set of addresses
 * that may not be forwarded, or whether datagrams to that destination
 * may be forwarded.
 */
boolean_t
in_canforward(struct in_addr in)
{
        u_int32_t i = ntohl(in.s_addr);
        u_int32_t net;

        if (IN_EXPERIMENTAL(i) || IN_MULTICAST(i))
                return (FALSE);
        if (IN_CLASSA(i)) {
                net = i & IN_CLASSA_NET;
                if (net == 0 || net == (IN_LOOPBACKNET << IN_CLASSA_NSHIFT))
                        return (FALSE);
        }
        return (TRUE);
}

/*
 * Trim a mask in a sockaddr
 */
static void
in_socktrim(struct sockaddr_in *ap)
{
        char *cplim = (char *)&ap->sin_addr;
        char *cp = (char *)(&ap->sin_addr + 1);

        ap->sin_len = 0;
        while (--cp >= cplim)
                if (*cp) {
                        (ap)->sin_len = cp - (char *)(ap) + 1;
                        break;
                }
}

static int in_interfaces;       /* number of external internet interfaces */

static int
in_domifattach(struct ifnet *ifp)
{
        int error;

        VERIFY(ifp != NULL);

        if ((error = proto_plumb(PF_INET, ifp)) && error != EEXIST) {
                log(LOG_ERR, "%s: proto_plumb returned %d if=%s\n",
                    __func__, error, if_name(ifp));
        } else if (error == 0 && ifp->if_inetdata == NULL) {
                void **pbuf, *base;
                struct in_ifextra *ext;
                int errorx;

                if ((ext = (struct in_ifextra *)_MALLOC(in_extra_bufsize,
                    M_IFADDR, M_WAITOK|M_ZERO)) == NULL) {
                        error = ENOMEM;
                        errorx = proto_unplumb(PF_INET, ifp);
                        if (errorx != 0) {
                                log(LOG_ERR,
                                    "%s: proto_unplumb returned %d if=%s%d\n",
                                    __func__, errorx, ifp->if_name,
                                    ifp->if_unit);
                        }
                        goto done;
                }

                /* Align on 64-bit boundary */
                base = (void *)P2ROUNDUP((intptr_t)ext + sizeof (uint64_t),
                    sizeof (uint64_t));
                VERIFY(((intptr_t)base + in_extra_size) <=
                    ((intptr_t)ext + in_extra_bufsize));
                pbuf = (void **)((intptr_t)base - sizeof (void *));
                *pbuf = ext;
                ifp->if_inetdata = base;
                VERIFY(IS_P2ALIGNED(ifp->if_inetdata, sizeof (uint64_t)));
        }
done:
        if (error == 0 && ifp->if_inetdata != NULL) {
                /*
                 * Since the structure is never freed, we need to
                 * zero out its contents to avoid reusing stale data.
                 * A little redundant with allocation above, but it
                 * keeps the code simpler for all cases.
                 */
                bzero(ifp->if_inetdata, in_extra_size);
        }
        return (error);
}

static __attribute__((noinline)) int
inctl_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 = in_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 = in_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
inctl_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 = in_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 = in_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
inctl_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 = in_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 = in_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);
}

/*
 * 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
inctl_autoaddr(struct ifnet *ifp, struct ifreq *ifr)
{
        int error = 0, intval;

        VERIFY(ifp != NULL);

        bcopy(&ifr->ifr_intval, &intval, sizeof (intval));

        ifnet_lock_exclusive(ifp);
        if (intval) {
                /*
                 * An interface in IPv4 router mode implies that it
                 * is configured with a static IP address and should
                 * not act as a DHCP client; prevent SIOCAUTOADDR from
                 * being set in that mode.
                 */
                if (ifp->if_eflags & IFEF_IPV4_ROUTER) {
                        intval = 0;     /* be safe; clear flag if set */
                        error = EBUSY;
                } else {
                        ifp->if_eflags |= IFEF_AUTOCONFIGURING;
                }
        }
        if (!intval)
                ifp->if_eflags &= ~IFEF_AUTOCONFIGURING;
        ifnet_lock_done(ifp);

        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
inctl_arpipll(struct ifnet *ifp, struct ifreq *ifr)
{
        int error = 0, intval;

        VERIFY(ifp != NULL);

        bcopy(&ifr->ifr_intval, &intval, sizeof (intval));
        ipv4_ll_arp_aware = 1;

        ifnet_lock_exclusive(ifp);
        if (intval) {
                /*
                 * An interface in IPv4 router mode implies that it
                 * is configured with a static IP address and should
                 * not have to deal with IPv4 Link-Local Address;
                 * prevent SIOCARPIPLL from being set in that mode.
                 */
                if (ifp->if_eflags & IFEF_IPV4_ROUTER) {
                        intval = 0;     /* be safe; clear flag if set */
                        error = EBUSY;
                } else {
                        ifp->if_eflags |= IFEF_ARPLL;
                }
        }
        if (!intval)
                ifp->if_eflags &= ~IFEF_ARPLL;
        ifnet_lock_done(ifp);

        return (error);
}

/*
 * Handle SIOCSETROUTERMODE to set or clear the IPv4 router mode flag on
 * the interface.  When in this mode, IPv4 Link-Local Address support is
 * disabled in ARP, and DHCP client support is disabled in IP input; turning
 * any of them on would cause an error to be returned.  Entering or exiting
 * this mode will result in the removal of IPv4 addresses currently configured
 * on the interface.
 *
 * 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
inctl_setrouter(struct ifnet *ifp, struct ifreq *ifr)
{
        int error = 0, intval;

        VERIFY(ifp != NULL);

        /* Router mode isn't valid for loopback */
        if (ifp->if_flags & IFF_LOOPBACK)
                return (ENODEV);

        bcopy(&ifr->ifr_intval, &intval, sizeof (intval));

        ifnet_lock_exclusive(ifp);
        if (intval) {
                ifp->if_eflags |= IFEF_IPV4_ROUTER;
                ifp->if_eflags &= ~(IFEF_ARPLL | IFEF_AUTOCONFIGURING);
        } else {
                ifp->if_eflags &= ~IFEF_IPV4_ROUTER;
        }
        ifnet_lock_done(ifp);

        /* purge all IPv4 addresses configured on this interface */
        in_purgeaddrs(ifp);

        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
inctl_ifaddr(struct ifnet *ifp, struct in_ifaddr *ia, u_long cmd,
    struct ifreq *ifr)
{
        struct kev_in_data in_event_data;
        struct kev_msg ev_msg;
        struct sockaddr_in addr;
        struct ifaddr *ifa;
        int error = 0;

        VERIFY(ifp != NULL);

        bzero(&in_event_data, sizeof (struct kev_in_data));
        bzero(&ev_msg, sizeof (struct kev_msg));

        switch (cmd) {
        case SIOCGIFADDR:               /* struct ifreq */
                if (ia == NULL) {
                        error = EADDRNOTAVAIL;
                        break;
                }
                IFA_LOCK(&ia->ia_ifa);
                bcopy(&ia->ia_addr, &ifr->ifr_addr, sizeof (addr));
                IFA_UNLOCK(&ia->ia_ifa);
                break;

        case SIOCSIFADDR:               /* struct ifreq */
                VERIFY(ia != NULL);
                bcopy(&ifr->ifr_addr, &addr, sizeof (addr));
                /*
                 * If this is a new address, the reference count for the
                 * hash table has been taken at creation time above.
                 */
                error = in_ifinit(ifp, ia, &addr, 1);
                if (error == 0) {
                        (void) ifnet_notify_address(ifp, AF_INET);
                }
                break;

        case SIOCAIFADDR: {             /* struct {if,in_}aliasreq */
                struct in_aliasreq *ifra = (struct in_aliasreq *)ifr;
                struct sockaddr_in broadaddr, mask;
                int hostIsNew, maskIsNew;

                VERIFY(ia != NULL);
                bcopy(&ifra->ifra_addr, &addr, sizeof (addr));
                bcopy(&ifra->ifra_broadaddr, &broadaddr, sizeof (broadaddr));
                bcopy(&ifra->ifra_mask, &mask, sizeof (mask));

                maskIsNew = 0;
                hostIsNew = 1;
                error = 0;

                IFA_LOCK(&ia->ia_ifa);
                if (ia->ia_addr.sin_family == AF_INET) {
                        if (addr.sin_len == 0) {
                                addr = ia->ia_addr;
                                hostIsNew = 0;
                        } else if (addr.sin_addr.s_addr ==
                            ia->ia_addr.sin_addr.s_addr) {
                                hostIsNew = 0;
                        }
                }
                if (mask.sin_len) {
                        IFA_UNLOCK(&ia->ia_ifa);
                        in_ifscrub(ifp, ia, 0);
                        IFA_LOCK(&ia->ia_ifa);
                        ia->ia_sockmask = mask;
                        ia->ia_subnetmask =
                            ntohl(ia->ia_sockmask.sin_addr.s_addr);
                        maskIsNew = 1;
                }
                if ((ifp->if_flags & IFF_POINTOPOINT) &&
                    (broadaddr.sin_family == AF_INET)) {
                        IFA_UNLOCK(&ia->ia_ifa);
                        in_ifscrub(ifp, ia, 0);
                        IFA_LOCK(&ia->ia_ifa);
                        ia->ia_dstaddr = broadaddr;
                        ia->ia_dstaddr.sin_len = sizeof (struct sockaddr_in);
                        maskIsNew  = 1; /* We lie; but the effect's the same */
                }
                if (addr.sin_family == AF_INET && (hostIsNew || maskIsNew)) {
                        IFA_UNLOCK(&ia->ia_ifa);
                        error = in_ifinit(ifp, ia, &addr, 0);
                } else {
                        IFA_UNLOCK(&ia->ia_ifa);
                }
                if (error == 0) {
                        (void) ifnet_notify_address(ifp, AF_INET);
                }
                IFA_LOCK(&ia->ia_ifa);
                if ((ifp->if_flags & IFF_BROADCAST) &&
                    (broadaddr.sin_family == AF_INET))
                        ia->ia_broadaddr = broadaddr;

                /*
                 * Report event.
                 */
                if ((error == 0) || (error == EEXIST)) {
                        ev_msg.vendor_code      = KEV_VENDOR_APPLE;
                        ev_msg.kev_class        = KEV_NETWORK_CLASS;
                        ev_msg.kev_subclass     = KEV_INET_SUBCLASS;

                        if (hostIsNew)
                                ev_msg.event_code = KEV_INET_NEW_ADDR;
                        else
                                ev_msg.event_code = KEV_INET_CHANGED_ADDR;

                        if (ia->ia_ifa.ifa_dstaddr) {
                                in_event_data.ia_dstaddr =
                                    ((struct sockaddr_in *)(void *)ia->
                                    ia_ifa.ifa_dstaddr)->sin_addr;
                        } else {
                                in_event_data.ia_dstaddr.s_addr = INADDR_ANY;
                        }
                        in_event_data.ia_addr           = ia->ia_addr.sin_addr;
                        in_event_data.ia_net            = ia->ia_net;
                        in_event_data.ia_netmask        = ia->ia_netmask;
                        in_event_data.ia_subnet         = ia->ia_subnet;
                        in_event_data.ia_subnetmask     = ia->ia_subnetmask;
                        in_event_data.ia_netbroadcast   = ia->ia_netbroadcast;
                        IFA_UNLOCK(&ia->ia_ifa);
                        (void) strlcpy(&in_event_data.link_data.if_name[0],
                            ifp->if_name, IFNAMSIZ);
                        in_event_data.link_data.if_family = ifp->if_family;
                        in_event_data.link_data.if_unit = ifp->if_unit;

                        ev_msg.dv[0].data_ptr    = &in_event_data;
                        ev_msg.dv[0].data_length = sizeof (struct kev_in_data);
                        ev_msg.dv[1].data_length = 0;

                        dlil_post_complete_msg(ifp, &ev_msg);
                } else {
                        IFA_UNLOCK(&ia->ia_ifa);
                }
                break;
        }

        case SIOCDIFADDR:               /* struct ifreq */
                VERIFY(ia != NULL);
                error = ifnet_ioctl(ifp, PF_INET, SIOCDIFADDR, ia);
                if (error == EOPNOTSUPP)
                        error = 0;
                if (error != 0) {
                        /* Reset the detaching flag */
                        IFA_LOCK(&ia->ia_ifa);
                        ia->ia_ifa.ifa_debug &= ~IFD_DETACHING;
                        IFA_UNLOCK(&ia->ia_ifa);
                        break;
                }

                /* Fill out the kernel event information */
                ev_msg.vendor_code      = KEV_VENDOR_APPLE;
                ev_msg.kev_class        = KEV_NETWORK_CLASS;
                ev_msg.kev_subclass     = KEV_INET_SUBCLASS;

                ev_msg.event_code       = KEV_INET_ADDR_DELETED;

                IFA_LOCK(&ia->ia_ifa);
                if (ia->ia_ifa.ifa_dstaddr) {
                        in_event_data.ia_dstaddr = ((struct sockaddr_in *)
                            (void *)ia->ia_ifa.ifa_dstaddr)->sin_addr;
                } else {
                        in_event_data.ia_dstaddr.s_addr = INADDR_ANY;
                }
                in_event_data.ia_addr           = ia->ia_addr.sin_addr;
                in_event_data.ia_net            = ia->ia_net;
                in_event_data.ia_netmask        = ia->ia_netmask;
                in_event_data.ia_subnet         = ia->ia_subnet;
                in_event_data.ia_subnetmask     = ia->ia_subnetmask;
                in_event_data.ia_netbroadcast   = ia->ia_netbroadcast;
                IFA_UNLOCK(&ia->ia_ifa);
                (void) strlcpy(&in_event_data.link_data.if_name[0],
                    ifp->if_name, IFNAMSIZ);
                in_event_data.link_data.if_family = ifp->if_family;
                in_event_data.link_data.if_unit  = (u_int32_t)ifp->if_unit;

                ev_msg.dv[0].data_ptr    = &in_event_data;
                ev_msg.dv[0].data_length = sizeof(struct kev_in_data);
                ev_msg.dv[1].data_length = 0;

                ifa = &ia->ia_ifa;
                lck_rw_lock_exclusive(in_ifaddr_rwlock);
                /* Release ia_link reference */
                IFA_REMREF(ifa);
                TAILQ_REMOVE(&in_ifaddrhead, ia, ia_link);
                IFA_LOCK(ifa);
                if (IA_IS_HASHED(ia))
                        in_iahash_remove(ia);
                IFA_UNLOCK(ifa);
                lck_rw_done(in_ifaddr_rwlock);

                /*
                 * in_ifscrub kills the interface route.
                 */
                in_ifscrub(ifp, ia, 0);
                ifnet_lock_exclusive(ifp);
                IFA_LOCK(ifa);
                /* if_detach_ifa() releases ifa_link reference */
                if_detach_ifa(ifp, ifa);
                /* Our reference to this address is dropped at the bottom */
                IFA_UNLOCK(ifa);

                /* invalidate route caches */
                routegenid_inet_update();

                /*
                 * If the interface supports multicast, and no address is left,
                 * remove the "all hosts" multicast group from that interface.
                 */
                if ((ifp->if_flags & IFF_MULTICAST) ||
                    ifp->if_allhostsinm != NULL) {

                        TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
                                IFA_LOCK(ifa);
                                if (ifa->ifa_addr->sa_family == AF_INET) {
                                        IFA_UNLOCK(ifa);
                                        break;
                                }
                                IFA_UNLOCK(ifa);
                        }
                        ifnet_lock_done(ifp);

                        lck_mtx_lock(&ifp->if_addrconfig_lock);
                        if (ifa == NULL && ifp->if_allhostsinm != NULL) {
                                struct in_multi *inm = ifp->if_allhostsinm;
                                ifp->if_allhostsinm = NULL;

                                in_delmulti(inm);
                                /* release the reference for allhostsinm */
                                INM_REMREF(inm);
                        }
                        lck_mtx_unlock(&ifp->if_addrconfig_lock);
                } else {
                        ifnet_lock_done(ifp);
                }

                /* Post the kernel event */
                dlil_post_complete_msg(ifp, &ev_msg);

                /*
                 * See if there is any IPV4 address left and if so,
                 * reconfigure KDP to use current primary address.
                 */
                ifa = ifa_ifpgetprimary(ifp, AF_INET);
                if (ifa != NULL) {
                        /*
                         * 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.
                         */
                        error = ifnet_ioctl(ifp, PF_INET, SIOCSIFADDR, ifa);
                        if (error == EOPNOTSUPP)
                                error = 0;

                        /* Release reference from ifa_ifpgetprimary() */
                        IFA_REMREF(ifa);
                }
                (void) ifnet_notify_address(ifp, AF_INET);
                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
inctl_ifdstaddr(struct ifnet *ifp, struct in_ifaddr *ia, u_long cmd,
    struct ifreq *ifr)
{
        struct kev_in_data in_event_data;
        struct kev_msg ev_msg;
        struct sockaddr_in dstaddr;
        int error = 0;

        VERIFY(ifp != NULL);

        if (!(ifp->if_flags & IFF_POINTOPOINT))
                return (EINVAL);

        bzero(&in_event_data, sizeof (struct kev_in_data));
        bzero(&ev_msg, sizeof (struct kev_msg));

        switch (cmd) {
        case SIOCGIFDSTADDR:            /* struct ifreq */
                if (ia == NULL) {
                        error = EADDRNOTAVAIL;
                        break;
                }
                IFA_LOCK(&ia->ia_ifa);
                bcopy(&ia->ia_dstaddr, &ifr->ifr_dstaddr, sizeof (dstaddr));
                IFA_UNLOCK(&ia->ia_ifa);
                break;

        case SIOCSIFDSTADDR:            /* struct ifreq */
                VERIFY(ia != NULL);
                IFA_LOCK(&ia->ia_ifa);
                dstaddr = ia->ia_dstaddr;
                bcopy(&ifr->ifr_dstaddr, &ia->ia_dstaddr, sizeof (dstaddr));
                if (ia->ia_dstaddr.sin_family == AF_INET)
                        ia->ia_dstaddr.sin_len = sizeof (struct sockaddr_in);
                IFA_UNLOCK(&ia->ia_ifa);
                /*
                 * NOTE: SIOCSIFDSTADDR 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.
                 */
                error = ifnet_ioctl(ifp, PF_INET, SIOCSIFDSTADDR, ia);
                IFA_LOCK(&ia->ia_ifa);
                if (error == EOPNOTSUPP)
                        error = 0;
                if (error != 0) {
                        ia->ia_dstaddr = dstaddr;
                        IFA_UNLOCK(&ia->ia_ifa);
                        break;
                }
                IFA_LOCK_ASSERT_HELD(&ia->ia_ifa);

                ev_msg.vendor_code      = KEV_VENDOR_APPLE;
                ev_msg.kev_class        = KEV_NETWORK_CLASS;
                ev_msg.kev_subclass     = KEV_INET_SUBCLASS;

                ev_msg.event_code       = KEV_INET_SIFDSTADDR;

                if (ia->ia_ifa.ifa_dstaddr) {
                        in_event_data.ia_dstaddr = ((struct sockaddr_in *)
                            (void *)ia->ia_ifa.ifa_dstaddr)->sin_addr;
                } else {
                        in_event_data.ia_dstaddr.s_addr = INADDR_ANY;
                }

                in_event_data.ia_addr           = ia->ia_addr.sin_addr;
                in_event_data.ia_net            = ia->ia_net;
                in_event_data.ia_netmask        = ia->ia_netmask;
                in_event_data.ia_subnet         = ia->ia_subnet;
                in_event_data.ia_subnetmask     = ia->ia_subnetmask;
                in_event_data.ia_netbroadcast   = ia->ia_netbroadcast;
                IFA_UNLOCK(&ia->ia_ifa);
                (void) strlcpy(&in_event_data.link_data.if_name[0],
                    ifp->if_name, IFNAMSIZ);
                in_event_data.link_data.if_family = ifp->if_family;
                in_event_data.link_data.if_unit  = (u_int32_t)ifp->if_unit;

                ev_msg.dv[0].data_ptr    = &in_event_data;
                ev_msg.dv[0].data_length = sizeof (struct kev_in_data);
                ev_msg.dv[1].data_length = 0;

                dlil_post_complete_msg(ifp, &ev_msg);

                lck_mtx_lock(rnh_lock);
                IFA_LOCK(&ia->ia_ifa);
                if (ia->ia_flags & IFA_ROUTE) {
                        ia->ia_ifa.ifa_dstaddr = (struct sockaddr *)&dstaddr;
                        IFA_UNLOCK(&ia->ia_ifa);
                        rtinit_locked(&(ia->ia_ifa), (int)RTM_DELETE, RTF_HOST);
                        IFA_LOCK(&ia->ia_ifa);
                        ia->ia_ifa.ifa_dstaddr =
                            (struct sockaddr *)&ia->ia_dstaddr;
                        IFA_UNLOCK(&ia->ia_ifa);
                        rtinit_locked(&(ia->ia_ifa), (int)RTM_ADD,
                            RTF_HOST|RTF_UP);
                } else {
                        IFA_UNLOCK(&ia->ia_ifa);
                }
                lck_mtx_unlock(rnh_lock);
                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
inctl_ifbrdaddr(struct ifnet *ifp, struct in_ifaddr *ia, u_long cmd,
    struct ifreq *ifr)
{
        struct kev_in_data in_event_data;
        struct kev_msg ev_msg;
        int error = 0;

        VERIFY(ifp != NULL);

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

        if (!(ifp->if_flags & IFF_BROADCAST))
                return (EINVAL);

        bzero(&in_event_data, sizeof (struct kev_in_data));
        bzero(&ev_msg, sizeof (struct kev_msg));

        switch (cmd) {
        case SIOCGIFBRDADDR:            /* struct ifreq */
                IFA_LOCK(&ia->ia_ifa);
                bcopy(&ia->ia_broadaddr, &ifr->ifr_broadaddr,
                    sizeof (struct sockaddr_in));
                IFA_UNLOCK(&ia->ia_ifa);
                break;

        case SIOCSIFBRDADDR:            /* struct ifreq */
                IFA_LOCK(&ia->ia_ifa);
                bcopy(&ifr->ifr_broadaddr, &ia->ia_broadaddr,
                    sizeof (struct sockaddr_in));

                ev_msg.vendor_code      = KEV_VENDOR_APPLE;
                ev_msg.kev_class        = KEV_NETWORK_CLASS;
                ev_msg.kev_subclass     = KEV_INET_SUBCLASS;

                ev_msg.event_code = KEV_INET_SIFBRDADDR;

                if (ia->ia_ifa.ifa_dstaddr) {
                        in_event_data.ia_dstaddr = ((struct sockaddr_in *)
                            (void *)ia->ia_ifa.ifa_dstaddr)->sin_addr;
                } else {
                        in_event_data.ia_dstaddr.s_addr = INADDR_ANY;
                }
                in_event_data.ia_addr           = ia->ia_addr.sin_addr;
                in_event_data.ia_net            = ia->ia_net;
                in_event_data.ia_netmask        = ia->ia_netmask;
                in_event_data.ia_subnet         = ia->ia_subnet;
                in_event_data.ia_subnetmask     = ia->ia_subnetmask;
                in_event_data.ia_netbroadcast   = ia->ia_netbroadcast;
                IFA_UNLOCK(&ia->ia_ifa);
                (void) strlcpy(&in_event_data.link_data.if_name[0],
                    ifp->if_name, IFNAMSIZ);
                in_event_data.link_data.if_family = ifp->if_family;
                in_event_data.link_data.if_unit  = (u_int32_t)ifp->if_unit;

                ev_msg.dv[0].data_ptr    = &in_event_data;
                ev_msg.dv[0].data_length = sizeof (struct kev_in_data);
                ev_msg.dv[1].data_length = 0;

                dlil_post_complete_msg(ifp, &ev_msg);
                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
inctl_ifnetmask(struct ifnet *ifp, struct in_ifaddr *ia, u_long cmd,
    struct ifreq *ifr)
{
        struct kev_in_data in_event_data;
        struct kev_msg ev_msg;
        struct sockaddr_in mask;
        int error = 0;

        VERIFY(ifp != NULL);

        bzero(&in_event_data, sizeof (struct kev_in_data));
        bzero(&ev_msg, sizeof (struct kev_msg));

        switch (cmd) {
        case SIOCGIFNETMASK:            /* struct ifreq */
                if (ia == NULL) {
                        error = EADDRNOTAVAIL;
                        break;
                }
                IFA_LOCK(&ia->ia_ifa);
                bcopy(&ia->ia_sockmask, &ifr->ifr_addr, sizeof (mask));
                IFA_UNLOCK(&ia->ia_ifa);
                break;

        case SIOCSIFNETMASK: {          /* struct ifreq */
                in_addr_t i;

                bcopy(&ifr->ifr_addr, &mask, sizeof (mask));
                i = mask.sin_addr.s_addr;

                VERIFY(ia != NULL);
                IFA_LOCK(&ia->ia_ifa);
                ia->ia_subnetmask = ntohl(ia->ia_sockmask.sin_addr.s_addr = i);
                ev_msg.vendor_code      = KEV_VENDOR_APPLE;
                ev_msg.kev_class        = KEV_NETWORK_CLASS;
                ev_msg.kev_subclass     = KEV_INET_SUBCLASS;

                ev_msg.event_code = KEV_INET_SIFNETMASK;

                if (ia->ia_ifa.ifa_dstaddr) {
                        in_event_data.ia_dstaddr = ((struct sockaddr_in *)
                            (void *)ia->ia_ifa.ifa_dstaddr)->sin_addr;
                } else {
                        in_event_data.ia_dstaddr.s_addr = INADDR_ANY;
                }
                in_event_data.ia_addr           = ia->ia_addr.sin_addr;
                in_event_data.ia_net            = ia->ia_net;
                in_event_data.ia_netmask        = ia->ia_netmask;
                in_event_data.ia_subnet         = ia->ia_subnet;
                in_event_data.ia_subnetmask     = ia->ia_subnetmask;
                in_event_data.ia_netbroadcast   = ia->ia_netbroadcast;
                IFA_UNLOCK(&ia->ia_ifa);
                (void) strlcpy(&in_event_data.link_data.if_name[0],
                    ifp->if_name, IFNAMSIZ);
                in_event_data.link_data.if_family = ifp->if_family;
                in_event_data.link_data.if_unit  = (u_int32_t)ifp->if_unit;

                ev_msg.dv[0].data_ptr    = &in_event_data;
                ev_msg.dv[0].data_length = sizeof (struct kev_in_data);
                ev_msg.dv[1].data_length = 0;

                dlil_post_complete_msg(ifp, &ev_msg);
                break;
        }

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

        return (error);
}

/*
 * Generic INET 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
in_control(struct socket *so, u_long cmd, caddr_t data, struct ifnet *ifp,
    struct proc *p)
{
        struct ifreq *ifr = (struct ifreq *)(void *)data;
        struct sockaddr_in addr, dstaddr;
        struct sockaddr_in sin, *sa = NULL;
        boolean_t privileged = (proc_suser(p) == 0);
        boolean_t so_unlocked = FALSE;
        struct in_ifaddr *ia = NULL;
        struct ifaddr *ifa;
        int 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, but require socket.
         */
        switch (cmd) {
        case SIOCGASSOCIDS32:           /* struct so_aidreq32 */
        case SIOCGASSOCIDS64:           /* struct so_aidreq64 */
                return (inctl_associd(so, cmd, data));
                /* NOTREACHED */

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

        case SIOCGCONNINFO32:           /* struct so_cinforeq32 */
        case SIOCGCONNINFO64:           /* struct so_cinforeq64 */
                return (inctl_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);

        /*
         * ioctls which require ifp but not interface address.
         */
        switch (cmd) {
        case SIOCAUTOADDR:              /* struct ifreq */
                if (!privileged)
                        return (EPERM);
                return (inctl_autoaddr(ifp, ifr));
                /* NOTREACHED */

        case SIOCARPIPLL:               /* struct ifreq */
                if (!privileged)
                        return (EPERM);
                return (inctl_arpipll(ifp, ifr));
                /* NOTREACHED */

        case SIOCSETROUTERMODE:         /* struct ifreq */
                if (!privileged)
                        return (EPERM);
                return (inctl_setrouter(ifp, ifr));
                /* NOTREACHED */

        case SIOCPROTOATTACH:           /* struct ifreq */
                if (!privileged)
                        return (EPERM);
                return (in_domifattach(ifp));
                /* NOTREACHED */

        case SIOCPROTODETACH:           /* struct ifreq */
                if (!privileged)
                        return (EPERM);

                /*
                 * If an IPv4 address is still present, refuse to detach.
                 */
                ifnet_lock_shared(ifp);
                TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
                        IFA_LOCK(ifa);
                        if (ifa->ifa_addr->sa_family == AF_INET) {
                                IFA_UNLOCK(ifa);
                                break;
                        }
                        IFA_UNLOCK(ifa);
                }
                ifnet_lock_done(ifp);
                return ((ifa == NULL) ? proto_unplumb(PF_INET, ifp) : EBUSY);
                /* NOTREACHED */
        }

        /*
         * ioctls which require interface address; obtain sockaddr_in.
         */
        switch (cmd) {
        case SIOCAIFADDR:               /* struct {if,in_}aliasreq */
                if (!privileged)
                        return (EPERM);
                bcopy(&((struct in_aliasreq *)(void *)data)->ifra_addr,
                    &sin, sizeof (sin));
                sa = &sin;
                break;

        case SIOCDIFADDR:               /* struct ifreq */
        case SIOCSIFADDR:               /* struct ifreq */
        case SIOCSIFDSTADDR:            /* struct ifreq */
        case SIOCSIFNETMASK:            /* struct ifreq */
        case SIOCSIFBRDADDR:            /* struct ifreq */
                if (!privileged)
                        return (EPERM);
                /* FALLTHRU */
        case SIOCGIFADDR:               /* struct ifreq */
        case SIOCGIFDSTADDR:            /* struct ifreq */
        case SIOCGIFNETMASK:            /* struct ifreq */
        case SIOCGIFBRDADDR:            /* struct ifreq */
                bcopy(&ifr->ifr_addr, &sin, sizeof (sin));
                sa = &sin;
                break;
        }

        /*
         * Find address for this interface, if it exists.
         *
         * If an alias address was specified, find that one instead of
         * the first one on the interface, if possible.
         */
        VERIFY(ia == NULL);
        if (sa != NULL) {
                struct in_ifaddr *iap;

                /*
                 * 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.
                 */
                lck_rw_lock_shared(in_ifaddr_rwlock);
                TAILQ_FOREACH(iap, INADDR_HASH(sa->sin_addr.s_addr), ia_hash) {
                        IFA_LOCK(&iap->ia_ifa);
                        if (iap->ia_ifp == ifp &&
                            iap->ia_addr.sin_addr.s_addr ==
                            sa->sin_addr.s_addr) {
                                /*
                                 * Avoid the race condition seen when two
                                 * threads process SIOCDIFADDR command
                                 * at the same time (radar 28942007)
                                 */
                                if (cmd == SIOCDIFADDR) {
                                        if (iap->ia_ifa.ifa_debug &
                                            IFD_DETACHING) {
                                                IFA_UNLOCK(&iap->ia_ifa);
                                                continue;
                                        } else {
                                                iap->ia_ifa.ifa_debug |=
                                                    IFD_DETACHING;
                                        }
                                }
                                ia = iap;
                                IFA_ADDREF_LOCKED(&iap->ia_ifa);
                                IFA_UNLOCK(&iap->ia_ifa);
                                break;
                        }
                        IFA_UNLOCK(&iap->ia_ifa);
                }
                lck_rw_done(in_ifaddr_rwlock);

                if (ia == NULL) {
                        ifnet_lock_shared(ifp);
                        TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
                                iap = ifatoia(ifa);
                                IFA_LOCK(&iap->ia_ifa);
                                if (iap->ia_addr.sin_family == AF_INET) {
                                        ia = iap;
                                        IFA_UNLOCK(&iap->ia_ifa);
                                        break;
                                }
                                IFA_UNLOCK(&iap->ia_ifa);
                        }
                        /* take a reference on ia before releasing lock */
                        if (ia != NULL)
                                IFA_ADDREF(&ia->ia_ifa);
                        ifnet_lock_done(ifp);
                }
        }

        /*
         * 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;
        }

        switch (cmd) {
        case SIOCAIFADDR:               /* struct {if,in_}aliasreq */
        case SIOCDIFADDR:               /* struct ifreq */
                if (cmd == SIOCAIFADDR) {
                        bcopy(&((struct in_aliasreq *)(void *)data)->
                            ifra_addr, &addr, sizeof (addr));
                        bcopy(&((struct in_aliasreq *)(void *)data)->
                            ifra_dstaddr, &dstaddr, sizeof (dstaddr));
                } else {
                        VERIFY(cmd == SIOCDIFADDR);
                        bcopy(&((struct ifreq *)(void *)data)->ifr_addr,
                            &addr, sizeof (addr));
                        bzero(&dstaddr, sizeof (dstaddr));
                }

                if (addr.sin_family == AF_INET) {
                        struct in_ifaddr *oia;

                        lck_rw_lock_shared(in_ifaddr_rwlock);
                        for (oia = ia; ia; ia = ia->ia_link.tqe_next) {
                                IFA_LOCK(&ia->ia_ifa);
                                if (ia->ia_ifp == ifp &&
                                    ia->ia_addr.sin_addr.s_addr ==
                                    addr.sin_addr.s_addr) {
                                        IFA_ADDREF_LOCKED(&ia->ia_ifa);
                                        IFA_UNLOCK(&ia->ia_ifa);
                                        break;
                                }
                                IFA_UNLOCK(&ia->ia_ifa);
                        }
                        lck_rw_done(in_ifaddr_rwlock);
                        if (oia != NULL)
                                IFA_REMREF(&oia->ia_ifa);
                        if ((ifp->if_flags & IFF_POINTOPOINT) &&
                            (cmd == SIOCAIFADDR) &&
                            (dstaddr.sin_addr.s_addr == INADDR_ANY)) {
                                error = EDESTADDRREQ;
                                goto done;
                        }
                } else if (cmd == SIOCAIFADDR) {
                        error = EINVAL;
                        goto done;
                }
                if (cmd == SIOCDIFADDR && ia == NULL) {
                        error = EADDRNOTAVAIL;
                        goto done;
                }
                /* FALLTHROUGH */
        case SIOCSIFADDR:               /* struct ifreq */
        case SIOCSIFDSTADDR:            /* struct ifreq */
        case SIOCSIFNETMASK:            /* struct ifreq */
                if (cmd == SIOCAIFADDR) {
                        /* fell thru from above; just repeat it */
                        bcopy(&((struct in_aliasreq *)(void *)data)->
                            ifra_addr, &addr, sizeof (addr));
                } else {
                        VERIFY(cmd == SIOCDIFADDR || cmd == SIOCSIFADDR ||
                            cmd == SIOCSIFNETMASK || cmd == SIOCSIFDSTADDR);
                        bcopy(&((struct ifreq *)(void *)data)->ifr_addr,
                            &addr, sizeof (addr));
                }

                if (addr.sin_family != AF_INET && cmd == SIOCSIFADDR) {
                        error = EINVAL;
                        goto done;
                }
                if (ia == NULL) {
                        ia = in_ifaddr_alloc(M_WAITOK);
                        if (ia == NULL) {
                                error = ENOBUFS;
                                goto done;
                        }
                        ifnet_lock_exclusive(ifp);
                        ifa = &ia->ia_ifa;
                        IFA_LOCK(ifa);
                        /* Hold a reference for this routine */
                        IFA_ADDREF_LOCKED(ifa);
                        IA_HASH_INIT(ia);
                        ifa->ifa_addr = (struct sockaddr *)&ia->ia_addr;
                        ifa->ifa_dstaddr = (struct sockaddr *)&ia->ia_dstaddr;
                        ifa->ifa_netmask = (struct sockaddr *)&ia->ia_sockmask;
                        ia->ia_sockmask.sin_len = 8;
                        if (ifp->if_flags & IFF_BROADCAST) {
                                ia->ia_broadaddr.sin_len = sizeof (ia->ia_addr);
                                ia->ia_broadaddr.sin_family = AF_INET;
                        }
                        ia->ia_ifp = ifp;
                        if (!(ifp->if_flags & IFF_LOOPBACK))
                                in_interfaces++;
                        /* if_attach_ifa() holds a reference for ifa_link */
                        if_attach_ifa(ifp, ifa);
                        /*
                         * If we have to go through in_ifinit(), make sure
                         * to avoid installing route(s) based on this address
                         * via PFC_IFUP event, before the link resolver (ARP)
                         * initializes it.
                         */
                        if (cmd == SIOCAIFADDR || cmd == SIOCSIFADDR)
                                ifa->ifa_debug |= IFD_NOTREADY;
                        IFA_UNLOCK(ifa);
                        ifnet_lock_done(ifp);
                        lck_rw_lock_exclusive(in_ifaddr_rwlock);
                        /* Hold a reference for ia_link */
                        IFA_ADDREF(ifa);
                        TAILQ_INSERT_TAIL(&in_ifaddrhead, ia, ia_link);
                        lck_rw_done(in_ifaddr_rwlock);
                        /* discard error */
                        (void) in_domifattach(ifp);
                        error = 0;
                }
                break;
        }

        switch (cmd) {
        case SIOCGIFDSTADDR:            /* struct ifreq */
        case SIOCSIFDSTADDR:            /* struct ifreq */
                error = inctl_ifdstaddr(ifp, ia, cmd, ifr);
                break;

        case SIOCGIFBRDADDR:            /* struct ifreq */
        case SIOCSIFBRDADDR:            /* struct ifreq */
                error = inctl_ifbrdaddr(ifp, ia, cmd, ifr);
                break;

        case SIOCGIFNETMASK:            /* struct ifreq */
        case SIOCSIFNETMASK:            /* struct ifreq */
                error = inctl_ifnetmask(ifp, ia, cmd, ifr);
                break;

        case SIOCGIFADDR:               /* struct ifreq */
        case SIOCSIFADDR:               /* struct ifreq */
        case SIOCAIFADDR:               /* struct {if,in_}aliasreq */
        case SIOCDIFADDR:               /* struct ifreq */
                error = inctl_ifaddr(ifp, ia, cmd, ifr);
                break;

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

        return (error);
}

/*
 * Delete any existing route for an interface.
 */
void
in_ifscrub(struct ifnet *ifp, struct in_ifaddr *ia, int locked)
{
        IFA_LOCK(&ia->ia_ifa);
        if ((ia->ia_flags & IFA_ROUTE) == 0) {
                IFA_UNLOCK(&ia->ia_ifa);
                return;
        }
        IFA_UNLOCK(&ia->ia_ifa);
        if (!locked)
                lck_mtx_lock(rnh_lock);
        if (ifp->if_flags & (IFF_LOOPBACK|IFF_POINTOPOINT))
                rtinit_locked(&(ia->ia_ifa), (int)RTM_DELETE, RTF_HOST);
        else
                rtinit_locked(&(ia->ia_ifa), (int)RTM_DELETE, 0);
        IFA_LOCK(&ia->ia_ifa);
        ia->ia_flags &= ~IFA_ROUTE;
        IFA_UNLOCK(&ia->ia_ifa);
        if (!locked)
                lck_mtx_unlock(rnh_lock);
}

/*
 * Caller must hold in_ifaddr_rwlock as writer.
 */
static void
in_iahash_remove(struct in_ifaddr *ia)
{
        lck_rw_assert(in_ifaddr_rwlock, LCK_RW_ASSERT_EXCLUSIVE);
        IFA_LOCK_ASSERT_HELD(&ia->ia_ifa);

        if (!IA_IS_HASHED(ia)) {
                panic("attempt to remove wrong ia %p from hash table\n", ia);
                /* NOTREACHED */
        }
        TAILQ_REMOVE(INADDR_HASH(ia->ia_addr.sin_addr.s_addr), ia, ia_hash);
        IA_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 in_ifaddr_rwlock as writer.
 */
static void
in_iahash_insert(struct in_ifaddr *ia)
{
        lck_rw_assert(in_ifaddr_rwlock, LCK_RW_ASSERT_EXCLUSIVE);
        IFA_LOCK_ASSERT_HELD(&ia->ia_ifa);

        if (ia->ia_addr.sin_family != AF_INET) {
                panic("attempt to insert wrong ia %p into hash table\n", ia);
                /* NOTREACHED */
        } else if (IA_IS_HASHED(ia)) {
                panic("attempt to double-insert ia %p into hash table\n", ia);
                /* NOTREACHED */
        }
        TAILQ_INSERT_HEAD(INADDR_HASH(ia->ia_addr.sin_addr.s_addr),
            ia, ia_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 in_ifaddr_rwlock as writer.
 */
static void
in_iahash_insert_ptp(struct in_ifaddr *ia)
{
        struct in_ifaddr *tmp_ifa;
        struct ifnet *tmp_ifp;

        lck_rw_assert(in_ifaddr_rwlock, LCK_RW_ASSERT_EXCLUSIVE);
        IFA_LOCK_ASSERT_HELD(&ia->ia_ifa);

        if (ia->ia_addr.sin_family != AF_INET) {
                panic("attempt to insert wrong ia %p into hash table\n", ia);
                /* NOTREACHED */
        } else if (IA_IS_HASHED(ia)) {
                panic("attempt to double-insert ia %p into hash table\n", ia);
                /* NOTREACHED */
        }
        IFA_UNLOCK(&ia->ia_ifa);
        TAILQ_FOREACH(tmp_ifa, INADDR_HASH(ia->ia_addr.sin_addr.s_addr),
            ia_hash) {
                IFA_LOCK(&tmp_ifa->ia_ifa);
                /* ia->ia_addr won't change, so check without lock */
                if (IA_SIN(tmp_ifa)->sin_addr.s_addr ==
                    ia->ia_addr.sin_addr.s_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(INADDR_HASH(ia->ia_addr.sin_addr.s_addr),
                    ia, ia_hash);
        } else {
                TAILQ_INSERT_TAIL(INADDR_HASH(ia->ia_addr.sin_addr.s_addr),
                    ia, ia_hash);
        }
        IFA_ADDREF_LOCKED(&ia->ia_ifa);
}

/*
 * Initialize an interface's internet address
 * and routing table entry.
 */
static int
in_ifinit(struct ifnet *ifp, struct in_ifaddr *ia, struct sockaddr_in *sin,
    int scrub)
{
        u_int32_t i = ntohl(sin->sin_addr.s_addr);
        struct sockaddr_in oldaddr;
        int flags = RTF_UP, error;
        struct ifaddr *ifa0;
        unsigned int cmd;
        int oldremoved = 0;

        /* Take an extra reference for this routine */
        IFA_ADDREF(&ia->ia_ifa);

        lck_rw_lock_exclusive(in_ifaddr_rwlock);
        IFA_LOCK(&ia->ia_ifa);
        oldaddr = ia->ia_addr;
        if (IA_IS_HASHED(ia)) {
                oldremoved = 1;
                in_iahash_remove(ia);
        }
        ia->ia_addr = *sin;
        /*
         * Interface addresses should not contain port or sin_zero information.
         */
        SIN(&ia->ia_addr)->sin_family = AF_INET;
        SIN(&ia->ia_addr)->sin_len = sizeof (struct sockaddr_in);
        SIN(&ia->ia_addr)->sin_port = 0;
        bzero(&SIN(&ia->ia_addr)->sin_zero, sizeof (sin->sin_zero));
        if ((ifp->if_flags & IFF_POINTOPOINT))
                in_iahash_insert_ptp(ia);
        else
                in_iahash_insert(ia);
        IFA_UNLOCK(&ia->ia_ifa);
        lck_rw_done(in_ifaddr_rwlock);

        /*
         * Give the interface a chance to initialize if this is its first
         * address, and to validate the address if necessary.  Send down
         * SIOCSIFADDR for first address, and SIOCAIFADDR for alias(es).
         * We find the first IPV4 address assigned to it and check if this
         * is the same as the one passed into this routine.
         */
        ifa0 = ifa_ifpgetprimary(ifp, AF_INET);
        cmd = (&ia->ia_ifa == ifa0) ? SIOCSIFADDR : SIOCAIFADDR;
        error = ifnet_ioctl(ifp, PF_INET, cmd, ia);
        if (error == EOPNOTSUPP)
                error = 0;
        /*
         * If we've just sent down SIOCAIFADDR, send another ioctl down
         * for SIOCSIFADDR for the first IPV4 address of the interface,
         * because an address change on one of the addresses will result
         * in the removal of the previous first IPV4 address.  KDP needs
         * be reconfigured with the current primary IPV4 address.
         */
        if (error == 0 && cmd == SIOCAIFADDR) {
                /*
                 * 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.
                 */
                error = ifnet_ioctl(ifp, PF_INET, SIOCSIFADDR, ifa0);
                if (error == EOPNOTSUPP)
                        error = 0;
        }

        /* Release reference from ifa_ifpgetprimary() */
        IFA_REMREF(ifa0);

        if (error) {
                lck_rw_lock_exclusive(in_ifaddr_rwlock);
                IFA_LOCK(&ia->ia_ifa);
                if (IA_IS_HASHED(ia))
                        in_iahash_remove(ia);
                ia->ia_addr = oldaddr;
                if (oldremoved) {
                        if ((ifp->if_flags & IFF_POINTOPOINT))
                                in_iahash_insert_ptp(ia);
                        else
                                in_iahash_insert(ia);
                }
                IFA_UNLOCK(&ia->ia_ifa);
                lck_rw_done(in_ifaddr_rwlock);
                /* Release extra reference taken above */
                IFA_REMREF(&ia->ia_ifa);
                return (error);
        }
        lck_mtx_lock(rnh_lock);
        IFA_LOCK(&ia->ia_ifa);
        /*
         * Address has been initialized by the link resolver (ARP)
         * via ifnet_ioctl() above; it may now generate route(s).
         */
        ia->ia_ifa.ifa_debug &= ~IFD_NOTREADY;
        if (scrub) {
                ia->ia_ifa.ifa_addr = (struct sockaddr *)&oldaddr;
                IFA_UNLOCK(&ia->ia_ifa);
                in_ifscrub(ifp, ia, 1);
                IFA_LOCK(&ia->ia_ifa);
                ia->ia_ifa.ifa_addr = (struct sockaddr *)&ia->ia_addr;
        }
        IFA_LOCK_ASSERT_HELD(&ia->ia_ifa);
        if (IN_CLASSA(i))
                ia->ia_netmask = IN_CLASSA_NET;
        else if (IN_CLASSB(i))
                ia->ia_netmask = IN_CLASSB_NET;
        else
                ia->ia_netmask = IN_CLASSC_NET;
        /*
         * The subnet mask usually includes at least the standard network part,
         * but may may be smaller in the case of supernetting.
         * If it is set, we believe it.
         */
        if (ia->ia_subnetmask == 0) {
                ia->ia_subnetmask = ia->ia_netmask;
                ia->ia_sockmask.sin_addr.s_addr = htonl(ia->ia_subnetmask);
        } else
                ia->ia_netmask &= ia->ia_subnetmask;
        ia->ia_net = i & ia->ia_netmask;
        ia->ia_subnet = i & ia->ia_subnetmask;
        in_socktrim(&ia->ia_sockmask);
        /*
         * Add route for the network.
         */
        ia->ia_ifa.ifa_metric = ifp->if_metric;
        if (ifp->if_flags & IFF_BROADCAST) {
                ia->ia_broadaddr.sin_addr.s_addr =
                    htonl(ia->ia_subnet | ~ia->ia_subnetmask);
                ia->ia_netbroadcast.s_addr =
                    htonl(ia->ia_net | ~ ia->ia_netmask);
        } else if (ifp->if_flags & IFF_LOOPBACK) {
                ia->ia_ifa.ifa_dstaddr = ia->ia_ifa.ifa_addr;
                flags |= RTF_HOST;
        } else if (ifp->if_flags & IFF_POINTOPOINT) {
                if (ia->ia_dstaddr.sin_family != AF_INET) {
                        IFA_UNLOCK(&ia->ia_ifa);
                        lck_mtx_unlock(rnh_lock);
                        /* Release extra reference taken above */
                        IFA_REMREF(&ia->ia_ifa);
                        return (0);
                }
                ia->ia_dstaddr.sin_len = sizeof (struct sockaddr_in);
                flags |= RTF_HOST;
        }
        IFA_UNLOCK(&ia->ia_ifa);

        if ((error = rtinit_locked(&(ia->ia_ifa), (int)RTM_ADD, flags)) == 0) {
                IFA_LOCK(&ia->ia_ifa);
                ia->ia_flags |= IFA_ROUTE;
                IFA_UNLOCK(&ia->ia_ifa);
        }
        lck_mtx_unlock(rnh_lock);

        /* XXX check if the subnet route points to the same interface */
        if (error == EEXIST)
                error = 0;

        /*
         * If the interface supports multicast, join the "all hosts"
         * multicast group on that interface.
         */
        if (ifp->if_flags & IFF_MULTICAST) {
                struct in_addr addr;

                lck_mtx_lock(&ifp->if_addrconfig_lock);
                addr.s_addr = htonl(INADDR_ALLHOSTS_GROUP);
                if (ifp->if_allhostsinm == NULL) {
                        struct in_multi *inm;
                        inm = in_addmulti(&addr, ifp);

                        if (inm != NULL) {
                                /*
                                 * Keep the reference on inm added by
                                 * in_addmulti above for storing the
                                 * pointer in allhostsinm.
                                 */
                                ifp->if_allhostsinm = inm;
                        } else {
                                printf("%s: failed to add membership to "
                                    "all-hosts multicast address on %s\n",
                                    __func__, if_name(ifp));
                        }
                }
                lck_mtx_unlock(&ifp->if_addrconfig_lock);
        }

        /* Release extra reference taken above */
        IFA_REMREF(&ia->ia_ifa);

        if (error == 0) {
                /* invalidate route caches */
                routegenid_inet_update();
        }

        return (error);
}

/*
 * Return TRUE if the address might be a local broadcast address.
 */
boolean_t
in_broadcast(struct in_addr in, struct ifnet *ifp)
{
        struct ifaddr *ifa;
        u_int32_t t;

        if (in.s_addr == INADDR_BROADCAST || in.s_addr == INADDR_ANY)
                return (TRUE);
        if (!(ifp->if_flags & IFF_BROADCAST))
                return (FALSE);
        t = ntohl(in.s_addr);

        /*
         * Look through the list of addresses for a match
         * with a broadcast address.
         */
#define ia ((struct in_ifaddr *)ifa)
        ifnet_lock_shared(ifp);
        TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
                IFA_LOCK(ifa);
                if (ifa->ifa_addr->sa_family == AF_INET &&
                    (in.s_addr == ia->ia_broadaddr.sin_addr.s_addr ||
                     in.s_addr == ia->ia_netbroadcast.s_addr ||
                     /*
                      * Check for old-style (host 0) broadcast.
                      */
                     t == ia->ia_subnet || t == ia->ia_net) &&
                     /*
                      * Check for an all one subnetmask. These
                      * only exist when an interface gets a secondary
                      * address.
                      */
                     ia->ia_subnetmask != (u_int32_t)0xffffffff) {
                        IFA_UNLOCK(ifa);
                        ifnet_lock_done(ifp);
                        return (TRUE);
                }
                IFA_UNLOCK(ifa);
        }
        ifnet_lock_done(ifp);
        return (FALSE);
#undef ia
}

void
in_purgeaddrs(struct ifnet *ifp)
{
        struct ifaddr **ifap;
        int err, i;

        VERIFY(ifp != NULL);

        /*
         * Be nice, and try the civilized way first.  If we can't get
         * rid of them this way, then do it the rough way.  We must
         * only get here during detach time, after the ifnet has been
         * removed from the global list and arrays.
         */
        err = ifnet_get_address_list_family_internal(ifp, &ifap, AF_INET, 1,
            M_WAITOK, 0);
        if (err == 0 && ifap != NULL) {
                struct ifreq ifr;

                bzero(&ifr, sizeof (ifr));
                (void) snprintf(ifr.ifr_name, sizeof (ifr.ifr_name),
                    "%s", if_name(ifp));

                for (i = 0; ifap[i] != NULL; i++) {
                        struct ifaddr *ifa;

                        ifa = ifap[i];
                        IFA_LOCK(ifa);
                        bcopy(ifa->ifa_addr, &ifr.ifr_addr,
                            sizeof (struct sockaddr_in));
                        IFA_UNLOCK(ifa);
                        err = in_control(NULL, SIOCDIFADDR, (caddr_t)&ifr, ifp,
                            kernproc);
                        /* if we lost the race, ignore it */
                        if (err == EADDRNOTAVAIL)
                                err = 0;
                        if (err != 0) {
                                char s_addr[MAX_IPv4_STR_LEN];
                                char s_dstaddr[MAX_IPv4_STR_LEN];
                                struct in_addr *s, *d;

                                IFA_LOCK(ifa);
                                s = &((struct sockaddr_in *)
                                    (void *)ifa->ifa_addr)->sin_addr;
                                d = &((struct sockaddr_in *)
                                    (void *)ifa->ifa_dstaddr)->sin_addr;
                                (void) inet_ntop(AF_INET, &s->s_addr, s_addr,
                                    sizeof (s_addr));
                                (void) inet_ntop(AF_INET, &d->s_addr, s_dstaddr,
                                    sizeof (s_dstaddr));
                                IFA_UNLOCK(ifa);

                                printf("%s: SIOCDIFADDR ifp=%s ifa_addr=%s "
                                    "ifa_dstaddr=%s (err=%d)\n", __func__,
                                    ifp->if_xname, s_addr, s_dstaddr, err);
                        }
                }
                ifnet_free_address_list(ifap);
        } else if (err != 0 && err != ENXIO) {
                printf("%s: error retrieving list of AF_INET addresses for "
                    "ifp=%s (err=%d)\n", __func__, ifp->if_xname, err);
        }
}

/*
 * Called as part of ip_init
 */
void
in_ifaddr_init(void)
{
        in_multi_init();

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

        inifa_size = (inifa_debug == 0) ? sizeof (struct in_ifaddr) :
            sizeof (struct in_ifaddr_dbg);

        inifa_zone = zinit(inifa_size, INIFA_ZONE_MAX * inifa_size,
            0, INIFA_ZONE_NAME);
        if (inifa_zone == NULL) {
                panic("%s: failed allocating %s", __func__, INIFA_ZONE_NAME);
                /* NOTREACHED */
        }
        zone_change(inifa_zone, Z_EXPAND, TRUE);
        zone_change(inifa_zone, Z_CALLERACCT, FALSE);

        lck_mtx_init(&inifa_trash_lock, ifa_mtx_grp, ifa_mtx_attr);
        TAILQ_INIT(&inifa_trash_head);
}

static struct in_ifaddr *
in_ifaddr_alloc(int how)
{
        struct in_ifaddr *inifa;

        inifa = (how == M_WAITOK) ? zalloc(inifa_zone) :
            zalloc_noblock(inifa_zone);
        if (inifa != NULL) {
                bzero(inifa, inifa_size);
                inifa->ia_ifa.ifa_free = in_ifaddr_free;
                inifa->ia_ifa.ifa_debug |= IFD_ALLOC;
                ifa_lock_init(&inifa->ia_ifa);
                if (inifa_debug != 0) {
                        struct in_ifaddr_dbg *inifa_dbg =
                            (struct in_ifaddr_dbg *)inifa;
                        inifa->ia_ifa.ifa_debug |= IFD_DEBUG;
                        inifa->ia_ifa.ifa_trace = in_ifaddr_trace;
                        inifa->ia_ifa.ifa_attached = in_ifaddr_attached;
                        inifa->ia_ifa.ifa_detached = in_ifaddr_detached;
                        ctrace_record(&inifa_dbg->inifa_alloc);
                }
        }
        return (inifa);
}

static void
in_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 */
        } if (!(ifa->ifa_debug & IFD_ALLOC)) {
                panic("%s: ifa %p cannot be freed", __func__, ifa);
                /* NOTREACHED */
        }
        if (ifa->ifa_debug & IFD_DEBUG) {
                struct in_ifaddr_dbg *inifa_dbg = (struct in_ifaddr_dbg *)ifa;
                ctrace_record(&inifa_dbg->inifa_free);
                bcopy(&inifa_dbg->inifa, &inifa_dbg->inifa_old,
                    sizeof (struct in_ifaddr));
                if (ifa->ifa_debug & IFD_TRASHED) {
                        /* Become a regular mutex, just in case */
                        IFA_CONVERT_LOCK(ifa);
                        lck_mtx_lock(&inifa_trash_lock);
                        TAILQ_REMOVE(&inifa_trash_head, inifa_dbg,
                            inifa_trash_link);
                        lck_mtx_unlock(&inifa_trash_lock);
                        ifa->ifa_debug &= ~IFD_TRASHED;
                }
        }
        IFA_UNLOCK(ifa);
        ifa_lock_destroy(ifa);
        bzero(ifa, sizeof (struct in_ifaddr));
        zfree(inifa_zone, ifa);
}

static void
in_ifaddr_attached(struct ifaddr *ifa)
{
        struct in_ifaddr_dbg *inifa_dbg = (struct in_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(&inifa_trash_lock);
                TAILQ_REMOVE(&inifa_trash_head, inifa_dbg, inifa_trash_link);
                lck_mtx_unlock(&inifa_trash_lock);
                ifa->ifa_debug &= ~IFD_TRASHED;
        }
}

static void
in_ifaddr_detached(struct ifaddr *ifa)
{
        struct in_ifaddr_dbg *inifa_dbg = (struct in_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(&inifa_trash_lock);
        TAILQ_INSERT_TAIL(&inifa_trash_head, inifa_dbg, inifa_trash_link);
        lck_mtx_unlock(&inifa_trash_lock);
}

static void
in_ifaddr_trace(struct ifaddr *ifa, int refhold)
{
        struct in_ifaddr_dbg *inifa_dbg = (struct in_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 = &inifa_dbg->inifa_refhold_cnt;
                tr = inifa_dbg->inifa_refhold;
        } else {
                cnt = &inifa_dbg->inifa_refrele_cnt;
                tr = inifa_dbg->inifa_refrele;
        }

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

/*
 * Handle SIOCGASSOCIDS ioctl for PF_INET domain.
 */
static int
in_getassocids(struct socket *so, uint32_t *cnt, user_addr_t aidp)
{
        struct inpcb *inp = sotoinpcb(so);
        sae_associd_t aid;

        if (inp == NULL || inp->inp_state == INPCB_STATE_DEAD)
                return (EINVAL);

        /* INPCB 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_INET domain.
 */
static int
in_getconnids(struct socket *so, sae_associd_t aid, uint32_t *cnt,
    user_addr_t cidp)
{
        struct inpcb *inp = sotoinpcb(so);
        sae_connid_t cid;

        if (inp == NULL || inp->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 INPCB is connected, assign it connid 1 */
        cid = ((*cnt != 0) ? 1 : SAE_CONNID_ANY);

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

/*
 * Handle SIOCGCONNINFO ioctl for PF_INET domain.
 */
static int
in_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)
{
#pragma unused(aux_data)
        struct inpcb *inp = sotoinpcb(so);
        struct sockaddr_in sin;
        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 (inp == NULL) {
                error = EINVAL;
                goto out;
        }

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

        ifp = inp->inp_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 (inp->inp_flags & INP_BOUND_IF)
                *flags |= CIF_BOUND_IF;
        if (!(inp->inp_flags & INP_INADDR_ANY))
                *flags |= CIF_BOUND_IP;
        if (!(inp->inp_flags & INP_ANONPORT))
                *flags |= CIF_BOUND_PORT;

        bzero(&sin, sizeof (sin));
        sin.sin_len = sizeof (sin);
        sin.sin_family = AF_INET;

        /* source address and port */
        sin.sin_port = inp->inp_lport;
        sin.sin_addr.s_addr = inp->inp_laddr.s_addr;
        if (*src_len == 0) {
                *src_len = sin.sin_len;
        } else {
                if (src != USER_ADDR_NULL) {
                        copy_len = min(*src_len, sizeof (sin));
                        error = copyout(&sin, src, copy_len);
                        if (error != 0)
                                goto out;
                        *src_len = copy_len;
                }
        }

        /* destination address and port */
        sin.sin_port = inp->inp_fport;
        sin.sin_addr.s_addr = inp->inp_faddr.s_addr;
        if (*dst_len == 0) {
                *dst_len = sin.sin_len;
        } else {
                if (dst != USER_ADDR_NULL) {
                        copy_len = min(*dst_len, sizeof (sin));
                        error = copyout(&sin, dst, copy_len);
                        if (error != 0)
                                goto out;
                        *dst_len = copy_len;
                }
        }

        *aux_type = 0;
        *aux_len = 0;
        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;
                        }
                }
        }

out:
        return (error);
}