isc/unix/ifiter_ioctl.c

	ifiter_ioctl.c revision fe4d3e1992d91943806251faf5b52457c6aed069
/*
 * Copyright (C) 1999-2001  Internet Software Consortium.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM
 * DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
 * INTERNET SOFTWARE CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT,
 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING
 * FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
 * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
 * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

/* $Id: ifiter_ioctl.c,v 1.30 2002/07/01 01:08:37 marka Exp $ */

/*
 * Obtain the list of network interfaces using the SIOCGLIFCONF ioctl.
 * See netintro(4).
 */

#if defined(SIOCGLIFCONF) && defined(SIOCGLIFADDR)
#ifdef ISC_PLATFORM_HAVEIF_LADDRCONF
#define lifc_len iflc_len
#define lifc_buf iflc_buf
#define lifc_req iflc_req
#define LIFCONF if_laddrconf
#else
#define ISC_HAVE_LIFC_FAMILY 1
#define ISC_HAVE_LIFC_FLAGS 1
#define LIFCONF lifconf
#endif

#ifdef ISC_PLATFORM_HAVEIF_LADDRREQ
#define lifr_addr iflr_addr
#define lifr_name iflr_name
#define lifr_dstaddr iflr_dstaddr
#define lifr_flags iflr_flags
#define ss_family sa_family
#define LIFREQ if_laddrreq
#else
#define LIFREQ lifreq
#endif
#endif

#define IFITER_MAGIC        ISC_MAGIC('I', 'F', 'I', 'T')
#define VALID_IFITER(t)     ISC_MAGIC_VALID(t, IFITER_MAGIC)

struct isc_interfaceiter {
    unsigned int        magic;      /* Magic number. */
    isc_mem_t       *mctx;
    int         socket;
    int         mode;
    struct ifconf       ifc;
#if defined(SIOCGLIFCONF) && defined(SIOCGLIFADDR)
    struct LIFCONF      lifc;
#endif
    void            *buf;       /* Buffer for sysctl data. */
    unsigned int        bufsize;    /* Bytes allocated. */
#ifdef HAVE_TRUCLUSTER
    int         clua_context;   /* Cluster alias context */
#endif
    unsigned int        pos;        /* Current offset in
                           SIOCGLIFCONF data */
    isc_interface_t     current;    /* Current interface data. */
    isc_result_t        result;     /* Last result code. */
};

#ifdef HAVE_TRUCLUSTER
#include <clua/clua.h>
#include <sys/socket.h>
#endif


/*
 * Size of buffer for SIOCGLIFCONF, in bytes.  We assume no sane system
 * will have more than a megabyte of interface configuration data.
 */
#define IFCONF_BUFSIZE_INITIAL  4096
#define IFCONF_BUFSIZE_MAX  1048576

static isc_result_t
getbuf4(isc_interfaceiter_t *iter) {
    char strbuf[ISC_STRERRORSIZE];

    iter->bufsize = IFCONF_BUFSIZE_INITIAL;

    for (;;) {
        iter->buf = isc_mem_get(iter->mctx, iter->bufsize);
        if (iter->buf == NULL)
            return (ISC_R_NOMEMORY);

        memset(&iter->ifc.ifc_len, 0, sizeof(iter->ifc.ifc_len));
        iter->ifc.ifc_len = iter->bufsize;
        iter->ifc.ifc_buf = iter->buf;
        /*
         * Ignore the HP/UX warning about "interger overflow during
         * conversion".  It comes from its own macro definition,
         * and is really hard to shut up.
         */
        if (ioctl(iter->socket, SIOCGIFCONF, (char *)&iter->ifc)
            == -1) {
            if (errno != EINVAL) {
                isc__strerror(errno, strbuf, sizeof(strbuf));
                UNEXPECTED_ERROR(__FILE__, __LINE__,
                         isc_msgcat_get(isc_msgcat,
                            ISC_MSGSET_IFITERIOCTL,
                            ISC_MSG_GETIFCONFIG,
                            "get interface "
                            "configuration: %s"),
                         strbuf);
                goto unexpected;
            }
            /*
             * EINVAL.  Retry with a bigger buffer.
             */
        } else {
            /*
             * The ioctl succeeded.
             * Some OS's just return what will fit rather
             * than set EINVAL if the buffer is too small
             * to fit all the interfaces in.  If
             * ifc.lifc_len is too near to the end of the
             * buffer we will grow it just in case and
             * retry.
             */
            if (iter->ifc.ifc_len + 2 * sizeof(struct ifreq)
                < iter->bufsize)
                break;
        }
        if (iter->bufsize >= IFCONF_BUFSIZE_MAX) {
            UNEXPECTED_ERROR(__FILE__, __LINE__,
                     isc_msgcat_get(isc_msgcat,
                            ISC_MSGSET_IFITERIOCTL,
                            ISC_MSG_BUFFERMAX,
                            "get interface "
                            "configuration: "
                            "maximum buffer "
                            "size exceeded"));
            goto unexpected;
        }
        isc_mem_put(iter->mctx, iter->buf, iter->bufsize);

        iter->bufsize *= 2;
    }
    iter->mode = 4;
    return (ISC_R_SUCCESS);

 unexpected:
    isc_mem_put(iter->mctx, iter->buf, iter->bufsize);
    iter->buf = NULL;
#ifdef HAVE_TRUCLUSTER
    iter->clua_context = 0;
#endif
    return (ISC_R_UNEXPECTED);
}

static isc_result_t
getbuf6(isc_interfaceiter_t *iter) {
#if !defined(SIOCGLIFCONF) || !defined(SIOCGLIFADDR)
    UNUSED(iter);
    return (ISC_R_NOTIMPLEMENTED);
#else
    char strbuf[ISC_STRERRORSIZE];

    iter->bufsize = IFCONF_BUFSIZE_INITIAL;

    for (;;) {
        iter->buf = isc_mem_get(iter->mctx, iter->bufsize);
        if (iter->buf == NULL)
            return (ISC_R_NOMEMORY);

        memset(&iter->lifc.lifc_len, 0, sizeof(iter->lifc.lifc_len));
#ifdef ISC_HAVE_LIFC_FAMILY
        iter->lifc.lifc_family = AF_UNSPEC;
#endif
#ifdef ISC_HAVE_LIFC_FLAGS
        iter->lifc.lifc_flags = 0;
#endif
        iter->lifc.lifc_len = iter->bufsize;
        iter->lifc.lifc_buf = iter->buf;
        /*
         * Ignore the HP/UX warning about "interger overflow during
         * conversion".  It comes from its own macro definition,
         * and is really hard to shut up.
         */
        if (ioctl(iter->socket, SIOCGLIFCONF, (char *)&iter->lifc)
            == -1) {
#ifdef __hpux
            /*
             * IPv6 interface scanning is not available on all
             * kernels w/ IPv6 sockets.
             */
            if (errno == ENOENT) {
                isc__strerror(errno, strbuf, sizeof(strbuf));
                isc_log_write(isc_lctx, ISC_LOGCATEGORY_GENERAL,
                          ISC_LOGMODULE_INTERFACE,
                          ISC_LOG_DEBUG(1),
                          isc_msgcat_get(isc_msgcat,
                            ISC_MSGSET_IFITERIOCTL,
                            ISC_MSG_GETIFCONFIG,
                            "get interface "
                            "configuration: %s"),
                           strbuf);
                result = ISC_R_FAILURE;
                goto cleanup;
            }
#endif
            if (errno != EINVAL) {
                isc__strerror(errno, strbuf, sizeof(strbuf));
                UNEXPECTED_ERROR(__FILE__, __LINE__,
                         isc_msgcat_get(isc_msgcat,
                            ISC_MSGSET_IFITERIOCTL,
                            ISC_MSG_GETIFCONFIG,
                            "get interface "
                            "configuration: %s"),
                         strbuf);
                result = ISC_R_UNEXPECTED;
                goto cleanup;
            }
            /*
             * EINVAL.  Retry with a bigger buffer.
             */
        } else {
            /*
             * The ioctl succeeded.
             * Some OS's just return what will fit rather
             * than set EINVAL if the buffer is too small
             * to fit all the interfaces in.  If
             * ifc.ifc_len is too near to the end of the
             * buffer we will grow it just in case and
             * retry.
             */
            if (iter->lifc.lifc_len + 2 * sizeof(struct LIFREQ)
                < iter->bufsize)
                break;
        }
        if (iter->bufsize >= IFCONF_BUFSIZE_MAX) {
            UNEXPECTED_ERROR(__FILE__, __LINE__,
                     isc_msgcat_get(isc_msgcat,
                            ISC_MSGSET_IFITERIOCTL,
                            ISC_MSG_BUFFERMAX,
                            "get interface "
                            "configuration: "
                            "maximum buffer "
                            "size exceeded"));
            result = ISC_R_UNEXPECTED;
            goto cleanup;
        }
        isc_mem_put(iter->mctx, iter->buf, iter->bufsize);

        iter->bufsize *= 2;
    }

    iter->mode = 6;
    return (ISC_R_SUCCESS);

 cleanup:
    isc_mem_put(iter->mctx, iter->buf, iter->bufsize);
    iter->buf = NULL;
    return (result);
#endif
}

isc_result_t
isc_interfaceiter_create(isc_mem_t *mctx, isc_interfaceiter_t **iterp) {
    isc_interfaceiter_t *iter;
    isc_result_t result;
    char strbuf[ISC_STRERRORSIZE];

    REQUIRE(mctx != NULL);
    REQUIRE(iterp != NULL);
    REQUIRE(*iterp == NULL);

    iter = isc_mem_get(mctx, sizeof(*iter));
    if (iter == NULL)
        return (ISC_R_NOMEMORY);

    iter->mctx = mctx;
    iter->buf = NULL;
    iter->mode = 0;

    /*
     * Create an unbound datagram socket to do the SIOCGLIFADDR ioctl on.
     */
    if ((iter->socket = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
        isc__strerror(errno, strbuf, sizeof(strbuf));
        UNEXPECTED_ERROR(__FILE__, __LINE__,
                 isc_msgcat_get(isc_msgcat,
                        ISC_MSGSET_IFITERIOCTL,
                        ISC_MSG_MAKESCANSOCKET,
                        "making interface "
                        "scan socket: %s"),
                 strbuf);
        result = ISC_R_UNEXPECTED;
        goto socket_failure;
    }

    /*
     * Get the interface configuration, allocating more memory if
     * necessary.
     */

    result = isc_net_probeipv6();
    if (result == ISC_R_SUCCESS)
        result = getbuf6(iter);
    if (result != ISC_R_SUCCESS)
        result = getbuf4(iter);
    if (result != ISC_R_SUCCESS)
        goto ioctl_failure;

    /*
     * A newly created iterator has an undefined position
     * until isc_interfaceiter_first() is called.
     */
    iter->pos = (unsigned int) -1;
    iter->result = ISC_R_FAILURE;

    iter->magic = IFITER_MAGIC;
    *iterp = iter;
    return (ISC_R_SUCCESS);

 ioctl_failure:
    if (iter->buf != NULL)
        isc_mem_put(mctx, iter->buf, iter->bufsize);
    (void) close(iter->socket);

 socket_failure:
    isc_mem_put(mctx, iter, sizeof(*iter));
    return (result);
}

#ifdef HAVE_TRUCLUSTER
static void
get_inaddr(isc_netaddr_t *dst, struct in_addr *src) {
    dst->family = AF_INET;
    memcpy(&dst->type.in, src, sizeof(struct in_addr));
}

static isc_result_t
internal_current_clusteralias(isc_interfaceiter_t *iter) {
    struct sockaddr sa;
    struct clua_info ci;
    while (clua_getaliasaddress(&sa, &iter->clua_context) == CLUA_SUCCESS) {
        if (clua_getaliasinfo(&sa, &ci) != CLUA_SUCCESS)
            continue;
        memset(&iter->current, 0, sizeof(iter->current));
        iter->current.af = sa.sa_family;
        memset(iter->current.name, 0, sizeof(iter->current.name));
        sprintf(iter->current.name, "clua%d", ci.aliasid);
        iter->current.flags = INTERFACE_F_UP;
        get_inaddr(&iter->current.address, &ci.addr);
        get_inaddr(&iter->current.netmask, &ci.netmask);
        return (ISC_R_SUCCESS);
    }
    return (ISC_R_NOMORE);
}
#endif

/*
 * Get information about the current interface to iter->current.
 * If successful, return ISC_R_SUCCESS.
 * If the interface has an unsupported address family, or if
 * some operation on it fails, return ISC_R_IGNORE to make
 * the higher-level iterator code ignore it.
 */

static isc_result_t
internal_current4(isc_interfaceiter_t *iter) {
    struct ifreq *ifrp;
    struct ifreq ifreq;
    int family;
    char strbuf[ISC_STRERRORSIZE];
#if !defined(SIOCGLIFCONF) && defined(SIOCGLIFADDR)
    struct if_laddrreq if_laddrreq;
    int i, bits;
#endif

    REQUIRE(VALID_IFITER(iter));
    REQUIRE (iter->pos < (unsigned int) iter->ifc.ifc_len);

    ifrp = (struct ifreq *)((char *) iter->ifc.ifc_req + iter->pos);

    memset(&ifreq, 0, sizeof(ifreq));
    memcpy(&ifreq, ifrp, sizeof(ifreq));

    family = ifreq.ifr_addr.sa_family;
#if !defined (SIOCGLIFCONF) && defined(SIOCGLIFADDR) && \
    defined(ISC_PLATFORM_HAVEIPV6)
    if (family != AF_INET && family != AF_INET6)
#else
    if (family != AF_INET)
#endif
        return (ISC_R_IGNORE);

    memset(&iter->current, 0, sizeof(iter->current));
    iter->current.af = family;

    INSIST(sizeof(ifreq.ifr_name) <= sizeof(iter->current.name));
    memset(iter->current.name, 0, sizeof(iter->current.name));
    memcpy(iter->current.name, ifreq.ifr_name, sizeof(ifreq.ifr_name));

    get_addr(family, &iter->current.address,
         (struct sockaddr *)&ifrp->ifr_addr);

    /*
     * If the interface does not have a address ignore it.
     */
    switch (family) {
    case AF_INET:
        if (iter->current.address.type.in.s_addr == htonl(INADDR_ANY))
            return (ISC_R_IGNORE);
        break;
    case AF_INET6:
        if (memcmp(&iter->current.address.type.in6, &in6addr_any,
               sizeof(in6addr_any)) == 0)
            return (ISC_R_IGNORE);
        break;
    }

    /*
     * Get interface flags.
     */

    iter->current.flags = 0;

    /*
     * Ignore the HP/UX warning about "interger overflow during
     * conversion.  It comes from its own macro definition,
     * and is really hard to shut up.
     */
    if (ioctl(iter->socket, SIOCGIFFLAGS, (char *) &ifreq) < 0) {
        isc__strerror(errno, strbuf, sizeof(strbuf));
        UNEXPECTED_ERROR(__FILE__, __LINE__,
                 "%s: getting interface flags: %s",
                 ifreq.ifr_name, strbuf);
        return (ISC_R_IGNORE);
    }

    if ((ifreq.ifr_flags & IFF_RUNNING) == 0)
        return (ISC_R_IGNORE);

    if ((ifreq.ifr_flags & IFF_UP) != 0)
        iter->current.flags |= INTERFACE_F_UP;

    if ((ifreq.ifr_flags & IFF_POINTOPOINT) != 0)
        iter->current.flags |= INTERFACE_F_POINTTOPOINT;

    if ((ifreq.ifr_flags & IFF_LOOPBACK) != 0)
        iter->current.flags |= INTERFACE_F_LOOPBACK;

#if !defined(SIOCGLIFCONF) && defined(SIOCGLIFADDR)
    if (family == AF_INET)
        goto inet;

    memset(&if_laddrreq, 0, sizeof(if_laddrreq));
    memcpy(if_laddrreq.iflr_name, iter->current.name,
           sizeof(if_laddrreq.iflr_name));
    memcpy(&if_laddrreq.addr, &iter->current.address.type.in6,
           sizeof(iter->current.address.type.in6));

    if (ioctl(iter->socket, SIOCGLIFADDR, &if_laddrreq) < 0) {
        isc__strerror(errno, strbuf, sizeof(strbuf));
        UNEXPECTED_ERROR(__FILE__, __LINE__,
                 "%s: getting interface address: %s",
                 ifreq.ifr_name, strbuf);
        return (ISC_R_IGNORE);
    }

    /*
     * Netmask already zeroed.
     */
    iter->current.netmask.family = family;
    for (i = 0; i < 16; i++) {
        if (if_laddrreq.prefixlen > 8) {
            bits = 0;
            if_laddrreq.prefixlen -= 8;
        } else {
            bits = 8 - if_laddrreq.prefixlen;
            if_laddrreq.prefixlen = 0;
        }
        iter->current.netmask.type.in6.s6_addr[i] = (~0 << bits) & 0xff;
    }
    return (ISC_R_SUCCESS);

 inet:
#endif
    if (family != AF_INET)
        return (ISC_R_IGNORE);
    /*
     * If the interface is point-to-point, get the destination address.
     */
    if ((iter->current.flags & INTERFACE_F_POINTTOPOINT) != 0) {
        /*
         * Ignore the HP/UX warning about "interger overflow during
         * conversion.  It comes from its own macro definition,
         * and is really hard to shut up.
         */
        if (ioctl(iter->socket, SIOCGIFDSTADDR, (char *)&ifreq)
            < 0) {
            isc__strerror(errno, strbuf, sizeof(strbuf));
            UNEXPECTED_ERROR(__FILE__, __LINE__,
                isc_msgcat_get(isc_msgcat,
                           ISC_MSGSET_IFITERIOCTL,
                           ISC_MSG_GETDESTADDR,
                           "%s: getting "
                           "destination address: %s"),
                     ifreq.ifr_name, strbuf);
            return (ISC_R_IGNORE);
        }
        get_addr(family, &iter->current.dstaddress,
             (struct sockaddr *)&ifreq.ifr_dstaddr);
    }

    /*
     * Get the network mask.
     */
    memset(&ifreq, 0, sizeof(ifreq));
    memcpy(&ifreq, ifrp, sizeof(ifreq));
    /*
     * Ignore the HP/UX warning about "interger overflow during
     * conversion.  It comes from its own macro definition,
     * and is really hard to shut up.
     */
    if (ioctl(iter->socket, SIOCGIFNETMASK, (char *)&ifreq)
        < 0) {
        isc__strerror(errno, strbuf, sizeof(strbuf));
        UNEXPECTED_ERROR(__FILE__, __LINE__,
            isc_msgcat_get(isc_msgcat,
                       ISC_MSGSET_IFITERIOCTL,
                       ISC_MSG_GETNETMASK,
                       "%s: getting netmask: %s"),
                       ifreq.ifr_name, strbuf);
        return (ISC_R_IGNORE);
    }
    get_addr(family, &iter->current.netmask,
         (struct sockaddr *)&ifreq.ifr_addr);
    return (ISC_R_SUCCESS);
}

static isc_result_t
internal_current6(isc_interfaceiter_t *iter) {
#if !defined(SIOCGLIFCONF) || !defined(SIOCGLIFADDR)
    UNUSED(iter);
    return (ISC_R_NOTIMPLEMENTED);
#else
    struct LIFREQ *ifrp;
    struct LIFREQ lifreq;
    int family;
    char strbuf[ISC_STRERRORSIZE];

    REQUIRE(VALID_IFITER(iter));
    REQUIRE (iter->pos < (unsigned int) iter->lifc.lifc_len);

    ifrp = (struct LIFREQ *)((char *) iter->lifc.lifc_req + iter->pos);

    memset(&lifreq, 0, sizeof(lifreq));
    memcpy(&lifreq, ifrp, sizeof(lifreq));

    family = lifreq.lifr_addr.ss_family;
#ifdef ISC_PLATFORM_HAVEIPV6
    if (family != AF_INET && family != AF_INET6)
#else
    if (family != AF_INET)
#endif
        return (ISC_R_IGNORE);

    memset(&iter->current, 0, sizeof(iter->current));
    iter->current.af = family;

    INSIST(sizeof(lifreq.lifr_name) <= sizeof(iter->current.name));
    memset(iter->current.name, 0, sizeof(iter->current.name));
    memcpy(iter->current.name, lifreq.lifr_name, sizeof(lifreq.lifr_name));

    get_addr(family, &iter->current.address,
         (struct sockaddr *)&lifreq.lifr_addr);

    /*
     * If the interface does not have a address ignore it.
     */
    switch (family) {
    case AF_INET:
        if (iter->current.address.type.in.s_addr == htonl(INADDR_ANY))
            return (ISC_R_IGNORE);
        break;
    case AF_INET6:
        if (memcmp(&iter->current.address.type.in6, &in6addr_any,
               sizeof(in6addr_any)) == 0)
            return (ISC_R_IGNORE);
        break;
    }

    /*
     * Get interface flags.
     */

    iter->current.flags = 0;

    /*
     * Ignore the HP/UX warning about "interger overflow during
     * conversion.  It comes from its own macro definition,
     * and is really hard to shut up.
     */
    if (ioctl(iter->socket, SIOCGLIFFLAGS, (char *) &lifreq) < 0) {
        isc__strerror(errno, strbuf, sizeof(strbuf));
        UNEXPECTED_ERROR(__FILE__, __LINE__,
                 "%s: getting interface flags: %s",
                 lifreq.lifr_name, strbuf);
        return (ISC_R_IGNORE);
    }

    if ((lifreq.lifr_flags & IFF_RUNNING) == 0)
        return (ISC_R_IGNORE);

    if ((lifreq.lifr_flags & IFF_UP) != 0)
        iter->current.flags |= INTERFACE_F_UP;

    if ((lifreq.lifr_flags & IFF_POINTOPOINT) != 0)
        iter->current.flags |= INTERFACE_F_POINTTOPOINT;

    if ((lifreq.lifr_flags & IFF_LOOPBACK) != 0)
        iter->current.flags |= INTERFACE_F_LOOPBACK;

    /*
     * If the interface is point-to-point, get the destination address.
     */
    if ((iter->current.flags & INTERFACE_F_POINTTOPOINT) != 0) {
        /*
         * Ignore the HP/UX warning about "interger overflow during
         * conversion.  It comes from its own macro definition,
         * and is really hard to shut up.
         */
        if (ioctl(iter->socket, SIOCGLIFDSTADDR, (char *)&lifreq)
            < 0) {
            isc__strerror(errno, strbuf, sizeof(strbuf));
            UNEXPECTED_ERROR(__FILE__, __LINE__,
                isc_msgcat_get(isc_msgcat,
                           ISC_MSGSET_IFITERIOCTL,
                           ISC_MSG_GETDESTADDR,
                           "%s: getting "
                           "destination address: %s"),
                     lifreq.lifr_name, strbuf);
            return (ISC_R_IGNORE);
        }
        get_addr(family, &iter->current.dstaddress,
             (struct sockaddr *)&lifreq.lifr_dstaddr);
    }

    /*
     * Get the network mask.
     */
    memset(&lifreq, 0, sizeof(lifreq));
    memcpy(&lifreq, ifrp, sizeof(lifreq));
    switch (family) {
    case AF_INET:
        /*
         * Ignore the HP/UX warning about "interger overflow during
         * conversion.  It comes from its own macro definition,
         * and is really hard to shut up.
         */
        if (ioctl(iter->socket, SIOCGLIFNETMASK, (char *)&lifreq)
            < 0) {
            isc__strerror(errno, strbuf, sizeof(strbuf));
            UNEXPECTED_ERROR(__FILE__, __LINE__,
                isc_msgcat_get(isc_msgcat,
                           ISC_MSGSET_IFITERIOCTL,
                           ISC_MSG_GETNETMASK,
                           "%s: getting netmask: %s"),
                     lifreq.lifr_name, strbuf);
            return (ISC_R_IGNORE);
        }
        get_addr(family, &iter->current.netmask,
             (struct sockaddr *)&lifreq.lifr_addr);
        break;
    case AF_INET6: {
#ifdef lifr_addrlen
        int i, bits;

        /*
         * Netmask already zeroed.
         */
        iter->current.netmask.family = family;
        for (i = 0; i < lifreq.lifr_addrlen; i += 8) {
            bits = lifreq.lifr_addrlen - i;
            bits = (bits < 8) ? (8 - bits) : 0;
            iter->current.netmask.type.in6.s6_addr[i / 8] =
                (~0 << bits) & 0xff;
        }
#endif
        break;
    }
    }

    return (ISC_R_SUCCESS);
#endif
}

static isc_result_t
internal_current(isc_interfaceiter_t *iter) {
    if (iter->mode == 6)
        return (internal_current6(iter));
    return (internal_current4(iter));
}

/*
 * Step the iterator to the next interface.  Unlike
 * isc_interfaceiter_next(), this may leave the iterator
 * positioned on an interface that will ultimately
 * be ignored.  Return ISC_R_NOMORE if there are no more
 * interfaces, otherwise ISC_R_SUCCESS.
 */
static isc_result_t
internal_next4(isc_interfaceiter_t *iter) {
    struct ifreq *ifrp;

    REQUIRE (iter->pos < (unsigned int) iter->ifc.ifc_len);

#ifdef HAVE_TRUCLUSTER
    if (internal_current_clusteralias(iter) == ISC_R_SUCCESS)
        return (ISC_R_SUCCESS);
#endif
    ifrp = (struct ifreq *)((char *) iter->ifc.ifc_req + iter->pos);

#ifdef ISC_PLATFORM_HAVESALEN
    if (ifrp->ifr_addr.sa_len > sizeof(struct sockaddr))
        iter->pos += sizeof(ifrp->ifr_name) + ifrp->ifr_addr.sa_len;
    else
#endif
        iter->pos += sizeof(*ifrp);

    if (iter->pos >= (unsigned int) iter->ifc.ifc_len)
        return (ISC_R_NOMORE);

    return (ISC_R_SUCCESS);
}

static isc_result_t
internal_next6(isc_interfaceiter_t *iter) {
#if !defined(SIOCGLIFCONF) || !defined(SIOCGLIFADDR)
    UNUSED(iter);
    return (ISC_R_NOTIMPLEMENTED);
#else
    struct LIFREQ *ifrp;

    REQUIRE (iter->pos < (unsigned int) iter->lifc.lifc_len);

    ifrp = (struct LIFREQ *)((char *) iter->lifc.lifc_req + iter->pos);

#ifdef ISC_PLATFORM_HAVESALEN
    if (ifrp->lifr_addr.sa_len > sizeof(struct sockaddr))
        iter->pos += sizeof(ifrp->lifr_name) + ifrp->lifr_addr.sa_len;
    else
#endif
        iter->pos += sizeof(*ifrp);

    if (iter->pos >= (unsigned int) iter->lifc.lifc_len)
        return (ISC_R_NOMORE);

    return (ISC_R_SUCCESS);
#endif
}

static isc_result_t
internal_next(isc_interfaceiter_t *iter) {
    if (iter->mode == 6)
        return (internal_next6(iter));
    return (internal_next4(iter));
}

static void
internal_destroy(isc_interfaceiter_t *iter) {
    (void) close(iter->socket);
}