ifiter_ioctl.c

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/*
 * Copyright (C) 2004-2009, 2014  Internet Systems Consortium, Inc. ("ISC")
 * Copyright (C) 1999-2003  Internet Software Consortium.
 *
 * Permission to use, copy, modify, and/or 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 ISC DISCLAIMS ALL WARRANTIES WITH
 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS.  IN NO EVENT SHALL ISC 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 1.62 2009/01/18 23:48:14 tbox Exp $ */

/*! \file
 * \brief
 * 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                     mode;
        int                     socket;
        struct ifconf           ifc;
        void                    *buf;           /* Buffer for sysctl data. */
        unsigned int            bufsize;        /* Bytes allocated. */
        unsigned int            pos;            /* Current offset in
                                                   SIOCGIFCONF data */
#if defined(SIOCGLIFCONF) && defined(SIOCGLIFADDR)
        int                     socket6;
        struct LIFCONF          lifc;
        void                    *buf6;          /* Buffer for sysctl data. */
        unsigned int            bufsize6;       /* Bytes allocated. */
        unsigned int            pos6;           /* Current offset in
                                                   SIOCGLIFCONF data */
        isc_result_t            result6;        /* Last result code. */
        isc_boolean_t           first6;
#endif
#ifdef HAVE_TRUCLUSTER
        int                     clua_context;   /* Cluster alias context */
        isc_boolean_t           clua_done;
        struct sockaddr         clua_sa;
#endif
#ifdef  __linux
        FILE *                  proc;
        char                    entry[ISC_IF_INET6_SZ];
        isc_result_t            valid;
#endif
        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

#ifdef __linux
#ifndef IF_NAMESIZE
# ifdef IFNAMSIZ
#  define IF_NAMESIZE  IFNAMSIZ
# else
#  define IF_NAMESIZE 16
# endif
#endif
#endif

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 "integer 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;
        }
        return (ISC_R_SUCCESS);

 unexpected:
        isc_mem_put(iter->mctx, iter->buf, iter->bufsize);
        iter->buf = NULL;
        return (ISC_R_UNEXPECTED);
}

#if defined(SIOCGLIFCONF) && defined(SIOCGLIFADDR)
static isc_result_t
getbuf6(isc_interfaceiter_t *iter) {
        char strbuf[ISC_STRERRORSIZE];
        isc_result_t result;

        iter->bufsize6 = IFCONF_BUFSIZE_INITIAL;

        for (;;) {
                iter->buf6 = isc_mem_get(iter->mctx, iter->bufsize6);
                if (iter->buf6 == NULL)
                        return (ISC_R_NOMEMORY);

                memset(&iter->lifc, 0, sizeof(iter->lifc));
#ifdef ISC_HAVE_LIFC_FAMILY
                iter->lifc.lifc_family = AF_INET6;
#endif
#ifdef ISC_HAVE_LIFC_FLAGS
                iter->lifc.lifc_flags = 0;
#endif
                iter->lifc.lifc_len = iter->bufsize6;
                iter->lifc.lifc_buf = iter->buf6;
                /*
                 * Ignore the HP/UX warning about "integer overflow during
                 * conversion".  It comes from its own macro definition,
                 * and is really hard to shut up.
                 */
                if (ioctl(iter->socket6, 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->bufsize6)
                                break;
                }
                if (iter->bufsize6 >= 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->buf6, iter->bufsize6);

                iter->bufsize6 *= 2;
        }

        if (iter->lifc.lifc_len != 0)
                iter->mode = 6;
        return (ISC_R_SUCCESS);

 cleanup:
        isc_mem_put(iter->mctx, iter->buf6, iter->bufsize6);
        iter->buf6 = 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->mode = 4;
        iter->buf = NULL;
        iter->pos = (unsigned int) -1;
#if defined(SIOCGLIFCONF) && defined(SIOCGLIFADDR)
        iter->buf6 = NULL;
        iter->pos6 = (unsigned int) -1;
        iter->result6 = ISC_R_NOMORE;
        iter->socket6 = -1;
        iter->first6 = ISC_FALSE;
#endif

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

#if defined(SIOCGLIFCONF) && defined(SIOCGLIFADDR)
        result = isc_net_probeipv6();
        if (result == ISC_R_SUCCESS) {
                /*
                 * Create an unbound datagram socket to do the SIOCGLIFCONF
                 * ioctl on.  HP/UX requires an AF_INET6 socket for
                 * SIOCGLIFCONF to get IPv6 addresses.
                 */
                if ((iter->socket6 = socket(AF_INET6, 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 socket6_failure;
                }
                result = iter->result6 = getbuf6(iter);
                if (result != ISC_R_NOTIMPLEMENTED && result != ISC_R_SUCCESS)
                        goto ioctl6_failure;
        }
#endif
        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;
        }
        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.
         */
#ifdef HAVE_TRUCLUSTER
        iter->clua_context = -1;
        iter->clua_done = ISC_TRUE;
#endif
#ifdef __linux
        iter->proc = fopen("/proc/net/if_inet6", "r");
        iter->valid = ISC_R_FAILURE;
#endif
        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:
#if defined(SIOCGLIFCONF) && defined(SIOCGLIFADDR)
        if (iter->buf6 != NULL)
                isc_mem_put(mctx, iter->buf6, iter->bufsize6);
  ioctl6_failure:
        if (iter->socket6 != -1)
                (void) close(iter->socket6);
  socket6_failure:
#endif

        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;
        memmove(&dst->type.in, src, sizeof(struct in_addr));
}

static isc_result_t
internal_current_clusteralias(isc_interfaceiter_t *iter) {
        struct clua_info ci;
        if (clua_getaliasinfo(&iter->clua_sa, &ci) != CLUA_SUCCESS)
                return (ISC_R_IGNORE);
        memset(&iter->current, 0, sizeof(iter->current));
        iter->current.af = iter->clua_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);
}
#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(ISC_PLATFORM_HAVEIF_LADDRREQ) && defined(SIOCGLIFADDR)
        struct lifreq lifreq;
#else
        char sabuf[256];
#endif
        int i, bits, prefixlen;

        REQUIRE(VALID_IFITER(iter));

        if (iter->ifc.ifc_len == 0 ||
            iter->pos == (unsigned int)iter->ifc.ifc_len) {
#ifdef __linux
                return (linux_if_inet6_current(iter));
#else
                return (ISC_R_NOMORE);
#endif
        }

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

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

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

        family = ifreq.ifr_addr.sa_family;
#if 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));
        memmove(iter->current.name, ifreq.ifr_name, sizeof(ifreq.ifr_name));

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

        /*
         * 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 "integer 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_UP) != 0)
                iter->current.flags |= INTERFACE_F_UP;

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

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

        if (family == AF_INET)
                goto inet;

#if !defined(ISC_PLATFORM_HAVEIF_LADDRREQ) && defined(SIOCGLIFADDR)
        memset(&lifreq, 0, sizeof(lifreq));
        memmove(lifreq.lifr_name, iter->current.name, sizeof(lifreq.lifr_name));
        memmove(&lifreq.lifr_addr, &iter->current.address.type.in6,
               sizeof(iter->current.address.type.in6));

        if (ioctl(iter->socket, SIOCGLIFADDR, &lifreq) < 0) {
                isc__strerror(errno, strbuf, sizeof(strbuf));
                UNEXPECTED_ERROR(__FILE__, __LINE__,
                                 "%s: getting interface address: %s",
                                 ifreq.ifr_name, strbuf);
                return (ISC_R_IGNORE);
        }
        prefixlen = lifreq.lifr_addrlen;
#else
        isc_netaddr_format(&iter->current.address, sabuf, sizeof(sabuf));
        isc_log_write(isc_lctx, ISC_LOGCATEGORY_GENERAL,
                      ISC_LOGMODULE_INTERFACE,
                      ISC_LOG_INFO,
                      isc_msgcat_get(isc_msgcat,
                                     ISC_MSGSET_IFITERIOCTL,
                                     ISC_MSG_GETIFCONFIG,
                                     "prefix length for %s is unknown "
                                     "(assume 128)"), sabuf);
        prefixlen = 128;
#endif

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

 inet:
        if (family != AF_INET)
                return (ISC_R_IGNORE);
#ifdef IFF_POINTOPOINT
        /*
         * 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 "integer 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, ifreq.ifr_name);
        }
#endif

        /*
         * Get the network mask.
         */
        memset(&ifreq, 0, sizeof(ifreq));
        memmove(&ifreq, ifrp, sizeof(ifreq));
        /*
         * Ignore the HP/UX warning about "integer 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, ifreq.ifr_name);
        return (ISC_R_SUCCESS);
}

#if defined(SIOCGLIFCONF) && defined(SIOCGLIFADDR)
static isc_result_t
internal_current6(isc_interfaceiter_t *iter) {
        struct LIFREQ *ifrp;
        struct LIFREQ lifreq;
        int family;
        char strbuf[ISC_STRERRORSIZE];
        int fd;

        REQUIRE(VALID_IFITER(iter));
        if (iter->result6 != ISC_R_SUCCESS)
                return (iter->result6);
        REQUIRE(iter->pos6 < (unsigned int) iter->lifc.lifc_len);

        ifrp = (struct LIFREQ *)((char *) iter->lifc.lifc_req + iter->pos6);

        memset(&lifreq, 0, sizeof(lifreq));
        memmove(&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));
        memmove(iter->current.name, lifreq.lifr_name, sizeof(lifreq.lifr_name));

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

        /*
         * 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;

        if (family == AF_INET6)
                fd = iter->socket6;
        else
                fd = iter->socket;

        /*
         * Ignore the HP/UX warning about "integer overflow during
         * conversion.  It comes from its own macro definition,
         * and is really hard to shut up.
         */
        if (ioctl(fd, 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_UP) != 0)
                iter->current.flags |= INTERFACE_F_UP;

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

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

#ifdef IFF_POINTOPOINT
        /*
         * 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 "integer overflow during
                 * conversion.  It comes from its own macro definition,
                 * and is really hard to shut up.
                 */
                if (ioctl(fd, 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,
                         lifreq.lifr_name);
        }
#endif

        /*
         * Get the network mask.  Netmask already zeroed.
         */
        memset(&lifreq, 0, sizeof(lifreq));
        memmove(&lifreq, ifrp, sizeof(lifreq));

#ifdef lifr_addrlen
        /*
         * Special case: if the system provides lifr_addrlen member, the
         * netmask of an IPv6 address can be derived from the length, since
         * an IPv6 address always has a contiguous mask.
         */
        if (family == AF_INET6) {
                int i, bits;

                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;
                }

                return (ISC_R_SUCCESS);
        }
#endif

        /*
         * Ignore the HP/UX warning about "integer overflow during
         * conversion.  It comes from its own macro definition,
         * and is really hard to shut up.
         */
        if (ioctl(fd, 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, lifreq.lifr_name);

        return (ISC_R_SUCCESS);
}
#endif

static isc_result_t
internal_current(isc_interfaceiter_t *iter) {
#if defined(SIOCGLIFCONF) && defined(SIOCGLIFADDR)
        if (iter->mode == 6) {
                iter->result6 = internal_current6(iter);
                if (iter->result6 != ISC_R_NOMORE)
                        return (iter->result6);
        }
#endif
#ifdef HAVE_TRUCLUSTER
        if (!iter->clua_done)
                return(internal_current_clusteralias(iter));
#endif
        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) {
#ifdef ISC_PLATFORM_HAVESALEN
        struct ifreq *ifrp;
#endif

        if (iter->pos < (unsigned int) iter->ifc.ifc_len) {
#ifdef ISC_PLATFORM_HAVESALEN
                ifrp = (struct ifreq *)((char *) iter->ifc.ifc_req + iter->pos);

                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(struct ifreq);

        } else {
                INSIST(iter->pos == (unsigned int) iter->ifc.ifc_len);
#ifdef __linux
                return (linux_if_inet6_next(iter));
#else
                return (ISC_R_NOMORE);
#endif
        }
        return (ISC_R_SUCCESS);
}

#if defined(SIOCGLIFCONF) && defined(SIOCGLIFADDR)
static isc_result_t
internal_next6(isc_interfaceiter_t *iter) {
#ifdef ISC_PLATFORM_HAVESALEN
        struct LIFREQ *ifrp;
#endif

        if (iter->result6 != ISC_R_SUCCESS && iter->result6 != ISC_R_IGNORE)
                return (iter->result6);

        REQUIRE(iter->pos6 < (unsigned int) iter->lifc.lifc_len);

#ifdef ISC_PLATFORM_HAVESALEN
        ifrp = (struct LIFREQ *)((char *) iter->lifc.lifc_req + iter->pos6);

        if (ifrp->lifr_addr.sa_len > sizeof(struct sockaddr))
                iter->pos6 += sizeof(ifrp->lifr_name) + ifrp->lifr_addr.sa_len;
        else
#endif
                iter->pos6 += sizeof(struct LIFREQ);

        if (iter->pos6 >= (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) {
#ifdef HAVE_TRUCLUSTER
        int clua_result;
#endif
#if defined(SIOCGLIFCONF) && defined(SIOCGLIFADDR)
        if (iter->mode == 6) {
                iter->result6 = internal_next6(iter);
                if (iter->result6 != ISC_R_NOMORE)
                        return (iter->result6);
                if (iter->first6) {
                        iter->first6 = ISC_FALSE;
                        return (ISC_R_SUCCESS);
                }
        }
#endif
#ifdef HAVE_TRUCLUSTER
        if (!iter->clua_done) {
                clua_result = clua_getaliasaddress(&iter->clua_sa,
                                                   &iter->clua_context);
                if (clua_result != CLUA_SUCCESS)
                        iter->clua_done = ISC_TRUE;
                return (ISC_R_SUCCESS);
        }
#endif
        return (internal_next4(iter));
}

static void
internal_destroy(isc_interfaceiter_t *iter) {
        (void) close(iter->socket);
#if defined(SIOCGLIFCONF) && defined(SIOCGLIFADDR)
        if (iter->socket6 != -1)
                (void) close(iter->socket6);
        if (iter->buf6 != NULL) {
                isc_mem_put(iter->mctx, iter->buf6, iter->bufsize6);
        }
#endif
#ifdef __linux
        if (iter->proc != NULL)
                fclose(iter->proc);
#endif
}

static
void internal_first(isc_interfaceiter_t *iter) {
#ifdef HAVE_TRUCLUSTER
        int clua_result;
#endif
        iter->pos = 0;
#if defined(SIOCGLIFCONF) && defined(SIOCGLIFADDR)
        iter->pos6 = 0;
        if (iter->result6 == ISC_R_NOMORE)
                iter->result6 = ISC_R_SUCCESS;
        iter->first6 = ISC_TRUE;
#endif
#ifdef HAVE_TRUCLUSTER
        iter->clua_context = 0;
        clua_result = clua_getaliasaddress(&iter->clua_sa,
                                           &iter->clua_context);
        iter->clua_done = ISC_TF(clua_result != CLUA_SUCCESS);
#endif
#ifdef __linux
        linux_if_inet6_first(iter);
#endif
}

---