common/irs/gethostent.c

	gethostent.c revision 7c478bd95313f5f23a4c958a745db2134aa03244
/*
 * Copyright 2003 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*
 * Copyright (c) 1996-1999 by 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.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

#if !defined(LINT) && !defined(CODECENTER)
static const char rcsid[] = "$Id: gethostent.c,v 1.34 2003/05/29 00:05:18 marka Exp $";
#endif

/* Imports */

#include "port_before.h"

#if !defined(__BIND_NOSTATIC)

#include <sys/types.h>
#include <sys/param.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <netinet/in.h>
#include <net/if.h>
#include <arpa/inet.h>
#include <arpa/nameser.h>

#include <ctype.h>
#include <errno.h>
#include <stdlib.h>
#include <netdb.h>
#include <resolv.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>

#include <irs.h>
#include <isc/memcluster.h>

#include "port_after.h"

#include "irs_p.h"
#include "irs_data.h"

/* Definitions */

struct pvt {
    char *      aliases[1];
    char *      addrs[2];
    char        addr[NS_IN6ADDRSZ];
    char        name[NS_MAXDNAME + 1];
    struct hostent  host;
};

/* Forward */

static struct net_data *init(void);
static void     freepvt(struct net_data *);
static struct hostent  *fakeaddr(const char *, int, struct net_data *);

#ifdef  SUNW_OVERRIDE_RETRY
extern int  __res_retry(int);
extern int  __res_retry_reset(void);
#endif  /* SUNW_OVERRIDE_RETRY */

/* Public */

struct hostent *
gethostbyname(const char *name) {
    struct net_data *net_data = init();

    return (gethostbyname_p(name, net_data));
}

struct hostent *
gethostbyname2(const char *name, int af) {
    struct net_data *net_data = init();

    return (gethostbyname2_p(name, af, net_data));
}

struct hostent *
#ifdef ORIGINAL_ISC_CODE
gethostbyaddr(const char *addr, int len, int af) {
#else
gethostbyaddr(const void *addr, socklen_t len, int af) {
#endif /* ORIGINAL_ISC_CODE */
    struct net_data *net_data = init();

    return (gethostbyaddr_p(addr, len, af, net_data));
}

struct hostent *
gethostent() {
    struct net_data *net_data = init();

    return (gethostent_p(net_data));
}

#ifdef  ORIGINAL_ISC_CODE
void
#else
int
#endif
sethostent(int stayopen) {
    struct net_data *net_data = init();
    sethostent_p(stayopen, net_data);
#ifdef  ORIGINAL_ISC_CODE
#else
    return (0);
#endif
}


#ifdef  ORIGINAL_ISC_CODE
void
#else
int
#endif
endhostent() {
    struct net_data *net_data = init();
    endhostent_p(net_data);
#ifdef  ORIGINAL_ISC_CODE
#else
    return (0);
#endif
}

/* Shared private. */

struct hostent *
gethostbyname_p(const char *name, struct net_data *net_data) {
    struct hostent *hp;

    if (!net_data)
#ifdef  SUNW_SETHERRNO
    {
        /*
        *  Should set the context h_errno, but since net_data
         * is NULL, we don't have a context.
         */
        h_errno = NETDB_INTERNAL;
        return (NULL);
    }
#else
        return (NULL);
#endif  /* SUNW_SETHERRNO */

    if (net_data->res->options & RES_USE_INET6) {
        hp = gethostbyname2_p(name, AF_INET6, net_data);
        if (hp)
            return (hp);
    }
    return (gethostbyname2_p(name, AF_INET, net_data));
}

struct hostent *
gethostbyname2_p(const char *name, int af, struct net_data *net_data) {
    struct irs_ho *ho;
    char tmp[NS_MAXDNAME];
    struct hostent *hp;
    const char *cp;
    char **hap;

    if (!net_data || !(ho = net_data->ho))
#ifdef  SUNW_SETHERRNO
    {
        h_errno = NETDB_INTERNAL;
        return (NULL);
    }
#else
        return (NULL);
#endif  /* SUNW_SETHERRNO */
    if (net_data->ho_stayopen && net_data->ho_last &&
    net_data->ho_last->h_addrtype == af) {
        if (ns_samename(name, net_data->ho_last->h_name) == 1)
            return (net_data->ho_last);
        for (hap = net_data->ho_last->h_aliases; hap && *hap; hap++)
            if (ns_samename(name, *hap) == 1)
                return (net_data->ho_last);
    }
    if (!strchr(name, '.') && (cp = res_hostalias(net_data->res, name,
                              tmp, sizeof tmp)))
        name = cp;
    if ((hp = fakeaddr(name, af, net_data)) != NULL)
        return (hp);
#ifdef  SUNW_OVERRIDE_RETRY
    net_data->res->retry = __res_retry(net_data->res->retry);
#endif  /* SUNW_OVERRIDE_RETRY */
    net_data->ho_last = (*ho->byname2)(ho, name, af);
#ifdef  SUNW_OVERRIDE_RETRY
    net_data->res->retry = __res_retry_reset();
#endif  /* SUNW_OVERRIDE_RETRY */
    if (!net_data->ho_stayopen)
        endhostent();
    return (net_data->ho_last);
}

struct hostent *
gethostbyaddr_p(const char *addr, int len, int af, struct net_data *net_data) {
    struct irs_ho *ho;
    char **hap;

    if (!net_data || !(ho = net_data->ho))
#ifdef  SUNW_SETHERRNO
    {
        h_errno = NETDB_INTERNAL;
        return (NULL);
    }
#else
        return (NULL);
#endif  /* SUNW_SETHERRNO */
    if (net_data->ho_stayopen && net_data->ho_last &&
        net_data->ho_last->h_length == len)
        for (hap = net_data->ho_last->h_addr_list;
             hap && *hap;
             hap++)
            if (!memcmp(addr, *hap, len))
                return (net_data->ho_last);
    net_data->ho_last = (*ho->byaddr)(ho, addr, len, af);
    if (!net_data->ho_stayopen)
        endhostent();
    return (net_data->ho_last);
}


struct hostent *
gethostent_p(struct net_data *net_data) {
    struct irs_ho *ho;
    struct hostent *hp;

    if (!net_data || !(ho = net_data->ho))
#ifdef  SUNW_SETHERRNO
    {
        h_errno = NETDB_INTERNAL;
        return (NULL);
    }
#else
        return (NULL);
#endif  /* SUNW_SETHERRNO */
    while ((hp = (*ho->next)(ho)) != NULL &&
           hp->h_addrtype == AF_INET6 &&
           (net_data->res->options & RES_USE_INET6) == 0)
        continue;
    net_data->ho_last = hp;
    return (net_data->ho_last);
}


void
sethostent_p(int stayopen, struct net_data *net_data) {
    struct irs_ho *ho;

    if (!net_data || !(ho = net_data->ho))
        return;
    freepvt(net_data);
    (*ho->rewind)(ho);
    net_data->ho_stayopen = (stayopen != 0);
    if (stayopen == 0)
        net_data_minimize(net_data);
}

void
endhostent_p(struct net_data *net_data) {
    struct irs_ho *ho;

    if ((net_data != NULL) && ((ho = net_data->ho) != NULL))
        (*ho->minimize)(ho);
}

#ifndef IN6_IS_ADDR_V4COMPAT
static const unsigned char in6addr_compat[12] = {
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
#define IN6_IS_ADDR_V4COMPAT(x) (!memcmp((x)->s6_addr, in6addr_compat, 12) && \
                 ((x)->s6_addr[12] != 0 || \
                  (x)->s6_addr[13] != 0 || \
                  (x)->s6_addr[14] != 0 || \
                   ((x)->s6_addr[15] != 0 && \
                    (x)->s6_addr[15] != 1)))
#endif
#ifndef IN6_IS_ADDR_V4MAPPED
#define IN6_IS_ADDR_V4MAPPED(x) (!memcmp((x)->s6_addr, in6addr_mapped, 12))
#endif

static const unsigned char in6addr_mapped[12] = {
    0, 0, 0, 0,  0, 0, 0, 0,  0, 0, 0xff, 0xff };

static int scan_interfaces(int *, int *);
static struct hostent *copyandmerge(struct hostent *, struct hostent *, int, int *);

/*
 *  Public functions
 */

/*
 *  AI_V4MAPPED + AF_INET6
 *  If no IPv6 address then a query for IPv4 and map returned values.
 *
 *  AI_ALL + AI_V4MAPPED + AF_INET6
 *  Return IPv6 and IPv4 mapped.
 *
 *  AI_ADDRCONFIG
 *  Only return IPv6 / IPv4 address if there is an interface of that
 *  type active.
 */

struct hostent *
getipnodebyname(const char *name, int af, int flags, int *error_num) {
    int have_v4 = 1, have_v6 = 1;
    struct in_addr in4;
    struct in6_addr in6;
    struct hostent he, *he1 = NULL, *he2 = NULL, *he3;
    int v4 = 0, v6 = 0;
    struct net_data *net_data = init();
    u_long options;
    int tmp_err;

    if (net_data == NULL) {
        *error_num = NO_RECOVERY;
        return (NULL);
    }

    /* If we care about active interfaces then check. */
    if ((flags & AI_ADDRCONFIG) != 0)
        if (scan_interfaces(&have_v4, &have_v6) == -1) {
            *error_num = NO_RECOVERY;
            return (NULL);
        }

    /* Check for literal address. */
    if ((v4 = inet_pton(AF_INET, name, &in4)) != 1)
        v6 = inet_pton(AF_INET6, name, &in6);

    /* Impossible combination? */

    if ((af == AF_INET6 && (flags & AI_V4MAPPED) == 0 && v4 == 1) ||
        (af == AF_INET && v6 == 1) ||
        (have_v4 == 0 && v4 == 1) ||
        (have_v6 == 0 && v6 == 1) ||
        (have_v4 == 0 && af == AF_INET) ||
        (have_v6 == 0 && af == AF_INET6)) {
        *error_num = HOST_NOT_FOUND;
        return (NULL);
    }

    /* Literal address? */
    if (v4 == 1 || v6 == 1) {
        char *addr_list[2];
        char *aliases[1];

        DE_CONST(name, he.h_name);
        he.h_addr_list = addr_list;
        he.h_addr_list[0] = (v4 == 1) ? (char *)&in4 : (char *)&in6;
        he.h_addr_list[1] = NULL;
        he.h_aliases = aliases;
        he.h_aliases[0] = NULL;
        he.h_length = (v4 == 1) ? INADDRSZ : IN6ADDRSZ;
        he.h_addrtype = (v4 == 1) ? AF_INET : AF_INET6;
        return (copyandmerge(&he, NULL, af, error_num));
    }

    options = net_data->res->options;
    net_data->res->options &= ~RES_USE_INET6;

    tmp_err = NO_RECOVERY;
    if (have_v6 && af == AF_INET6) {
        he2 = gethostbyname2_p(name, AF_INET6, net_data);
        if (he2 != NULL) {
            he1 = copyandmerge(he2, NULL, af, error_num);
            if (he1 == NULL)
                return (NULL);
            he2 = NULL;
        } else {
            tmp_err = net_data->res->res_h_errno;
        }
    }

    if (have_v4 &&
        ((af == AF_INET) ||
         (af == AF_INET6 && (flags & AI_V4MAPPED) != 0 &&
          (he1 == NULL || (flags & AI_ALL) != 0)))) {
        he2 = gethostbyname2_p(name, AF_INET, net_data);
        if (he1 == NULL && he2 == NULL) {
            *error_num = net_data->res->res_h_errno;
            return (NULL);
        }
    } else
        *error_num = tmp_err;

    net_data->res->options = options;

    he3 = copyandmerge(he1, he2, af, error_num);

    if (he1 != NULL)
        freehostent(he1);
    return (he3);
}

struct hostent *
getipnodebyaddr(const void *src, size_t len, int af, int *error_num) {
    struct hostent *he1, *he2;
    struct net_data *net_data = init();

    /* Sanity Checks. */
    if (src == NULL) {
        *error_num = NO_RECOVERY;
        return (NULL);
    }

    switch (af) {
    case AF_INET:
        if (len != INADDRSZ) {
            *error_num = NO_RECOVERY;
            return (NULL);
        }
        break;
    case AF_INET6:
        if (len != IN6ADDRSZ) {
            *error_num = NO_RECOVERY;
            return (NULL);
        }
        break;
    default:
        *error_num = NO_RECOVERY;
        return (NULL);
    }

    /*
     * Lookup IPv4 and IPv4 mapped/compatible addresses
     */
    if ((af == AF_INET6 &&
         IN6_IS_ADDR_V4COMPAT((const struct in6_addr *)src)) ||
        (af == AF_INET6 &&
         IN6_IS_ADDR_V4MAPPED((const struct in6_addr *)src)) ||
        (af == AF_INET)) {
        const char *cp = src;

        if (af == AF_INET6)
            cp += 12;
        he1 = gethostbyaddr_p(cp, 4, AF_INET, net_data);
        if (he1 == NULL) {
            *error_num = net_data->res->res_h_errno;
            return (NULL);
        }
        he2 = copyandmerge(he1, NULL, af, error_num);
        if (he2 == NULL)
            return (NULL);
        /*
         * Restore original address if mapped/compatible.
         */
        if (af == AF_INET6)
            memcpy(he1->h_addr, src, len);
        return (he2);
    }

    /*
     * Lookup IPv6 address.
     */
    if (memcmp((const struct in6_addr *)src, &in6addr_any, 16) == 0) {
        *error_num = HOST_NOT_FOUND;
        return (NULL);
    }

    he1 = gethostbyaddr_p(src, 16, AF_INET6, net_data);
    if (he1 == NULL) {
        *error_num = net_data->res->res_h_errno;
        return (NULL);
    }
    return (copyandmerge(he1, NULL, af, error_num));
}

void
freehostent(struct hostent *he) {
    char **cpp;
    int names = 1;
    int addresses = 1;

    memput(he->h_name, strlen(he->h_name) + 1);

    cpp = he->h_addr_list;
    while (*cpp != NULL) {
        memput(*cpp, (he->h_addrtype == AF_INET) ?
                 INADDRSZ : IN6ADDRSZ);
        *cpp = NULL;
        cpp++;
        addresses++;
    }

    cpp = he->h_aliases;
    while (*cpp != NULL) {
        memput(*cpp, strlen(*cpp) + 1);
        cpp++;
        names++;
    }

    memput(he->h_aliases, sizeof(char *) * (names));
    memput(he->h_addr_list, sizeof(char *) * (addresses));
    memput(he, sizeof *he);
}

/*
 * Private
 */

/*
 * Scan the interface table and set have_v4 and have_v6 depending
 * upon whether there are IPv4 and IPv6 interface addresses.
 *
 * Returns:
 *  0 on success
 *  -1 on failure.
 */

#if defined(SIOCGLIFCONF) && defined(SIOCGLIFADDR) && \
    !defined(IRIX_EMUL_IOCTL_SIOCGIFCONF)

#define SETFAMILYFLAGS
#define LIFCONF lifconf
#define LIFREQ lifreq

static void
scan_interfaces6(int *have_v4, int *have_v6) {
    struct LIFCONF lifc;
    struct LIFREQ lifreq;
    struct in_addr in4;
    struct in6_addr in6;
    char *buf = NULL, *cp, *cplim;
    static unsigned int bufsiz = 4095;
    int s, cpsize, n;

    /* Get interface list from system. */
    if ((s = socket(AF_INET6, SOCK_DGRAM, 0)) == -1)
        goto cleanup;

    /*
     * Grow buffer until large enough to contain all interface
     * descriptions.
     */
    for (;;) {
        buf = memget(bufsiz);
        if (buf == NULL)
            goto cleanup;
#ifdef SETFAMILYFLAGS
        lifc.lifc_family = AF_UNSPEC;   /* request all families */
        lifc.lifc_flags = 0;
#endif
        lifc.lifc_len = bufsiz;
        lifc.lifc_buf = buf;
        if ((n = ioctl(s, SIOCGLIFCONF, (char *)&lifc)) != -1) {
            /*
             * 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
             * lifc.lifc_len is too near to the end of the
             * buffer we will grow it just in case and
             * retry.
             */
            if (lifc.lifc_len + 2 * sizeof(lifreq) < bufsiz)
                break;
        }
        if ((n == -1) && errno != EINVAL)
            goto cleanup;

        if (bufsiz > 1000000)
            goto cleanup;

        memput(buf, bufsiz);
        bufsiz += 4096;
    }

    /* Parse system's interface list. */
    cplim = buf + lifc.lifc_len;    /* skip over if's with big ifr_addr's */
    for (cp = buf;
         (*have_v4 == 0 || *have_v6 == 0) && cp < cplim;
         cp += cpsize) {
        memcpy(&lifreq, cp, sizeof lifreq);
#ifdef HAVE_SA_LEN
#ifdef FIX_ZERO_SA_LEN
        if (lifreq.lifr_addr.sa_len == 0)
            lifreq.lifr_addr.sa_len = 16;
#endif
#ifdef HAVE_MINIMUM_IFREQ
        cpsize = sizeof lifreq;
        if (lifreq.lifr_addr.sa_len > sizeof (struct sockaddr))
            cpsize += (int)lifreq.lifr_addr.sa_len -
                (int)(sizeof (struct sockaddr));
#else
        cpsize = sizeof lifreq.lifr_name + lifreq.lifr_addr.sa_len;
#endif /* HAVE_MINIMUM_IFREQ */
#elif defined SIOCGIFCONF_ADDR
        cpsize = sizeof lifreq;
#else
        cpsize = sizeof lifreq.lifr_name;
        /* XXX maybe this should be a hard error? */
        if (ioctl(s, SIOCGLIFADDR, (char *)&lifreq) < 0)
            continue;
#endif
        switch (lifreq.lifr_addr.ss_family) {
        case AF_INET:
            if (*have_v4 == 0) {
                memcpy(&in4,
                       &((struct sockaddr_in *)
                       &lifreq.lifr_addr)->sin_addr,
                       sizeof in4);
                if (in4.s_addr == INADDR_ANY)
                    break;
                n = ioctl(s, SIOCGLIFFLAGS, (char *)&lifreq);
                if (n < 0)
                    break;
                if ((lifreq.lifr_flags & IFF_UP) == 0)
                    break;
                *have_v4 = 1;
            }
            break;
        case AF_INET6:
            if (*have_v6 == 0) {
                memcpy(&in6,
                       &((struct sockaddr_in6 *)
                       &lifreq.lifr_addr)->sin6_addr, sizeof in6);
                if (memcmp(&in6, &in6addr_any, sizeof in6) == 0)
                    break;
                n = ioctl(s, SIOCGLIFFLAGS, (char *)&lifreq);
                if (n < 0)
                    break;
                if ((lifreq.lifr_flags & IFF_UP) == 0)
                    break;
                *have_v6 = 1;
            }
            break;
        }
    }
    if (buf != NULL)
        memput(buf, bufsiz);
    close(s);
    /* printf("scan interface -> 4=%d 6=%d\n", *have_v4, *have_v6); */
    return;
 cleanup:
    if (buf != NULL)
        memput(buf, bufsiz);
    if (s != -1)
        close(s);
    /* printf("scan interface -> 4=%d 6=%d\n", *have_v4, *have_v6); */
    return;
}
#endif

static int
scan_interfaces(int *have_v4, int *have_v6) {
    struct ifconf ifc;
    union {
        char _pad[256];     /* leave space for IPv6 addresses */
        struct ifreq ifreq;
    } u;
    struct in_addr in4;
    struct in6_addr in6;
    char *buf = NULL, *cp, *cplim;
    static unsigned int bufsiz = 4095;
    int s, n;
    size_t cpsize;

    /* Set to zero.  Used as loop terminators below. */
    *have_v4 = *have_v6 = 0;

#if defined(SIOCGLIFCONF) && defined(SIOCGLIFADDR) && \
    !defined(IRIX_EMUL_IOCTL_SIOCGIFCONF)
    /*
     * Try to scan the interfaces using IPv6 ioctls().
     */
    scan_interfaces6(have_v4, have_v6);
    if (*have_v4 != 0 && *have_v6 != 0)
        return (0);
#endif

    /* Get interface list from system. */
    if ((s = socket(AF_INET, SOCK_DGRAM, 0)) == -1)
        goto err_ret;

    /*
     * Grow buffer until large enough to contain all interface
     * descriptions.
     */
    for (;;) {
        buf = memget(bufsiz);
        if (buf == NULL)
            goto err_ret;
        ifc.ifc_len = bufsiz;
        ifc.ifc_buf = buf;
#ifdef IRIX_EMUL_IOCTL_SIOCGIFCONF
        /*
         * This is a fix for IRIX OS in which the call to ioctl with
         * the flag SIOCGIFCONF may not return an entry for all the
         * interfaces like most flavors of Unix.
         */
        if (emul_ioctl(&ifc) >= 0)
            break;
#else
        if ((n = ioctl(s, SIOCGIFCONF, (char *)&ifc)) != -1) {
            /*
             * 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 (ifc.ifc_len + 2 * sizeof(u.ifreq) < bufsiz)
                break;
        }
#endif
        if ((n == -1) && errno != EINVAL)
            goto err_ret;

        if (bufsiz > 1000000)
            goto err_ret;

        memput(buf, bufsiz);
        bufsiz += 4096;
    }

    /* Parse system's interface list. */
    cplim = buf + ifc.ifc_len;    /* skip over if's with big ifr_addr's */
    for (cp = buf;
         (*have_v4 == 0 || *have_v6 == 0) && cp < cplim;
         cp += cpsize) {
        memcpy(&u.ifreq, cp, sizeof u.ifreq);
#ifdef HAVE_SA_LEN
#ifdef FIX_ZERO_SA_LEN
        if (u.ifreq.ifr_addr.sa_len == 0)
            u.ifreq.ifr_addr.sa_len = 16;
#endif
#ifdef HAVE_MINIMUM_IFREQ
        cpsize = sizeof u.ifreq;
        if (u.ifreq.ifr_addr.sa_len > sizeof (struct sockaddr))
            cpsize += (int)u.ifreq.ifr_addr.sa_len -
                (int)(sizeof (struct sockaddr));
#else
        cpsize = sizeof u.ifreq.ifr_name + u.ifreq.ifr_addr.sa_len;
#endif /* HAVE_MINIMUM_IFREQ */
        if (cpsize > sizeof u.ifreq && cpsize <= sizeof u)
            memcpy(&u.ifreq, cp, cpsize);
#elif defined SIOCGIFCONF_ADDR
        cpsize = sizeof u.ifreq;
#else
        cpsize = sizeof u.ifreq.ifr_name;
        /* XXX maybe this should be a hard error? */
        if (ioctl(s, SIOCGIFADDR, (char *)&u.ifreq) < 0)
            continue;
#endif
        switch (u.ifreq.ifr_addr.sa_family) {
        case AF_INET:
            if (*have_v4 == 0) {
                memcpy(&in4,
                       &((struct sockaddr_in *)
                       &u.ifreq.ifr_addr)->sin_addr,
                       sizeof in4);
                if (in4.s_addr == INADDR_ANY)
                    break;
                n = ioctl(s, SIOCGIFFLAGS, (char *)&u.ifreq);
                if (n < 0)
                    break;
                if ((u.ifreq.ifr_flags & IFF_UP) == 0)
                    break;
                *have_v4 = 1;
            }
            break;
        case AF_INET6:
            if (*have_v6 == 0) {
                memcpy(&in6,
                       &((struct sockaddr_in6 *)
                       &u.ifreq.ifr_addr)->sin6_addr,
                       sizeof in6);
                if (memcmp(&in6, &in6addr_any, sizeof in6) == 0)
                    break;
                n = ioctl(s, SIOCGIFFLAGS, (char *)&u.ifreq);
                if (n < 0)
                    break;
                if ((u.ifreq.ifr_flags & IFF_UP) == 0)
                    break;
                *have_v6 = 1;
            }
            break;
        }
    }
    if (buf != NULL)
        memput(buf, bufsiz);
    close(s);
    /* printf("scan interface -> 4=%d 6=%d\n", *have_v4, *have_v6); */
    return (0);
 err_ret:
    if (buf != NULL)
        memput(buf, bufsiz);
    if (s != -1)
        close(s);
    /* printf("scan interface -> 4=%d 6=%d\n", *have_v4, *have_v6); */
    return (-1);
}

static struct hostent *
copyandmerge(struct hostent *he1, struct hostent *he2, int af, int *error_num) {
    struct hostent *he = NULL;
    int addresses = 1;  /* NULL terminator */
    int names = 1;      /* NULL terminator */
    int len = 0;
    char **cpp, **npp;

    /*
     * Work out array sizes;
     */
    if (he1 != NULL) {
        cpp = he1->h_addr_list;
        while (*cpp != NULL) {
            addresses++;
            cpp++;
        }
        cpp = he1->h_aliases;
        while (*cpp != NULL) {
            names++;
            cpp++;
        }
    }

    if (he2 != NULL) {
        cpp = he2->h_addr_list;
        while (*cpp != NULL) {
            addresses++;
            cpp++;
        }
        if (he1 == NULL) {
            cpp = he2->h_aliases;
            while (*cpp != NULL) {
                names++;
                cpp++;
            }
        }
    }

    if (addresses == 1) {
        *error_num = NO_ADDRESS;
        return (NULL);
    }

    he = memget(sizeof *he);
    if (he == NULL)
        goto no_recovery;

    he->h_addr_list = memget(sizeof(char *) * (addresses));
    if (he->h_addr_list == NULL)
        goto cleanup0;
    memset(he->h_addr_list, 0, sizeof(char *) * (addresses));

    /* copy addresses */
    npp = he->h_addr_list;
    if (he1 != NULL) {
        cpp = he1->h_addr_list;
        while (*cpp != NULL) {
            *npp = memget((af == AF_INET) ? INADDRSZ : IN6ADDRSZ);
            if (*npp == NULL)
                goto cleanup1;
            /* convert to mapped if required */
            if (af == AF_INET6 && he1->h_addrtype == AF_INET) {
                memcpy(*npp, in6addr_mapped,
                       sizeof in6addr_mapped);
                memcpy(*npp + sizeof in6addr_mapped, *cpp,
                       INADDRSZ);
            } else {
                memcpy(*npp, *cpp,
                       (af == AF_INET) ? INADDRSZ : IN6ADDRSZ);
            }
            cpp++;
            npp++;
        }
    }

    if (he2 != NULL) {
        cpp = he2->h_addr_list;
        while (*cpp != NULL) {
            *npp = memget((af == AF_INET) ? INADDRSZ : IN6ADDRSZ);
            if (*npp == NULL)
                goto cleanup1;
            /* convert to mapped if required */
            if (af == AF_INET6 && he2->h_addrtype == AF_INET) {
                memcpy(*npp, in6addr_mapped,
                       sizeof in6addr_mapped);
                memcpy(*npp + sizeof in6addr_mapped, *cpp,
                       INADDRSZ);
            } else {
                memcpy(*npp, *cpp,
                       (af == AF_INET) ? INADDRSZ : IN6ADDRSZ);
            }
            cpp++;
            npp++;
        }
    }

    he->h_aliases = memget(sizeof(char *) * (names));
    if (he->h_aliases == NULL)
        goto cleanup1;
    memset(he->h_aliases, 0, sizeof(char *) * (names));

    /* copy aliases */
    npp = he->h_aliases;
    cpp = (he1 != NULL) ? he1->h_aliases : he2->h_aliases;
    while (*cpp != NULL) {
        len = strlen (*cpp) + 1;
        *npp = memget(len);
        if (*npp == NULL)
            goto cleanup2;
        strcpy(*npp, *cpp);
        npp++;
        cpp++;
    }

    /* copy hostname */
    he->h_name = memget(strlen((he1 != NULL) ?
                he1->h_name : he2->h_name) + 1);
    if (he->h_name == NULL)
        goto cleanup2;
    strcpy(he->h_name, (he1 != NULL) ? he1->h_name : he2->h_name);

    /* set address type and length */
    he->h_addrtype = af;
    he->h_length = (af == AF_INET) ? INADDRSZ : IN6ADDRSZ;
    return(he);

 cleanup2:
    cpp = he->h_aliases;
    while (*cpp != NULL) {
        memput(*cpp, strlen(*cpp) + 1);
        cpp++;
    }
    memput(he->h_aliases, sizeof(char *) * (names));

 cleanup1:
    cpp = he->h_addr_list;
    while (*cpp != NULL) {
        memput(*cpp, (af == AF_INET) ? INADDRSZ : IN6ADDRSZ);
        *cpp = NULL;
        cpp++;
    }
    memput(he->h_addr_list, sizeof(char *) * (addresses));

 cleanup0:
    memput(he, sizeof *he);

 no_recovery:
    *error_num = NO_RECOVERY;
    return (NULL);
}

static struct net_data *
init() {
    struct net_data *net_data;

    if (!(net_data = net_data_init(NULL)))
        goto error;
    if (!net_data->ho) {
        net_data->ho = (*net_data->irs->ho_map)(net_data->irs);
        if (!net_data->ho || !net_data->res) {
  error:
            errno = EIO;
            if (net_data && net_data->res)
                RES_SET_H_ERRNO(net_data->res, NETDB_INTERNAL);
            return (NULL);
        }

        (*net_data->ho->res_set)(net_data->ho, net_data->res, NULL);
    }

    return (net_data);
}

static void
freepvt(struct net_data *net_data) {
    if (net_data->ho_data) {
        free(net_data->ho_data);
        net_data->ho_data = NULL;
    }
}

static struct hostent *
fakeaddr(const char *name, int af, struct net_data *net_data) {
    struct pvt *pvt;

    freepvt(net_data);
    net_data->ho_data = malloc(sizeof (struct pvt));
    if (!net_data->ho_data) {
        errno = ENOMEM;
        RES_SET_H_ERRNO(net_data->res, NETDB_INTERNAL);
        return (NULL);
    }
    pvt = net_data->ho_data;
#ifndef __bsdi__
    /*
     * Unlike its forebear(inet_aton), our friendly inet_pton() is strict
     * in its interpretation of its input, and it will only return "1" if
     * the input string is a formally valid(and thus unambiguous with
     * respect to host names) internet address specification for this AF.
     *
     * This means "telnet 0xdeadbeef" and "telnet 127.1" are dead now.
     */
    if (inet_pton(af, name, pvt->addr) != 1) {
#else
    /* BSDI XXX
     * We put this back to inet_aton -- we really want the old behavior
     * Long live 127.1...
     */
    if ((af != AF_INET ||
        inet_aton(name, (struct in_addr *)pvt->addr) != 1) &&
        inet_pton(af, name, pvt->addr) != 1) {
#endif
        RES_SET_H_ERRNO(net_data->res, HOST_NOT_FOUND);
        return (NULL);
    }
    strncpy(pvt->name, name, NS_MAXDNAME);
    pvt->name[NS_MAXDNAME] = '\0';
    if (af == AF_INET && (net_data->res->options & RES_USE_INET6) != 0) {
        map_v4v6_address(pvt->addr, pvt->addr);
        af = AF_INET6;
    }
    pvt->host.h_addrtype = af;
    switch(af) {
    case AF_INET:
        pvt->host.h_length = NS_INADDRSZ;
        break;
    case AF_INET6:
        pvt->host.h_length = NS_IN6ADDRSZ;
        break;
    default:
        errno = EAFNOSUPPORT;
        RES_SET_H_ERRNO(net_data->res, NETDB_INTERNAL);
        return (NULL);
    }
    pvt->host.h_name = pvt->name;
    pvt->host.h_aliases = pvt->aliases;
    pvt->aliases[0] = NULL;
    pvt->addrs[0] = (char *)pvt->addr;
    pvt->addrs[1] = NULL;
    pvt->host.h_addr_list = pvt->addrs;
    RES_SET_H_ERRNO(net_data->res, NETDB_SUCCESS);
    return (&pvt->host);
}

#ifdef grot /* for future use in gethostbyaddr(), for "SUNSECURITY" */
    struct hostent *rhp;
    char **haddr;
    u_long old_options;
    char hname2[MAXDNAME+1];

    if (af == AF_INET) {
        /*
         * turn off search as the name should be absolute,
         * 'localhost' should be matched by defnames
         */
        strncpy(hname2, hp->h_name, MAXDNAME);
        hname2[MAXDNAME] = '\0';
        old_options = net_data->res->options;
        net_data->res->options &= ~RES_DNSRCH;
        net_data->res->options |= RES_DEFNAMES;
        if (!(rhp = gethostbyname(hname2))) {
        net_data->res->options = old_options;
        RES_SET_H_ERRNO(net_data->res, HOST_NOT_FOUND);
        return (NULL);
        }
        net_data->res->options = old_options;
        for (haddr = rhp->h_addr_list; *haddr; haddr++)
        if (!memcmp(*haddr, addr, INADDRSZ))
            break;
        if (!*haddr) {
        RES_SET_H_ERRNO(net_data->res, HOST_NOT_FOUND);
        return (NULL);
        }
    }
#endif /* grot */

#endif /*__BIND_NOSTATIC*/