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/* Copyright (C) 1997,98,99,2000,02 Free Software Foundation, Inc.

 * This file is part of the GNU C Library.

 *

 * The GNU C Library is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2.1 of the License, or (at your option) any later version.

 *

 * The GNU C Library is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with the GNU C Library; if not, write to the Free

 * Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA

 * 02111-1307 USA.

 *

 * Reworked Dec 2002 by Erik Andersen <andersen@codepoet.org>

 */

#define __FORCE_GLIBC

#include <features.h>

#include <string.h>

#include <errno.h>

#include <net/if.h>

#include <sys/ioctl.h>

#include <unistd.h>

#include <stdlib.h>

static int __opensock(void)

{

    int fd;

#ifdef __UCLIBC_HAS_IPV6__

    fd=socket(AF_INET6,SOCK_DGRAM,0);

    if (fd<0)

#endif /* __UCLIBC_HAS_IPV6__ */

        fd=socket(AF_INET,SOCK_DGRAM,0);

    return(fd);

}

unsigned int if_nametoindex(const char* ifname)

{

#ifndef SIOCGIFINDEX

    __set_errno (ENOSYS);

    return 0;

#else

    int fd;

    struct ifreq ifr;

    fd = __opensock();

    if (fd < 0)

        return 0;

    strncpy (ifr.ifr_name, ifname, sizeof (ifr.ifr_name));

    if (ioctl(fd,SIOCGIFINDEX,&ifr) < 0) {

        int saved_errno = errno;

        close(fd);

        if (saved_errno == EINVAL)

            __set_errno(ENOSYS);

        return 0;

    }

    close(fd);

    return ifr.ifr_ifindex;

#endif /* SIOCGIFINDEX */

}

void if_freenameindex (struct if_nameindex *ifn)

{

    struct if_nameindex *ptr = ifn;

    while (ptr->if_name || ptr->if_index) {

        if (ptr->if_name) {

            free (ptr->if_name);

        }

        ++ptr;

    }

    free (ifn);

}

struct if_nameindex * if_nameindex (void)

{

#ifndef SIOCGIFINDEX

    __set_errno (ENOSYS);

    return NULL;

#else

    int fd;

    struct ifconf ifc;

    unsigned int nifs, i;

    int rq_len;

    struct if_nameindex *idx = NULL;

# define RQ_IFS 4

    fd = __opensock();

    if (fd < 0)

        return 0;

    ifc.ifc_buf = NULL;

    /* Guess on the correct buffer size... */

    rq_len = RQ_IFS * sizeof (struct ifreq);

    /* Read all the interfaces out of the kernel.  */

    do {

        ifc.ifc_buf = realloc(ifc.ifc_buf, ifc.ifc_len = rq_len);

        if (ifc.ifc_buf == NULL || ioctl(fd, SIOCGIFCONF, &ifc) < 0) {

            close(fd);

            return NULL;

        }

        rq_len *= 2;

    } while (ifc.ifc_len == rq_len);

    nifs = ifc.ifc_len / sizeof(struct ifreq);

    idx = malloc ((nifs + 1) * sizeof(struct if_nameindex));

    if (idx == NULL) {

        close(fd);

        __set_errno(ENOBUFS);

        return NULL;

    }

    for (i = 0; i < nifs; ++i) {

        struct ifreq *ifr = &ifc.ifc_req[i];

        idx[i].if_name = strdup (ifr->ifr_name);

        if (idx[i].if_name == NULL || ioctl(fd,SIOCGIFINDEX,ifr) < 0) {

            int saved_errno = errno;

            unsigned int j;

            for (j =  0; j < i; ++j)

                free (idx[j].if_name);

            free(idx);

            close(fd);

            if (saved_errno == EINVAL)

                saved_errno = ENOSYS;

            else if (saved_errno == ENOMEM)

                saved_errno = ENOBUFS;

            __set_errno (saved_errno);

            return NULL;

        }

        idx[i].if_index = ifr->ifr_ifindex;

    }

    idx[i].if_index = 0;

    idx[i].if_name = NULL;

    close(fd);

    return idx;

#endif

}

char * if_indextoname (unsigned int ifindex, char *ifname)

{

    struct if_nameindex *idx;

    struct if_nameindex *p;

    char *result = NULL;

    idx = if_nameindex();

    if (idx != NULL) {

        for (p = idx; p->if_index || p->if_name; ++p) {

            if (p->if_index == ifindex) {

                result = strncpy (ifname, p->if_name, IFNAMSIZ);

                break;

            }

        }

        if_freenameindex (idx);

    }

    return result;

}