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/* Copyright (C) 1997 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 Library General Public License as
published by the Free Software Foundation; either version 2 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <net/if.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <bits/libc-lock.h>
/* Try to get a socket to talk to the kernel. */
static int
opensock (void)
{
/* Cache the last AF that worked, to avoid many redundant calls to
socket(). */
static int sock_af = -1;
int fd = -1;
__libc_lock_define_initialized (static, lock);
if (sock_af != -1)
{
fd = socket (sock_af, SOCK_DGRAM, 0);
if (fd != -1)
return fd;
}
__libc_lock_lock (lock);
if (sock_af != -1)
fd = socket (sock_af, SOCK_DGRAM, 0);
if (fd == -1)
{
fd = socket (sock_af = AF_INET6, SOCK_DGRAM, 0);
if (fd < 0)
fd = socket (sock_af = AF_INET, SOCK_DGRAM, 0);
if (fd < 0)
fd = socket (sock_af = AF_IPX, SOCK_DGRAM, 0);
if (fd < 0)
fd = socket (sock_af = AF_AX25, SOCK_DGRAM, 0);
if (fd < 0)
fd = socket (sock_af = AF_APPLETALK, SOCK_DGRAM, 0);
}
__libc_lock_unlock (lock);
return fd;
}
unsigned int
if_nametoindex (const char *ifname)
{
struct ifreq ifr;
int fd = opensock ();
if (fd < 0)
return 0;
strncpy (ifr.ifr_name, ifname, sizeof (ifr.ifr_name));
if (ioctl (fd, SIOGIFINDEX, &ifr) < 0)
{
close (fd);
return 0;
}
close (fd);
return ifr.ifr_ifindex;
}
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)
{
int fd = opensock ();
struct ifconf ifc;
unsigned int rq_ifs = 4, nifs, i;
struct if_nameindex *idx = NULL;
if (fd < 0)
return NULL;
ifc.ifc_buf = NULL;
/* Read all the interfaces out of the kernel. */
do
{
rq_ifs *= 2;
ifc.ifc_len = rq_ifs * sizeof (struct ifreq);
ifc.ifc_buf = realloc (ifc.ifc_buf, ifc.ifc_len);
if (ifc.ifc_buf == NULL)
{
close(fd);
return NULL;
}
if (ioctl (fd, SIOCGIFCONF, &ifc) < 0)
goto jump;
}
while ((unsigned int) ifc.ifc_len == (rq_ifs * sizeof (struct ifreq)));
nifs = ifc.ifc_len / sizeof (struct ifreq);
ifc.ifc_buf = realloc (ifc.ifc_buf, ifc.ifc_len);
idx = malloc ((nifs+1) * sizeof (struct if_nameindex));
if (idx == NULL)
goto jump;
for (i = 0; i < nifs; ++i)
{
struct ifreq *ifr = &ifc.ifc_req[i];
if ((idx[i].if_name = malloc (strlen (ifr->ifr_name)+1)) == NULL)
{
free (idx);
idx = NULL;
goto jump;
}
strcpy (idx[i].if_name, ifr->ifr_name);
if (ioctl (fd, SIOGIFINDEX, ifr) < 0)
{
free (idx);
idx = NULL;
goto jump;
}
idx[i].if_index = ifr->ifr_ifindex;
}
idx[i].if_index = 0;
idx[i].if_name = NULL;
jump:
free (ifc.ifc_buf);
close (fd);
return idx;
}
char *
if_indextoname (unsigned int ifindex, char *ifname)
{
struct if_nameindex *idx = if_nameindex ();
struct if_nameindex *p;
for (p = idx; p->if_index || p->if_name; ++p)
if (p->if_index == ifindex)
{
strncpy (ifname, p->if_name, IFNAMSIZ);
if_freenameindex (idx);
return ifname;
}
if_freenameindex (idx);
return NULL;
}
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