glibc/sysdeps/unix/sysv/linux/if_index.c
Ulrich Drepper edecfcda2a Update.
* sysdeps/unix/sysv/linux/if_index.c (if_nameindex): Set errno to
	ENOBUFS if we are out of memory.
2000-04-30 09:40:55 +00:00

319 lines
7.0 KiB
C

/* Copyright (C) 1997, 1998, 1999, 2000 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 <errno.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <net/if.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <bits/libc-lock.h>
#include "kernel-features.h"
/* Variable to signal whether SIOCGIFCONF is not available. */
#if __ASSUME_SIOCGIFNAME == 0
static int old_siocgifconf;
#else
# define old_siocgifconf 0
#endif
unsigned int
if_nametoindex (const char *ifname)
{
#ifndef SIOCGIFINDEX
__set_errno (ENOSYS);
return 0;
#else
struct ifreq ifr;
int 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
}
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 = __opensock ();
struct ifconf ifc;
unsigned int nifs, i;
int rq_len;
struct if_nameindex *idx = NULL;
# define RQ_IFS 4
if (fd < 0)
return NULL;
ifc.ifc_buf = NULL;
/* We may be able to get the needed buffer size directly, rather than
guessing. */
if (! old_siocgifconf)
{
ifc.ifc_buf = NULL;
ifc.ifc_len = 0;
if (__ioctl (fd, SIOCGIFCONF, &ifc) < 0 || ifc.ifc_len == 0)
{
# if __ASSUME_SIOCGIFNAME == 0
old_siocgifconf = 1;
# endif
rq_len = RQ_IFS * sizeof (struct ifreq);
}
else
rq_len = ifc.ifc_len;
}
else
rq_len = RQ_IFS * sizeof (struct ifreq);
/* Read all the interfaces out of the kernel. */
do
{
ifc.ifc_buf = alloca (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 && old_siocgifconf);
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)
{
#if !defined SIOCGIFINDEX && __ASSUME_SIOCGIFNAME == 0
__set_errno (ENOSYS);
return NULL;
#else
# if __ASSUME_SIOCGIFNAME == 0
struct if_nameindex *idx;
struct if_nameindex *p;
char *result = NULL;
# endif
# if defined SIOCGIFNAME || __ASSUME_SIOCGIFNAME > 0
/* We may be able to do the conversion directly, rather than searching a
list. This ioctl is not present in kernels before version 2.1.50. */
struct ifreq ifr;
int fd;
# if __ASSUME_SIOCGIFNAME == 0
static int siocgifname_works_not;
if (!siocgifname_works_not)
# endif
{
# if __ASSUME_SIOCGIFNAME == 0
int serrno = errno;
# endif
int status;
fd = __opensock ();
if (fd < 0)
return NULL;
ifr.ifr_ifindex = ifindex;
status = __ioctl (fd, SIOCGIFNAME, &ifr);
__close (fd);
# if __ASSUME_SIOCGIFNAME == 0
if (status < 0)
{
if (errno == EINVAL)
siocgifname_works_not = 1; /* Don't make the same mistake twice. */
}
else
return strncpy (ifname, ifr.ifr_name, IFNAMSIZ);
__set_errno (serrno);
# else
return status < 0 ? NULL : strncpy (ifname, ifr.ifr_name, IFNAMSIZ);
# endif
}
# endif
# if __ASSUME_SIOCGIFNAME == 0
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;
# endif
#endif
}
void
internal_function
__protocol_available (int *have_inet, int *have_inet6)
{
int fd = __opensock ();
unsigned int nifs;
int rq_len;
struct ifconf ifc;
# define RQ_IFS 4
/* Wirst case assumption. */
*have_inet = 0;
*have_inet6 = 0;
if (fd < 0)
/* We cannot open the socket. No networking at all? */
return;
/* We may be able to get the needed buffer size directly, rather than
guessing. */
if (! old_siocgifconf)
{
ifc.ifc_buf = NULL;
ifc.ifc_len = 0;
if (__ioctl (fd, SIOCGIFCONF, &ifc) < 0 || ifc.ifc_len == 0)
{
# if __ASSUME_SIOCGIFNAME == 0
old_siocgifconf = 1;
# endif
rq_len = RQ_IFS * sizeof (struct ifreq);
}
else
rq_len = ifc.ifc_len;
}
else
rq_len = RQ_IFS * sizeof (struct ifreq);
/* Read all the interfaces out of the kernel. */
do
{
ifc.ifc_buf = alloca (ifc.ifc_len = rq_len);
if (ifc.ifc_buf == NULL || __ioctl (fd, SIOCGIFCONF, &ifc) < 0)
{
__close (fd);
return;
}
rq_len *= 2;
}
while (ifc.ifc_len == rq_len && old_siocgifconf);
nifs = ifc.ifc_len / sizeof (struct ifreq);
/* Go through all the interfaces and get the address. */
while (nifs-- > 0)
if (__ioctl (fd, SIOCGIFADDR, &ifc.ifc_req[nifs]) >= 0)
{
/* We successfully got information about this interface. Now
test whether it is an IPv4 or IPv6 address. */
if (ifc.ifc_req[nifs].ifr_addr.sa_family == AF_INET)
*have_inet = 1;
else if (ifc.ifc_req[nifs].ifr_addr.sa_family == AF_INET6)
*have_inet6 = 1;
/* Note, this is & not &&. It works since the values are always
0 or 1. */
if (*have_inet & *have_inet6)
/* We can stop early. */
break;
}
__close (fd);
}