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/* Copyright (C) 1999, 2002 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. */
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <net/if.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <ifreq.h>
/* The FreeBSD ioctl SIOCGIFCONF returns the list if interfaces as a
concatenation of records of different size, each having at least
sizeof (struct ifreq) bytes. */
void
__ifreq (struct ifreq **ifreqs, int *num_ifs, int sockfd)
{
int fd = sockfd;
struct ifconf ifc;
int rq_len;
int nifs;
char *ifstart;
char *ifend;
struct ifreq *ifr;
/* FreeBSD has many interfaces, many of them are usually down. */
# define RQ_IFS 16
/* We have to assume all records are of limited size, so that we know
when we can stop enlarging the buffer. */
# define RQ_MAXSIZE 256
if (fd < 0)
fd = __opensock ();
if (fd < 0)
{
*num_ifs = 0;
*ifreqs = NULL;
return;
}
ifc.ifc_buf = NULL;
rq_len = RQ_IFS * sizeof (struct ifreq) + RQ_MAXSIZE;
for (;;)
{
ifc.ifc_len = rq_len;
ifc.ifc_buf = realloc (ifc.ifc_buf, ifc.ifc_len);
if (ifc.ifc_buf == NULL || __ioctl (fd, SIOCGIFCONF, &ifc) < 0)
{
if (ifc.ifc_buf)
free (ifc.ifc_buf);
if (fd != sockfd)
__close (fd);
*num_ifs = 0;
*ifreqs = NULL;
return;
}
if (ifc.ifc_len + RQ_MAXSIZE <= rq_len)
break;
rq_len *= 2;
}
nifs = 0;
ifstart = (char *) ifc.ifc_buf;
ifend = ifstart + ifc.ifc_len;
for (ifr = (struct ifreq *) ifstart;
(char *) ifr < ifend;
ifr = __if_nextreq (ifr))
nifs++;
if (fd != sockfd)
__close (fd);
*num_ifs = nifs;
*ifreqs = realloc (ifc.ifc_buf, ifc.ifc_len);
}
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