/*
  Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009,
  2010, 2011, 2012, 2013, 2014 Free Software Foundation, Inc.

  This file is part of GNU Inetutils.

  GNU Inetutils is free software: you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 3 of the License, or (at
  your option) any later version.

  GNU Inetutils 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
  General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program.  If not, see `http://www.gnu.org/licenses/'. */

#include <config.h>

#include <errno.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>

/* Solaris at least earlier 2.6 and before does not include
   the ioctl definitions if BSD_COMP is not set.  */
#if defined __svr4__
# define BSD_COMP 1
#endif

#include <sys/ioctl.h>
#include <net/if.h>

#ifndef HAVE_STRUCT_IF_NAMEINDEX
unsigned int
if_nametoindex (const char *ifname)
{
  int result = 0;
#ifdef SIOCGIFINDEX
  {
    int fd = socket (AF_INET, SOCK_DGRAM, 0);
    if (fd >= 0)
      {
	int rc;
	struct ifreq ifr;
	strncpy (ifr.ifr_name, ifname, sizeof (ifr.ifr_name));
	ifr.ifr_name[IFNAMSIZ - 1] = '\0';
	rc = ioctl (fd, SIOCGIFINDEX, &ifr);
	close (fd);
	if (rc == 0)
	  return ifr.ifr_index;
      }
  }
#endif
  {
    struct if_nameindex *idx;
    idx = if_nameindex ();
    if (idx != NULL)
      {
	struct if_nameindex *p;
	for (p = idx; p->if_index || p->if_name; ++p)
	  {
	    if (strncmp (p->if_name, ifname, IFNAMSIZ) == 0)
	      {
		result = p->if_index;
		break;
	      }
	  }
	if_freenameindex (idx);
      }
    return result;
  }
}

void
if_freenameindex (struct if_nameindex *ifn)
{
  struct if_nameindex *ptr = ifn;
  if (!ifn)
    return;
  while (ptr->if_name || ptr->if_index)
    {
      free (ptr->if_name);
      ++ptr;
    }
  free (ifn);
}

struct if_nameindex *
if_nameindex (void)
{
#if defined SIOCGIFCONF
  int fd = socket (AF_INET, SOCK_DGRAM, 0);
  struct ifconf ifc;
  unsigned int i = 0;
  int rq_len, last_len;
  struct if_nameindex *idx = NULL;
  struct ifreq *ifr, *end, *cur;

  if (fd < 0)
    return NULL;

  /* A first estimate.  */
  rq_len = 4 * sizeof (struct ifreq);

  ifc.ifc_buf = NULL;
  ifc.ifc_len = 0;
  /* Read all the interfaces out of the kernel.  */
  do
    {
      last_len = ifc.ifc_len;
      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 != last_len);

  i = 0;
  ifr = (struct ifreq *) ifc.ifc_req;
  end = (struct ifreq *) ((caddr_t) ifr + ifc.ifc_len);
  while (ifr < end)
    {
      cur = ifr;

      ++ifr;

      /* We ignore the other families .. OK ?  */
      if (cur->ifr_addr.sa_family != AF_INET)
	continue;

      /* Make Room safely.  */
      {
	struct if_nameindex *tidx = NULL;
	tidx = realloc (idx, (i + 1) * sizeof (*idx));
	if (tidx == NULL)
	  {
	    if_freenameindex (idx);
	    close (fd);
	    errno = ENOBUFS;
	    return NULL;
	  }
	idx = tidx;
      }

      /* FIXME: We did not deal with duplicates or interface aliases.  */

      idx[i].if_name = strdup (cur->ifr_name);
      if (idx[i].if_name == NULL)
	{
	  if_freenameindex (idx);
	  close (fd);
	  errno = ENOBUFS;
	  return NULL;
	}

# if defined SIOCGIFINDEX
      if (ioctl (fd, SIOCGIFINDEX, cur) >= 0)
	idx[i].if_index = cur->ifr_index;
      else
# endif
	idx[i].if_index = i + 1;
      i++;
    }

  /* Terminate the array with an empty solt.  */
  {
    struct if_nameindex *tidx = NULL;
    tidx = realloc (idx, (i + 1) * sizeof (*idx));
    if (tidx == NULL)
      {
	if_freenameindex (idx);
	close (fd);
	errno = ENOBUFS;
	return NULL;
      }
    idx = tidx;
  }
  idx[i].if_index = 0;
  idx[i].if_name = NULL;

  close (fd);
  return idx;

#else
  errno = ENOSYS;
  return NULL;
#endif
}
#endif
