/* Copyright (C) 1997-2018 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, see

   <http://www.gnu.org/licenses/>.  */

#include <alloca.h>

#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 <libc-lock.h>

#include <not-cancel.h>

#include "netlinkaccess.h"

unsigned int

__if_nametoindex (const char *ifname)

{

#ifndef SIOCGIFINDEX

  __set_errno (ENOSYS);

  return 0;

#else

  struct ifreq ifr;

  if (strlen (ifname) >= IFNAMSIZ)

    {

      __set_errno (ENODEV);

      return 0;

    }

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

  int fd = __opensock ();

  if (fd < 0)

    return 0;

  if (__ioctl (fd, SIOCGIFINDEX, &ifr) < 0)

    {

      int saved_errno = errno;

      __close_nocancel_nostatus (fd);

      if (saved_errno == EINVAL)

	__set_errno (ENOSYS);

      return 0;

    }

  __close_nocancel_nostatus (fd);

  return ifr.ifr_ifindex;

#endif

}

libc_hidden_def (__if_nametoindex)

weak_alias (__if_nametoindex, if_nametoindex)

libc_hidden_weak (if_nametoindex)

void

__if_freenameindex (struct if_nameindex *ifn)

{

  struct if_nameindex *ptr = ifn;

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

    {

      free (ptr->if_name);

      ++ptr;

    }

  free (ifn);

}

libc_hidden_def (__if_freenameindex)

weak_alias (__if_freenameindex, if_freenameindex)

libc_hidden_weak (if_freenameindex)

static struct if_nameindex *

if_nameindex_netlink (void)

{

  struct netlink_handle nh = { 0, 0, 0, NULL, NULL };

  struct if_nameindex *idx = NULL;

  if (__netlink_open (&nh) < 0)

    return NULL;

  /* Tell the kernel that we wish to get a list of all

     active interfaces.  Collect all data for every interface.  */

  if (__netlink_request (&nh, RTM_GETLINK) < 0)

    goto exit_free;

  /* Count the interfaces.  */

  unsigned int nifs = 0;

  for (struct netlink_res *nlp = nh.nlm_list; nlp; nlp = nlp->next)

    {

      struct nlmsghdr *nlh;

      size_t size = nlp->size;

      if (nlp->nlh == NULL)

	continue;

      /* Walk through all entries we got from the kernel and look, which

         message type they contain.  */

      for (nlh = nlp->nlh; NLMSG_OK (nlh, size); nlh = NLMSG_NEXT (nlh, size))

	{

	  /* Check if the message is what we want.  */

	  if ((pid_t) nlh->nlmsg_pid != nh.pid || nlh->nlmsg_seq != nlp->seq)

	    continue;

	  if (nlh->nlmsg_type == NLMSG_DONE)

	    break;		/* ok */

	  if (nlh->nlmsg_type == RTM_NEWLINK)

	    ++nifs;

	}

    }

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

  if (idx == NULL)

    {

    nomem:

      __set_errno (ENOBUFS);

      goto exit_free;

    }

  /* Add the interfaces.  */

  nifs = 0;

  for (struct netlink_res *nlp = nh.nlm_list; nlp; nlp = nlp->next)

    {

      struct nlmsghdr *nlh;

      size_t size = nlp->size;

      if (nlp->nlh == NULL)

	continue;

      /* Walk through all entries we got from the kernel and look, which

         message type they contain.  */

      for (nlh = nlp->nlh; NLMSG_OK (nlh, size); nlh = NLMSG_NEXT (nlh, size))

	{

	  /* Check if the message is what we want.  */

	  if ((pid_t) nlh->nlmsg_pid != nh.pid || nlh->nlmsg_seq != nlp->seq)

	    continue;

	  if (nlh->nlmsg_type == NLMSG_DONE)

	    break;		/* ok */

	  if (nlh->nlmsg_type == RTM_NEWLINK)

	    {

	      struct ifinfomsg *ifim = (struct ifinfomsg *) NLMSG_DATA (nlh);

	      struct rtattr *rta = IFLA_RTA (ifim);

	      size_t rtasize = IFLA_PAYLOAD (nlh);

	      idx[nifs].if_index = ifim->ifi_index;

	      while (RTA_OK (rta, rtasize))

		{

		  char *rta_data = RTA_DATA (rta);

		  size_t rta_payload = RTA_PAYLOAD (rta);

		  if (rta->rta_type == IFLA_IFNAME)

		    {

		      idx[nifs].if_name = __strndup (rta_data, rta_payload);

		      if (idx[nifs].if_name == NULL)

			{

			  idx[nifs].if_index = 0;

			  __if_freenameindex (idx);

			  idx = NULL;

			  goto nomem;

			}

		      break;

		    }

		  rta = RTA_NEXT (rta, rtasize);

		}

	      ++nifs;

	    }

	}

    }

  idx[nifs].if_index = 0;

  idx[nifs].if_name = NULL;

 exit_free:

  __netlink_free_handle (&nh);

  __netlink_close (&nh);

  return idx;

}

struct if_nameindex *

__if_nameindex (void)

{

#ifndef SIOCGIFINDEX

  __set_errno (ENOSYS);

  return NULL;

#else

  struct if_nameindex *result = if_nameindex_netlink ();

  return result;

#endif

}

weak_alias (__if_nameindex, if_nameindex)

libc_hidden_weak (if_nameindex)

char *

__if_indextoname (unsigned int ifindex, char *ifname)

{

  /* 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;

  int status;

  fd = __opensock ();

  if (fd < 0)

    return NULL;

  ifr.ifr_ifindex = ifindex;

  status = __ioctl (fd, SIOCGIFNAME, &ifr);

  __close_nocancel_nostatus (fd);

  if (status  < 0)

    {

      if (errno == ENODEV)

	/* POSIX requires ENXIO.  */

	__set_errno (ENXIO);

      return NULL;

    }

  else

    return strncpy (ifname, ifr.ifr_name, IFNAMSIZ);

}

weak_alias (__if_indextoname, if_indextoname)

libc_hidden_weak (if_indextoname)