/* Enter a network namespace.

   Copyright (C) 2016-2018 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 <support/namespace.h>

#include <net/if.h>

#include <sched.h>

#include <stdio.h>

#include <string.h>

#include <support/check.h>

#include <support/xsocket.h>

#include <support/xunistd.h>

#include <sys/ioctl.h>

#include <unistd.h>

static bool in_uts_namespace;

bool

support_enter_network_namespace (void)

{

#ifdef CLONE_NEWUTS

  if (unshare (CLONE_NEWUTS) == 0)

    in_uts_namespace = true;

  else

    printf ("warning: unshare (CLONE_NEWUTS) failed: %m\n");

#endif

#ifdef CLONE_NEWNET

  if (unshare (CLONE_NEWNET) == 0)

    {

      /* Bring up the loopback interface.  */

      int fd = xsocket (AF_UNIX, SOCK_DGRAM | SOCK_CLOEXEC, 0);

      struct ifreq req;

      strcpy (req.ifr_name, "lo");

      TEST_VERIFY_EXIT (ioctl (fd, SIOCGIFFLAGS, &req) == 0);

      bool already_up = req.ifr_flags & IFF_UP;

      if (already_up)

        /* This means that we likely have not achieved isolation from

           the parent namespace.  */

        printf ("warning: loopback interface already exists"

                " in new network namespace\n");

      else

        {

          req.ifr_flags |= IFF_UP | IFF_RUNNING;

          TEST_VERIFY_EXIT (ioctl (fd, SIOCSIFFLAGS, &req) == 0);

        }

      xclose (fd);

      return !already_up;

    }

#endif

  printf ("warning: could not enter network namespace\n");

  return false;

}

bool

support_in_uts_namespace (void)

{

  return in_uts_namespace;

}