/* getifaddrs -- get names and addresses of all network interfaces

   Copyright (C) 2002-2018 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 <ifaddrs.h>

#include <net/if.h>

#include <sys/socket.h>

#include <sys/ioctl.h>

#include <unistd.h>

#include <stdlib.h>

#include <string.h>

#include <errno.h>

#include <netinet/in.h>

#include "ifreq.h"

/* Create a linked list of `struct ifaddrs' structures, one for each

   network interface on the host machine.  If successful, store the

   list in *IFAP and return 0.  On errors, return -1 and set `errno'.  */

int

__getifaddrs (struct ifaddrs **ifap)

{

  /* This implementation handles only IPv4 interfaces.

     The various ioctls below will only work on an AF_INET socket.

     Some different mechanism entirely must be used for IPv6.  */

  int fd = __socket (AF_INET, SOCK_DGRAM, 0);

  struct ifreq *ifreqs;

  int nifs;

  if (fd < 0)

    return -1;

  __ifreq (&ifreqs, &nifs, fd);

  if (ifreqs == NULL)		/* XXX doesn't distinguish error vs none */

    {

      __close (fd);

      return -1;

    }

  /* Now we have the list of interfaces and each one's address.

     Put it into the expected format and fill in the remaining details.  */

  if (nifs == 0)

    *ifap = NULL;

  else

    {

      struct

      {

	struct ifaddrs ia;

	struct sockaddr addr, netmask, broadaddr;

	char name[IF_NAMESIZE];

      } *storage;

      struct ifreq *ifr;

      int i;

      storage = malloc (nifs * sizeof storage[0]);

      if (storage == NULL)

	{

	  __close (fd);

	  __if_freereq (ifreqs, nifs);

	  return -1;

	}

      i = 0;

      ifr = ifreqs;

      do

	{

	  /* Fill in pointers to the storage we've already allocated.  */

	  storage[i].ia.ifa_next = &storage[i + 1].ia;

	  storage[i].ia.ifa_addr = &storage[i].addr;

	  /* Now copy the information we already have from SIOCGIFCONF.  */

	  storage[i].ia.ifa_name = strncpy (storage[i].name, ifr->ifr_name,

					    sizeof storage[i].name);

	  storage[i].addr = ifr->ifr_addr;

	  /* The SIOCGIFCONF call filled in only the name and address.

	     Now we must also ask for the other information we need.  */

	  if (__ioctl (fd, SIOCGIFFLAGS, ifr) < 0)

	    break;

	  storage[i].ia.ifa_flags = ifr->ifr_flags;

	  ifr->ifr_addr = storage[i].addr;

	  if (__ioctl (fd, SIOCGIFNETMASK, ifr) < 0)

	    storage[i].ia.ifa_netmask = NULL;

	  else

	    {

	      storage[i].ia.ifa_netmask = &storage[i].netmask;

	      storage[i].netmask = ifr->ifr_netmask;

	    }

	  if (ifr->ifr_flags & IFF_BROADCAST)

	    {

	      ifr->ifr_addr = storage[i].addr;

	      if (__ioctl (fd, SIOCGIFBRDADDR, ifr) < 0)

		storage[i].ia.ifa_broadaddr = NULL;

	      {

		storage[i].ia.ifa_broadaddr = &storage[i].broadaddr;

		storage[i].broadaddr = ifr->ifr_broadaddr;

	      }

	    }

	  else if (ifr->ifr_flags & IFF_POINTOPOINT)

	    {

	      ifr->ifr_addr = storage[i].addr;

	      if (__ioctl (fd, SIOCGIFDSTADDR, ifr) < 0)

		storage[i].ia.ifa_broadaddr = NULL;

	      else

		{

		  storage[i].ia.ifa_broadaddr = &storage[i].broadaddr;

		  storage[i].broadaddr = ifr->ifr_dstaddr;

		}

	    }

	  else

	    storage[i].ia.ifa_broadaddr = NULL;

	  storage[i].ia.ifa_data = NULL; /* Nothing here for now.  */

	  ifr = __if_nextreq (ifr);

	} while (++i < nifs);

      if (i < nifs)		/* Broke out early on error.  */

	{

	  __close (fd);

	  free (storage);

	  __if_freereq (ifreqs, nifs);

	  return -1;

	}

      storage[i - 1].ia.ifa_next = NULL;

      *ifap = &storage[0].ia;

      __close (fd);

      __if_freereq (ifreqs, nifs);

    }

  return 0;

}

weak_alias (__getifaddrs, getifaddrs)

libc_hidden_def (__getifaddrs)

#ifndef getifaddrs

libc_hidden_weak (getifaddrs)

#endif

void

__freeifaddrs (struct ifaddrs *ifa)

{

  free (ifa);

}

weak_alias (__freeifaddrs, freeifaddrs)

libc_hidden_def (__freeifaddrs)

libc_hidden_weak (freeifaddrs)