/* Copyright (C) 1997-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   Contributed by H.J. Lu <hjl@gnu.ai.mit.edu>, 1997.

   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 <assert.h>

#include <errno.h>

#include <string.h>

#include <stdlib.h>

#include <ctype.h>

#include <wctype.h>

#include <resolv/resolv-internal.h>

#include <resolv/resolv_context.h>

#include <netdb.h>

#include <arpa/inet.h>

#include "nsswitch.h"

#ifdef USE_NSCD

# include <nscd/nscd_proto.h>

#endif

int

__nss_hostname_digits_dots (const char *name, struct hostent *resbuf,

			    char **buffer, size_t *buffer_size,

			    size_t buflen, struct hostent **result,

			    enum nss_status *status, int af, int *h_errnop)

{

  /* We have to test for the use of IPv6 which can only be done by

     examining `_res'.  */

  struct resolv_context *ctx = __resolv_context_get ();

  if (ctx == NULL)

    {

      if (h_errnop)

	*h_errnop = NETDB_INTERNAL;

      if (buffer_size == NULL)

	*status = NSS_STATUS_TRYAGAIN;

      else

	*result = NULL;

      return -1;

    }

  int ret = __nss_hostname_digits_dots_context

    (ctx, name, resbuf, buffer, buffer_size, buflen,

     result, status, af, h_errnop);

  __resolv_context_put (ctx);

  return ret;

}

int

__nss_hostname_digits_dots_context (struct resolv_context *ctx,

				    const char *name, struct hostent *resbuf,

				    char **buffer, size_t *buffer_size,

				    size_t buflen, struct hostent **result,

				    enum nss_status *status, int af, int *h_errnop)

{

  int save;

  /*

   * disallow names consisting only of digits/dots, unless

   * they end in a dot.

   */

  if (isdigit (name[0]) || isxdigit (name[0]) || name[0] == ':')

    {

      const char *cp;

      char *hostname;

      typedef unsigned char host_addr_t[16];

      host_addr_t *host_addr;

      typedef char *host_addr_list_t[2];

      host_addr_list_t *h_addr_ptrs;

      char **h_alias_ptr;

      size_t size_needed;

      int addr_size;

      switch (af)

	{

	case AF_INET:

	  addr_size = INADDRSZ;

	  break;

	case AF_INET6:

	  addr_size = IN6ADDRSZ;

	  break;

	default:

	  af = res_use_inet6 () ? AF_INET6 : AF_INET;

	  addr_size = af == AF_INET6 ? IN6ADDRSZ : INADDRSZ;

	  break;

	}

      size_needed = (sizeof (*host_addr)

		     + sizeof (*h_addr_ptrs)

		     + sizeof (*h_alias_ptr) + strlen (name) + 1);

      if (buffer_size == NULL)

        {

	  if (buflen < size_needed)

	    {

	      *status = NSS_STATUS_TRYAGAIN;

	      if (h_errnop != NULL)

		*h_errnop = NETDB_INTERNAL;

	      __set_errno (ERANGE);

	      goto done;

	    }

	}

      else if (buffer_size != NULL && *buffer_size < size_needed)

	{

	  char *new_buf;

	  *buffer_size = size_needed;

	  new_buf = (char *) realloc (*buffer, *buffer_size);

	  if (new_buf == NULL)

	    {

	      save = errno;

	      free (*buffer);

	      *buffer = NULL;

	      *buffer_size = 0;

	      __set_errno (save);

	      if (h_errnop != NULL)

		*h_errnop = NETDB_INTERNAL;

	      *result = NULL;

	      goto done;

	    }

	  *buffer = new_buf;

	}

      memset (*buffer, '\0', size_needed);

      host_addr = (host_addr_t *) *buffer;

      h_addr_ptrs = (host_addr_list_t *)

	((char *) host_addr + sizeof (*host_addr));

      h_alias_ptr = (char **) ((char *) h_addr_ptrs + sizeof (*h_addr_ptrs));

      hostname = (char *) h_alias_ptr + sizeof (*h_alias_ptr);

      if (isdigit (name[0]))

	{

	  for (cp = name;; ++cp)

	    {

	      if (*cp == '\0')

		{

		  int ok;

		  if (*--cp == '.')

		    break;

		  /* All-numeric, no dot at the end. Fake up a hostent as if

		     we'd actually done a lookup.  What if someone types

		     255.255.255.255?  The test below will succeed

		     spuriously... ???  */

		  if (af == AF_INET)

		    ok = __inet_aton_exact (name, (struct in_addr *) host_addr);

		  else

		    {

		      assert (af == AF_INET6);

		      ok = inet_pton (af, name, host_addr) > 0;

		    }

		  if (! ok)

		    {

		      *h_errnop = HOST_NOT_FOUND;

		      if (buffer_size == NULL)

			*status = NSS_STATUS_NOTFOUND;

		      else

			*result = NULL;

		      goto done;

		    }

		  resbuf->h_name = strcpy (hostname, name);

		  h_alias_ptr[0] = NULL;

		  resbuf->h_aliases = h_alias_ptr;

		  (*h_addr_ptrs)[0] = (char *) host_addr;

		  (*h_addr_ptrs)[1] = NULL;

		  resbuf->h_addr_list = *h_addr_ptrs;

		  if (af == AF_INET && res_use_inet6 ())

		    {

		      /* We need to change the IP v4 address into the

			 IP v6 address.  */

		      char tmp[INADDRSZ];

		      char *p = (char *) host_addr;

		      int i;

		      /* Save a copy of the IP v4 address. */

		      memcpy (tmp, host_addr, INADDRSZ);

		      /* Mark this ipv6 addr as a mapped ipv4. */

		      for (i = 0; i < 10; i++)

			*p++ = 0x00;

		      *p++ = 0xff;

		      *p++ = 0xff;

		      /* Copy the IP v4 address. */

		      memcpy (p, tmp, INADDRSZ);

		      resbuf->h_addrtype = AF_INET6;

		      resbuf->h_length = IN6ADDRSZ;

		    }

		  else

		    {

		      resbuf->h_addrtype = af;

		      resbuf->h_length = addr_size;

		    }

		  if (h_errnop != NULL)

		    *h_errnop = NETDB_SUCCESS;

		  if (buffer_size == NULL)

		    *status = NSS_STATUS_SUCCESS;

		  else

		    *result = resbuf;

		  goto done;

		}

	      if (!isdigit (*cp) && *cp != '.')

		break;

	    }

	}

      if ((isxdigit (name[0]) && strchr (name, ':') != NULL) || name[0] == ':')

	{

	  switch (af)

	    {

	    default:

	      af = res_use_inet6 () ? AF_INET6 : AF_INET;

	      if (af == AF_INET6)

		{

		  addr_size = IN6ADDRSZ;

		  break;

		}

	      /* FALLTHROUGH */

	    case AF_INET:

	      /* This is not possible.  We cannot represent an IPv6 address

		 in an `struct in_addr' variable.  */

	      *h_errnop = HOST_NOT_FOUND;

	      if (buffer_size == NULL)

		*status = NSS_STATUS_NOTFOUND;

	      else

		*result = NULL;

	      goto done;

	    case AF_INET6:

	      addr_size = IN6ADDRSZ;

	      break;

	    }

	  for (cp = name;; ++cp)

	    {

	      if (!*cp)

		{

		  if (*--cp == '.')

		    break;

		  /* All-IPv6-legal, no dot at the end. Fake up a

		     hostent as if we'd actually done a lookup.  */

		  if (inet_pton (AF_INET6, name, host_addr) <= 0)

		    {

		      *h_errnop = HOST_NOT_FOUND;

		      if (buffer_size == NULL)

			*status = NSS_STATUS_NOTFOUND;

		      else

			*result = NULL;

		      goto done;

		    }

		  resbuf->h_name = strcpy (hostname, name);

		  h_alias_ptr[0] = NULL;

		  resbuf->h_aliases = h_alias_ptr;

		  (*h_addr_ptrs)[0] = (char *) host_addr;

		  (*h_addr_ptrs)[1] = (char *) 0;

		  resbuf->h_addr_list = *h_addr_ptrs;

		  resbuf->h_addrtype = AF_INET6;

		  resbuf->h_length = addr_size;

		  *h_errnop = NETDB_SUCCESS;

		  if (buffer_size == NULL)

		    *status = NSS_STATUS_SUCCESS;

		  else

		    *result = resbuf;

		  goto done;

		}

	      if (!isxdigit (*cp) && *cp != ':' && *cp != '.')

		break;

	    }

	}

    }

  return 0;

done:

  return 1;

}

libc_hidden_def (__nss_hostname_digits_dots)