path: root/src/dns/dnsparser.c

/*
      This file is part of GNUnet
      Copyright (C) 2010-2014 GNUnet e.V.

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

      GNUnet 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
      Affero General Public License for more details.
     
      You should have received a copy of the GNU Affero General Public License
      along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

/**
 * @file dns/dnsparser.c
 * @brief helper library to parse DNS packets.
 * @author Philipp Toelke
 * @author Christian Grothoff
 */
#include "platform.h"
#include <idna.h>
#if WINDOWS
#include <idn-free.h>
#endif
#include "gnunet_util_lib.h"
#include "gnunet_dnsparser_lib.h"
#include "gnunet_tun_lib.h"


/**
 * Check if a label in UTF-8 format can be coded into valid IDNA.
 * This can fail if the ASCII-conversion becomes longer than 63 characters.
 *
 * @param label label to check (UTF-8 string)
 * @return #GNUNET_OK if the label can be converted to IDNA,
 *         #GNUNET_SYSERR if the label is not valid for DNS names
 */
int
GNUNET_DNSPARSER_check_label (const char *label)
{
  char *output;
  size_t slen;

  if (NULL != strchr (label, '.'))
    return GNUNET_SYSERR; /* not a label! Did you mean GNUNET_DNSPARSER_check_name? */
  if (IDNA_SUCCESS !=
      idna_to_ascii_8z (label, &output, IDNA_ALLOW_UNASSIGNED))
    return GNUNET_SYSERR;
  slen = strlen (output);
#if WINDOWS
  idn_free (output);
#else
  free (output);
#endif
  return (slen > 63) ? GNUNET_SYSERR : GNUNET_OK;
}


/**
 * Check if a label in UTF-8 format can be coded into valid IDNA.
 * This can fail if the ASCII-conversion becomes longer than 253 characters.
 *
 * @param name name to check (UTF-8 string)
 * @return #GNUNET_OK if the label can be converted to IDNA,
 *         #GNUNET_SYSERR if the label is not valid for DNS names
 */
int
GNUNET_DNSPARSER_check_name (const char *name)
{
  char *ldup;
  char *output;
  size_t slen;
  char *tok;

  ldup = GNUNET_strdup (name);
  for (tok = strtok (ldup, "."); NULL != tok; tok = strtok (NULL, "."))
    if (GNUNET_OK !=
	GNUNET_DNSPARSER_check_label (tok))
    {
      GNUNET_free (ldup);
      return GNUNET_SYSERR;
    }
  GNUNET_free (ldup);
  if (IDNA_SUCCESS !=
      idna_to_ascii_8z (name, &output, IDNA_ALLOW_UNASSIGNED))
    return GNUNET_SYSERR;
  slen = strlen (output);
#if WINDOWS
  idn_free (output);
#else
  free (output);
#endif
  return (slen > 253) ? GNUNET_SYSERR : GNUNET_OK;
}


/**
 * Free SOA information record.
 *
 * @param soa record to free
 */
void
GNUNET_DNSPARSER_free_soa (