1  #!/usr/bin/python3
       2  # Generate DNS RR type constants for resolv header files.
       3  # Copyright (C) 2016-2023 Free Software Foundation, Inc.
       4  # This file is part of the GNU C Library.
       5  #
       6  # The GNU C Library is free software; you can redistribute it and/or
       7  # modify it under the terms of the GNU Lesser General Public
       8  # License as published by the Free Software Foundation; either
       9  # version 2.1 of the License, or (at your option) any later version.
      10  #
      11  # The GNU C Library is distributed in the hope that it will be useful,
      12  # but WITHOUT ANY WARRANTY; without even the implied warranty of
      13  # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      14  # Lesser General Public License for more details.
      15  #
      16  # You should have received a copy of the GNU Lesser General Public
      17  # License along with the GNU C Library; if not, see
      18  # <https://www.gnu.org/licenses/>.
      19  
      20  """Generate DNS RR type constants for resolv header files.
      21  
      22  resolv/arpa/nameser.h and resolv/arpa/nameser_compat.h contain lists
      23  of RR type constants.  This script downloads the current definitions
      24  from the IANA DNS Parameters protocol registry and translates it into
      25  the two different lists.
      26  
      27  Two lists are written to standard output.  The first one contains enum
      28  constants for resolv/arpa/nameser.h.  The second one lists the
      29  preprocessor macros for resolv/arpa/nameser_compat.h.
      30  
      31  """
      32  
      33  # URL of the IANA registry.
      34  source = "http://www.iana.org/assignments/dns-parameters/dns-parameters-4.csv"
      35  
      36  import collections
      37  import csv
      38  import io
      39  import urllib.request
      40  
      41  Type = collections.namedtuple("Type", "name number comment")
      42  
      43  def get_types(source):
      44      for row in csv.reader(io.TextIOWrapper(urllib.request.urlopen(source))):
      45          if row[0] in ('TYPE', 'Unassigned', 'Private use', 'Reserved'):
      46              continue
      47          name, number, comment = row[:3]
      48          if name == '*':
      49              name = 'ANY'
      50              comment = 'request for all cached records'
      51          number = int(number)
      52          yield Type(name, number, comment)
      53  
      54  types = list(get_types(source))
      55  
      56  print("// enum constants for resolv/arpa/nameser.h")
      57  print()
      58  for typ in types:
      59      name = typ.name.replace("-", "_").lower()
      60      print("    ns_t_{0} = {1.number},".format(name, typ))
      61  print()
      62  
      63  print("// macro aliases resolv/arpa/nameser_compat.h")
      64  print()
      65  for typ in types:
      66      name = typ.name.replace("-", "_")
      67      print("#define T_{0} ns_t_{1}".format(name.upper(), name.lower()))
      68  print()