scripts/gen-rrtypes.py

   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()