djbdns/common.py

   1 from struct import pack
   2
   3 # A pattern to match the timestamp format that the tai64nlocal program
   4 # produces. It appears in both dnscache and tinydns lines, after
   5 # they've been piped through tai64nlocal, of course.
   6 timestamp_pat = r'[\d-]+ [\d:\.]+'
   7
   8 # A dictionary mapping query type identifiers, in decimal, to their
   9 # friendly names for tinydns. Reference:
  10 #
  11 #   https://en.wikipedia.org/wiki/List_of_DNS_record_types
  12 #
  13 # Note that mapping here is non-exhaustive, and that tinydns will
  14 # log responses for record types that it does not know about.
  15 query_type_name = {
  16       1: "a",
  17       2: "ns",
  18       5: "cname",
  19       6: "soa",
  20      12: "ptr",
  21      13: "hinfo",
  22      15: "mx",
  23      16: "txt",
  24      17: "rp",
  25      24: "sig",
  26      25: "key",
  27      28: "aaaa",
  28      33: "srv",
  29      35: "naptr",
  30      38: "a6",
  31      48: "dnskey",
  32      52: "tlsa",
  33      65: "https",
  34     252: "axfr",
  35     255: "any",
  36     257: "caa"
  37 }
  38
  39 def convert_ip(ip : str) -> str:
  40     r"""
  41     Convert a hex string representing an IP address to
  42     human-readable form.
  43
  44     Parameters
  45     ----------
  46
  47     ip : str
  48         The hexadecimal representation of either an IPv4 or an IPv6
  49         address.
  50
  51     Returns
  52     -------
  53
  54     The usual decimal dotted-quad representation is returned for an
  55     IPv4 address. IPv6 addresses are returned almost as-is, but with
  56     colons inserted in the appropriate places, between every four
  57     characters.
  58
  59     Examples
  60     --------
  61
  62         >>> convert_ip("7f000001")
  63         '127.0.0.1'
  64         >>> convert_ip("00000000000000000000ffff7f000001")
  65         '0000:0000:0000:0000:0000:ffff:7f00:0001'
  66     """
  67     if len(ip) == 8:
  68         # IPv4, eg. "7f000001" -> "7f 00 00 01" -> "127.0.0.1"
  69         return ".".join(map(str, pack(">L", int(ip, 16))))
  70
  71     # IPv6 is actually simpler -- it's just a string-slicing operation.
  72     return ":".join([ip[(4*i) : (4*i+4)] for i in range(8)])