djbdns/common.py

   1 r"""
   2 Information needed to parse *both* tinydns and dnscache logs.
   3 """
   4 from struct import pack
   5
   6 # A pattern to match the timestamp format that the tai64nlocal program
   7 # produces. It appears in both dnscache and tinydns lines, after
   8 # they've been piped through tai64nlocal, of course.
   9 TIMESTAMP_PAT = r'[\d-]+ [\d:\.]+'
  10
  11 # A dictionary mapping query type identifiers, in decimal, to their
  12 # friendly names for tinydns. Reference:
  13 #
  14 #   https://en.wikipedia.org/wiki/List_of_DNS_record_types
  15 #
  16 # Note that mapping here is non-exhaustive, and that tinydns will
  17 # log responses for record types that it does not know about.
  18 QUERY_TYPE_NAME = {
  19       1: "a",
  20       2: "ns",
  21       5: "cname",
  22       6: "soa",
  23      12: "ptr",
  24      13: "hinfo",
  25      15: "mx",
  26      16: "txt",
  27      17: "rp",
  28      24: "sig",
  29      25: "key",
  30      28: "aaaa",
  31      33: "srv",
  32      35: "naptr",
  33      38: "a6",
  34      48: "dnskey",
  35      52: "tlsa",
  36      65: "https",
  37     252: "axfr",
  38     255: "any",
  39     257: "caa"
  40 }
  41
  42 def convert_ip(ip : str) -> str:
  43     r"""
  44     Convert a hex string representing an IP address to
  45     human-readable form.
  46
  47     Parameters
  48     ----------
  49
  50     ip : str
  51         The hexadecimal representation of either an IPv4 or an IPv6
  52         address.
  53
  54     Returns
  55     -------
  56
  57     The usual decimal dotted-quad representation is returned for an
  58     IPv4 address. IPv6 addresses are returned almost as-is, but with
  59     colons inserted in the appropriate places, between every four
  60     characters.
  61
  62     Examples
  63     --------
  64
  65         >>> convert_ip("7f000001")
  66         '127.0.0.1'
  67         >>> convert_ip("00000000000000000000ffff7f000001")
  68         '0000:0000:0000:0000:0000:ffff:7f00:0001'
  69     """
  70     if len(ip) == 8:
  71         # IPv4, eg. "7f000001" -> "7f 00 00 01" -> "127.0.0.1"
  72         return ".".join(map(str, pack(">L", int(ip, 16))))
  73
  74     # IPv6 is actually simpler -- it's just a string-slicing operation.
  75     return ":".join([ip[(4*i) : (4*i+4)] for i in range(8)])