regression-tests.recursor-dnssec/cookiesoption.py

   1 #!/usr/bin/env python2
   2
   3 import dns
   4 import dns.edns
   5 import dns.flags
   6 import dns.message
   7 import dns.query
   8
   9 class CookiesOption(dns.edns.Option):
  10     """Implementation of draft-ietf-dnsop-cookies-09.
  11     """
  12
  13     def __init__(self, client, server):
  14         super(CookiesOption, self).__init__(10)
  15
  16         if len(client) != 8:
  17             raise Exception('invalid client cookie length')
  18
  19         if server is not None and len(server) != 0 and (len(server) < 8 or len(server) > 32):
  20             raise Exception('invalid server cookie length')
  21
  22         self.client = client
  23         self.server = server
  24
  25     def to_wire(self, file):
  26         """Create EDNS packet as defined in draft-ietf-dnsop-cookies-09."""
  27
  28         file.write(self.client)
  29         if self.server and len(self.server) > 0:
  30             file.write(self.server)
  31
  32     def from_wire(cls, otype, wire, current, olen):
  33         """Read EDNS packet as defined in draft-ietf-dnsop-cookies-09.
  34
  35         Returns:
  36             An instance of CookiesOption based on the EDNS packet
  37         """
  38
  39         data = wire[current:current + olen]
  40         if len(data) != 8 and (len(data) < 16 or len(data) > 40):
  41             raise Exception('Invalid EDNS Cookies option')
  42
  43         client = data[:8]
  44         if len(data) > 8:
  45             server = data[8:]
  46         else:
  47             server = None
  48
  49         return cls(client, server)
  50
  51     from_wire = classmethod(from_wire)
  52
  53     def __repr__(self):
  54         return '%s(%s, %s)' % (
  55             self.__class__.__name__,
  56             self.client,
  57             self.server
  58         )
  59
  60     def __eq__(self, other):
  61         if not isinstance(other, CookiesOption):
  62             return False
  63         if self.client != other.client:
  64             return False
  65         if self.server != other.server:
  66             return False
  67         return True
  68
  69     def __ne__(self, other):
  70         return not self.__eq__(other)
  71
  72
  73 dns.edns._type_to_class[0x000A] = CookiesOption
  74