twisted/pair/rawudp.py

   1 # -*- test-case-name: twisted.pair.test.test_rawudp -*-
   2 # Copyright (c) Twisted Matrix Laboratories.
   3 # See LICENSE for details.
   4
   5 #
   6
   7 """Implementation of raw packet interfaces for UDP"""
   8
   9 import struct
  10
  11 from twisted.internet import protocol
  12 from twisted.pair import raw
  13 from zope.interface import implements
  14
  15 class UDPHeader:
  16     def __init__(self, data):
  17
  18         (self.source, self.dest, self.len, self.check) \
  19                  = struct.unpack("!HHHH", data[:8])
  20
  21 class RawUDPProtocol(protocol.AbstractDatagramProtocol):
  22     implements(raw.IRawDatagramProtocol)
  23     def __init__(self):
  24         self.udpProtos = {}
  25
  26     def addProto(self, num, proto):
  27         if not isinstance(proto, protocol.DatagramProtocol):
  28             raise TypeError, 'Added protocol must be an instance of DatagramProtocol'
  29         if num < 0:
  30             raise TypeError, 'Added protocol must be positive or zero'
  31         if num >= 2**16:
  32             raise TypeError, 'Added protocol must fit in 16 bits'
  33         if num not in self.udpProtos:
  34             self.udpProtos[num] = []
  35         self.udpProtos[num].append(proto)
  36
  37     def datagramReceived(self,
  38                          data,
  39                          partial,
  40                          source,
  41                          dest,
  42                          protocol,
  43                          version,
  44                          ihl,
  45                          tos,
  46                          tot_len,
  47                          fragment_id,
  48                          fragment_offset,
  49                          dont_fragment,
  50                          more_fragments,
  51                          ttl):
  52         header = UDPHeader(data)
  53         for proto in self.udpProtos.get(header.dest, ()):
  54             proto.datagramReceived(data[8:],
  55                                    (source, header.source))