File Content: ethernet.py # -*- test-case-name: twisted.pair.test.test_ethernet -*- # Copyright (c) Twisted Matrix Laboratories. # See LICENSE for details. # """Support for working directly with ethernet frames""" import struct from zope.interface import Interface, implementer from twisted.internet import protocol from twisted.pair import raw class IEthernetProtocol(Interface): """An interface for protocols that handle Ethernet frames""" def addProto(num, proto): """Add an IRawPacketProtocol protocol""" def datagramReceived(data, partial): """An Ethernet frame has been received""" class EthernetHeader: def __init__(self, data): (self.dest, self.source, self.proto) = struct.unpack( "!6s6sH", data[: 6 + 6 + 2] ) @implementer(IEthernetProtocol) class EthernetProtocol(protocol.AbstractDatagramProtocol): def __init__(self): self.etherProtos = {} def addProto(self, num, proto): proto = raw.IRawPacketProtocol(proto) if num < 0: raise TypeError("Added protocol must be positive or zero") if num >= 2 ** 16: raise TypeError("Added protocol must fit in 16 bits") if num not in self.etherProtos: self.etherProtos[num] = [] self.etherProtos[num].append(proto) def datagramReceived(self, data, partial=0): header = EthernetHeader(data[:14]) for proto in self.etherProtos.get(header.proto, ()): proto.datagramReceived( data=data[14:], partial=partial, dest=header.dest, source=header.source, protocol=header.proto, ) Submit