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