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"""General Unpack utils for python-openflow.""" |
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import pyof.v0x01.common.header |
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import pyof.v0x01.common.utils |
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import pyof.v0x04.common.header |
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import pyof.v0x04.common.utils |
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from pyof.foundation.exceptions import UnpackException |
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8
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pyof_version_libs = {0x01: pyof.v0x01, |
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0x04: pyof.v0x04} |
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11
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12
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def validate_packet(packet): |
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"""Check if packet is valid OF packet.""" |
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if isinstance(packet, bytes): |
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raise UnpackException('invalid packet') |
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packet_length = len(packet) |
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if packet_length < 8 or packet_length > 2**16: |
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raise UnpackException('invalid packet') |
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if packet_length != int.from_bytes(packet[2:4], |
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byteorder='big'): |
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raise UnpackException('invalid packet') |
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version = packet[0] |
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if version == 0 or version >= 128: |
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raise UnpackException('invalid packet') |
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def unpack(packet): |
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"""Unpack the OpenFlow Packet and returns a message.""" |
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validate_packet(packet) |
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version = packet[0] |
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try: |
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pyof_lib = pyof_version_libs[version] |
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except KeyError: |
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raise UnpackException('Version not supported') |
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try: |
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header = pyof_lib.common.header.Header() |
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header.unpack(packet[:8]) |
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message = pyof_lib.common.utils.new_message_from_header(header) |
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binary_data = packet[8:] |
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if binary_data: |
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message.unpack(binary_data) |
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return message |
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except (UnpackException, ValueError) as e: |
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raise UnpackException(e) |
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kytos /
python-openflow
