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https://github.com/skelsec/aardwolf
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skelsec
43 lines
1.2 KiB
Python
43 lines
1.2 KiB
Python
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import io
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from aardwolf.protocol.x224.constants import TPDU_TYPE
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# https://www.itu.int/rec/T-REC-X.224-199511-I/en (13.7)
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class Data:
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def __init__(self):
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# fixed
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self.length = None #here it's always 2
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self.DT:TPDU_TYPE = TPDU_TYPE.DATA
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self.ROA:bool = False #indicates we want ACK for this packet
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self.TPDU_NR = b'\x80'
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self.data = None #remaining data which is not indicated by the length field (most of the data)
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def to_bytes(self):
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t = (self.DT.value << 4 | (int(self.ROA) & 0b0001)).to_bytes(1, byteorder='big', signed = False)
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t += self.TPDU_NR
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t = b'\x02' + t + self.data
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return t
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@staticmethod
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def from_bytes(bbuff: bytes):
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return Data.from_buffer(io.BytesIO(bbuff))
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@staticmethod
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def from_buffer(buff: io.BytesIO):
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# be careful, this consumes the enitre buffer!
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msg = Data()
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msg.length = int.from_bytes(buff.read(1), byteorder='big', signed = False)
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t = buff.read(msg.length)
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msg.DT = TPDU_TYPE(t[0] >> 4)
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msg.ROA = bool(t[0] & 0b0001)
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msg.TPDU_NR = t[1]
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msg.data = buff.read()
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return msg
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def __repr__(self):
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t = '==== Data ====\r\n'
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t += 'length :%s\r\n' % self.length
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t += 'DT :%s\r\n' % self.DT
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t += 'ROA :%s\r\n' % self.ROA
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t += 'data :%s\r\n' % self.data
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return t |