69 lines
2.0 KiB
Python
69 lines
2.0 KiB
Python
# −*− coding: UTF−8 −*−
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#/**
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# * Software Name : pycrate
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# * Version : 0.4
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# *
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# * Copyright 2019. Benoit Michau. P1Sec.
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# *
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# * This library is free software; you can redistribute it and/or
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# * modify it under the terms of the GNU Lesser General Public
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# * License as published by the Free Software Foundation; either
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# * version 2.1 of the License, or (at your option) any later version.
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# *
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# * This library is distributed in the hope that it will be useful,
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# * but WITHOUT ANY WARRANTY; without even the implied warranty of
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# * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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# * Lesser General Public License for more details.
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# *
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# * You should have received a copy of the GNU Lesser General Public
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# * License along with this library; if not, write to the Free Software
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# * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
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# * MA 02110-1301 USA
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# *
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# *--------------------------------------------------------
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# * File Name : pycrate_ether/MPLS.py
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# * Created : 2019-07-02
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# * Authors : Benoit Michau
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# *--------------------------------------------------------
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#*/
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from pycrate_core.elt import Envelope, Sequence, REPR_RAW, REPR_HEX, REPR_BIN
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from pycrate_core.base import *
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from pycrate_core.repr import *
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class MPLSLabel(Envelope):
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_GEN = (
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Uint('Label', bl=20),
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Uint('Exp', bl=3),
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Uint('S', bl=1),
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Uint8('TTL')
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)
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def __init__(self, *args, **kwargs):
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Envelope.__init__(self, *args, **kwargs)
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self[2].set_valauto(lambda: self._s_set())
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def _s_set(self):
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n = self.get_next()
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if n and isinstance(n, self.__class__):
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self[2].set_val(0)
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else:
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self[2].set_val(1)
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class MPLSHeader(Envelope):
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_GEN = (
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MPLSLabel(),
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)
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def _from_char(self, char):
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if self.get_trans():
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return
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self.__init__()
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self[0]._from_char(char)
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while char.len_bit() >= 32 and self[-1]['S']() == 0:
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self.append( MPLSLabel() )
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self[-1]._from_char(char)
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