284 lines
8.3 KiB
Python
284 lines
8.3 KiB
Python
"""Classes and Functions which deal with the APDU Layer."""
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from typing import TypeVar, Type
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from collections import OrderedDict
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from .fields import *
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from .bitmaps import BITMAPS
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# Currencies
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CC_EUR = '0978'
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# Command Classes
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CMD_STD = 0x6 # all standard commands, mostly ecr to pt
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CMD_SERVICE = 0x8 # commands mostly for service. mostly ecr to pt.
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CMD_PT = 0x4 # commands from pt to ecr.
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CMD_STATUS = 0x5 # only seen in 05 01 : status inquiry.
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# from pt to ecr only:
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CMD_RESP_OK = 0x80 # work done
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CMD_RESP_ERROR = 0x84 # work had errors
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class FieldContainer(type):
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@classmethod
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def __prepare__(mcs, name, bases):
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return OrderedDict()
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def __new__(cls, name, bases, classdict):
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retval = super().__new__(cls, name, bases, classdict)
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retval.FIELDS = OrderedDict()
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for supercls in reversed(bases):
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if hasattr(supercls, 'FIELDS'):
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retval.FIELDS.update((k, v) for (k, v) in supercls.FIELDS.items())
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retval.FIELDS.update((k, v) for (k, v) in classdict.items() if isinstance(v, Field))
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have_optional = False
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for k, v in retval.FIELDS.items():
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if v.required:
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if have_optional:
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raise TypeError("Cannot include required field {} after optional fields".format(k))
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else:
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if not v.ignore_parse_error:
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have_optional = True
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return retval
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APDUType = TypeVar('APDUType', bound='APDU')
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class APDU(metaclass=FieldContainer):
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AUTOMATIC_SUBCLASS = True
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REQUIRED_BITMAPS = []
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ALLOWED_BITMAPS = None # None == all
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def __init__(self, *args, **kwargs):
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self._values = {}
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self._bitmaps = OrderedDict()
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for (name, field), arg in zip(self.FIELDS.items(), args):
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setattr(self, name, arg)
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for name, arg in kwargs.items():
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setattr(self, name, arg)
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def as_dict(self):
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return OrderedDict(self.items())
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def items(self):
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return \
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[(name, getattr(self, name)) for (name, field) in self.FIELDS.items() if field in self._values] + \
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[(name, getattr(self, name)) for name in self._bitmaps.keys()]
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def __repr__(self):
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reps = [
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(
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k,
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self.FIELDS[k].represent(v) if k in self.FIELDS
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else BITMAPS[self._bitmaps[k]][0].represent(v) if k in self._bitmaps
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else "{!r}".format(v)
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)
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for (k, v) in self.items()
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]
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return "{}({})".format(
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self.__class__.__name__,
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", ".join(
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"{}={}".format(k, v)
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for (k, v) in reps
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)
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)
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def __getattr__(self, item):
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bmp = self._bitmaps.get(item, None)
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if bmp is None:
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for key, (field, name, description) in BITMAPS.items():
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if item == name:
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self._bitmaps[name] = key
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bmp = key
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if bmp is None:
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raise AttributeError("{!r} object has no attribute {!r}".format(self.__class__.__name__, item))
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return BITMAPS[bmp][0].__get__(self)
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def __delattr__(self, item):
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bmp = self._bitmaps.get(item, None)
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if bmp is not None:
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BITMAPS[bmp][0].__delete__(self)
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super().__delattr__(item)
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def __setattr__(self, item, value):
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if item.startswith('_') or item == "FIELDS" or item in self.FIELDS:
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object.__setattr__(self, item, value)
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return
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bmp = self._bitmaps.get(item, None)
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if bmp is None:
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for key, (field, name, description) in BITMAPS.items():
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if item == name:
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self._bitmaps[name] = key
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bmp = key
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if bmp is not None:
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if self.ALLOWED_BITMAPS is not None and BITMAPS[bmp][1] not in self.ALLOWED_BITMAPS:
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raise AttributeError("Bitmap {:02X} not allowed on {}".format(bmp, self))
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BITMAPS[bmp][0].__set__(self, value)
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else:
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super().__setattr__(item, value)
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@staticmethod
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def compute_length_field(l: int) -> bytes:
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if l < 255:
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return bytes([l])
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if l < 256 * 256 - 1:
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return bytes([0xff, l & 0xff, (l >> 8) & 0xff])
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raise ValueError
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@classmethod
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def _iterate_subclasses(cls):
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for clazz in cls.__subclasses__():
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yield from clazz._iterate_subclasses()
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yield cls
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@classmethod
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def can_parse(cls, data: Union[bytes, List[int]]) -> bool:
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return True
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def parser_hook(self, data: Union[bytes, List[int]]) -> Union[bytes, List[int]]:
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return data
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@classmethod
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def parse(cls: Type[APDUType], data: Union[bytes, List[int]]) -> APDUType:
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data = bytes(data)
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# Find more appropriate subclass and use that
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if cls.AUTOMATIC_SUBCLASS:
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for clazz in cls._iterate_subclasses():
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if clazz.can_parse(data) and clazz is not cls:
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return clazz.parse(data)
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retval = cls()
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if len(data) >= 2:
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retval.control_field = bytearray(data[:2])
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data = data[2:]
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length, data = data[0], data[1:]
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if length == 0xff:
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length, data = data[0] + (data << 8), data[2:]
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data = data[:length]
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data = retval.parser_hook(data)
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for name, field in retval.FIELDS.items():
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if not data:
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break
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try:
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value, data = field.parse(data)
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except ParseError:
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if field.ignore_parse_error:
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continue
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else:
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raise
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setattr(retval, name, value)
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# Try to parse the remainder as bitmaps
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while len(data):
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key = data[0]
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field, name, description = BITMAPS.get(key, (None, None, None))
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if field is None:
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raise ParseError("Invalid bitmap 0x{:02X}".format(key))
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value, data = field.parse(data[1:])
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setattr(retval, name, value)
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# FIXME Mandatory fields.
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return retval
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def serialize(self) -> bytes:
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data = bytearray()
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for name, field in self.FIELDS.items():
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# FIXME: Mandatory fields. Esp. in conjunction with bitmaps (defaults?)
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d = getattr(self, name)
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if d is not None:
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data.extend(field.serialize(d))
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for name, key in self._bitmaps.items():
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d = getattr(self, name)
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if d is not None:
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data.append(key)
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data.extend(BITMAPS[key][0].serialize(d))
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return bytes(self.control_field) + self.compute_length_field(len(data)) + data
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# FIXME Command vs. response vs. packet
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# Is everything a CommandAPDU?
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class CommandAPDU(APDU):
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CMD_CLASS = None
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CMD_INSTR = None
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def __init__(self, *args, **kwargs):
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super().__init__(*args, **kwargs)
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self.control_field = [self.CMD_CLASS, self.CMD_INSTR]
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@classmethod
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def can_parse(cls, data: Union[bytes, List[int]]) -> bool:
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data = bytes(data)
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return len(data) >= 2 and (
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cls.CMD_CLASS is Ellipsis or cls.CMD_CLASS == data[0]
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) and (
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cls.CMD_INSTR is Ellipsis or cls.CMD_INSTR == data[1]
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)
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@property
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def cmd_class(self):
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return self.control_field[0]
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@cmd_class.setter
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def cmd_class(self, v):
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self.control_field[0] = v
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@property
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def cmd_instr(self):
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return self.control_field[1]
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@cmd_instr.setter
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def cmd_instr(self, v):
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self.control_field[1] = v
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class ResponseAPDU(APDU):
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RESP_CCRC = None
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RESP_APRC = None
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def __init__(self, *args, **kwargs):
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super().__init__(*args, **kwargs)
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self.control_field = [self.RESP_CCRC, self.RESP_APRC]
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def can_parse(cls, data: Union[bytes, List[int]]) -> bool:
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data = bytes(data)
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return len(data) >= 2 and (
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cls.RESP_CCRC is Ellipsis or cls.RESP_CCRC == data[0]
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) and (
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cls.RESP_APRC is Ellipsis or cls.RESP_APRC == data[1]
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)
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@property
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def resp_ccrc(self):
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return self.control_field[0]
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@resp_ccrc.setter
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def resp_ccrc(self, v):
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self.control_field[0] = v
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@property
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def resp_aprc(self):
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return self.control_field[1]
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@resp_aprc.setter
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def resp_aprc(self, v):
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self.control_field[1] = v
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