def __init__(self, name, default, *args, **kwargs):
if "implicit_tag" in kwargs:
err_msg = "ASN1F_CHOICE has been called with an implicit_tag"
raise ASN1_Error(err_msg)
self.implicit_tag = None
for kwarg in ["context", "explicit_tag"]:
setattr(self, kwarg, kwargs.get(kwarg))
ASN1F_field.__init__(self,
name,
None,
context=self.context,
explicit_tag=self.explicit_tag)
self.default = default
self.current_choice = None
self.choices = {}
self.pktchoices = {}
for p in args:
if hasattr(p, "ASN1_root"): # should be ASN1_Packet
if hasattr(p.ASN1_root, "choices"):
for k, v in six.iteritems(p.ASN1_root.choices):
self.choices[k] = v # ASN1F_CHOICE recursion
else:
self.choices[p.ASN1_root.network_tag] = p
elif hasattr(p, "ASN1_tag"):
if isinstance(p, type): # should be ASN1F_field class
self.choices[p.ASN1_tag] = p
else: # should be ASN1F_PACKET instance
self.choices[p.network_tag] = p
self.pktchoices[hash(p.cls)] = (p.implicit_tag,
p.explicit_tag
) # noqa: E501
else:
raise ASN1_Error("ASN1F_CHOICE: no tag found for one field")
def m2i(self, pkt, s):
"""
First we have to retrieve the appropriate choice.
Then we extract the field/packet, according to this choice.
"""
if len(s) == 0:
raise ASN1_Error("ASN1F_CHOICE: got empty string")
_, s = BER_tagging_dec(s,
hidden_tag=self.ASN1_tag,
explicit_tag=self.explicit_tag)
tag, _ = BER_id_dec(s)
if tag not in self.choices:
if self.flexible_tag:
choice = ASN1F_field
else:
raise ASN1_Error("ASN1F_CHOICE: unexpected field")
else:
choice = self.choices[tag]
if hasattr(choice, "ASN1_root"):
# we don't want to import ASN1_Packet in this module...
return self.extract_packet(choice, s)
elif isinstance(choice, type):
# XXX find a way not to instantiate the ASN1F_field
return choice(self.name, b"").m2i(pkt, s)
else:
# XXX check properly if this is an ASN1F_PACKET
return choice.m2i(pkt, s)
def m2i(self, pkt, s):
# type: (ASN1_Packet, bytes) -> Tuple[ASN1_Object[Any], bytes]
"""
First we have to retrieve the appropriate choice.
Then we extract the field/packet, according to this choice.
"""
if len(s) == 0:
raise ASN1_Error("ASN1F_CHOICE: got empty string")
_, s = BER_tagging_dec(s,
hidden_tag=self.ASN1_tag,
explicit_tag=self.explicit_tag)
tag, _ = BER_id_dec(s)
if tag in self.choices:
choice = self.choices[tag]
else:
if tag & 0x1f in self.choices: # Try resolve only the tag number
choice = self.choices[tag & 0x1f]
elif self.flexible_tag:
choice = ASN1F_field
else:
raise ASN1_Error("ASN1F_CHOICE: unexpected field in '%s' "
"(tag %s not in possible tags %s)" %
(self.name, tag, list(self.choices.keys())))
if hasattr(choice, "ASN1_root"):
choice = cast('ASN1_Packet', choice)
# we don't want to import ASN1_Packet in this module...
return self.extract_packet(choice, s, _underlayer=pkt)
elif isinstance(choice, type):
return choice(self.name, b"").m2i(pkt, s)
else:
# XXX check properly if this is an ASN1F_PACKET
return choice.m2i(pkt, s)
def __init__(
self,
name, # type: str
default, # type: Optional[_A]
context=None, # type: Optional[Type[ASN1_Class]]
implicit_tag=None, # type: Optional[int]
explicit_tag=None, # type: Optional[int]
flexible_tag=False, # type: Optional[bool]
):
# type: (...) -> None
if context is not None:
self.context = context
self.name = name
if default is None:
self.default = default # type: Optional[_A]
elif isinstance(default, ASN1_NULL):
self.default = default # type: ignore
else:
self.default = self.ASN1_tag.asn1_object(default) # type: ignore
self.flexible_tag = flexible_tag
if (implicit_tag is not None) and (explicit_tag is not None):
err_msg = "field cannot be both implicitly and explicitly tagged"
raise ASN1_Error(err_msg)
self.implicit_tag = implicit_tag
self.explicit_tag = explicit_tag
# network_tag gets useful for ASN1F_CHOICE
self.network_tag = int(implicit_tag or explicit_tag or self.ASN1_tag)
def __init__(self, name, default, *args, **kwargs):
# type: (str, Any, *_CHOICE_T, **Any) -> None
if "implicit_tag" in kwargs:
err_msg = "ASN1F_CHOICE has been called with an implicit_tag"
raise ASN1_Error(err_msg)
self.implicit_tag = None
for kwarg in ["context", "explicit_tag"]:
setattr(self, kwarg, kwargs.get(kwarg))
super(ASN1F_CHOICE, self).__init__(name,
None,
context=self.context,
explicit_tag=self.explicit_tag)
self.default = default
self.current_choice = None
self.choices = {} # type: Dict[int, _CHOICE_T]
self.pktchoices = {}
for p in args:
if hasattr(p, "ASN1_root"):
p = cast('ASN1_Packet', p)
# should be ASN1_Packet
if hasattr(p.ASN1_root, "choices"):
root = cast(ASN1F_CHOICE, p.ASN1_root)
for k, v in six.iteritems(root.choices):
# ASN1F_CHOICE recursion
self.choices[k] = v
else:
self.choices[p.ASN1_root.network_tag] = p
elif hasattr(p, "ASN1_tag"):
p = cast(Union[ASN1F_PACKET, Type[ASN1F_field[Any, Any]]], p)
if isinstance(p, type):
# should be ASN1F_field class
self.choices[int(p.ASN1_tag)] = p
else:
# should be ASN1F_field instance
self.choices[p.network_tag] = p
if p.implicit_tag is not None:
self.choices[p.implicit_tag & 0x1f] = p
self.pktchoices[hash(p.cls)] = (p.implicit_tag,
p.explicit_tag
) # noqa: E501
else:
raise ASN1_Error("ASN1F_CHOICE: no tag found for one field")
def i2m(self, pkt, x):
# type: (ASN1_Packet, Union[bytes, _I, _A]) -> bytes
if x is None:
return b""
if isinstance(x, ASN1_Object):
if (self.ASN1_tag == ASN1_Class_UNIVERSAL.ANY or
x.tag == ASN1_Class_UNIVERSAL.RAW or
x.tag == ASN1_Class_UNIVERSAL.ERROR or
self.ASN1_tag == x.tag):
s = x.enc(pkt.ASN1_codec)
else:
raise ASN1_Error("Encoding Error: got %r instead of an %r for field [%s]" % (x, self.ASN1_tag, self.name)) # noqa: E501
else:
s = self.ASN1_tag.get_codec(pkt.ASN1_codec).enc(x)
return BER_tagging_enc(s, implicit_tag=self.implicit_tag,
explicit_tag=self.explicit_tag)
def __init__(self,
name,
default,
context=None,
implicit_tag=None,
explicit_tag=None,
flexible_tag=False):
self.context = context
self.name = name
if default is None:
self.default = None
elif isinstance(default, ASN1_NULL):
self.default = default
else:
self.default = self.ASN1_tag.asn1_object(default)
self.flexible_tag = flexible_tag
if (implicit_tag is not None) and (explicit_tag is not None):
err_msg = "field cannot be both implicitly and explicitly tagged"
raise ASN1_Error(err_msg)
self.implicit_tag = implicit_tag
self.explicit_tag = explicit_tag
# network_tag gets useful for ASN1F_CHOICE
self.network_tag = implicit_tag or explicit_tag or self.ASN1_tag
