/usr/lib/python2.7/dist-packages/impacket/IP6_Extension_Headers.py is in python-impacket 0.9.15-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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#
# This software is provided under under a slightly modified version
# of the Apache Software License. See the accompanying LICENSE file
# for more information.
#
import array
from ImpactPacket import Header, ImpactPacketException, PacketBuffer
class IP6_Extension_Header(Header):
# --------------------------------- - - - - - - -
# | Next Header | Header Ext Len | Options
# --------------------------------- - - - - - - -
HEADER_TYPE_VALUE = -1
EXTENSION_HEADER_FIELDS_SIZE = 2
EXTENSION_HEADER_DECODER = None
def __init__(self, buffer = None):
Header.__init__(self, self.get_headers_field_size())
self._option_list = []
if buffer:
self.load_header(buffer)
else:
self.reset()
def __str__(self):
header_type = self.get_header_type()
next_header_value = self.get_next_header()
header_ext_length = self.get_header_extension_length()
s = "Header Extension Name: " + self.__class__.HEADER_EXTENSION_DESCRIPTION + "\n"
s += "Header Type Value: " + str(header_type) + "\n"
s += "Next Header: " + str(next_header_value) + "\n"
s += "Header Extension Length: " + str(header_ext_length) + "\n"
s += "Options:\n"
for option in self._option_list:
option_str = str(option)
option_str = option_str.split('\n')
option_str = map(lambda s: (' ' * 4) + s, option_str)
s += '\n'.join(option_str) + '\n'
return s
def load_header(self, buffer):
self.set_bytes_from_string(buffer[:self.get_headers_field_size()])
remaining_bytes = (self.get_header_extension_length() + 1) * 8
remaining_bytes -= self.get_headers_field_size()
buffer = array.array('B', buffer[self.get_headers_field_size():])
if remaining_bytes > len(buffer):
raise ImpactPacketException, "Cannot load options from truncated packet"
while remaining_bytes > 0:
option_type = buffer[0]
if option_type == Option_PAD1.OPTION_TYPE_VALUE:
# Pad1
self._option_list.append(Option_PAD1())
remaining_bytes -= 1
buffer = buffer[1:]
else:
# PadN
# From RFC 2460: For N octets of padding, the Opt Data Len
# field contains the value N-2, and the Option Data consists
# of N-2 zero-valued octets.
option_length = buffer[1]
option_length += 2
self._option_list.append(Option_PADN(option_length))
remaining_bytes -= option_length
buffer = buffer[option_length:]
def reset(self):
pass
@classmethod
def get_header_type_value(cls):
return cls.HEADER_TYPE_VALUE
@classmethod
def get_extension_headers(cls):
header_types = {}
for subclass in cls.__subclasses__():
subclass_header_types = subclass.get_extension_headers()
if not subclass_header_types:
# If the subclass did not return anything it means
# that it is a leaf subclass, so we take its header
# type value
header_types[subclass.get_header_type_value()] = subclass
else:
# Else we extend the list of the obtained types
header_types.update(subclass_header_types)
return header_types
@classmethod
def get_decoder(cls):
raise RuntimeError("Class method %s.get_decoder must be overridden." % cls)
def get_header_type(self):
return self.__class__.get_header_type_value()
def get_headers_field_size(self):
return IP6_Extension_Header.EXTENSION_HEADER_FIELDS_SIZE
def get_header_size(self):
header_size = self.get_headers_field_size()
for option in self._option_list:
header_size += option.get_len()
return header_size
def get_next_header(self):
return self.get_byte(0)
def get_header_extension_length(self):
return self.get_byte(1)
def set_next_header(self, next_header):
self.set_byte(0, next_header & 0xFF)
def set_header_extension_length(self, header_extension_length):
self.set_byte(1, header_extension_length & 0xFF)
def add_option(self, option):
self._option_list.append(option)
def get_options(self):
return self._option_list
def get_packet(self):
data = self.get_data_as_string()
# Update the header length
self.set_header_extension_length(self.get_header_size() / 8 - 1)
# Build the entire extension header packet
header_bytes = self.get_buffer_as_string()
for option in self._option_list:
header_bytes += option.get_buffer_as_string()
if data:
return header_bytes + data
else:
return header_bytes
def contains(self, aHeader):
Header.contains(self, aHeader)
if isinstance(aHeader, IP6_Extension_Header):
self.set_next_header(aHeader.get_header_type())
def get_pseudo_header(self):
# The pseudo-header only contains data from the IPv6 header.
# So we pass the message to the parent until it reaches it.
return self.parent().get_pseudo_header()
class Extension_Option(PacketBuffer):
MAX_OPTION_LEN = 256
OPTION_TYPE_VALUE = -1
def __init__(self, option_type, size):
if size > Extension_Option.MAX_OPTION_LEN:
raise ImpactPacketException, "Option size of % is greater than the maximum of %d" % (size, Extension_Option.MAX_OPTION_LEN)
PacketBuffer.__init__(self, size)
self.set_option_type(option_type)
def __str__(self):
option_type = self.get_option_type()
option_length = self.get_option_length()
s = "Option Name: " + str(self.__class__.OPTION_DESCRIPTION) + "\n"
s += "Option Type: " + str(option_type) + "\n"
s += "Option Length: " + str(option_length) + "\n"
return s
def set_option_type(self, option_type):
self.set_byte(0, option_type)
def get_option_type(self):
return self.get_byte(0)
def set_option_length(self, length):
self.set_byte(1, length)
def get_option_length(self):
return self.get_byte(1)
def set_data(self, data):
self.set_option_length(len(data))
option_bytes = self.get_bytes()
option_bytes = self.get_bytes()
option_bytes[2:2+len(data)] = array.array('B', data)
self.set_bytes(option_bytes)
def get_len(self):
return len(self.get_bytes())
class Option_PAD1(Extension_Option):
OPTION_TYPE_VALUE = 0x00 # Pad1 (RFC 2460)
OPTION_DESCRIPTION = "Pad1 Option"
def __init__(self):
Extension_Option.__init__(self, Option_PAD1.OPTION_TYPE_VALUE, 1)
def get_len(self):
return 1
class Option_PADN(Extension_Option):
OPTION_TYPE_VALUE = 0x01 # Pad1 (RFC 2460)
OPTION_DESCRIPTION = "PadN Option"
def __init__(self, padding_size):
if padding_size < 2:
raise ImpactPacketException, "PadN Extension Option must be greater than 2 bytes"
Extension_Option.__init__(self, Option_PADN.OPTION_TYPE_VALUE, padding_size)
self.set_data('\x00' * (padding_size - 2))
class Basic_Extension_Header(IP6_Extension_Header):
MAX_OPTIONS_LEN = 256 * 8
MIN_HEADER_LEN = 8
MAX_HEADER_LEN = MIN_HEADER_LEN + MAX_OPTIONS_LEN
def __init__(self, buffer = None):
self.padded = False
IP6_Extension_Header.__init__(self, buffer)
def reset(self):
self.set_next_header(0)
self.set_header_extension_length(0)
self.add_padding()
def add_option(self, option):
if self.padded:
self._option_list.pop()
self.padded = False
IP6_Extension_Header.add_option(self, option)
self.add_padding()
def add_padding(self):
required_octets = 8 - (self.get_header_size() % 8)
if self.get_header_size() + required_octets > Basic_Extension_Header.MAX_HEADER_LEN:
raise Exception("Not enough space for the padding")
# Insert Pad1 or PadN to fill the necessary octets
if 0 < required_octets < 8:
if required_octets == 1:
self.add_option(Option_PAD1())
else:
self.add_option(Option_PADN(required_octets))
self.padded = True
else:
self.padded = False
class Hop_By_Hop(Basic_Extension_Header):
HEADER_TYPE_VALUE = 0x00
HEADER_EXTENSION_DESCRIPTION = "Hop By Hop Options"
@classmethod
def get_decoder(self):
import ImpactDecoder
return ImpactDecoder.HopByHopDecoder
class Destination_Options(Basic_Extension_Header):
HEADER_TYPE_VALUE = 0x3c
HEADER_EXTENSION_DESCRIPTION = "Destination Options"
@classmethod
def get_decoder(self):
import ImpactDecoder
return ImpactDecoder.DestinationOptionsDecoder
class Routing_Options(IP6_Extension_Header):
HEADER_TYPE_VALUE = 0x2b
HEADER_EXTENSION_DESCRIPTION = "Routing Options"
ROUTING_OPTIONS_HEADER_FIELDS_SIZE = 8
def reset(self):
self.set_next_header(0)
self.set_header_extension_length(0)
self.set_routing_type(0)
self.set_segments_left(0)
def __str__(self):
header_type = self.get_header_type()
next_header_value = self.get_next_header()
header_ext_length = self.get_header_extension_length()
routing_type = self.get_routing_type()
segments_left = self.get_segments_left()
s = "Header Extension Name: " + self.__class__.HEADER_EXTENSION_DESCRIPTION + "\n"
s += "Header Type Value: " + str(header_type) + "\n"
s += "Next Header: " + str(next_header_value) + "\n"
s += "Header Extension Length: " + str(header_ext_length) + "\n"
s += "Routing Type: " + str(routing_type) + "\n"
s += "Segments Left: " + str(segments_left) + "\n"
return s
@classmethod
def get_decoder(self):
import ImpactDecoder
return ImpactDecoder.RoutingOptionsDecoder
def get_headers_field_size(self):
return Routing_Options.ROUTING_OPTIONS_HEADER_FIELDS_SIZE
def set_routing_type(self, routing_type):
self.set_byte(2, routing_type)
def get_routing_type(self):
return self.get_byte(2)
def set_segments_left(self, segments_left):
self.set_byte(3, segments_left)
def get_segments_left(self):
return self.get_byte(3)
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