Source code for dhcpkit.tests.ipv6.options.test_option_length

Test the implementation of option length checking
import unittest
from struct import pack

from dhcpkit.ipv6.option_registry import option_registry
from dhcpkit.ipv6.options import Option
from dhcpkit.tests.ipv6.options import test_option
from typing import Union

# A dummy option that may not be in a RelayMessageOption
[docs]class LengthTestingOption(Option): """ Fake DHCPv6 option for testing length checks """ option_type = 65535 def __init__(self, data: bytes = b''): = data
[docs] def load_from(self, buffer: bytes, offset: int = 0, length: int = None) -> int: """ Load the internal state of this object from the given buffer. The buffer may contain more data after the structured element is parsed. This data is ignored. :param buffer: The buffer to read data from :param offset: The offset in the buffer where to start reading :param length: The amount of data we are allowed to read from the buffer :return: The number of bytes used from the buffer """ my_offset, option_len = self.parse_option_header(buffer, offset, length, min_length=1, max_length=2) = buffer[offset + my_offset:offset + my_offset + option_len] my_offset += option_len return my_offset
[docs] def save(self) -> Union[bytes, bytearray]: """ Save the internal state of this object as a buffer. :return: The buffer with the data from this element """ return pack('!HH', self.option_type, len( +
[docs]class RelayMessageOptionTestCase(test_option.OptionTestCase):
[docs] def setUp(self): option_registry[65535] = LengthTestingOption self.option_bytes = bytes.fromhex('ffff000161') self.option_object = LengthTestingOption(data=b'a') self.parse_option()
[docs] def tearDown(self): del option_registry[65535]
[docs] def test_bad_option_length(self): with self.assertRaisesRegex(ValueError, 'shorter than the minimum length'): LengthTestingOption.parse(bytes.fromhex('ffff0000')) with self.assertRaisesRegex(ValueError, 'longer than the maximum length'): LengthTestingOption.parse(bytes.fromhex('ffff0003'))
if __name__ == '__main__': # pragma: no cover unittest.main()