commit 73078881ad4ad0908f85915fa6142322a1d86774 Author: Damian Johnson <atagar@torproject.org> Date: Wed Jan 10 10:34:54 2018 -0800 Replace IS_FOR_CIRCUIT with CircuitCell class Adding an intermediate class for the family of cells that concern circuits, rather than a class attribute. --- stem/client/cell.py | 86 ++++++++++++++++++++++-------------------------- test/unit/client/cell.py | 2 -- 2 files changed, 40 insertions(+), 48 deletions(-) diff --git a/stem/client/cell.py b/stem/client/cell.py index e3fb6a71..1f70b685 100644 --- a/stem/client/cell.py +++ b/stem/client/cell.py @@ -28,7 +28,6 @@ class Cell(collections.namedtuple('Cell', ['name', 'value', 'fixed_size', 'for_c NAME = 'UNKNOWN' VALUE = -1 IS_FIXED_SIZE = False - IS_FOR_CIRCUIT = False @staticmethod def by_name(name): @@ -63,37 +62,21 @@ class Cell(collections.namedtuple('Cell', ['name', 'value', 'fixed_size', 'for_c raise ValueError("'%s' isn't a valid cell value" % value) @classmethod - def _pack(cls, link_version, payload, circ_id = None): + def _pack(cls, link_version, payload, circ_id = 0): """ Provides bytes that can be used on the wire for these cell attributes. :param str name: cell command :param int link_version: link protocol version :param bytes payload: cell payload - :param int circ_id: circuit id, if for a circuit + :param int circ_id: circuit id, if a CircuitCell :raise: **ValueError** if... * cell type or circuit id is invalid * payload is too large """ - circ_id_len = Pack.LONG if link_version > 3 else Pack.SHORT - - if cls.IS_FOR_CIRCUIT and circ_id is None: - if cls.NAME.startswith('CREATE'): - # Since we're initiating the circuit we pick any value from a range - # that's determined by our link version. - - circ_id = 0x80000000 if link_version > 3 else 0x01 - else: - raise ValueError('%s cells require a circ_id' % cls.NAME) - elif not cls.IS_FOR_CIRCUIT: - if circ_id: - raise ValueError("%s cells don't concern circuits, circ_id is unused" % cls.NAME) - - circ_id = 0 # field is still mandatory for all cells - - packed_circ_id = struct.pack(circ_id_len, circ_id) + packed_circ_id = struct.pack(Pack.LONG if link_version > 3 else Pack.SHORT, circ_id) packed_command = struct.pack(Pack.CHAR, cls.VALUE) packed_size = b'' if cls.IS_FIXED_SIZE else struct.pack(Pack.SHORT, len(payload)) cell = b''.join((packed_circ_id, packed_command, packed_size, payload)) @@ -111,53 +94,75 @@ class Cell(collections.namedtuple('Cell', ['name', 'value', 'fixed_size', 'for_c return cell +class CircuitCell(Cell): + """ + Cell concerning circuits. + """ + + @classmethod + def _pack(cls, link_version, payload, circ_id): + """ + Provides bytes that can be used on the wire for these cell attributes. + + :param str name: cell command + :param int link_version: link protocol version + :param bytes payload: cell payload + :param int circ_id: circuit id + + :raise: **ValueError** if cell type is invalid or payload is too large + """ + + if circ_id is None and cls.NAME.startswith('CREATE'): + # Since we're initiating the circuit we pick any value from a range + # that's determined by our link version. + + circ_id = 0x80000000 if link_version > 3 else 0x01 + else: + raise ValueError('%s cells require a circ_id' % cls.NAME) + + return Cell._pack(link_version, payload, circ_id) + + class PaddingCell(Cell): NAME = 'PADDING' VALUE = 0 IS_FIXED_SIZE = True - IS_FOR_CIRCUIT = False -class CreateCell(Cell): +class CreateCell(CircuitCell): NAME = 'CREATE' VALUE = 1 IS_FIXED_SIZE = True - IS_FOR_CIRCUIT = True -class CreatedCell(Cell): +class CreatedCell(CircuitCell): NAME = 'CREATED' VALUE = 2 IS_FIXED_SIZE = True - IS_FOR_CIRCUIT = True -class RelayCell(Cell): +class RelayCell(CircuitCell): NAME = 'RELAY' VALUE = 3 IS_FIXED_SIZE = True - IS_FOR_CIRCUIT = True -class DestroyCell(Cell): +class DestroyCell(CircuitCell): NAME = 'DESTROY' VALUE = 4 IS_FIXED_SIZE = True - IS_FOR_CIRCUIT = True -class CreateFastCell(Cell): +class CreateFastCell(CircuitCell): NAME = 'CREATE_FAST' VALUE = 5 IS_FIXED_SIZE = True - IS_FOR_CIRCUIT = True -class CreatedFastCell(Cell): +class CreatedFastCell(CircuitCell): NAME = 'CREATED_FAST' VALUE = 6 IS_FIXED_SIZE = True - IS_FOR_CIRCUIT = True class VersionsCell(Cell): @@ -168,7 +173,6 @@ class VersionsCell(Cell): NAME = 'VERSIONS' VALUE = 7 IS_FIXED_SIZE = False - IS_FOR_CIRCUIT = False @classmethod def pack(cls, versions): @@ -191,70 +195,60 @@ class NetinfoCell(Cell): NAME = 'NETINFO' VALUE = 8 IS_FIXED_SIZE = True - IS_FOR_CIRCUIT = False -class RelayEarlyCell(Cell): +class RelayEarlyCell(CircuitCell): NAME = 'RELAY_EARLY' VALUE = 9 IS_FIXED_SIZE = True - IS_FOR_CIRCUIT = True -class Create2Cell(Cell): +class Create2Cell(CircuitCell): NAME = 'CREATE2' VALUE = 10 IS_FIXED_SIZE = True - IS_FOR_CIRCUIT = True class Created2Cell(Cell): NAME = 'CREATED2' VALUE = 11 IS_FIXED_SIZE = True - IS_FOR_CIRCUIT = False class PaddingNegotiateCell(Cell): NAME = 'PADDING_NEGOTIATE' VALUE = 12 IS_FIXED_SIZE = True - IS_FOR_CIRCUIT = False class VPaddingCell(Cell): NAME = 'VPADDING' VALUE = 128 IS_FIXED_SIZE = False - IS_FOR_CIRCUIT = False class CertsCell(Cell): NAME = 'CERTS' VALUE = 129 IS_FIXED_SIZE = False - IS_FOR_CIRCUIT = False class AuthChallengeCell(Cell): NAME = 'AUTH_CHALLENGE' VALUE = 130 IS_FIXED_SIZE = False - IS_FOR_CIRCUIT = False class AuthenticateCell(Cell): NAME = 'AUTHENTICATE' VALUE = 131 IS_FIXED_SIZE = False - IS_FOR_CIRCUIT = False class AuthorizeCell(Cell): NAME = 'AUTHORIZE' VALUE = 132 IS_FIXED_SIZE = False - IS_FOR_CIRCUIT = False CELL_TYPES = ( diff --git a/test/unit/client/cell.py b/test/unit/client/cell.py index c8161a7e..b688d9e5 100644 --- a/test/unit/client/cell.py +++ b/test/unit/client/cell.py @@ -13,7 +13,6 @@ class TestCell(unittest.TestCase): self.assertEqual('NETINFO', cls.NAME) self.assertEqual(8, cls.VALUE) self.assertEqual(True, cls.IS_FIXED_SIZE) - self.assertEqual(False, cls.IS_FOR_CIRCUIT) self.assertRaises(ValueError, Cell.by_name, 'NOPE') self.assertRaises(ValueError, Cell.by_name, 85) @@ -24,7 +23,6 @@ class TestCell(unittest.TestCase): self.assertEqual('NETINFO', cls.NAME) self.assertEqual(8, cls.VALUE) self.assertEqual(True, cls.IS_FIXED_SIZE) - self.assertEqual(False, cls.IS_FOR_CIRCUIT) self.assertRaises(ValueError, Cell.by_value, 'NOPE') self.assertRaises(ValueError, Cell.by_value, 85)