commit 3db7fab9c3ea84a68c154a0a33829bbcf5da8cdf Author: Damian Johnson atagar@torproject.org Date: Sat Jan 13 12:07:18 2018 -0800

Have Cell.unpack() provide a list of cells

On reflection ORPort socket responses contain a series of cells, not just one. Changing our unpack function to parse a series. We'll need CERTS, AUTH_CHALLENGE, and NETINFO cell support before we can open links. --- stem/client/cell.py | 33 ++++++++++++++++++++++----------- test/unit/client/__init__.py | 17 +++++++++++++++++ test/unit/client/cell.py | 11 ++++++++--- test/unit/client/data/new_link_cells | Bin 0 -> 2043 bytes 4 files changed, 47 insertions(+), 14 deletions(-)

diff --git a/stem/client/cell.py b/stem/client/cell.py index e29e404f..4d4667d0 100644 --- a/stem/client/cell.py +++ b/stem/client/cell.py @@ -42,7 +42,7 @@ import sys from stem import UNDEFINED from stem.client import ZERO, Size

-MAX_FIXED_PAYLOAD_LEN = 509 +FIXED_PAYLOAD_LEN = 509

class Cell(object): @@ -96,28 +96,39 @@ class Cell(object): @staticmethod def unpack(content, link_version): """ - Unpacks encoded bytes into a Cell subclass. + Unpacks encoded bytes into a series of cells.

:param bytes content: payload to decode :param int link_version: link protocol version

- :returns: :class:`~stem.client.cell.Cell` subclass + :returns: **list** of :class:`~stem.client.cell.Cell` subclasses

:raises: * ValueError if content is malformed * NotImplementedError if unable to unpack this cell type """

- circ_id, content = Size.LONG.pop(content) if link_version > 3 else Size.SHORT.pop(content) - command, content = Size.CHAR.pop(content) - cls = Cell.by_value(command) + cells = []

- if cls.IS_FIXED_SIZE: - payload_len = MAX_FIXED_PAYLOAD_LEN - else: - payload_len, content = Size.SHORT.pop(content) + while content: + circ_id, content = Size.SHORT.pop(content) if link_version < 4 else Size.LONG.pop(content) + command, content = Size.CHAR.pop(content) + cls = Cell.by_value(command) + + if cls.IS_FIXED_SIZE: + payload_len = FIXED_PAYLOAD_LEN + else: + payload_len, content = Size.SHORT.pop(content) + + if len(content) < payload_len: + raise ValueError('%s cell should have a payload of %i bytes, but only had %i' % (cls.NAME, payload_len, len(content))) + + payload = content[:payload_len].rstrip(ZERO) # strip padding + content = content[payload_len:] + + cells.append(cls._unpack(payload, link_version, circ_id))

- return cls._unpack(content, link_version, circ_id) + return cells

@classmethod def _pack(cls, link_version, payload, circ_id = 0): diff --git a/test/unit/client/__init__.py b/test/unit/client/__init__.py index e35416a8..f5b82e7e 100644 --- a/test/unit/client/__init__.py +++ b/test/unit/client/__init__.py @@ -5,3 +5,20 @@ Unit tests for stem.client.* contents. __all__ = [ 'cell', ] + +import os + +TEST_DATA = os.path.join(os.path.dirname(__file__), 'data') + + +def test_data(filename): + """ + Provides test data in the given file. + + :param str filename: test data to provide + + :returns: **bytes** with the data + """ + + with open(os.path.join(TEST_DATA, filename), 'rb') as data_file: + return data_file.read() diff --git a/test/unit/client/cell.py b/test/unit/client/cell.py index 9502975e..3a2a55f2 100644 --- a/test/unit/client/cell.py +++ b/test/unit/client/cell.py @@ -5,6 +5,7 @@ Unit tests for the stem.client.cell. import unittest

from stem.client.cell import Cell, VersionsCell +from test.unit.client import test_data

class TestCell(unittest.TestCase): @@ -31,12 +32,16 @@ class TestCell(unittest.TestCase): def test_unpack_not_implemented(self): self.assertRaisesRegexp(NotImplementedError, 'Unpacking not yet implemented for AUTHORIZE cells', Cell.unpack, '\x00\x00\x84\x00\x06\x00\x01\x00\x02\x00\x03', 2)

+ def test_unpack_for_new_link(self): + # TODO: we need to support more cell types before we can test this + self.assertRaisesRegexp(NotImplementedError, 'Unpacking not yet implemented for CERTS cells', Cell.unpack, test_data('new_link_cells'), 2) + def test_versions_pack(self): self.assertEqual('\x00\x00\x07\x00\x00', VersionsCell.pack([])) self.assertEqual('\x00\x00\x07\x00\x02\x00\x01', VersionsCell.pack([1])) self.assertEqual('\x00\x00\x07\x00\x06\x00\x01\x00\x02\x00\x03', VersionsCell.pack([1, 2, 3]))

def test_versions_unpack(self): - self.assertEqual([], Cell.unpack('\x00\x00\x07\x00\x00', 2).versions) - self.assertEqual([1], Cell.unpack('\x00\x00\x07\x00\x02\x00\x01', 2).versions) - self.assertEqual([1, 2, 3], Cell.unpack('\x00\x00\x07\x00\x06\x00\x01\x00\x02\x00\x03', 2).versions) + self.assertEqual([], Cell.unpack('\x00\x00\x07\x00\x00', 2)[0].versions) + self.assertEqual([1], Cell.unpack('\x00\x00\x07\x00\x02\x00\x01', 2)[0].versions) + self.assertEqual([1, 2, 3], Cell.unpack('\x00\x00\x07\x00\x06\x00\x01\x00\x02\x00\x03', 2)[0].versions) diff --git a/test/unit/client/data/new_link_cells b/test/unit/client/data/new_link_cells new file mode 100644 index 00000000..38e68613 Binary files /dev/null and b/test/unit/client/data/new_link_cells differ