# Copyright 2024 Google LLC
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
from __future__ import absolute_import
import unittest
try:
from unittest import mock
except ImportError:
import mock
import construct
from pebble.pulse2 import ppp, exceptions
from .fake_timer import FakeTimer
from . import timer_helper
class TestPPPEncapsulation(unittest.TestCase):
def test_ppp_encapsulate(self):
self.assertEqual(ppp.encapsulate(0xc021, b'Information'),
b'\xc0\x21Information')
class TestPPPUnencapsulate(unittest.TestCase):
def test_ppp_unencapsulate(self):
protocol, information = ppp.unencapsulate(b'\xc0\x21Information')
self.assertEqual((protocol, information), (0xc021, b'Information'))
def test_unencapsulate_empty_frame(self):
with self.assertRaises(ppp.UnencapsulationError):
ppp.unencapsulate(b'')
def test_unencapsulate_too_short_frame(self):
with self.assertRaises(ppp.UnencapsulationError):
ppp.unencapsulate(b'\x21')
def test_unencapsulate_empty_information(self):
protocol, information = ppp.unencapsulate(b'\xc0\x21')
self.assertEqual((protocol, information), (0xc021, b''))
class TestConfigurationOptionsParser(unittest.TestCase):
def test_no_options(self):
options = ppp.OptionList.parse(b'')
self.assertEqual(len(options), 0)
def test_one_empty_option(self):
options = ppp.OptionList.parse(b'\xaa\x02')
self.assertEqual(len(options), 1)
self.assertEqual(options[0].type, 0xaa)
self.assertEqual(options[0].data, b'')
def test_one_option_with_length(self):
options = ppp.OptionList.parse(b'\xab\x07Data!')
self.assertEqual((0xab, b'Data!'), options[0])
def test_multiple_options_empty_first(self):
options = ppp.OptionList.parse(b'\x22\x02\x23\x03a\x21\x04ab')
self.assertEqual([(0x22, b''), (0x23, b'a'), (0x21, b'ab')], options)
def test_multiple_options_dataful_first(self):
options = ppp.OptionList.parse(b'\x31\x08option\x32\x02')
self.assertEqual([(0x31, b'option'), (0x32, b'')], options)
def test_option_with_length_too_short(self):
with self.assertRaises(ppp.ParseError):
ppp.OptionList.parse(b'\x41\x01')
def test_option_list_with_malformed_option(self):
with self.assertRaises(ppp.ParseError):
ppp.OptionList.parse(b'\x0a\x02\x0b\x01\x0c\x03a')
def test_truncated_terminal_option(self):
with self.assertRaises(ppp.ParseError):
ppp.OptionList.parse(b'\x61\x02\x62\x03a\x63\x0ccandleja')
class TestConfigurationOptionsBuilder(unittest.TestCase):
def test_no_options(self):
serialized = ppp.OptionList.build([])
self.assertEqual(b'', serialized)
def test_one_empty_option(self):
serialized = ppp.OptionList.build([ppp.Option(0xaa, b'')])
self.assertEqual(b'\xaa\x02', serialized)
def test_one_option_with_length(self):
serialized = ppp.OptionList.build([ppp.Option(0xbb, b'Data!')])
self.assertEqual(b'\xbb\x07Data!', serialized)
def test_two_options(self):
serialized = ppp.OptionList.build([
ppp.Option(0xcc, b'foo'), ppp.Option(0xdd, b'xyzzy')])
self.assertEqual(b'\xcc\x05foo\xdd\x07xyzzy', serialized)
class TestLCPEnvelopeParsing(unittest.TestCase):
def test_packet_no_padding(self):
parsed = ppp.LCPEncapsulation.parse(b'\x01\xab\x00\x0aabcdef')
self.assertEqual(parsed.code, 1)
self.assertEqual(parsed.identifier, 0xab)
self.assertEqual(parsed.data, b'abcdef')
self.assertEqual(parsed.padding, b'')
def test_padding(self):
parsed = ppp.LCPEncapsulation.parse(b'\x01\xab\x00\x0aabcdefpadding')
self.assertEqual(parsed.data, b'abcdef')
self.assertEqual(parsed.padding, b'padding')
def test_truncated_packet(self):
with self.assertRaises(ppp.ParseError):
ppp.LCPEncapsulation.parse(b'\x01\xab\x00\x0aabcde')
def test_bogus_length(self):
with self.assertRaises(ppp.ParseError):
ppp.LCPEncapsulation.parse(b'\x01\xbc\x00\x03')
def test_empty_data(self):
parsed = ppp.LCPEncapsulation.parse(b'\x03\x01\x00\x04')
self.assertEqual((3, 1, b'', b''), parsed)
class TestLCPEnvelopeBuilder(unittest.TestCase):
def test_build_empty_data(self):
serialized = ppp.LCPEncapsulation.build(1, 0xfe, b'')
self.assertEqual(b'\x01\xfe\x00\x04', serialized)
def test_build_with_data(self):
serialized = ppp.LCPEncapsulation.build(3, 0x2a, b'Hello, world!')
self.assertEqual(b'\x03\x2a\x00\x11Hello, world!', serialized)
class TestProtocolRejectParsing(unittest.TestCase):
def test_protocol_and_info(self):
self.assertEqual((0xabcd, b'asdfasdf'),
ppp.ProtocolReject.parse(b'\xab\xcdasdfasdf'))
def test_empty_info(self):
self.assertEqual((0xf00d, b''),
ppp.ProtocolReject.parse(b'\xf0\x0d'))
def test_truncated_packet(self):
with self.assertRaises(ppp.ParseError):
ppp.ProtocolReject.parse(b'\xab')
class TestMagicNumberAndDataParsing(unittest.TestCase):
def test_magic_and_data(self):
self.assertEqual(
(0xabcdef01, b'datadata'),
ppp.MagicNumberAndData.parse(b'\xab\xcd\xef\x01datadata'))
def test_magic_no_data(self):
self.assertEqual(
(0xfeedface, b''),
ppp.MagicNumberAndData.parse(b'\xfe\xed\xfa\xce'))
def test_truncated_packet(self):
with self.assertRaises(ppp.ParseError):
ppp.MagicNumberAndData.parse(b'abc')
class TestMagicNumberAndDataBuilder(unittest.TestCase):
def test_build_empty_data(self):
serialized = ppp.MagicNumberAndData.build(0x12345678, b'')
self.assertEqual(b'\x12\x34\x56\x78', serialized)
def test_build_with_data(self):
serialized = ppp.MagicNumberAndData.build(0xabcdef01, b'foobar')
self.assertEqual(b'\xab\xcd\xef\x01foobar', serialized)
def test_build_with_named_attributes(self):
serialized = ppp.MagicNumberAndData.build(magic_number=0, data=b'abc')
self.assertEqual(b'\0\0\0\0abc', serialized)
class TestControlProtocolRestartTimer(unittest.TestCase):
def setUp(self):
FakeTimer.clear_timer_list()
timer_patcher = mock.patch('threading.Timer', new=FakeTimer)
timer_patcher.start()
self.addCleanup(timer_patcher.stop)
self.uut = ppp.ControlProtocol()
self.uut.timeout_retry = mock.Mock()
self.uut.timeout_giveup = mock.Mock()
self.uut.restart_count = 5
def test_timeout_event_called_if_generation_ids_match(self):
self.uut.restart_timer_expired(self.uut.restart_timer_generation_id)
self.uut.timeout_retry.assert_called_once_with()
def test_timeout_event_not_called_if_generation_ids_mismatch(self):
self.uut.restart_timer_expired(42)
self.uut.timeout_retry.assert_not_called()
self.uut.timeout_giveup.assert_not_called()
def test_timeout_event_not_called_after_stopped(self):
self.uut.start_restart_timer(1)
self.uut.stop_restart_timer()
FakeTimer.TIMERS[-1].expire()
self.uut.timeout_retry.assert_not_called()
self.uut.timeout_giveup.assert_not_called()
def test_timeout_event_not_called_from_old_timer_after_restart(self):
self.uut.start_restart_timer(1)
zombie_timer = FakeTimer.get_active_timers()[-1]
self.uut.start_restart_timer(1)
zombie_timer.expire()
self.uut.timeout_retry.assert_not_called()
self.uut.timeout_giveup.assert_not_called()
def test_timeout_event_called_only_once_after_restart(self):
self.uut.start_restart_timer(1)
self.uut.start_restart_timer(1)
for timer in FakeTimer.TIMERS:
timer.expire()
self.uut.timeout_retry.assert_called_once_with()
self.uut.timeout_giveup.assert_not_called()
class InstrumentedControlProtocol(ppp.ControlProtocol):
methods_to_mock = (
'this_layer_up this_layer_down this_layer_started '
'this_layer_finished send_packet start_restart_timer '
'stop_restart_timer').split()
attributes_to_mock = ('restart_timer',)
def __init__(self):
ppp.ControlProtocol.__init__(self)
for method in self.methods_to_mock:
setattr(self, method, mock.Mock())
for attr in self.attributes_to_mock:
setattr(self, attr, mock.NonCallableMock())
class ControlProtocolTestMixin(object):
CONTROL_CODE_ENUM = ppp.ControlCode
def _map_control_code(self, code):
try:
return int(code)
except ValueError:
return self.CONTROL_CODE_ENUM[code].value
def assert_packet_sent(self, code, identifier, body=b''):
self.fsm.send_packet.assert_called_once_with(
ppp.LCPEncapsulation.build(
self._map_control_code(code), identifier, body))
self.fsm.send_packet.reset_mock()
def incoming_packet(self, code, identifier, body=b''):
self.fsm.packet_received(
ppp.LCPEncapsulation.build(self._map_control_code(code),
identifier, body))
class TestControlProtocolFSM(ControlProtocolTestMixin, unittest.TestCase):
def setUp(self):
self.addCleanup(timer_helper.cancel_all_timers)
self.fsm = InstrumentedControlProtocol()
def test_open_down(self):
self.fsm.open()
self.fsm.this_layer_started.assert_called_once_with()
self.fsm.this_layer_up.assert_not_called()
self.fsm.this_layer_down.assert_not_called()
self.fsm.this_layer_finished.assert_not_called()
def test_closed_up(self):
self.fsm.up(mock.Mock())
self.fsm.this_layer_up.assert_not_called()
self.fsm.this_layer_down.assert_not_called()
self.fsm.this_layer_started.assert_not_called()
self.fsm.this_layer_finished.assert_not_called()
def test_trivial_handshake(self):
self.fsm.open()
self.fsm.up(mock.Mock())
self.assert_packet_sent('Configure_Request', 0)
self.incoming_packet('Configure_Ack', 0)
self.incoming_packet('Configure_Request', 17)
self.assert_packet_sent('Configure_Ack', 17)
self.assertEqual('Opened', self.fsm.state)
self.assertTrue(self.fsm.this_layer_up.called)
self.assertEqual(self.fsm.restart_count, self.fsm.max_configure)
def test_terminate_cleanly(self):
self.test_trivial_handshake()
self.fsm.close()
self.fsm.this_layer_down.assert_called_once_with()
self.assert_packet_sent('Terminate_Request', 42)
def test_remote_terminate(self):
self.test_trivial_handshake()
self.incoming_packet('Terminate_Request', 42)
self.assert_packet_sent('Terminate_Ack', 42)
self.assertTrue(self.fsm.this_layer_down.called)
self.assertTrue(self.fsm.start_restart_timer.called)
self.fsm.this_layer_finished.assert_not_called()
self.fsm.restart_timer_expired(self.fsm.restart_timer_generation_id)
self.assertTrue(self.fsm.this_layer_finished.called)
self.assertEqual('Stopped', self.fsm.state)
def test_remote_rejects_configure_request_code(self):
self.fsm.open()
self.fsm.up(mock.Mock())
received_packet = self.fsm.send_packet.call_args[0][0]
self.assert_packet_sent('Configure_Request', 0)
self.incoming_packet('Code_Reject', 3, received_packet)
self.assertEqual('Stopped', self.fsm.state)
self.assertTrue(self.fsm.this_layer_finished.called)
def test_receive_extended_code(self):
self.fsm.handle_unknown_code = mock.Mock()
self.test_trivial_handshake()
self.incoming_packet(42, 11, b'Life, the universe and everything')
self.fsm.handle_unknown_code.assert_called_once_with(
42, 11, b'Life, the universe and everything')
def test_receive_unimplemented_code(self):
self.test_trivial_handshake()
self.incoming_packet(0x55, 0)
self.assert_packet_sent('Code_Reject', 0, b'\x55\0\0\x04')
def test_code_reject_truncates_rejected_packet(self):
self.test_trivial_handshake()
self.incoming_packet(0xaa, 0x20, 'a'*1496) # 1500-byte Info
self.assert_packet_sent('Code_Reject', 0,
b'\xaa\x20\x05\xdc' + b'a'*1492)
def test_code_reject_identifier_changes(self):
self.test_trivial_handshake()
self.incoming_packet(0xaa, 0)
self.assert_packet_sent('Code_Reject', 0, b'\xaa\0\0\x04')
self.incoming_packet(0xaa, 0)
self.assert_packet_sent('Code_Reject', 1, b'\xaa\0\0\x04')
# Local events: up, down, open, close
# Option negotiation: reject, nak
# Exceptional situations: catastrophic code-reject
# Restart negotiation after opening
# Remote Terminate-Req, -Ack at various points in the lifecycle
# Negotiation infinite loop
# Local side gives up on negotiation
# Corrupt packets received
class TestLCPReceiveEchoRequest(ControlProtocolTestMixin, unittest.TestCase):
CONTROL_CODE_ENUM = ppp.LCPCode
def setUp(self):
self.addCleanup(timer_helper.cancel_all_timers)
self.fsm = ppp.LinkControlProtocol(mock.Mock())
self.fsm.send_packet = mock.Mock()
self.fsm.state = 'Opened'
def send_echo_request(self, identifier=0, data=b'\0\0\0\0'):
result = self.fsm.handle_unknown_code(
ppp.LCPCode.Echo_Request.value, identifier, data)
self.assertIsNot(result, NotImplemented)
def test_echo_request_is_dropped_when_not_in_opened_state(self):
self.fsm.state = 'Ack-Sent'
self.send_echo_request()
self.fsm.send_packet.assert_not_called()
def test_echo_request_elicits_reply(self):
self.send_echo_request()
self.assert_packet_sent('Echo_Reply', 0, b'\0\0\0\0')
def test_echo_request_with_data_is_echoed_in_reply(self):
self.send_echo_request(5, b'\0\0\0\0datadata')
self.assert_packet_sent('Echo_Reply', 5, b'\0\0\0\0datadata')
def test_echo_request_missing_magic_number_field_is_dropped(self):
self.send_echo_request(data=b'')
self.fsm.send_packet.assert_not_called()
def test_echo_request_with_nonzero_magic_number_is_dropped(self):
self.send_echo_request(data=b'\0\0\0\x01')
self.fsm.send_packet.assert_not_called()
class TestLCPPing(ControlProtocolTestMixin, unittest.TestCase):
CONTROL_CODE_ENUM = ppp.LCPCode
def setUp(self):
FakeTimer.clear_timer_list()
timer_patcher = mock.patch('threading.Timer', new=FakeTimer)
timer_patcher.start()
self.addCleanup(timer_patcher.stop)
self.fsm = ppp.LinkControlProtocol(mock.Mock())
self.fsm.send_packet = mock.Mock()
self.fsm.state = 'Opened'
def respond_to_ping(self):
[echo_request_packet], _ = self.fsm.send_packet.call_args
self.assertEqual(b'\x09'[0], echo_request_packet[0])
echo_response_packet = b'\x0a' + echo_request_packet[1:]
self.fsm.packet_received(echo_response_packet)
def test_ping_when_lcp_is_not_opened_is_an_error(self):
cb = mock.Mock()
self.fsm.state = 'Ack-Rcvd'
with self.assertRaises(ppp.LinkStateError):
self.fsm.ping(cb)
cb.assert_not_called()
def test_zero_attempts_is_an_error(self):
with self.assertRaises(ValueError):
self.fsm.ping(mock.Mock(), attempts=0)
def test_negative_attempts_is_an_error(self):
with self.assertRaises(ValueError):
self.fsm.ping(mock.Mock(), attempts=-1)
def test_zero_timeout_is_an_error(self):
with self.assertRaises(ValueError):
self.fsm.ping(mock.Mock(), timeout=0)
def test_negative_timeout_is_an_error(self):
with self.assertRaises(ValueError):
self.fsm.ping(mock.Mock(), timeout=-0.1)
def test_straightforward_ping(self):
cb = mock.Mock()
self.fsm.ping(cb)
cb.assert_not_called()
self.assertEqual(1, self.fsm.send_packet.call_count)
self.respond_to_ping()
cb.assert_called_once_with(True)
def test_one_timeout_before_responding(self):
cb = mock.Mock()
self.fsm.ping(cb, attempts=2)
FakeTimer.TIMERS[-1].expire()
cb.assert_not_called()
self.assertEqual(2, self.fsm.send_packet.call_count)
self.respond_to_ping()
cb.assert_called_once_with(True)
def test_one_attempt_with_no_reply(self):
cb = mock.Mock()
self.fsm.ping(cb, attempts=1)
FakeTimer.TIMERS[-1].expire()
self.assertEqual(1, self.fsm.send_packet.call_count)
cb.assert_called_once_with(False)
def test_multiple_attempts_with_no_reply(self):
cb = mock.Mock()
self.fsm.ping(cb, attempts=2)
timer_one = FakeTimer.TIMERS[-1]
timer_one.expire()
timer_two = FakeTimer.TIMERS[-1]
self.assertIsNot(timer_one, timer_two)
timer_two.expire()
self.assertEqual(2, self.fsm.send_packet.call_count)
cb.assert_called_once_with(False)
def test_late_reply(self):
cb = mock.Mock()
self.fsm.ping(cb, attempts=1)
FakeTimer.TIMERS[-1].expire()
self.respond_to_ping()
cb.assert_called_once_with(False)
def test_this_layer_down_during_ping(self):
cb = mock.Mock()
self.fsm.ping(cb)
self.fsm.this_layer_down()
FakeTimer.TIMERS[-1].expire()
cb.assert_not_called()
def test_echo_reply_with_wrong_identifier(self):
cb = mock.Mock()
self.fsm.ping(cb, attempts=1)
[echo_request_packet], _ = self.fsm.send_packet.call_args
echo_response_packet = bytearray(echo_request_packet)
echo_response_packet[0] = 0x0a
echo_response_packet[1] += 1
self.fsm.packet_received(bytes(echo_response_packet))
cb.assert_not_called()
FakeTimer.TIMERS[-1].expire()
cb.assert_called_once_with(False)
def test_echo_reply_with_wrong_data(self):
cb = mock.Mock()
self.fsm.ping(cb, attempts=1)
[echo_request_packet], _ = self.fsm.send_packet.call_args
# Generate a syntactically valid Echo-Reply with the right
# identifier but completely different data.
identifier = bytearray(echo_request_packet)[1]
echo_response_packet = bytes(
b'\x0a' + bytearray([identifier]) +
b'\0\x26\0\0\0\0bad reply bad reply bad reply.')
self.fsm.packet_received(bytes(echo_response_packet))
cb.assert_not_called()
FakeTimer.TIMERS[-1].expire()
cb.assert_called_once_with(False)
def test_successive_pings_use_different_identifiers(self):
self.fsm.ping(mock.Mock(), attempts=1)
[echo_request_packet_1], _ = self.fsm.send_packet.call_args
identifier_1 = bytearray(echo_request_packet_1)[1]
self.respond_to_ping()
self.fsm.ping(mock.Mock(), attempts=1)
[echo_request_packet_2], _ = self.fsm.send_packet.call_args
identifier_2 = bytearray(echo_request_packet_2)[1]
self.assertNotEqual(identifier_1, identifier_2)
def test_unsolicited_echo_reply_doesnt_break_anything(self):
self.fsm.packet_received(b'\x0a\0\0\x08\0\0\0\0')
def test_malformed_echo_reply(self):
cb = mock.Mock()
self.fsm.ping(cb, attempts=1)
# Only three bytes of Magic-Number
self.fsm.packet_received(b'\x0a\0\0\x07\0\0\0')
cb.assert_not_called()
# Trying to start a second ping while the first ping is still happening
def test_starting_a_ping_while_another_is_active_is_an_error(self):
cb = mock.Mock()
self.fsm.ping(cb, attempts=1)
cb2 = mock.Mock()
with self.assertRaises(exceptions.AlreadyInProgressError):
self.fsm.ping(cb2, attempts=1)
FakeTimer.TIMERS[-1].expire()
cb.assert_called_once_with(False)
cb2.assert_not_called()
# General tests:
# - Length too short for a valid packet
# - Packet truncated (length field > packet len)
# - Packet with padding
# OptionList codes:
# 1 Configure-Request
# 2 Configure-Ack
# 3 Configure-Nak
# 4 Configure-Reject
# Raw data codes:
# 5 Terminate-Request
# 6 Terminate-Ack
# 7 Code-Reject
# 8 Protocol-Reject
# - Empty Rejected-Information field
# - Rejected-Protocol field too short
# Magic number + data codes:
# 10 Echo-Reply
# 11 Discard-Request
# 12 Identification (RFC 1570)