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"""Test Multiplexer channels."""
import asyncio
import ipaddress
from unittest.mock import patch
import pytest
import snitun
from snitun.exceptions import MultiplexerTransportClose, MultiplexerTransportError
from snitun.multiplexer import channel as channel_module
from snitun.multiplexer.channel import ChannelFlowControlBase, MultiplexerChannel
from snitun.multiplexer.const import (
OUTGOING_QUEUE_HIGH_WATERMARK,
OUTGOING_QUEUE_LOW_WATERMARK,
OUTGOING_QUEUE_MAX_BYTES_CHANNEL,
)
from snitun.multiplexer.message import (
CHANNEL_FLOW_CLOSE,
CHANNEL_FLOW_DATA,
CHANNEL_FLOW_NEW,
CHANNEL_FLOW_PAUSE,
CHANNEL_FLOW_RESUME,
HEADER_SIZE,
MultiplexerChannelId,
MultiplexerMessage,
)
from snitun.multiplexer.queue import MultiplexerMultiChannelQueue
from snitun.utils.ipaddress import ip_address_to_bytes
IP_ADDR = ipaddress.ip_address("8.8.8.8")
async def test_initial_channel_msg() -> None:
"""Test new MultiplexerChannel with id."""
output = MultiplexerMultiChannelQueue(
OUTGOING_QUEUE_MAX_BYTES_CHANNEL,
OUTGOING_QUEUE_LOW_WATERMARK,
OUTGOING_QUEUE_HIGH_WATERMARK,
)
channel = MultiplexerChannel(output, IP_ADDR, snitun.PROTOCOL_VERSION)
assert isinstance(channel.id, MultiplexerChannelId)
message = channel.init_new()
assert message.id == channel.id
assert message.flow_type == CHANNEL_FLOW_NEW
assert message.data == b""
assert message.extra == b"4" + ip_address_to_bytes(IP_ADDR)
async def test_close_channel_msg() -> None:
"""Test close MultiplexerChannel."""
output = MultiplexerMultiChannelQueue(
OUTGOING_QUEUE_MAX_BYTES_CHANNEL,
OUTGOING_QUEUE_LOW_WATERMARK,
OUTGOING_QUEUE_HIGH_WATERMARK,
)
channel = MultiplexerChannel(output, IP_ADDR, snitun.PROTOCOL_VERSION)
assert isinstance(channel.id, MultiplexerChannelId)
message = channel.init_close()
assert message.id == channel.id
assert message.flow_type == CHANNEL_FLOW_CLOSE
assert message.data == b""
async def test_write_data() -> None:
"""Test send data over MultiplexerChannel."""
output = MultiplexerMultiChannelQueue(
OUTGOING_QUEUE_MAX_BYTES_CHANNEL,
OUTGOING_QUEUE_LOW_WATERMARK,
OUTGOING_QUEUE_HIGH_WATERMARK,
)
channel = MultiplexerChannel(output, IP_ADDR, snitun.PROTOCOL_VERSION)
assert isinstance(channel.id, MultiplexerChannelId)
await channel.write(b"test")
assert not output.empty(channel.id)
message = output.get_nowait()
assert message.id == channel.id
assert message.flow_type == CHANNEL_FLOW_DATA
assert message.data == b"test"
async def test_closing() -> None:
"""Test send data over MultiplexerChannel."""
output = MultiplexerMultiChannelQueue(
OUTGOING_QUEUE_MAX_BYTES_CHANNEL,
OUTGOING_QUEUE_LOW_WATERMARK,
OUTGOING_QUEUE_HIGH_WATERMARK,
)
channel = MultiplexerChannel(output, IP_ADDR, snitun.PROTOCOL_VERSION)
assert isinstance(channel.id, MultiplexerChannelId)
assert not channel.closing
channel.close()
assert channel.closing
async def test_write_data_after_close() -> None:
"""Test send data over MultiplexerChannel."""
output = MultiplexerMultiChannelQueue(
OUTGOING_QUEUE_MAX_BYTES_CHANNEL,
OUTGOING_QUEUE_LOW_WATERMARK,
OUTGOING_QUEUE_HIGH_WATERMARK,
)
channel = MultiplexerChannel(output, IP_ADDR, snitun.PROTOCOL_VERSION)
assert isinstance(channel.id, MultiplexerChannelId)
assert not channel.closing
channel.close()
with pytest.raises(MultiplexerTransportClose):
await channel.write(b"test")
assert channel.closing
async def test_write_data_empty() -> None:
"""Test send data over MultiplexerChannel."""
output = MultiplexerMultiChannelQueue(
OUTGOING_QUEUE_MAX_BYTES_CHANNEL,
OUTGOING_QUEUE_LOW_WATERMARK,
OUTGOING_QUEUE_HIGH_WATERMARK,
)
channel = MultiplexerChannel(output, IP_ADDR, snitun.PROTOCOL_VERSION)
assert isinstance(channel.id, MultiplexerChannelId)
with pytest.raises(MultiplexerTransportError):
await channel.write(b"")
async def test_read_data() -> None:
"""Test send data over MultiplexerChannel."""
output = MultiplexerMultiChannelQueue(
OUTGOING_QUEUE_MAX_BYTES_CHANNEL,
OUTGOING_QUEUE_LOW_WATERMARK,
OUTGOING_QUEUE_HIGH_WATERMARK,
)
channel = MultiplexerChannel(output, IP_ADDR, snitun.PROTOCOL_VERSION)
assert isinstance(channel.id, MultiplexerChannelId)
message = MultiplexerMessage(channel.id, CHANNEL_FLOW_DATA, b"test")
channel.message_transport(message)
data = await channel.read()
assert data == b"test"
async def test_read_data_on_close() -> None:
"""Test send data over MultiplexerChannel on close."""
output = MultiplexerMultiChannelQueue(
OUTGOING_QUEUE_MAX_BYTES_CHANNEL,
OUTGOING_QUEUE_LOW_WATERMARK,
OUTGOING_QUEUE_HIGH_WATERMARK,
)
channel = MultiplexerChannel(output, IP_ADDR, snitun.PROTOCOL_VERSION)
assert isinstance(channel.id, MultiplexerChannelId)
assert not channel.closing
channel.close()
with pytest.raises(MultiplexerTransportClose):
await channel.read()
assert channel.closing
async def test_write_data_peer_error(raise_timeout: None) -> None:
"""Test send data over MultiplexerChannel but peer don't response."""
output = MultiplexerMultiChannelQueue(1, 1, 1)
channel = MultiplexerChannel(output, IP_ADDR, snitun.PROTOCOL_VERSION)
assert isinstance(channel.id, MultiplexerChannelId)
# fill peer queue
output.put_nowait(channel.id, None)
with pytest.raises(MultiplexerTransportError):
await channel.write(b"test")
async def test_message_transport_never_lock() -> None:
"""Message transport should never lock down even when it goes unhealthy."""
output = MultiplexerMultiChannelQueue(1, 1, 1)
with patch.object(channel_module, "INCOMING_QUEUE_MAX_BYTES_CHANNEL", 1):
channel = MultiplexerChannel(output, IP_ADDR, snitun.PROTOCOL_VERSION)
assert isinstance(channel.id, MultiplexerChannelId)
assert not channel.unhealthy
assert not channel.closing
for _ in range(3):
channel.message_transport(channel.init_close())
assert channel.unhealthy
async def test_write_throttling() -> None:
"""Message transport should never lock down."""
loop = asyncio.get_running_loop()
output = MultiplexerMultiChannelQueue(500, 1, 100)
channel = MultiplexerChannel(
output,
IP_ADDR,
snitun.PROTOCOL_VERSION,
throttling=0.1,
)
assert isinstance(channel.id, MultiplexerChannelId)
message = b"test"
message_size = HEADER_SIZE + len(message)
async def _write_background():
"""Write message in background."""
for _ in range(1, 10000):
await channel.write(message)
background_task = loop.create_task(_write_background())
await asyncio.sleep(0.3)
assert not background_task.done()
assert output.size(channel.id) <= message_size * 4
background_task.cancel()
with pytest.raises(asyncio.CancelledError):
await background_task
async def test_channel_input_queue_goes_under_water() -> None:
"""Test when a channel input queue goes under water.
The channel should inform the peer to pause the reader.
"""
output = MultiplexerMultiChannelQueue(
HEADER_SIZE * 2,
HEADER_SIZE,
HEADER_SIZE * 2,
)
with (
patch.object(
channel_module,
"INCOMING_QUEUE_MAX_BYTES_CHANNEL",
HEADER_SIZE * 10,
),
patch.object(channel_module, "INCOMING_QUEUE_LOW_WATERMARK", HEADER_SIZE),
patch.object(channel_module, "INCOMING_QUEUE_HIGH_WATERMARK", HEADER_SIZE * 2),
):
channel = MultiplexerChannel(output, IP_ADDR, snitun.PROTOCOL_VERSION)
assert isinstance(channel.id, MultiplexerChannelId)
# Fake some data coming from the remote
data_msg = MultiplexerMessage(channel.id, CHANNEL_FLOW_DATA)
channel.message_transport(data_msg)
channel.message_transport(data_msg)
# The input queue is now under water
assert channel._input._under_water
# We should have told the remote to pause
assert output.get_nowait() == MultiplexerMessage(channel.id, CHANNEL_FLOW_PAUSE)
await channel.read() == data_msg.data
# The input queue is now back to normal
# We should have told the remote to resume
assert output.get_nowait() == MultiplexerMessage(channel.id, CHANNEL_FLOW_RESUME)
async def test_channel_input_queue_goes_under_water_output_full(
caplog: pytest.LogCaptureFixture,
) -> None:
"""Test when a channel input queue goes under water when output is full.
The channel should inform the peer to pause the reader.
"""
output = MultiplexerMultiChannelQueue(
HEADER_SIZE * 2,
HEADER_SIZE,
HEADER_SIZE * 2,
)
with (
patch.object(
channel_module,
"INCOMING_QUEUE_MAX_BYTES_CHANNEL",
HEADER_SIZE * 10,
),
patch.object(channel_module, "INCOMING_QUEUE_LOW_WATERMARK", HEADER_SIZE),
patch.object(channel_module, "INCOMING_QUEUE_HIGH_WATERMARK", HEADER_SIZE * 2),
):
channel = MultiplexerChannel(output, IP_ADDR, snitun.PROTOCOL_VERSION)
assert isinstance(channel.id, MultiplexerChannelId)
data_msg = MultiplexerMessage(channel.id, CHANNEL_FLOW_DATA)
# Fill the output queue so it's full
output.put_nowait(channel.id, data_msg)
output.put_nowait(channel.id, data_msg)
# Fake some data coming from the remote
channel.message_transport(data_msg)
channel.message_transport(data_msg)
# The input queue is now under water
assert channel._input._under_water
# We can't tell the remote to pause because
# our output queue is full
assert (
f"{channel.id}: Cannot send pause/resume message to peer, "
"output queue is full" in caplog.text
)
async def test_flow_control_allow_multiple_pause_resume(
caplog: pytest.LogCaptureFixture,
) -> None:
"""Test that we can pause and resume multiple times idempotently."""
class ChannelConsumer(ChannelFlowControlBase):
"""Channel consumer for testing."""
def __init__(self) -> None:
super().__init__(asyncio.get_running_loop())
output = MultiplexerMultiChannelQueue(
OUTGOING_QUEUE_MAX_BYTES_CHANNEL,
OUTGOING_QUEUE_LOW_WATERMARK,
OUTGOING_QUEUE_HIGH_WATERMARK,
)
self._channel = MultiplexerChannel(output, IP_ADDR, snitun.PROTOCOL_VERSION)
base_channel = ChannelConsumer()
base_channel._pause_resume_reader_callback(True)
assert base_channel._pause_future is not None
assert not base_channel._pause_future.done()
# Calling pause again should be idempotent (no error)
base_channel._pause_resume_reader_callback(True)
assert base_channel._pause_future is not None
assert not base_channel._pause_future.done()
base_channel._pause_resume_reader_callback(False)
assert base_channel._pause_future is None
# Calling resume again should be idempotent (no error)
base_channel._pause_resume_reader_callback(False)
assert base_channel._pause_future is None
async def test_concurrent_pause_resume_race_condition() -> None:
"""Test that concurrent pause/resume operations don't cause race conditions."""
output = MultiplexerMultiChannelQueue(
OUTGOING_QUEUE_MAX_BYTES_CHANNEL,
OUTGOING_QUEUE_LOW_WATERMARK,
OUTGOING_QUEUE_HIGH_WATERMARK,
)
channel = MultiplexerChannel(output, IP_ADDR, snitun.PROTOCOL_VERSION)
# Set up a callback counter to track invocations
callback_count = {"pause": 0, "resume": 0}
def counting_callback(pause: bool) -> None:
"""Count callback invocations."""
if pause:
callback_count["pause"] += 1
else:
callback_count["resume"] += 1
channel.set_pause_resume_reader_callback(counting_callback)
# Simulate concurrent water level changes
# This would previously cause "Reader already resumed" errors
# Pauses
channel._on_local_output_under_water(True)
assert callback_count["pause"] == 1
# Already paused, no callback
channel.on_remote_input_under_water(True)
assert callback_count["pause"] == 1
# Still paused due to remote
channel._on_local_output_under_water(False)
assert callback_count["resume"] == 0
# Now resumes
channel.on_remote_input_under_water(False)
assert callback_count["resume"] == 1
# Multiple resume signals should be idempotent
# Already resumed
channel._on_local_output_under_water(False)
assert callback_count["resume"] == 1
# Already resumed
channel.on_remote_input_under_water(False)
assert callback_count["resume"] == 1
|
