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|
"""Connector to end resource."""
from __future__ import annotations
import asyncio
from collections.abc import Callable, Coroutine
from contextlib import suppress
import ipaddress
from ipaddress import IPv4Address
import logging
from typing import Any
from ..exceptions import MultiplexerTransportClose, MultiplexerTransportError
from ..multiplexer.channel import ChannelFlowControlBase, MultiplexerChannel
from ..multiplexer.core import Multiplexer
_LOGGER = logging.getLogger(__name__)
class Connector:
"""Connector to end resource."""
def __init__(
self,
end_host: str,
end_port: int | None = None,
whitelist: bool = False,
endpoint_connection_error_callback: Callable[[], Coroutine[Any, Any, None]]
| None = None,
) -> None:
"""Initialize Connector."""
self._loop = asyncio.get_event_loop()
self._end_host = end_host
self._end_port = end_port or 443
self._whitelist: set[IPv4Address] = set()
self._whitelist_enabled = whitelist
self._endpoint_connection_error_callback = endpoint_connection_error_callback
@property
def whitelist(self) -> set:
"""Allow to block requests per IP Return None or access to a set."""
return self._whitelist
def _whitelist_policy(self, ip_address: ipaddress.IPv4Address) -> bool:
"""Return True if the ip address can access to endpoint."""
if self._whitelist_enabled:
return ip_address in self._whitelist
return True
async def handler(
self,
multiplexer: Multiplexer,
channel: MultiplexerChannel,
) -> None:
"""Handle new connection from SNIProxy."""
_LOGGER.debug(
"Receive from %s a request for %s",
channel.ip_address,
self._end_host,
)
# Check policy
if not self._whitelist_policy(channel.ip_address):
_LOGGER.warning("Block request from %s per policy", channel.ip_address)
multiplexer.delete_channel(channel)
return
await ConnectorHandler(self._loop, channel).start(
multiplexer,
self._end_host,
self._end_port,
self._endpoint_connection_error_callback,
)
class ConnectorHandler(ChannelFlowControlBase):
"""Handle connection to endpoint."""
def __init__(
self,
loop: asyncio.AbstractEventLoop,
channel: MultiplexerChannel,
) -> None:
"""Initialize ConnectorHandler."""
super().__init__(loop)
self._channel = channel
async def start(
self,
multiplexer: Multiplexer,
end_host: str,
end_port: int,
endpoint_connection_error_callback: Callable[[], Coroutine[Any, Any, None]]
| None = None,
) -> None:
"""Start handler."""
channel = self._channel
channel.set_pause_resume_reader_callback(self._pause_resume_reader_callback)
# Open connection to endpoint
try:
reader, writer = await asyncio.open_connection(host=end_host, port=end_port)
except OSError:
_LOGGER.error(
"Can't connect to endpoint %s:%s",
end_host,
end_port,
)
multiplexer.delete_channel(channel)
if endpoint_connection_error_callback:
await endpoint_connection_error_callback()
return
from_endpoint: asyncio.Future[None] | asyncio.Task[bytes] | None = None
from_peer: asyncio.Task[bytes] | None = None
try:
# Process stream from multiplexer
while not writer.transport.is_closing():
if not from_endpoint:
# If the multiplexer channel queue is under water, pause the reader
# by waiting for the future to be set, once the queue is not under
# water the future will be set and cleared to resume the reader
from_endpoint = self._pause_future or self._loop.create_task(
reader.read(4096), # type: ignore[arg-type]
)
if not from_peer:
from_peer = self._loop.create_task(channel.read())
# Wait until data need to be processed
await asyncio.wait(
[from_endpoint, from_peer],
return_when=asyncio.FIRST_COMPLETED,
)
# From proxy
if from_endpoint.done():
if from_endpoint_exc := from_endpoint.exception():
raise from_endpoint_exc
if (from_endpoint_result := from_endpoint.result()) is not None:
await channel.write(from_endpoint_result)
from_endpoint = None
# From peer
if from_peer.done():
if from_peer_exc := from_peer.exception():
raise from_peer_exc
writer.write(from_peer.result())
from_peer = None
# Flush buffer
await writer.drain()
except (MultiplexerTransportError, OSError, RuntimeError):
_LOGGER.debug("Transport closed by endpoint for %s", channel.id)
multiplexer.delete_channel(channel)
except MultiplexerTransportClose:
_LOGGER.debug("Peer close connection for %s", channel.id)
finally:
# Cleanup peer reader
if from_peer:
if not from_peer.done():
from_peer.cancel()
else:
# Avoid exception was never retrieved
from_peer.exception()
# Cleanup endpoint reader
if from_endpoint and not from_endpoint.done():
from_endpoint.cancel()
# Close Transport
if not writer.transport.is_closing():
with suppress(OSError):
writer.close()
|
