%PDF-
%PDF-
Mini Shell
Mini Shell
# Copyright (C) Dnspython Contributors, see LICENSE for text of ISC license
import socket
import ssl
import struct
import time
import aioquic.quic.configuration # type: ignore
import aioquic.quic.connection # type: ignore
import aioquic.quic.events # type: ignore
import trio
import dns.exception
import dns.inet
from dns._asyncbackend import NullContext
from dns.quic._common import (
QUIC_MAX_DATAGRAM,
AsyncQuicConnection,
AsyncQuicManager,
BaseQuicStream,
UnexpectedEOF,
)
class TrioQuicStream(BaseQuicStream):
def __init__(self, connection, stream_id):
super().__init__(connection, stream_id)
self._wake_up = trio.Condition()
async def wait_for(self, amount):
while True:
if self._buffer.have(amount):
return
self._expecting = amount
async with self._wake_up:
await self._wake_up.wait()
self._expecting = 0
async def receive(self, timeout=None):
if timeout is None:
context = NullContext(None)
else:
context = trio.move_on_after(timeout)
with context:
await self.wait_for(2)
(size,) = struct.unpack("!H", self._buffer.get(2))
await self.wait_for(size)
return self._buffer.get(size)
raise dns.exception.Timeout
async def send(self, datagram, is_end=False):
data = self._encapsulate(datagram)
await self._connection.write(self._stream_id, data, is_end)
async def _add_input(self, data, is_end):
if self._common_add_input(data, is_end):
async with self._wake_up:
self._wake_up.notify()
async def close(self):
self._close()
# Streams are async context managers
async def __aenter__(self):
return self
async def __aexit__(self, exc_type, exc_val, exc_tb):
await self.close()
async with self._wake_up:
self._wake_up.notify()
return False
class TrioQuicConnection(AsyncQuicConnection):
def __init__(self, connection, address, port, source, source_port, manager=None):
super().__init__(connection, address, port, source, source_port, manager)
self._socket = trio.socket.socket(self._af, socket.SOCK_DGRAM, 0)
self._handshake_complete = trio.Event()
self._run_done = trio.Event()
self._worker_scope = None
self._send_pending = False
async def _worker(self):
try:
if self._source:
await self._socket.bind(
dns.inet.low_level_address_tuple(self._source, self._af)
)
await self._socket.connect(self._peer)
while not self._done:
(expiration, interval) = self._get_timer_values(False)
if self._send_pending:
# Do not block forever if sends are pending. Even though we
# have a wake-up mechanism if we've already started the blocking
# read, the possibility of context switching in send means that
# more writes can happen while we have no wake up context, so
# we need self._send_pending to avoid (effectively) a "lost wakeup"
# race.
interval = 0.0
with trio.CancelScope(
deadline=trio.current_time() + interval
) as self._worker_scope:
datagram = await self._socket.recv(QUIC_MAX_DATAGRAM)
self._connection.receive_datagram(datagram, self._peer, time.time())
self._worker_scope = None
self._handle_timer(expiration)
await self._handle_events()
# We clear this now, before sending anything, as sending can cause
# context switches that do more sends. We want to know if that
# happens so we don't block a long time on the recv() above.
self._send_pending = False
datagrams = self._connection.datagrams_to_send(time.time())
for datagram, _ in datagrams:
await self._socket.send(datagram)
finally:
self._done = True
self._handshake_complete.set()
async def _handle_events(self):
count = 0
while True:
event = self._connection.next_event()
if event is None:
return
if isinstance(event, aioquic.quic.events.StreamDataReceived):
stream = self._streams.get(event.stream_id)
if stream:
await stream._add_input(event.data, event.end_stream)
elif isinstance(event, aioquic.quic.events.HandshakeCompleted):
self._handshake_complete.set()
elif isinstance(event, aioquic.quic.events.ConnectionTerminated):
self._done = True
self._socket.close()
elif isinstance(event, aioquic.quic.events.StreamReset):
stream = self._streams.get(event.stream_id)
if stream:
await stream._add_input(b"", True)
count += 1
if count > 10:
# yield
count = 0
await trio.sleep(0)
async def write(self, stream, data, is_end=False):
self._connection.send_stream_data(stream, data, is_end)
self._send_pending = True
if self._worker_scope is not None:
self._worker_scope.cancel()
async def run(self):
if self._closed:
return
async with trio.open_nursery() as nursery:
nursery.start_soon(self._worker)
self._run_done.set()
async def make_stream(self, timeout=None):
if timeout is None:
context = NullContext(None)
else:
context = trio.move_on_after(timeout)
with context:
await self._handshake_complete.wait()
if self._done:
raise UnexpectedEOF
stream_id = self._connection.get_next_available_stream_id(False)
stream = TrioQuicStream(self, stream_id)
self._streams[stream_id] = stream
return stream
raise dns.exception.Timeout
async def close(self):
if not self._closed:
self._manager.closed(self._peer[0], self._peer[1])
self._closed = True
self._connection.close()
self._send_pending = True
if self._worker_scope is not None:
self._worker_scope.cancel()
await self._run_done.wait()
class TrioQuicManager(AsyncQuicManager):
def __init__(
self, nursery, conf=None, verify_mode=ssl.CERT_REQUIRED, server_name=None
):
super().__init__(conf, verify_mode, TrioQuicConnection, server_name)
self._nursery = nursery
def connect(
self, address, port=853, source=None, source_port=0, want_session_ticket=True
):
(connection, start) = self._connect(
address, port, source, source_port, want_session_ticket
)
if start:
self._nursery.start_soon(connection.run)
return connection
async def __aenter__(self):
return self
async def __aexit__(self, exc_type, exc_val, exc_tb):
# Copy the iterator into a list as exiting things will mutate the connections
# table.
connections = list(self._connections.values())
for connection in connections:
await connection.close()
return False
Zerion Mini Shell 1.0