Current File : //backups/router/usr/local/lib/python3.11/site-packages/aioquic/quic/stream.py
from typing import Optional
from . import events
from .packet import (
QuicErrorCode,
QuicResetStreamFrame,
QuicStopSendingFrame,
QuicStreamFrame,
)
from .packet_builder import QuicDeliveryState
from .rangeset import RangeSet
class FinalSizeError(Exception):
pass
class StreamFinishedError(Exception):
pass
class QuicStreamReceiver:
"""
The receive part of a QUIC stream.
It finishes:
- immediately for a send-only stream
- upon reception of a STREAM_RESET frame
- upon reception of a data frame with the FIN bit set
"""
def __init__(self, stream_id: Optional[int], readable: bool) -> None:
self.highest_offset = 0 # the highest offset ever seen
self.is_finished = False
self.stop_pending = False
self._buffer = bytearray()
self._buffer_start = 0 # the offset for the start of the buffer
self._final_size: Optional[int] = None
self._ranges = RangeSet()
self._stream_id = stream_id
self._stop_error_code: Optional[int] = None
def get_stop_frame(self) -> QuicStopSendingFrame:
self.stop_pending = False
return QuicStopSendingFrame(
error_code=self._stop_error_code,
stream_id=self._stream_id,
)
def starting_offset(self) -> int:
return self._buffer_start
def handle_frame(
self, frame: QuicStreamFrame
) -> Optional[events.StreamDataReceived]:
"""
Handle a frame of received data.
"""
pos = frame.offset - self._buffer_start
count = len(frame.data)
frame_end = frame.offset + count
# we should receive no more data beyond FIN!
if self._final_size is not None:
if frame_end > self._final_size:
raise FinalSizeError("Data received beyond final size")
elif frame.fin and frame_end != self._final_size:
raise FinalSizeError("Cannot change final size")
if frame.fin:
self._final_size = frame_end
if frame_end > self.highest_offset:
self.highest_offset = frame_end
# fast path: new in-order chunk
if pos == 0 and count and not self._buffer:
self._buffer_start += count
if frame.fin:
# all data up to the FIN has been received, we're done receiving
self.is_finished = True
return events.StreamDataReceived(
data=frame.data, end_stream=frame.fin, stream_id=self._stream_id
)
# discard duplicate data
if pos < 0:
frame.data = frame.data[-pos:]
frame.offset -= pos
pos = 0
count = len(frame.data)
# marked received range
if frame_end > frame.offset:
self._ranges.add(frame.offset, frame_end)
# add new data
gap = pos - len(self._buffer)
if gap > 0:
self._buffer += bytearray(gap)
self._buffer[pos : pos + count] = frame.data
# return data from the front of the buffer
data = self._pull_data()
end_stream = self._buffer_start == self._final_size
if end_stream:
# all data up to the FIN has been received, we're done receiving
self.is_finished = True
if data or end_stream:
return events.StreamDataReceived(
data=data, end_stream=end_stream, stream_id=self._stream_id
)
else:
return None
def handle_reset(
self, *, final_size: int, error_code: int = QuicErrorCode.NO_ERROR
) -> Optional[events.StreamReset]:
"""
Handle an abrupt termination of the receiving part of the QUIC stream.
"""
if self._final_size is not None and final_size != self._final_size:
raise FinalSizeError("Cannot change final size")
# we are done receiving
self._final_size = final_size
self.is_finished = True
return events.StreamReset(error_code=error_code, stream_id=self._stream_id)
def on_stop_sending_delivery(self, delivery: QuicDeliveryState) -> None:
"""
Callback when a STOP_SENDING is ACK'd.
"""
if delivery != QuicDeliveryState.ACKED:
self.stop_pending = True
def stop(self, error_code: int = QuicErrorCode.NO_ERROR) -> None:
"""
Request the peer stop sending data on the QUIC stream.
"""
self._stop_error_code = error_code
self.stop_pending = True
def _pull_data(self) -> bytes:
"""
Remove data from the front of the buffer.
"""
try:
has_data_to_read = self._ranges[0].start == self._buffer_start
except IndexError:
has_data_to_read = False
if not has_data_to_read:
return b""
r = self._ranges.shift()
pos = r.stop - r.start
data = bytes(self._buffer[:pos])
del self._buffer[:pos]
self._buffer_start = r.stop
return data
class QuicStreamSender:
"""
The send part of a QUIC stream.
It finishes:
- immediately for a receive-only stream
- upon acknowledgement of a STREAM_RESET frame
- upon acknowledgement of a data frame with the FIN bit set
"""
def __init__(self, stream_id: Optional[int], writable: bool) -> None:
self.buffer_is_empty = True
self.highest_offset = 0
self.is_finished = not writable
self.reset_pending = False
self._acked = RangeSet()
self._acked_fin = False
self._buffer = bytearray()
self._buffer_fin: Optional[int] = None
self._buffer_start = 0 # the offset for the start of the buffer
self._buffer_stop = 0 # the offset for the stop of the buffer
self._pending = RangeSet()
self._pending_eof = False
self._reset_error_code: Optional[int] = None
self._stream_id = stream_id
@property
def next_offset(self) -> int:
"""
The offset for the next frame to send.
This is used to determine the space needed for the frame's `offset` field.
"""
try:
return self._pending[0].start
except IndexError:
return self._buffer_stop
def get_frame(
self, max_size: int, max_offset: Optional[int] = None
) -> Optional[QuicStreamFrame]:
"""
Get a frame of data to send.
"""
assert self._reset_error_code is None, "cannot call get_frame() after reset()"
# get the first pending data range
try:
r = self._pending[0]
except IndexError:
if self._pending_eof:
# FIN only
self._pending_eof = False
return QuicStreamFrame(fin=True, offset=self._buffer_fin)
self.buffer_is_empty = True
return None
# apply flow control
start = r.start
stop = min(r.stop, start + max_size)
if max_offset is not None and stop > max_offset:
stop = max_offset
if stop <= start:
return None
# create frame
frame = QuicStreamFrame(
data=bytes(
self._buffer[start - self._buffer_start : stop - self._buffer_start]
),
offset=start,
)
self._pending.subtract(start, stop)
# track the highest offset ever sent
if stop > self.highest_offset:
self.highest_offset = stop
# if the buffer is empty and EOF was written, set the FIN bit
if self._buffer_fin == stop:
frame.fin = True
self._pending_eof = False
return frame
def get_reset_frame(self) -> QuicResetStreamFrame:
self.reset_pending = False
return QuicResetStreamFrame(
error_code=self._reset_error_code,
final_size=self.highest_offset,
stream_id=self._stream_id,
)
def on_data_delivery(
self, delivery: QuicDeliveryState, start: int, stop: int, fin: bool
) -> None:
"""
Callback when sent data is ACK'd.
"""
# If the frame had the FIN bit set, its end MUST match otherwise
# we have a programming error.
assert (
not fin or stop == self._buffer_fin
), "on_data_delivered() was called with inconsistent fin / stop"
# If a reset has been requested, stop processing data delivery.
# The transition to the finished state only depends on the reset
# being acknowledged.
if self._reset_error_code is not None:
return
if delivery == QuicDeliveryState.ACKED:
if stop > start:
# Some data has been ACK'd, discard it.
self._acked.add(start, stop)
first_range = self._acked[0]
if first_range.start == self._buffer_start:
size = first_range.stop - first_range.start
self._acked.shift()
self._buffer_start += size
del self._buffer[:size]
if fin:
# The FIN has been ACK'd.
self._acked_fin = True
if self._buffer_start == self._buffer_fin and self._acked_fin:
# All data and the FIN have been ACK'd, we're done sending.
self.is_finished = True
else:
if stop > start:
# Some data has been lost, reschedule it.
self.buffer_is_empty = False
self._pending.add(start, stop)
if fin:
# The FIN has been lost, reschedule it.
self.buffer_is_empty = False
self._pending_eof = True
def on_reset_delivery(self, delivery: QuicDeliveryState) -> None:
"""
Callback when a reset is ACK'd.
"""
if delivery == QuicDeliveryState.ACKED:
# The reset has been ACK'd, we're done sending.
self.is_finished = True
else:
# The reset has been lost, reschedule it.
self.reset_pending = True
def reset(self, error_code: int) -> None:
"""
Abruptly terminate the sending part of the QUIC stream.
"""
assert self._reset_error_code is None, "cannot call reset() more than once"
self._reset_error_code = error_code
self.reset_pending = True
# Prevent any more data from being sent or re-sent.
self.buffer_is_empty = True
def write(self, data: bytes, end_stream: bool = False) -> None:
"""
Write some data bytes to the QUIC stream.
"""
assert self._buffer_fin is None, "cannot call write() after FIN"
assert self._reset_error_code is None, "cannot call write() after reset()"
size = len(data)
if size:
self.buffer_is_empty = False
self._pending.add(self._buffer_stop, self._buffer_stop + size)
self._buffer += data
self._buffer_stop += size
if end_stream:
self.buffer_is_empty = False
self._buffer_fin = self._buffer_stop
self._pending_eof = True
class QuicStream:
def __init__(
self,
stream_id: Optional[int] = None,
max_stream_data_local: int = 0,
max_stream_data_remote: int = 0,
readable: bool = True,
writable: bool = True,
) -> None:
self.is_blocked = False
self.max_stream_data_local = max_stream_data_local
self.max_stream_data_local_sent = max_stream_data_local
self.max_stream_data_remote = max_stream_data_remote
self.receiver = QuicStreamReceiver(stream_id=stream_id, readable=readable)
self.sender = QuicStreamSender(stream_id=stream_id, writable=writable)
self.stream_id = stream_id
@property
def is_finished(self) -> bool:
return self.receiver.is_finished and self.sender.is_finished
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