def parse_settings(data: bytes) -> Dict[int, int]:
buf = Buffer(data=data)
settings: Dict[int, int] = {}
while not buf.eof():
setting = buf.pull_uint_var()
value = buf.pull_uint_var()
if setting in RESERVED_SETTINGS:
raise SettingsError("Setting identifier 0x%x is reserved" %
setting)
if setting in settings:
raise SettingsError("Setting identifier 0x%x is included twice" %
setting)
settings[setting] = value
return dict(settings)
def roundtrip(self, data, value):
buf = Buffer(data=data)
self.assertEqual(buf.pull_uint_var(), value)
self.assertEqual(buf.tell(), len(data))
buf = Buffer(capacity=8)
buf.push_uint_var(value)
self.assertEqual(buf.data, data)
def _receive_datagram(self, data: bytes) -> List[H3Event]:
"""
Handle a datagram.
"""
buf = Buffer(data=data)
try:
flow_id = buf.pull_uint_var()
except BufferReadError:
raise ProtocolError("Could not parse flow ID")
return [DatagramReceived(data=data[buf.tell():], flow_id=flow_id)]
def _receive_data_on_session_stream(self, data: bytes, fin: bool) -> None:
self._capsule_decoder_for_session_stream.append(data)
if fin:
self._capsule_decoder_for_session_stream.final()
for capsule in self._capsule_decoder_for_session_stream:
if capsule.type in {
CapsuleType.DATAGRAM,
CapsuleType.REGISTER_DATAGRAM_CONTEXT,
CapsuleType.CLOSE_DATAGRAM_CONTEXT
}:
raise ProtocolError(
f"Unimplemented capsule type: {capsule.type}")
if capsule.type in {
CapsuleType.REGISTER_DATAGRAM_NO_CONTEXT,
CapsuleType.CLOSE_WEBTRANSPORT_SESSION
}:
# We'll handle this case below.
pass
else:
# We should ignore unknown capsules.
continue
if self._close_info is not None:
raise ProtocolError(
("Receiving a capsule with type = {} after receiving " +
"CLOSE_WEBTRANSPORT_SESSION").format(capsule.type))
if capsule.type == CapsuleType.REGISTER_DATAGRAM_NO_CONTEXT:
buffer = Buffer(data=capsule.data)
format_type = buffer.pull_uint_var()
# https://ietf-wg-webtrans.github.io/draft-ietf-webtrans-http3/draft-ietf-webtrans-http3.html#name-datagram-format-type
WEBTRANPORT_FORMAT_TYPE = 0xff7c00
if format_type != WEBTRANPORT_FORMAT_TYPE:
raise ProtocolError(
"Unexpected datagram format type: {}".format(
format_type))
self._allow_datagrams = True
elif capsule.type == CapsuleType.CLOSE_WEBTRANSPORT_SESSION:
buffer = Buffer(data=capsule.data)
code = buffer.pull_uint32()
# 4 bytes for the uint32.
reason = buffer.pull_bytes(len(capsule.data) - 4)
# TODO(yutakahirano): Make sure `reason` is a UTF-8 text.
self._close_info = (code, reason)
if fin:
self._call_session_closed(self._close_info, abruptly=False)
class H3CapsuleDecoder:
"""
A decoder of H3Capsule. This is a streaming decoder and can handle multiple
decoders.
"""
def __init__(self) -> None:
self._buffer: Optional[Buffer] = None
self._type: Optional[int] = None
self._length: Optional[int] = None
self._final: bool = False
def append(self, data: bytes) -> None:
"""
Appends the given bytes to this decoder.
"""
assert not self._final
if len(data) == 0:
return
if self._buffer:
remaining = self._buffer.pull_bytes(self._buffer.capacity -
self._buffer.tell())
self._buffer = Buffer(data=(remaining + data))
else:
self._buffer = Buffer(data=data)
def final(self) -> None:
"""
Pushes the end-of-stream mark to this decoder. After calling this,
calling append() will be invalid.
"""
self._final = True
def __iter__(self) -> Iterator[H3Capsule]:
"""
Yields decoded capsules.
"""
try:
while self._buffer is not None:
if self._type is None:
self._type = self._buffer.pull_uint_var()
if self._length is None:
self._length = self._buffer.pull_uint_var()
if self._buffer.capacity - self._buffer.tell() < self._length:
if self._final:
raise ValueError('insufficient buffer')
return
capsule = H3Capsule(self._type,
self._buffer.pull_bytes(self._length))
self._type = None
self._length = None
if self._buffer.tell() == self._buffer.capacity:
self._buffer = None
yield capsule
except BufferReadError as e:
if self._final:
raise e
if not self._buffer:
return 0
size = self._buffer.capacity - self._buffer.tell()
if size >= UINT_VAR_MAX_SIZE:
raise e
# Ignore the error because there may not be sufficient input.
return
def _receive_stream_data_uni(self, stream: H3Stream, data: bytes,
stream_ended: bool) -> List[H3Event]:
http_events: List[H3Event] = []
stream.buffer += data
if stream_ended:
stream.ended = True
buf = Buffer(data=stream.buffer)
consumed = 0
unblocked_streams: Set[int] = set()
while stream.stream_type == StreamType.PUSH or not buf.eof():
# fetch stream type for unidirectional streams
if stream.stream_type is None:
try:
stream.stream_type = buf.pull_uint_var()
except BufferReadError:
break
consumed = buf.tell()
# check unicity
if stream.stream_type == StreamType.CONTROL:
if self._peer_control_stream_id is not None:
raise StreamCreationError(
"Only one control stream is allowed")
self._peer_control_stream_id = stream.stream_id
elif stream.stream_type == StreamType.QPACK_DECODER:
if self._peer_decoder_stream_id is not None:
raise StreamCreationError(
"Only one QPACK decoder stream is allowed")
self._peer_decoder_stream_id = stream.stream_id
elif stream.stream_type == StreamType.QPACK_ENCODER:
if self._peer_encoder_stream_id is not None:
raise StreamCreationError(
"Only one QPACK encoder stream is allowed")
self._peer_encoder_stream_id = stream.stream_id
if stream.stream_type == StreamType.CONTROL:
# fetch next frame
try:
frame_type = buf.pull_uint_var()
frame_length = buf.pull_uint_var()
frame_data = buf.pull_bytes(frame_length)
except BufferReadError:
break
consumed = buf.tell()
self._handle_control_frame(frame_type, frame_data)
elif stream.stream_type == StreamType.PUSH:
# fetch push id
if stream.push_id is None:
try:
stream.push_id = buf.pull_uint_var()
except BufferReadError:
break
consumed = buf.tell()
# remove processed data from buffer
stream.buffer = stream.buffer[consumed:]
return self._receive_request_or_push_data(
stream, b"", stream_ended)
elif stream.stream_type == StreamType.QPACK_DECODER:
# feed unframed data to decoder
data = buf.pull_bytes(buf.capacity - buf.tell())
consumed = buf.tell()
try:
self._encoder.feed_decoder(data)
except pylsqpack.DecoderStreamError as exc:
raise QpackDecoderStreamError() from exc
self._decoder_bytes_received += len(data)
elif stream.stream_type == StreamType.QPACK_ENCODER:
# feed unframed data to encoder
data = buf.pull_bytes(buf.capacity - buf.tell())
consumed = buf.tell()
try:
unblocked_streams.update(self._decoder.feed_encoder(data))
except pylsqpack.EncoderStreamError as exc:
raise QpackEncoderStreamError() from exc
self._encoder_bytes_received += len(data)
else:
# unknown stream type, discard data
buf.seek(buf.capacity)
consumed = buf.tell()
# remove processed data from buffer
stream.buffer = stream.buffer[consumed:]
# process unblocked streams
for stream_id in unblocked_streams:
stream = self._stream[stream_id]
# resume headers
http_events.extend(
self._handle_request_or_push_frame(
frame_type=FrameType.HEADERS,
frame_data=None,
stream=stream,
stream_ended=stream.ended and not stream.buffer,
))
stream.blocked = False
stream.blocked_frame_size = None
# resume processing
if stream.buffer:
http_events.extend(
self._receive_request_or_push_data(stream, b"",
stream.ended))
return http_events
def _receive_request_or_push_data(self, stream: H3Stream, data: bytes,
stream_ended: bool) -> List[H3Event]:
"""
Handle data received on a request or push stream.
"""
http_events: List[H3Event] = []
stream.buffer += data
if stream_ended:
stream.ended = True
if stream.blocked:
return http_events
# shortcut for DATA frame fragments
if (stream.frame_type == FrameType.DATA
and stream.frame_size is not None
and len(stream.buffer) < stream.frame_size):
http_events.append(
DataReceived(
data=stream.buffer,
push_id=stream.push_id,
stream_id=stream.stream_id,
stream_ended=False,
))
stream.frame_size -= len(stream.buffer)
stream.buffer = b""
return http_events
# handle lone FIN
if stream_ended and not stream.buffer:
http_events.append(
DataReceived(
data=b"",
push_id=stream.push_id,
stream_id=stream.stream_id,
stream_ended=True,
))
return http_events
buf = Buffer(data=stream.buffer)
consumed = 0
while not buf.eof():
# fetch next frame header
if stream.frame_size is None:
try:
stream.frame_type = buf.pull_uint_var()
stream.frame_size = buf.pull_uint_var()
except BufferReadError:
break
consumed = buf.tell()
# log frame
if (self._quic_logger is not None
and stream.frame_type == FrameType.DATA):
self._quic_logger.log_event(
category="http",
event="frame_parsed",
data=qlog_encode_data_frame(
byte_length=stream.frame_size,
stream_id=stream.stream_id),
)
# check how much data is available
chunk_size = min(stream.frame_size, buf.capacity - consumed)
if stream.frame_type != FrameType.DATA and chunk_size < stream.frame_size:
break
# read available data
frame_data = buf.pull_bytes(chunk_size)
consumed = buf.tell()
# detect end of frame
stream.frame_size -= chunk_size
if not stream.frame_size:
stream.frame_size = None
try:
http_events.extend(
self._handle_request_or_push_frame(
frame_type=stream.frame_type,
frame_data=frame_data,
stream=stream,
stream_ended=stream.ended and buf.eof(),
))
except pylsqpack.StreamBlocked:
stream.blocked = True
stream.blocked_frame_size = len(frame_data)
break
# remove processed data from buffer
stream.buffer = stream.buffer[consumed:]
return http_events
def _handle_request_or_push_frame(
self,
frame_type: int,
frame_data: Optional[bytes],
stream: H3Stream,
stream_ended: bool,
) -> List[H3Event]:
"""
Handle a frame received on a request or push stream.
"""
http_events: List[H3Event] = []
if frame_type == FrameType.DATA:
# check DATA frame is allowed
if stream.headers_recv_state != HeadersState.AFTER_HEADERS:
raise FrameUnexpected(
"DATA frame is not allowed in this state")
if stream_ended or frame_data:
http_events.append(
DataReceived(
data=frame_data,
push_id=stream.push_id,
stream_ended=stream_ended,
stream_id=stream.stream_id,
))
elif frame_type == FrameType.HEADERS:
# check HEADERS frame is allowed
if stream.headers_recv_state == HeadersState.AFTER_TRAILERS:
raise FrameUnexpected(
"HEADERS frame is not allowed in this state")
# try to decode HEADERS, may raise pylsqpack.StreamBlocked
headers = self._decode_headers(stream.stream_id, frame_data)
# log frame
if self._quic_logger is not None:
self._quic_logger.log_event(
category="http",
event="frame_parsed",
data=qlog_encode_headers_frame(
byte_length=stream.blocked_frame_size
if frame_data is None else len(frame_data),
headers=headers,
stream_id=stream.stream_id,
),
)
# update state and emit headers
if stream.headers_recv_state == HeadersState.INITIAL:
stream.headers_recv_state = HeadersState.AFTER_HEADERS
else:
stream.headers_recv_state = HeadersState.AFTER_TRAILERS
http_events.append(
HeadersReceived(
headers=headers,
push_id=stream.push_id,
stream_id=stream.stream_id,
stream_ended=stream_ended,
))
elif stream.frame_type == FrameType.PUSH_PROMISE and stream.push_id is None:
if not self._is_client:
raise FrameUnexpected("Clients must not send PUSH_PROMISE")
frame_buf = Buffer(data=frame_data)
push_id = frame_buf.pull_uint_var()
headers = self._decode_headers(stream.stream_id,
frame_data[frame_buf.tell():])
# log frame
if self._quic_logger is not None:
self._quic_logger.log_event(
category="http",
event="frame_parsed",
data=qlog_encode_push_promise_frame(
byte_length=len(frame_data),
headers=headers,
push_id=push_id,
stream_id=stream.stream_id,
),
)
# emit event
http_events.append(
PushPromiseReceived(headers=headers,
push_id=push_id,
stream_id=stream.stream_id))
elif frame_type in (
FrameType.PRIORITY,
FrameType.CANCEL_PUSH,
FrameType.SETTINGS,
FrameType.PUSH_PROMISE,
FrameType.GOAWAY,
FrameType.MAX_PUSH_ID,
FrameType.DUPLICATE_PUSH,
):
raise FrameUnexpected(
"Invalid frame type on request stream" if stream.
push_id is None else "Invalid frame type on push stream")
return http_events
def parse_max_push_id(data: bytes) -> int:
buf = Buffer(data=data)
max_push_id = buf.pull_uint_var()
assert buf.eof()
return max_push_id
def _receive_stream_data(
self, stream_id: int, data: bytes, stream_ended: bool
) -> List[Event]:
http_events: List[Event] = []
if stream_id in self._stream_buffers:
self._stream_buffers[stream_id] += data
else:
self._stream_buffers[stream_id] = data
consumed = 0
buf = Buffer(data=self._stream_buffers[stream_id])
while not buf.eof():
# fetch stream type for unidirectional streams
if (
stream_is_unidirectional(stream_id)
and stream_id not in self._stream_types
):
try:
stream_type = buf.pull_uint_var()
except BufferReadError:
break
consumed = buf.tell()
if stream_type == StreamType.CONTROL:
assert self._peer_control_stream_id is None
self._peer_control_stream_id = stream_id
elif stream_type == StreamType.QPACK_DECODER:
assert self._peer_decoder_stream_id is None
self._peer_decoder_stream_id = stream_id
elif stream_type == StreamType.QPACK_ENCODER:
assert self._peer_encoder_stream_id is None
self._peer_encoder_stream_id = stream_id
self._stream_types[stream_id] = stream_type
# fetch next frame
try:
frame_type = buf.pull_uint_var()
frame_length = buf.pull_uint_var()
frame_data = buf.pull_bytes(frame_length)
except BufferReadError:
break
consumed = buf.tell()
if (stream_id % 4) == 0:
# client-initiated bidirectional streams carry requests and responses
if frame_type == FrameType.DATA:
http_events.append(
DataReceived(
data=frame_data,
stream_id=stream_id,
stream_ended=stream_ended and buf.eof(),
)
)
elif frame_type == FrameType.HEADERS:
control, headers = self._decoder.feed_header(stream_id, frame_data)
cls = ResponseReceived if self._is_client else RequestReceived
http_events.append(
cls(
headers=headers,
stream_id=stream_id,
stream_ended=stream_ended and buf.eof(),
)
)
elif stream_id == self._peer_control_stream_id:
# unidirectional control stream
if frame_type == FrameType.SETTINGS:
settings = parse_settings(frame_data)
self._encoder.apply_settings(
max_table_capacity=settings.get(
Setting.QPACK_MAX_TABLE_CAPACITY, 0
),
blocked_streams=settings.get(Setting.QPACK_BLOCKED_STREAMS, 0),
)
# remove processed data from buffer
self._stream_buffers[stream_id] = self._stream_buffers[stream_id][consumed:]
return http_events
def _receive_stream_data_uni(self, stream_id: int,
data: bytes) -> List[HttpEvent]:
http_events: List[HttpEvent] = []
stream = self._stream[stream_id]
stream.buffer += data
buf = Buffer(data=stream.buffer)
consumed = 0
unblocked_streams: Set[int] = set()
while not buf.eof():
# fetch stream type for unidirectional streams
if stream.stream_type is None:
try:
stream.stream_type = buf.pull_uint_var()
except BufferReadError:
break
consumed = buf.tell()
if stream.stream_type == StreamType.CONTROL:
assert self._peer_control_stream_id is None
self._peer_control_stream_id = stream_id
elif stream.stream_type == StreamType.QPACK_DECODER:
assert self._peer_decoder_stream_id is None
self._peer_decoder_stream_id = stream_id
elif stream.stream_type == StreamType.QPACK_ENCODER:
assert self._peer_encoder_stream_id is None
self._peer_encoder_stream_id = stream_id
if stream_id == self._peer_control_stream_id:
# fetch next frame
try:
frame_type = buf.pull_uint_var()
frame_length = buf.pull_uint_var()
frame_data = buf.pull_bytes(frame_length)
except BufferReadError:
break
consumed = buf.tell()
# unidirectional control stream
if frame_type == FrameType.SETTINGS:
settings = parse_settings(frame_data)
encoder = self._encoder.apply_settings(
max_table_capacity=settings.get(
Setting.QPACK_MAX_TABLE_CAPACITY, 0),
blocked_streams=settings.get(
Setting.QPACK_BLOCKED_STREAMS, 0),
)
self._quic.send_stream_data(self._local_encoder_stream_id,
encoder)
else:
# fetch unframed data
data = buf.pull_bytes(buf.capacity - buf.tell())
consumed = buf.tell()
if stream_id == self._peer_decoder_stream_id:
self._encoder.feed_decoder(data)
elif stream_id == self._peer_encoder_stream_id:
unblocked_streams.update(self._decoder.feed_encoder(data))
# remove processed data from buffer
stream.buffer = stream.buffer[consumed:]
# process unblocked streams
for stream_id in unblocked_streams:
stream = self._stream[stream_id]
decoder, headers = self._decoder.resume_header(stream_id)
stream.blocked = False
cls = ResponseReceived if self._is_client else RequestReceived
http_events.append(
cls(
headers=headers,
stream_id=stream_id,
stream_ended=stream.ended and not stream.buffer,
))
http_events.extend(
self._receive_stream_data_bidi(stream_id, b"", stream.ended))
return http_events
def _receive_stream_data_bidi(self, stream_id: int, data: bytes,
stream_ended: bool) -> List[HttpEvent]:
"""
Client-initiated bidirectional streams carry requests and responses.
"""
http_events: List[HttpEvent] = []
stream = self._stream[stream_id]
stream.buffer += data
if stream_ended:
stream.ended = True
if stream.blocked:
return http_events
# shortcut DATA frame bits
if (stream.frame_size is not None
and stream.frame_type == FrameType.DATA
and len(stream.buffer) < stream.frame_size):
http_events.append(
DataReceived(data=stream.buffer,
stream_id=stream_id,
stream_ended=False))
stream.frame_size -= len(stream.buffer)
stream.buffer = b""
return http_events
# some peers (e.g. f5) end the stream with no data
if stream_ended and not stream.buffer:
http_events.append(
DataReceived(data=b"", stream_id=stream_id, stream_ended=True))
return http_events
buf = Buffer(data=stream.buffer)
consumed = 0
while not buf.eof():
# fetch next frame header
if stream.frame_size is None:
try:
stream.frame_type = buf.pull_uint_var()
stream.frame_size = buf.pull_uint_var()
except BufferReadError:
break
consumed = buf.tell()
# check how much data is available
chunk_size = min(stream.frame_size, buf.capacity - consumed)
if (stream.frame_type == FrameType.HEADERS
and chunk_size < stream.frame_size):
break
# read available data
frame_data = buf.pull_bytes(chunk_size)
consumed = buf.tell()
# detect end of frame
stream.frame_size -= chunk_size
if not stream.frame_size:
stream.frame_size = None
if stream.frame_type == FrameType.DATA and (stream_ended
or frame_data):
http_events.append(
DataReceived(
data=frame_data,
stream_id=stream_id,
stream_ended=stream_ended and buf.eof(),
))
elif stream.frame_type == FrameType.HEADERS:
try:
decoder, headers = self._decoder.feed_header(
stream_id, frame_data)
except StreamBlocked:
stream.blocked = True
break
self._quic.send_stream_data(self._local_decoder_stream_id,
decoder)
cls = ResponseReceived if self._is_client else RequestReceived
http_events.append(
cls(
headers=headers,
stream_id=stream_id,
stream_ended=stream_ended and buf.eof(),
))
# remove processed data from buffer
stream.buffer = stream.buffer[consumed:]
return http_events
