diff options
Diffstat (limited to 'third_party/rust/h2/src/proto/connection.rs')
| -rw-r--r-- | third_party/rust/h2/src/proto/connection.rs | 583 |
1 files changed, 583 insertions, 0 deletions
diff --git a/third_party/rust/h2/src/proto/connection.rs b/third_party/rust/h2/src/proto/connection.rs new file mode 100644 index 0000000000..cd011a1d58 --- /dev/null +++ b/third_party/rust/h2/src/proto/connection.rs @@ -0,0 +1,583 @@ +use crate::codec::UserError; +use crate::frame::{Reason, StreamId}; +use crate::{client, frame, server}; + +use crate::frame::DEFAULT_INITIAL_WINDOW_SIZE; +use crate::proto::*; + +use bytes::{Buf, Bytes}; +use futures_core::Stream; +use std::io; +use std::marker::PhantomData; +use std::pin::Pin; +use std::task::{Context, Poll}; +use std::time::Duration; +use tokio::io::{AsyncRead, AsyncWrite}; + +/// An H2 connection +#[derive(Debug)] +pub(crate) struct Connection<T, P, B: Buf = Bytes> +where + P: Peer, +{ + /// Read / write frame values + codec: Codec<T, Prioritized<B>>, + + inner: ConnectionInner<P, B>, +} + +// Extracted part of `Connection` which does not depend on `T`. Reduces the amount of duplicated +// method instantiations. +#[derive(Debug)] +struct ConnectionInner<P, B: Buf = Bytes> +where + P: Peer, +{ + /// Tracks the connection level state transitions. + state: State, + + /// An error to report back once complete. + /// + /// This exists separately from State in order to support + /// graceful shutdown. + error: Option<frame::GoAway>, + + /// Pending GOAWAY frames to write. + go_away: GoAway, + + /// Ping/pong handler + ping_pong: PingPong, + + /// Connection settings + settings: Settings, + + /// Stream state handler + streams: Streams<B, P>, + + /// A `tracing` span tracking the lifetime of the connection. + span: tracing::Span, + + /// Client or server + _phantom: PhantomData<P>, +} + +struct DynConnection<'a, B: Buf = Bytes> { + state: &'a mut State, + + go_away: &'a mut GoAway, + + streams: DynStreams<'a, B>, + + error: &'a mut Option<frame::GoAway>, + + ping_pong: &'a mut PingPong, +} + +#[derive(Debug, Clone)] +pub(crate) struct Config { + pub next_stream_id: StreamId, + pub initial_max_send_streams: usize, + pub max_send_buffer_size: usize, + pub reset_stream_duration: Duration, + pub reset_stream_max: usize, + pub settings: frame::Settings, +} + +#[derive(Debug)] +enum State { + /// Currently open in a sane state + Open, + + /// The codec must be flushed + Closing(Reason, Initiator), + + /// In a closed state + Closed(Reason, Initiator), +} + +impl<T, P, B> Connection<T, P, B> +where + T: AsyncRead + AsyncWrite + Unpin, + P: Peer, + B: Buf, +{ + pub fn new(codec: Codec<T, Prioritized<B>>, config: Config) -> Connection<T, P, B> { + fn streams_config(config: &Config) -> streams::Config { + streams::Config { + local_init_window_sz: config + .settings + .initial_window_size() + .unwrap_or(DEFAULT_INITIAL_WINDOW_SIZE), + initial_max_send_streams: config.initial_max_send_streams, + local_max_buffer_size: config.max_send_buffer_size, + local_next_stream_id: config.next_stream_id, + local_push_enabled: config.settings.is_push_enabled().unwrap_or(true), + extended_connect_protocol_enabled: config + .settings + .is_extended_connect_protocol_enabled() + .unwrap_or(false), + local_reset_duration: config.reset_stream_duration, + local_reset_max: config.reset_stream_max, + remote_init_window_sz: DEFAULT_INITIAL_WINDOW_SIZE, + remote_max_initiated: config + .settings + .max_concurrent_streams() + .map(|max| max as usize), + } + } + let streams = Streams::new(streams_config(&config)); + Connection { + codec, + inner: ConnectionInner { + state: State::Open, + error: None, + go_away: GoAway::new(), + ping_pong: PingPong::new(), + settings: Settings::new(config.settings), + streams, + span: tracing::debug_span!("Connection", peer = %P::NAME), + _phantom: PhantomData, + }, + } + } + + /// connection flow control + pub(crate) fn set_target_window_size(&mut self, size: WindowSize) { + self.inner.streams.set_target_connection_window_size(size); + } + + /// Send a new SETTINGS frame with an updated initial window size. + pub(crate) fn set_initial_window_size(&mut self, size: WindowSize) -> Result<(), UserError> { + let mut settings = frame::Settings::default(); + settings.set_initial_window_size(Some(size)); + self.inner.settings.send_settings(settings) + } + + /// Send a new SETTINGS frame with extended CONNECT protocol enabled. + pub(crate) fn set_enable_connect_protocol(&mut self) -> Result<(), UserError> { + let mut settings = frame::Settings::default(); + settings.set_enable_connect_protocol(Some(1)); + self.inner.settings.send_settings(settings) + } + + /// Returns the maximum number of concurrent streams that may be initiated + /// by this peer. + pub(crate) fn max_send_streams(&self) -> usize { + self.inner.streams.max_send_streams() + } + + /// Returns the maximum number of concurrent streams that may be initiated + /// by the remote peer. + pub(crate) fn max_recv_streams(&self) -> usize { + self.inner.streams.max_recv_streams() + } + + /// Returns `Ready` when the connection is ready to receive a frame. + /// + /// Returns `Error` as this may raise errors that are caused by delayed + /// processing of received frames. + fn poll_ready(&mut self, cx: &mut Context) -> Poll<Result<(), Error>> { + let _e = self.inner.span.enter(); + let span = tracing::trace_span!("poll_ready"); + let _e = span.enter(); + // The order of these calls don't really matter too much + ready!(self.inner.ping_pong.send_pending_pong(cx, &mut self.codec))?; + ready!(self.inner.ping_pong.send_pending_ping(cx, &mut self.codec))?; + ready!(self + .inner + .settings + .poll_send(cx, &mut self.codec, &mut self.inner.streams))?; + ready!(self.inner.streams.send_pending_refusal(cx, &mut self.codec))?; + + Poll::Ready(Ok(())) + } + + /// Send any pending GOAWAY frames. + /// + /// This will return `Some(reason)` if the connection should be closed + /// afterwards. If this is a graceful shutdown, this returns `None`. + fn poll_go_away(&mut self, cx: &mut Context) -> Poll<Option<io::Result<Reason>>> { + self.inner.go_away.send_pending_go_away(cx, &mut self.codec) + } + + pub fn go_away_from_user(&mut self, e: Reason) { + self.inner.as_dyn().go_away_from_user(e) + } + + fn take_error(&mut self, ours: Reason, initiator: Initiator) -> Result<(), Error> { + let (debug_data, theirs) = self + .inner + .error + .take() + .as_ref() + .map_or((Bytes::new(), Reason::NO_ERROR), |frame| { + (frame.debug_data().clone(), frame.reason()) + }); + + match (ours, theirs) { + (Reason::NO_ERROR, Reason::NO_ERROR) => return Ok(()), + (ours, Reason::NO_ERROR) => Err(Error::GoAway(Bytes::new(), ours, initiator)), + // If both sides reported an error, give their + // error back to th user. We assume our error + // was a consequence of their error, and less + // important. + (_, theirs) => Err(Error::remote_go_away(debug_data, theirs)), + } + } + + /// Closes the connection by transitioning to a GOAWAY state + /// iff there are no streams or references + pub fn maybe_close_connection_if_no_streams(&mut self) { + // If we poll() and realize that there are no streams or references + // then we can close the connection by transitioning to GOAWAY + if !self.inner.streams.has_streams_or_other_references() { + self.inner.as_dyn().go_away_now(Reason::NO_ERROR); + } + } + + pub(crate) fn take_user_pings(&mut self) -> Option<UserPings> { + self.inner.ping_pong.take_user_pings() + } + + /// Advances the internal state of the connection. + pub fn poll(&mut self, cx: &mut Context) -> Poll<Result<(), Error>> { + // XXX(eliza): cloning the span is unfortunately necessary here in + // order to placate the borrow checker — `self` is mutably borrowed by + // `poll2`, which means that we can't borrow `self.span` to enter it. + // The clone is just an atomic ref bump. + let span = self.inner.span.clone(); + let _e = span.enter(); + let span = tracing::trace_span!("poll"); + let _e = span.enter(); + + loop { + tracing::trace!(connection.state = ?self.inner.state); + // TODO: probably clean up this glob of code + match self.inner.state { + // When open, continue to poll a frame + State::Open => { + let result = match self.poll2(cx) { + Poll::Ready(result) => result, + // The connection is not ready to make progress + Poll::Pending => { + // Ensure all window updates have been sent. + // + // This will also handle flushing `self.codec` + ready!(self.inner.streams.poll_complete(cx, &mut self.codec))?; + + if (self.inner.error.is_some() + || self.inner.go_away.should_close_on_idle()) + && !self.inner.streams.has_streams() + { + self.inner.as_dyn().go_away_now(Reason::NO_ERROR); + continue; + } + + return Poll::Pending; + } + }; + + self.inner.as_dyn().handle_poll2_result(result)? + } + State::Closing(reason, initiator) => { + tracing::trace!("connection closing after flush"); + // Flush/shutdown the codec + ready!(self.codec.shutdown(cx))?; + + // Transition the state to error + self.inner.state = State::Closed(reason, initiator); + } + State::Closed(reason, initiator) => { + return Poll::Ready(self.take_error(reason, initiator)); + } + } + } + } + + fn poll2(&mut self, cx: &mut Context) -> Poll<Result<(), Error>> { + // This happens outside of the loop to prevent needing to do a clock + // check and then comparison of the queue possibly multiple times a + // second (and thus, the clock wouldn't have changed enough to matter). + self.clear_expired_reset_streams(); + + loop { + // First, ensure that the `Connection` is able to receive a frame + // + // The order here matters: + // - poll_go_away may buffer a graceful shutdown GOAWAY frame + // - If it has, we've also added a PING to be sent in poll_ready + if let Some(reason) = ready!(self.poll_go_away(cx)?) { + if self.inner.go_away.should_close_now() { + if self.inner.go_away.is_user_initiated() { + // A user initiated abrupt shutdown shouldn't return + // the same error back to the user. + return Poll::Ready(Ok(())); + } else { + return Poll::Ready(Err(Error::library_go_away(reason))); + } + } + // Only NO_ERROR should be waiting for idle + debug_assert_eq!( + reason, + Reason::NO_ERROR, + "graceful GOAWAY should be NO_ERROR" + ); + } + ready!(self.poll_ready(cx))?; + + match self + .inner + .as_dyn() + .recv_frame(ready!(Pin::new(&mut self.codec).poll_next(cx)?))? + { + ReceivedFrame::Settings(frame) => { + self.inner.settings.recv_settings( + frame, + &mut self.codec, + &mut self.inner.streams, + )?; + } + ReceivedFrame::Continue => (), + ReceivedFrame::Done => { + return Poll::Ready(Ok(())); + } + } + } + } + + fn clear_expired_reset_streams(&mut self) { + self.inner.streams.clear_expired_reset_streams(); + } +} + +impl<P, B> ConnectionInner<P, B> +where + P: Peer, + B: Buf, +{ + fn as_dyn(&mut self) -> DynConnection<'_, B> { + let ConnectionInner { + state, + go_away, + streams, + error, + ping_pong, + .. + } = self; + let streams = streams.as_dyn(); + DynConnection { + state, + go_away, + streams, + error, + ping_pong, + } + } +} + +impl<B> DynConnection<'_, B> +where + B: Buf, +{ + fn go_away(&mut self, id: StreamId, e: Reason) { + let frame = frame::GoAway::new(id, e); + self.streams.send_go_away(id); + self.go_away.go_away(frame); + } + + fn go_away_now(&mut self, e: Reason) { + let last_processed_id = self.streams.last_processed_id(); + let frame = frame::GoAway::new(last_processed_id, e); + self.go_away.go_away_now(frame); + } + + fn go_away_from_user(&mut self, e: Reason) { + let last_processed_id = self.streams.last_processed_id(); + let frame = frame::GoAway::new(last_processed_id, e); + self.go_away.go_away_from_user(frame); + + // Notify all streams of reason we're abruptly closing. + self.streams.handle_error(Error::user_go_away(e)); + } + + fn handle_poll2_result(&mut self, result: Result<(), Error>) -> Result<(), Error> { + match result { + // The connection has shutdown normally + Ok(()) => { + *self.state = State::Closing(Reason::NO_ERROR, Initiator::Library); + Ok(()) + } + // Attempting to read a frame resulted in a connection level + // error. This is handled by setting a GOAWAY frame followed by + // terminating the connection. + Err(Error::GoAway(debug_data, reason, initiator)) => { + let e = Error::GoAway(debug_data, reason, initiator); + tracing::debug!(error = ?e, "Connection::poll; connection error"); + + // We may have already sent a GOAWAY for this error, + // if so, don't send another, just flush and close up. + if self + .go_away + .going_away() + .map_or(false, |frame| frame.reason() == reason) + { + tracing::trace!(" -> already going away"); + *self.state = State::Closing(reason, initiator); + return Ok(()); + } + + // Reset all active streams + self.streams.handle_error(e); + self.go_away_now(reason); + Ok(()) + } + // Attempting to read a frame resulted in a stream level error. + // This is handled by resetting the frame then trying to read + // another frame. + Err(Error::Reset(id, reason, initiator)) => { + debug_assert_eq!(initiator, Initiator::Library); + tracing::trace!(?id, ?reason, "stream error"); + self.streams.send_reset(id, reason); + Ok(()) + } + // Attempting to read a frame resulted in an I/O error. All + // active streams must be reset. + // + // TODO: Are I/O errors recoverable? + Err(Error::Io(e, inner)) => { + tracing::debug!(error = ?e, "Connection::poll; IO error"); + let e = Error::Io(e, inner); + + // Reset all active streams + self.streams.handle_error(e.clone()); + + // Return the error + Err(e) + } + } + } + + fn recv_frame(&mut self, frame: Option<Frame>) -> Result<ReceivedFrame, Error> { + use crate::frame::Frame::*; + match frame { + Some(Headers(frame)) => { + tracing::trace!(?frame, "recv HEADERS"); + self.streams.recv_headers(frame)?; + } + Some(Data(frame)) => { + tracing::trace!(?frame, "recv DATA"); + self.streams.recv_data(frame)?; + } + Some(Reset(frame)) => { + tracing::trace!(?frame, "recv RST_STREAM"); + self.streams.recv_reset(frame)?; + } + Some(PushPromise(frame)) => { + tracing::trace!(?frame, "recv PUSH_PROMISE"); + self.streams.recv_push_promise(frame)?; + } + Some(Settings(frame)) => { + tracing::trace!(?frame, "recv SETTINGS"); + return Ok(ReceivedFrame::Settings(frame)); + } + Some(GoAway(frame)) => { + tracing::trace!(?frame, "recv GOAWAY"); + // This should prevent starting new streams, + // but should allow continuing to process current streams + // until they are all EOS. Once they are, State should + // transition to GoAway. + self.streams.recv_go_away(&frame)?; + *self.error = Some(frame); + } + Some(Ping(frame)) => { + tracing::trace!(?frame, "recv PING"); + let status = self.ping_pong.recv_ping(frame); + if status.is_shutdown() { + assert!( + self.go_away.is_going_away(), + "received unexpected shutdown ping" + ); + + let last_processed_id = self.streams.last_processed_id(); + self.go_away(last_processed_id, Reason::NO_ERROR); + } + } + Some(WindowUpdate(frame)) => { + tracing::trace!(?frame, "recv WINDOW_UPDATE"); + self.streams.recv_window_update(frame)?; + } + Some(Priority(frame)) => { + tracing::trace!(?frame, "recv PRIORITY"); + // TODO: handle + } + None => { + tracing::trace!("codec closed"); + self.streams.recv_eof(false).expect("mutex poisoned"); + return Ok(ReceivedFrame::Done); + } + } + Ok(ReceivedFrame::Continue) + } +} + +enum ReceivedFrame { + Settings(frame::Settings), + Continue, + Done, +} + +impl<T, B> Connection<T, client::Peer, B> +where + T: AsyncRead + AsyncWrite, + B: Buf, +{ + pub(crate) fn streams(&self) -> &Streams<B, client::Peer> { + &self.inner.streams + } +} + +impl<T, B> Connection<T, server::Peer, B> +where + T: AsyncRead + AsyncWrite + Unpin, + B: Buf, +{ + pub fn next_incoming(&mut self) -> Option<StreamRef<B>> { + self.inner.streams.next_incoming() + } + + // Graceful shutdown only makes sense for server peers. + pub fn go_away_gracefully(&mut self) { + if self.inner.go_away.is_going_away() { + // No reason to start a new one. + return; + } + + // According to http://httpwg.org/specs/rfc7540.html#GOAWAY: + // + // > A server that is attempting to gracefully shut down a connection + // > SHOULD send an initial GOAWAY frame with the last stream + // > identifier set to 2^31-1 and a NO_ERROR code. This signals to the + // > client that a shutdown is imminent and that initiating further + // > requests is prohibited. After allowing time for any in-flight + // > stream creation (at least one round-trip time), the server can + // > send another GOAWAY frame with an updated last stream identifier. + // > This ensures that a connection can be cleanly shut down without + // > losing requests. + self.inner.as_dyn().go_away(StreamId::MAX, Reason::NO_ERROR); + + // We take the advice of waiting 1 RTT literally, and wait + // for a pong before proceeding. + self.inner.ping_pong.ping_shutdown(); + } +} + +impl<T, P, B> Drop for Connection<T, P, B> +where + P: Peer, + B: Buf, +{ + fn drop(&mut self) { + // Ignore errors as this indicates that the mutex is poisoned. + let _ = self.inner.streams.recv_eof(true); + } +} |