swarm/connection: Enforce limit on inbound substreams via StreamMuxer (#2861)

* Provide separate functions for injecting in- and outbound streams

* Inline `HandlerWrapper` into `Connection`

* Only poll for new inbound streams if we are below the limit

* yamux: Buffer inbound streams in `StreamMuxer::poll`
This commit is contained in:
Thomas Eizinger
2022-09-21 23:02:21 +10:00
committed by GitHub
parent f4362cb8aa
commit a4d1e58836
8 changed files with 699 additions and 601 deletions

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@ -4,7 +4,11 @@
- Remove `OpenSubstreamToken` as it is dead code. See [PR 2873].
- Drive connection also via `StreamMuxer::poll`. Any received streams will be buffered up to a maximum of 25 streams.
See [PR 2861].
[PR 2873]: https://github.com/libp2p/rust-libp2p/pull/2873/
[PR 2861]: https://github.com/libp2p/rust-libp2p/pull/2861/
# 0.39.0

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@ -16,3 +16,4 @@ libp2p-core = { version = "0.36.0", path = "../../core", default-features = fals
parking_lot = "0.12"
thiserror = "1.0"
yamux = "0.10.0"
log = "0.4"

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@ -24,10 +24,12 @@
use futures::{
future,
prelude::*,
ready,
stream::{BoxStream, LocalBoxStream},
};
use libp2p_core::muxing::{StreamMuxer, StreamMuxerEvent};
use libp2p_core::upgrade::{InboundUpgrade, OutboundUpgrade, UpgradeInfo};
use std::collections::VecDeque;
use std::{
fmt, io, iter, mem,
pin::Pin,
@ -42,8 +44,20 @@ pub struct Yamux<S> {
incoming: S,
/// Handle to control the connection.
control: yamux::Control,
/// Temporarily buffers inbound streams in case our node is performing backpressure on the remote.
///
/// The only way how yamux can make progress is by driving the [`Incoming`] stream. However, the
/// [`StreamMuxer`] interface is designed to allow a caller to selectively make progress via
/// [`StreamMuxer::poll_inbound`] and [`StreamMuxer::poll_outbound`] whilst the more general
/// [`StreamMuxer::poll`] is designed to make progress on existing streams etc.
///
/// This buffer stores inbound streams that are created whilst [`StreamMuxer::poll`] is called.
/// Once the buffer is full, new inbound streams are dropped.
inbound_stream_buffer: VecDeque<yamux::Stream>,
}
const MAX_BUFFERED_INBOUND_STREAMS: usize = 25;
impl<S> fmt::Debug for Yamux<S> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.write_str("Yamux")
@ -65,6 +79,7 @@ where
_marker: std::marker::PhantomData,
},
control: ctrl,
inbound_stream_buffer: VecDeque::default(),
}
}
}
@ -84,6 +99,7 @@ where
_marker: std::marker::PhantomData,
},
control: ctrl,
inbound_stream_buffer: VecDeque::default(),
}
}
}
@ -101,13 +117,11 @@ where
mut self: Pin<&mut Self>,
cx: &mut Context<'_>,
) -> Poll<Result<Self::Substream, Self::Error>> {
self.incoming.poll_next_unpin(cx).map(|maybe_stream| {
let stream = maybe_stream
.transpose()?
.ok_or(YamuxError(ConnectionError::Closed))?;
if let Some(stream) = self.inbound_stream_buffer.pop_front() {
return Poll::Ready(Ok(stream));
}
Ok(stream)
})
self.poll_inner(cx)
}
fn poll_outbound(
@ -121,9 +135,21 @@ where
fn poll(
self: Pin<&mut Self>,
_: &mut Context<'_>,
cx: &mut Context<'_>,
) -> Poll<Result<StreamMuxerEvent, Self::Error>> {
Poll::Pending
let this = self.get_mut();
loop {
let inbound_stream = ready!(this.poll_inner(cx))?;
if this.inbound_stream_buffer.len() >= MAX_BUFFERED_INBOUND_STREAMS {
log::warn!("dropping {inbound_stream} because buffer is full");
drop(inbound_stream);
continue;
}
this.inbound_stream_buffer.push_back(inbound_stream);
}
}
fn poll_close(mut self: Pin<&mut Self>, c: &mut Context<'_>) -> Poll<YamuxResult<()>> {
@ -145,6 +171,21 @@ where
}
}
impl<S> Yamux<S>
where
S: Stream<Item = Result<yamux::Stream, YamuxError>> + Unpin,
{
fn poll_inner(&mut self, cx: &mut Context<'_>) -> Poll<Result<yamux::Stream, YamuxError>> {
self.incoming.poll_next_unpin(cx).map(|maybe_stream| {
let stream = maybe_stream
.transpose()?
.ok_or(YamuxError(ConnectionError::Closed))?;
Ok(stream)
})
}
}
/// The yamux configuration.
#[derive(Debug, Clone)]
pub struct YamuxConfig {

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@ -5,7 +5,12 @@
- Update to `libp2p-core` `v0.36.0`.
- Enforce backpressure on incoming streams via `StreamMuxer` interface. In case we hit the configured limit of maximum
number of inbound streams, we will stop polling the `StreamMuxer` for new inbound streams. Depending on the muxer
implementation in use, this may lead to instant dropping of inbound streams. See [PR 2861].
[libp2p-swarm v0.38.0 changelog entry]: https://github.com/libp2p/rust-libp2p/blob/master/swarm/CHANGELOG.md#0380
[PR 2861]: https://github.com/libp2p/rust-libp2p/pull/2861/
# 0.38.0

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@ -19,7 +19,6 @@
// DEALINGS IN THE SOFTWARE.
mod error;
mod handler_wrapper;
pub(crate) mod pool;
@ -31,16 +30,23 @@ pub use pool::{ConnectionCounters, ConnectionLimits};
pub use pool::{EstablishedConnection, PendingConnection};
use crate::handler::ConnectionHandler;
use crate::IntoConnectionHandler;
use handler_wrapper::HandlerWrapper;
use crate::upgrade::{InboundUpgradeSend, OutboundUpgradeSend, SendWrapper};
use crate::{ConnectionHandlerEvent, ConnectionHandlerUpgrErr, KeepAlive, SubstreamProtocol};
use futures::stream::FuturesUnordered;
use futures::FutureExt;
use futures::StreamExt;
use futures_timer::Delay;
use instant::Instant;
use libp2p_core::connection::ConnectedPoint;
use libp2p_core::multiaddr::Multiaddr;
use libp2p_core::muxing::{StreamMuxerBox, StreamMuxerEvent, StreamMuxerExt};
use libp2p_core::upgrade;
use libp2p_core::muxing::{StreamMuxerBox, StreamMuxerEvent, StreamMuxerExt, SubstreamBox};
use libp2p_core::upgrade::{InboundUpgradeApply, OutboundUpgradeApply};
use libp2p_core::PeerId;
use std::collections::VecDeque;
use libp2p_core::{upgrade, UpgradeError};
use std::future::Future;
use std::{error::Error, fmt, io, pin::Pin, task::Context, task::Poll};
use std::task::Waker;
use std::time::Duration;
use std::{fmt, io, mem, pin::Pin, task::Context, task::Poll};
/// Information about a successfully established connection.
#[derive(Debug, Clone, PartialEq, Eq)]
@ -51,13 +57,6 @@ pub struct Connected {
pub peer_id: PeerId,
}
/// Endpoint for a received substream.
#[derive(Debug, Copy, Clone, PartialEq, Eq)]
pub enum SubstreamEndpoint<TDialInfo> {
Dialer(TDialInfo),
Listener,
}
/// Event generated by a [`Connection`].
#[derive(Debug, Clone)]
pub enum Event<T> {
@ -74,10 +73,43 @@ where
{
/// Node that handles the muxing.
muxing: StreamMuxerBox,
/// Handler that processes substreams.
handler: HandlerWrapper<THandler>,
/// List of "open_info" that is waiting for new outbound substreams.
open_info: VecDeque<handler_wrapper::OutboundOpenInfo<THandler>>,
/// The underlying handler.
handler: THandler,
/// Futures that upgrade incoming substreams.
negotiating_in: FuturesUnordered<
SubstreamUpgrade<
THandler::InboundOpenInfo,
InboundUpgradeApply<SubstreamBox, SendWrapper<THandler::InboundProtocol>>,
>,
>,
/// Futures that upgrade outgoing substreams.
negotiating_out: FuturesUnordered<
SubstreamUpgrade<
THandler::OutboundOpenInfo,
OutboundUpgradeApply<SubstreamBox, SendWrapper<THandler::OutboundProtocol>>,
>,
>,
/// The currently planned connection & handler shutdown.
shutdown: Shutdown,
/// The substream upgrade protocol override, if any.
substream_upgrade_protocol_override: Option<upgrade::Version>,
/// The maximum number of inbound streams concurrently negotiating on a
/// connection. New inbound streams exceeding the limit are dropped and thus
/// reset.
///
/// Note: This only enforces a limit on the number of concurrently
/// negotiating inbound streams. The total number of inbound streams on a
/// connection is the sum of negotiating and negotiated streams. A limit on
/// the total number of streams can be enforced at the
/// [`StreamMuxerBox`](libp2p_core::muxing::StreamMuxerBox) level.
max_negotiating_inbound_streams: usize,
/// Contains all upgrades that are waiting for a new outbound substream.
///
/// The upgrade timeout is already ticking here so this may fail in case the remote is not quick
/// enough in providing us with a new stream.
requested_substreams: FuturesUnordered<
SubstreamRequested<THandler::OutboundOpenInfo, THandler::OutboundProtocol>,
>,
}
impl<THandler> fmt::Debug for Connection<THandler>
@ -88,7 +120,6 @@ where
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_struct("Connection")
.field("handler", &self.handler)
.field("open_info", &self.open_info)
.finish()
}
}
@ -102,24 +133,20 @@ where
/// Builds a new `Connection` from the given substream multiplexer
/// and connection handler.
pub fn new(
peer_id: PeerId,
endpoint: ConnectedPoint,
muxer: StreamMuxerBox,
handler: impl IntoConnectionHandler<Handler = THandler>,
handler: THandler,
substream_upgrade_protocol_override: Option<upgrade::Version>,
max_negotiating_inbound_streams: usize,
) -> Self {
let wrapped_handler = HandlerWrapper::new(
peer_id,
endpoint,
handler,
substream_upgrade_protocol_override,
max_negotiating_inbound_streams,
);
Connection {
muxing: muxer,
handler: wrapped_handler,
open_info: VecDeque::with_capacity(8),
handler,
negotiating_in: Default::default(),
negotiating_out: Default::default(),
shutdown: Shutdown::None,
substream_upgrade_protocol_override,
max_negotiating_inbound_streams,
requested_substreams: Default::default(),
}
}
@ -131,57 +158,157 @@ where
/// Begins an orderly shutdown of the connection, returning the connection
/// handler and a `Future` that resolves when connection shutdown is complete.
pub fn close(self) -> (THandler, impl Future<Output = io::Result<()>>) {
(self.handler.into_connection_handler(), self.muxing.close())
(self.handler, self.muxing.close())
}
/// Polls the handler and the substream, forwarding events from the former to the latter and
/// vice versa.
pub fn poll(
mut self: Pin<&mut Self>,
self: Pin<&mut Self>,
cx: &mut Context<'_>,
) -> Poll<Result<Event<THandler::OutEvent>, ConnectionError<THandler::Error>>> {
let Self {
requested_substreams,
muxing,
handler,
negotiating_out,
negotiating_in,
shutdown,
max_negotiating_inbound_streams,
substream_upgrade_protocol_override,
} = self.get_mut();
loop {
// Poll the handler for new events.
match self.handler.poll(cx)? {
match requested_substreams.poll_next_unpin(cx) {
Poll::Ready(Some(Ok(()))) => continue,
Poll::Ready(Some(Err(user_data))) => {
handler.inject_dial_upgrade_error(user_data, ConnectionHandlerUpgrErr::Timeout);
continue;
}
Poll::Ready(None) | Poll::Pending => {}
}
// Poll the [`ConnectionHandler`].
match handler.poll(cx) {
Poll::Pending => {}
Poll::Ready(handler_wrapper::Event::OutboundSubstreamRequest(user_data)) => {
self.open_info.push_back(user_data);
Poll::Ready(ConnectionHandlerEvent::OutboundSubstreamRequest { protocol }) => {
let timeout = *protocol.timeout();
let (upgrade, user_data) = protocol.into_upgrade();
requested_substreams.push(SubstreamRequested::new(user_data, timeout, upgrade));
continue; // Poll handler until exhausted.
}
Poll::Ready(handler_wrapper::Event::Custom(event)) => {
Poll::Ready(ConnectionHandlerEvent::Custom(event)) => {
return Poll::Ready(Ok(Event::Handler(event)));
}
Poll::Ready(ConnectionHandlerEvent::Close(err)) => {
return Poll::Ready(Err(ConnectionError::Handler(err)));
}
}
match self.muxing.poll_unpin(cx)? {
// In case the [`ConnectionHandler`] can not make any more progress, poll the negotiating outbound streams.
match negotiating_out.poll_next_unpin(cx) {
Poll::Pending | Poll::Ready(None) => {}
Poll::Ready(Some((user_data, Ok(upgrade)))) => {
handler.inject_fully_negotiated_outbound(upgrade, user_data);
continue;
}
Poll::Ready(Some((user_data, Err(err)))) => {
handler.inject_dial_upgrade_error(user_data, err);
continue;
}
}
// In case both the [`ConnectionHandler`] and the negotiating outbound streams can not
// make any more progress, poll the negotiating inbound streams.
match negotiating_in.poll_next_unpin(cx) {
Poll::Pending | Poll::Ready(None) => {}
Poll::Ready(Some((user_data, Ok(upgrade)))) => {
handler.inject_fully_negotiated_inbound(upgrade, user_data);
continue;
}
Poll::Ready(Some((user_data, Err(err)))) => {
handler.inject_listen_upgrade_error(user_data, err);
continue;
}
}
// Ask the handler whether it wants the connection (and the handler itself)
// to be kept alive, which determines the planned shutdown, if any.
let keep_alive = handler.connection_keep_alive();
match (&mut *shutdown, keep_alive) {
(Shutdown::Later(timer, deadline), KeepAlive::Until(t)) => {
if *deadline != t {
*deadline = t;
if let Some(dur) = deadline.checked_duration_since(Instant::now()) {
timer.reset(dur)
}
}
}
(_, KeepAlive::Until(t)) => {
if let Some(dur) = t.checked_duration_since(Instant::now()) {
*shutdown = Shutdown::Later(Delay::new(dur), t)
}
}
(_, KeepAlive::No) => *shutdown = Shutdown::Asap,
(_, KeepAlive::Yes) => *shutdown = Shutdown::None,
};
// Check if the connection (and handler) should be shut down.
// As long as we're still negotiating substreams, shutdown is always postponed.
if negotiating_in.is_empty()
&& negotiating_out.is_empty()
&& requested_substreams.is_empty()
{
match shutdown {
Shutdown::None => {}
Shutdown::Asap => return Poll::Ready(Err(ConnectionError::KeepAliveTimeout)),
Shutdown::Later(delay, _) => match Future::poll(Pin::new(delay), cx) {
Poll::Ready(_) => {
return Poll::Ready(Err(ConnectionError::KeepAliveTimeout))
}
Poll::Pending => {}
},
}
}
match muxing.poll_unpin(cx)? {
Poll::Pending => {}
Poll::Ready(StreamMuxerEvent::AddressChange(address)) => {
self.handler.inject_address_change(&address);
handler.inject_address_change(&address);
return Poll::Ready(Ok(Event::AddressChange(address)));
}
}
if !self.open_info.is_empty() {
match self.muxing.poll_outbound_unpin(cx)? {
if let Some(requested_substream) = requested_substreams.iter_mut().next() {
match muxing.poll_outbound_unpin(cx)? {
Poll::Pending => {}
Poll::Ready(substream) => {
let user_data = self
.open_info
.pop_front()
.expect("`open_info` is not empty");
let endpoint = SubstreamEndpoint::Dialer(user_data);
self.handler.inject_substream(substream, endpoint);
let (user_data, timeout, upgrade) = requested_substream.extract();
negotiating_out.push(SubstreamUpgrade::new_outbound(
substream,
user_data,
timeout,
upgrade,
*substream_upgrade_protocol_override,
));
continue; // Go back to the top, handler can potentially make progress again.
}
}
}
match self.muxing.poll_inbound_unpin(cx)? {
Poll::Pending => {}
Poll::Ready(substream) => {
self.handler
.inject_substream(substream, SubstreamEndpoint::Listener);
continue; // Go back to the top, handler can potentially make progress again.
if negotiating_in.len() < *max_negotiating_inbound_streams {
match muxing.poll_inbound_unpin(cx)? {
Poll::Pending => {}
Poll::Ready(substream) => {
let protocol = handler.listen_protocol();
negotiating_in.push(SubstreamUpgrade::new_inbound(substream, protocol));
continue; // Go back to the top, handler can potentially make progress again.
}
}
}
@ -225,4 +352,456 @@ impl fmt::Display for ConnectionLimit {
}
/// A `ConnectionLimit` can represent an error if it has been exceeded.
impl Error for ConnectionLimit {}
impl std::error::Error for ConnectionLimit {}
struct SubstreamUpgrade<UserData, Upgrade> {
user_data: Option<UserData>,
timeout: Delay,
upgrade: Upgrade,
}
impl<UserData, Upgrade>
SubstreamUpgrade<UserData, OutboundUpgradeApply<SubstreamBox, SendWrapper<Upgrade>>>
where
Upgrade: Send + OutboundUpgradeSend,
{
fn new_outbound(
substream: SubstreamBox,
user_data: UserData,
timeout: Delay,
upgrade: Upgrade,
version_override: Option<upgrade::Version>,
) -> Self {
let effective_version = match version_override {
Some(version_override) if version_override != upgrade::Version::default() => {
log::debug!(
"Substream upgrade protocol override: {:?} -> {:?}",
upgrade::Version::default(),
version_override
);
version_override
}
_ => upgrade::Version::default(),
};
Self {
user_data: Some(user_data),
timeout,
upgrade: upgrade::apply_outbound(substream, SendWrapper(upgrade), effective_version),
}
}
}
impl<UserData, Upgrade>
SubstreamUpgrade<UserData, InboundUpgradeApply<SubstreamBox, SendWrapper<Upgrade>>>
where
Upgrade: Send + InboundUpgradeSend,
{
fn new_inbound(
substream: SubstreamBox,
protocol: SubstreamProtocol<Upgrade, UserData>,
) -> Self {
let timeout = *protocol.timeout();
let (upgrade, open_info) = protocol.into_upgrade();
Self {
user_data: Some(open_info),
timeout: Delay::new(timeout),
upgrade: upgrade::apply_inbound(substream, SendWrapper(upgrade)),
}
}
}
impl<UserData, Upgrade> Unpin for SubstreamUpgrade<UserData, Upgrade> {}
impl<UserData, Upgrade, UpgradeOutput, TUpgradeError> Future for SubstreamUpgrade<UserData, Upgrade>
where
Upgrade: Future<Output = Result<UpgradeOutput, UpgradeError<TUpgradeError>>> + Unpin,
{
type Output = (
UserData,
Result<UpgradeOutput, ConnectionHandlerUpgrErr<TUpgradeError>>,
);
fn poll(mut self: Pin<&mut Self>, cx: &mut Context) -> Poll<Self::Output> {
match self.timeout.poll_unpin(cx) {
Poll::Ready(()) => {
return Poll::Ready((
self.user_data
.take()
.expect("Future not to be polled again once ready."),
Err(ConnectionHandlerUpgrErr::Timeout),
))
}
Poll::Pending => {}
}
match self.upgrade.poll_unpin(cx) {
Poll::Ready(Ok(upgrade)) => Poll::Ready((
self.user_data
.take()
.expect("Future not to be polled again once ready."),
Ok(upgrade),
)),
Poll::Ready(Err(err)) => Poll::Ready((
self.user_data
.take()
.expect("Future not to be polled again once ready."),
Err(ConnectionHandlerUpgrErr::Upgrade(err)),
)),
Poll::Pending => Poll::Pending,
}
}
}
enum SubstreamRequested<UserData, Upgrade> {
Waiting {
user_data: UserData,
timeout: Delay,
upgrade: Upgrade,
/// A waker to notify our [`FuturesUnordered`] that we have extracted the data.
///
/// This will ensure that we will get polled again in the next iteration which allows us to
/// resolve with `Ok(())` and be removed from the [`FuturesUnordered`].
extracted_waker: Option<Waker>,
},
Done,
}
impl<UserData, Upgrade> SubstreamRequested<UserData, Upgrade> {
fn new(user_data: UserData, timeout: Duration, upgrade: Upgrade) -> Self {
Self::Waiting {
user_data,
timeout: Delay::new(timeout),
upgrade,
extracted_waker: None,
}
}
fn extract(&mut self) -> (UserData, Delay, Upgrade) {
match mem::replace(self, Self::Done) {
SubstreamRequested::Waiting {
user_data,
timeout,
upgrade,
extracted_waker: waker,
} => {
if let Some(waker) = waker {
waker.wake();
}
(user_data, timeout, upgrade)
}
SubstreamRequested::Done => panic!("cannot extract twice"),
}
}
}
impl<UserData, Upgrade> Unpin for SubstreamRequested<UserData, Upgrade> {}
impl<UserData, Upgrade> Future for SubstreamRequested<UserData, Upgrade> {
type Output = Result<(), UserData>;
fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
let this = self.get_mut();
match mem::replace(this, Self::Done) {
SubstreamRequested::Waiting {
user_data,
upgrade,
mut timeout,
..
} => match timeout.poll_unpin(cx) {
Poll::Ready(()) => Poll::Ready(Err(user_data)),
Poll::Pending => {
*this = Self::Waiting {
user_data,
upgrade,
timeout,
extracted_waker: Some(cx.waker().clone()),
};
Poll::Pending
}
},
SubstreamRequested::Done => Poll::Ready(Ok(())),
}
}
}
/// The options for a planned connection & handler shutdown.
///
/// A shutdown is planned anew based on the the return value of
/// [`ConnectionHandler::connection_keep_alive`] of the underlying handler
/// after every invocation of [`ConnectionHandler::poll`].
///
/// A planned shutdown is always postponed for as long as there are ingoing
/// or outgoing substreams being negotiated, i.e. it is a graceful, "idle"
/// shutdown.
#[derive(Debug)]
enum Shutdown {
/// No shutdown is planned.
None,
/// A shut down is planned as soon as possible.
Asap,
/// A shut down is planned for when a `Delay` has elapsed.
Later(Delay, Instant),
}
#[cfg(test)]
mod tests {
use super::*;
use crate::handler::DummyConnectionHandler;
use futures::AsyncRead;
use futures::AsyncWrite;
use libp2p_core::upgrade::DeniedUpgrade;
use libp2p_core::StreamMuxer;
use quickcheck::*;
use std::sync::{Arc, Weak};
use void::Void;
#[test]
fn max_negotiating_inbound_streams() {
fn prop(max_negotiating_inbound_streams: u8) {
let max_negotiating_inbound_streams: usize = max_negotiating_inbound_streams.into();
let alive_substream_counter = Arc::new(());
let mut connection = Connection::new(
StreamMuxerBox::new(DummyStreamMuxer {
counter: alive_substream_counter.clone(),
}),
DummyConnectionHandler {
keep_alive: KeepAlive::Yes,
},
None,
max_negotiating_inbound_streams,
);
let result = Pin::new(&mut connection)
.poll(&mut Context::from_waker(futures::task::noop_waker_ref()));
assert!(result.is_pending());
assert_eq!(
Arc::weak_count(&alive_substream_counter),
max_negotiating_inbound_streams,
"Expect no more than the maximum number of allowed streams"
);
}
QuickCheck::new().quickcheck(prop as fn(_));
}
#[test]
fn outbound_stream_timeout_starts_on_request() {
let upgrade_timeout = Duration::from_secs(1);
let mut connection = Connection::new(
StreamMuxerBox::new(PendingStreamMuxer),
MockConnectionHandler::new(upgrade_timeout.clone()),
None,
2,
);
connection.handler.open_new_outbound();
let _ = Pin::new(&mut connection)
.poll(&mut Context::from_waker(futures::task::noop_waker_ref()));
std::thread::sleep(upgrade_timeout + Duration::from_secs(1));
let _ = Pin::new(&mut connection)
.poll(&mut Context::from_waker(futures::task::noop_waker_ref()));
assert!(matches!(
connection.handler.error.unwrap(),
ConnectionHandlerUpgrErr::Timeout
))
}
struct DummyStreamMuxer {
counter: Arc<()>,
}
impl StreamMuxer for DummyStreamMuxer {
type Substream = PendingSubstream;
type Error = Void;
fn poll_inbound(
self: Pin<&mut Self>,
_: &mut Context<'_>,
) -> Poll<Result<Self::Substream, Self::Error>> {
Poll::Ready(Ok(PendingSubstream(Arc::downgrade(&self.counter))))
}
fn poll_outbound(
self: Pin<&mut Self>,
_: &mut Context<'_>,
) -> Poll<Result<Self::Substream, Self::Error>> {
Poll::Pending
}
fn poll_close(self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
Poll::Ready(Ok(()))
}
fn poll(
self: Pin<&mut Self>,
_: &mut Context<'_>,
) -> Poll<Result<StreamMuxerEvent, Self::Error>> {
Poll::Pending
}
}
/// A [`StreamMuxer`] which never returns a stream.
struct PendingStreamMuxer;
impl StreamMuxer for PendingStreamMuxer {
type Substream = PendingSubstream;
type Error = Void;
fn poll_inbound(
self: Pin<&mut Self>,
_: &mut Context<'_>,
) -> Poll<Result<Self::Substream, Self::Error>> {
Poll::Pending
}
fn poll_outbound(
self: Pin<&mut Self>,
_: &mut Context<'_>,
) -> Poll<Result<Self::Substream, Self::Error>> {
Poll::Pending
}
fn poll_close(self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
Poll::Pending
}
fn poll(
self: Pin<&mut Self>,
_: &mut Context<'_>,
) -> Poll<Result<StreamMuxerEvent, Self::Error>> {
Poll::Pending
}
}
struct PendingSubstream(Weak<()>);
impl AsyncRead for PendingSubstream {
fn poll_read(
self: Pin<&mut Self>,
_cx: &mut Context<'_>,
_buf: &mut [u8],
) -> Poll<std::io::Result<usize>> {
Poll::Pending
}
}
impl AsyncWrite for PendingSubstream {
fn poll_write(
self: Pin<&mut Self>,
_cx: &mut Context<'_>,
_buf: &[u8],
) -> Poll<std::io::Result<usize>> {
Poll::Pending
}
fn poll_flush(self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<std::io::Result<()>> {
Poll::Pending
}
fn poll_close(self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<std::io::Result<()>> {
Poll::Pending
}
}
struct MockConnectionHandler {
outbound_requested: bool,
error: Option<ConnectionHandlerUpgrErr<Void>>,
upgrade_timeout: Duration,
}
impl MockConnectionHandler {
fn new(upgrade_timeout: Duration) -> Self {
Self {
outbound_requested: false,
error: None,
upgrade_timeout,
}
}
fn open_new_outbound(&mut self) {
self.outbound_requested = true;
}
}
impl ConnectionHandler for MockConnectionHandler {
type InEvent = Void;
type OutEvent = Void;
type Error = Void;
type InboundProtocol = DeniedUpgrade;
type OutboundProtocol = DeniedUpgrade;
type InboundOpenInfo = ();
type OutboundOpenInfo = ();
fn listen_protocol(
&self,
) -> SubstreamProtocol<Self::InboundProtocol, Self::InboundOpenInfo> {
SubstreamProtocol::new(DeniedUpgrade, ()).with_timeout(self.upgrade_timeout)
}
fn inject_fully_negotiated_inbound(
&mut self,
protocol: <Self::InboundProtocol as InboundUpgradeSend>::Output,
_: Self::InboundOpenInfo,
) {
void::unreachable(protocol)
}
fn inject_fully_negotiated_outbound(
&mut self,
protocol: <Self::OutboundProtocol as OutboundUpgradeSend>::Output,
_: Self::OutboundOpenInfo,
) {
void::unreachable(protocol)
}
fn inject_event(&mut self, event: Self::InEvent) {
void::unreachable(event)
}
fn inject_dial_upgrade_error(
&mut self,
_: Self::OutboundOpenInfo,
error: ConnectionHandlerUpgrErr<<Self::OutboundProtocol as OutboundUpgradeSend>::Error>,
) {
self.error = Some(error)
}
fn connection_keep_alive(&self) -> KeepAlive {
KeepAlive::Yes
}
fn poll(
&mut self,
_: &mut Context<'_>,
) -> Poll<
ConnectionHandlerEvent<
Self::OutboundProtocol,
Self::OutboundOpenInfo,
Self::OutEvent,
Self::Error,
>,
> {
if self.outbound_requested {
self.outbound_requested = false;
return Poll::Ready(ConnectionHandlerEvent::OutboundSubstreamRequest {
protocol: SubstreamProtocol::new(DeniedUpgrade, ())
.with_timeout(self.upgrade_timeout),
});
}
Poll::Pending
}
}
}

View File

@ -18,7 +18,6 @@
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
use super::handler_wrapper;
use crate::transport::TransportError;
use crate::Multiaddr;
use crate::{connection::ConnectionLimit, ConnectedPoint, PeerId};
@ -66,15 +65,6 @@ where
}
}
impl<THandlerErr> From<handler_wrapper::Error<THandlerErr>> for ConnectionError<THandlerErr> {
fn from(error: handler_wrapper::Error<THandlerErr>) -> Self {
match error {
handler_wrapper::Error::Handler(e) => Self::Handler(e),
handler_wrapper::Error::KeepAliveTimeout => Self::KeepAliveTimeout,
}
}
}
impl<THandlerErr> From<io::Error> for ConnectionError<THandlerErr> {
fn from(error: io::Error) -> Self {
ConnectionError::IO(error)

View File

@ -1,521 +0,0 @@
// Copyright 2018 Parity Technologies (UK) Ltd.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation
// the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
use crate::connection::SubstreamEndpoint;
use crate::handler::{
ConnectionHandler, ConnectionHandlerEvent, ConnectionHandlerUpgrErr, KeepAlive,
};
use crate::upgrade::SendWrapper;
use crate::IntoConnectionHandler;
use futures::prelude::*;
use futures::stream::FuturesUnordered;
use futures_timer::Delay;
use instant::Instant;
use libp2p_core::{
muxing::SubstreamBox,
upgrade::{self, InboundUpgradeApply, OutboundUpgradeApply, UpgradeError},
Multiaddr,
};
use libp2p_core::{ConnectedPoint, PeerId};
use std::{error, fmt, pin::Pin, task::Context, task::Poll, time::Duration};
/// A wrapper for an underlying [`ConnectionHandler`].
///
/// It extends [`ConnectionHandler`] with:
/// - Enforced substream upgrade timeouts
/// - Driving substream upgrades
/// - Handling connection timeout
// TODO: add a caching system for protocols that are supported or not
pub struct HandlerWrapper<TConnectionHandler>
where
TConnectionHandler: ConnectionHandler,
{
remote_peer_id: PeerId,
/// The underlying handler.
handler: TConnectionHandler,
/// Futures that upgrade incoming substreams.
negotiating_in: FuturesUnordered<
SubstreamUpgrade<
TConnectionHandler::InboundOpenInfo,
InboundUpgradeApply<SubstreamBox, SendWrapper<TConnectionHandler::InboundProtocol>>,
>,
>,
/// Futures that upgrade outgoing substreams.
negotiating_out: FuturesUnordered<
SubstreamUpgrade<
TConnectionHandler::OutboundOpenInfo,
OutboundUpgradeApply<SubstreamBox, SendWrapper<TConnectionHandler::OutboundProtocol>>,
>,
>,
/// For each outbound substream request, how to upgrade it. The first element of the tuple
/// is the unique identifier (see `unique_dial_upgrade_id`).
queued_dial_upgrades: Vec<(u64, SendWrapper<TConnectionHandler::OutboundProtocol>)>,
/// Unique identifier assigned to each queued dial upgrade.
unique_dial_upgrade_id: u64,
/// The currently planned connection & handler shutdown.
shutdown: Shutdown,
/// The substream upgrade protocol override, if any.
substream_upgrade_protocol_override: Option<upgrade::Version>,
/// The maximum number of inbound streams concurrently negotiating on a
/// connection. New inbound streams exceeding the limit are dropped and thus
/// reset.
///
/// Note: This only enforces a limit on the number of concurrently
/// negotiating inbound streams. The total number of inbound streams on a
/// connection is the sum of negotiating and negotiated streams. A limit on
/// the total number of streams can be enforced at the
/// [`StreamMuxerBox`](libp2p_core::muxing::StreamMuxerBox) level.
max_negotiating_inbound_streams: usize,
}
impl<TConnectionHandler: ConnectionHandler> std::fmt::Debug for HandlerWrapper<TConnectionHandler> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_struct("HandlerWrapper")
.field("negotiating_in", &self.negotiating_in)
.field("negotiating_out", &self.negotiating_out)
.field("unique_dial_upgrade_id", &self.unique_dial_upgrade_id)
.field("shutdown", &self.shutdown)
.field(
"substream_upgrade_protocol_override",
&self.substream_upgrade_protocol_override,
)
.finish()
}
}
impl<TConnectionHandler: ConnectionHandler> HandlerWrapper<TConnectionHandler> {
pub(crate) fn new(
remote_peer_id: PeerId,
endpoint: ConnectedPoint,
handler: impl IntoConnectionHandler<Handler = TConnectionHandler>,
substream_upgrade_protocol_override: Option<upgrade::Version>,
max_negotiating_inbound_streams: usize,
) -> Self {
Self {
remote_peer_id,
handler: handler.into_handler(&remote_peer_id, &endpoint),
negotiating_in: Default::default(),
negotiating_out: Default::default(),
queued_dial_upgrades: Vec::new(),
unique_dial_upgrade_id: 0,
shutdown: Shutdown::None,
substream_upgrade_protocol_override,
max_negotiating_inbound_streams,
}
}
pub(crate) fn into_connection_handler(self) -> TConnectionHandler {
self.handler
}
}
struct SubstreamUpgrade<UserData, Upgrade> {
user_data: Option<UserData>,
timeout: Delay,
upgrade: Upgrade,
}
impl<UserData, Upgrade> Unpin for SubstreamUpgrade<UserData, Upgrade> {}
impl<UserData, Upgrade, UpgradeOutput, TUpgradeError> Future for SubstreamUpgrade<UserData, Upgrade>
where
Upgrade: Future<Output = Result<UpgradeOutput, UpgradeError<TUpgradeError>>> + Unpin,
{
type Output = (
UserData,
Result<UpgradeOutput, ConnectionHandlerUpgrErr<TUpgradeError>>,
);
fn poll(mut self: Pin<&mut Self>, cx: &mut Context) -> Poll<Self::Output> {
match self.timeout.poll_unpin(cx) {
Poll::Ready(()) => {
return Poll::Ready((
self.user_data
.take()
.expect("Future not to be polled again once ready."),
Err(ConnectionHandlerUpgrErr::Timeout),
))
}
Poll::Pending => {}
}
match self.upgrade.poll_unpin(cx) {
Poll::Ready(Ok(upgrade)) => Poll::Ready((
self.user_data
.take()
.expect("Future not to be polled again once ready."),
Ok(upgrade),
)),
Poll::Ready(Err(err)) => Poll::Ready((
self.user_data
.take()
.expect("Future not to be polled again once ready."),
Err(ConnectionHandlerUpgrErr::Upgrade(err)),
)),
Poll::Pending => Poll::Pending,
}
}
}
/// The options for a planned connection & handler shutdown.
///
/// A shutdown is planned anew based on the the return value of
/// [`ConnectionHandler::connection_keep_alive`] of the underlying handler
/// after every invocation of [`ConnectionHandler::poll`].
///
/// A planned shutdown is always postponed for as long as there are ingoing
/// or outgoing substreams being negotiated, i.e. it is a graceful, "idle"
/// shutdown.
#[derive(Debug)]
enum Shutdown {
/// No shutdown is planned.
None,
/// A shut down is planned as soon as possible.
Asap,
/// A shut down is planned for when a `Delay` has elapsed.
Later(Delay, Instant),
}
/// Error generated by the [`HandlerWrapper`].
#[derive(Debug)]
pub enum Error<TErr> {
/// The connection handler encountered an error.
Handler(TErr),
/// The connection keep-alive timeout expired.
KeepAliveTimeout,
}
impl<TErr> From<TErr> for Error<TErr> {
fn from(err: TErr) -> Error<TErr> {
Error::Handler(err)
}
}
impl<TErr> fmt::Display for Error<TErr>
where
TErr: fmt::Display,
{
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match self {
Error::Handler(err) => write!(f, "{}", err),
Error::KeepAliveTimeout => {
write!(f, "Connection closed due to expired keep-alive timeout.")
}
}
}
}
impl<TErr> error::Error for Error<TErr>
where
TErr: error::Error + 'static,
{
fn source(&self) -> Option<&(dyn error::Error + 'static)> {
match self {
Error::Handler(err) => Some(err),
Error::KeepAliveTimeout => None,
}
}
}
pub type OutboundOpenInfo<TConnectionHandler> = (
u64,
<TConnectionHandler as ConnectionHandler>::OutboundOpenInfo,
Duration,
);
impl<TConnectionHandler> HandlerWrapper<TConnectionHandler>
where
TConnectionHandler: ConnectionHandler,
{
pub fn inject_substream(
&mut self,
substream: SubstreamBox,
// The first element of the tuple is the unique upgrade identifier
// (see `unique_dial_upgrade_id`).
endpoint: SubstreamEndpoint<OutboundOpenInfo<TConnectionHandler>>,
) {
match endpoint {
SubstreamEndpoint::Listener => {
if self.negotiating_in.len() == self.max_negotiating_inbound_streams {
log::warn!(
"Incoming substream from {} exceeding maximum number \
of negotiating inbound streams {} on connection. \
Dropping. See PoolConfig::with_max_negotiating_inbound_streams.",
self.remote_peer_id,
self.max_negotiating_inbound_streams,
);
return;
}
let protocol = self.handler.listen_protocol();
let timeout = *protocol.timeout();
let (upgrade, user_data) = protocol.into_upgrade();
let upgrade = upgrade::apply_inbound(substream, SendWrapper(upgrade));
let timeout = Delay::new(timeout);
self.negotiating_in.push(SubstreamUpgrade {
user_data: Some(user_data),
timeout,
upgrade,
});
}
SubstreamEndpoint::Dialer((upgrade_id, user_data, timeout)) => {
let pos = match self
.queued_dial_upgrades
.iter()
.position(|(id, _)| id == &upgrade_id)
{
Some(p) => p,
None => {
debug_assert!(false, "Received an upgrade with an invalid upgrade ID");
return;
}
};
let (_, upgrade) = self.queued_dial_upgrades.remove(pos);
let mut version = upgrade::Version::default();
if let Some(v) = self.substream_upgrade_protocol_override {
if v != version {
log::debug!(
"Substream upgrade protocol override: {:?} -> {:?}",
version,
v
);
version = v;
}
}
let upgrade = upgrade::apply_outbound(substream, upgrade, version);
let timeout = Delay::new(timeout);
self.negotiating_out.push(SubstreamUpgrade {
user_data: Some(user_data),
timeout,
upgrade,
});
}
}
}
pub fn inject_event(&mut self, event: TConnectionHandler::InEvent) {
self.handler.inject_event(event);
}
pub fn inject_address_change(&mut self, new_address: &Multiaddr) {
self.handler.inject_address_change(new_address);
}
fn handle_connection_handler_event(
&mut self,
handler_event: ConnectionHandlerEvent<
TConnectionHandler::OutboundProtocol,
TConnectionHandler::OutboundOpenInfo,
TConnectionHandler::OutEvent,
TConnectionHandler::Error,
>,
) -> Result<
Event<OutboundOpenInfo<TConnectionHandler>, TConnectionHandler::OutEvent>,
Error<TConnectionHandler::Error>,
> {
match handler_event {
ConnectionHandlerEvent::Custom(event) => Ok(Event::Custom(event)),
ConnectionHandlerEvent::OutboundSubstreamRequest { protocol } => {
let id = self.unique_dial_upgrade_id;
let timeout = *protocol.timeout();
self.unique_dial_upgrade_id += 1;
let (upgrade, info) = protocol.into_upgrade();
self.queued_dial_upgrades.push((id, SendWrapper(upgrade)));
Ok(Event::OutboundSubstreamRequest((id, info, timeout)))
}
ConnectionHandlerEvent::Close(err) => Err(err.into()),
}
}
pub fn poll(
&mut self,
cx: &mut Context<'_>,
) -> Poll<
Result<
Event<OutboundOpenInfo<TConnectionHandler>, TConnectionHandler::OutEvent>,
Error<TConnectionHandler::Error>,
>,
> {
loop {
// Poll the [`ConnectionHandler`].
if let Poll::Ready(handler_event) = self.handler.poll(cx) {
let wrapper_event = self.handle_connection_handler_event(handler_event)?;
return Poll::Ready(Ok(wrapper_event));
}
// In case the [`ConnectionHandler`] can not make any more progress, poll the negotiating outbound streams.
if let Poll::Ready(Some((user_data, res))) = self.negotiating_out.poll_next_unpin(cx) {
match res {
Ok(upgrade) => self
.handler
.inject_fully_negotiated_outbound(upgrade, user_data),
Err(err) => self.handler.inject_dial_upgrade_error(user_data, err),
}
// After the `inject_*` calls, the [`ConnectionHandler`] might be able to make progress.
continue;
}
// In case both the [`ConnectionHandler`] and the negotiating outbound streams can not
// make any more progress, poll the negotiating inbound streams.
if let Poll::Ready(Some((user_data, res))) = self.negotiating_in.poll_next_unpin(cx) {
match res {
Ok(upgrade) => self
.handler
.inject_fully_negotiated_inbound(upgrade, user_data),
Err(err) => self.handler.inject_listen_upgrade_error(user_data, err),
}
// After the `inject_*` calls, the [`ConnectionHandler`] might be able to make progress.
continue;
}
// None of the three can make any more progress, thus breaking the loop.
break;
}
// Ask the handler whether it wants the connection (and the handler itself)
// to be kept alive, which determines the planned shutdown, if any.
match (&mut self.shutdown, self.handler.connection_keep_alive()) {
(Shutdown::Later(timer, deadline), KeepAlive::Until(t)) => {
if *deadline != t {
*deadline = t;
if let Some(dur) = deadline.checked_duration_since(Instant::now()) {
timer.reset(dur)
}
}
}
(_, KeepAlive::Until(t)) => {
if let Some(dur) = t.checked_duration_since(Instant::now()) {
self.shutdown = Shutdown::Later(Delay::new(dur), t)
}
}
(_, KeepAlive::No) => self.shutdown = Shutdown::Asap,
(_, KeepAlive::Yes) => self.shutdown = Shutdown::None,
};
// Check if the connection (and handler) should be shut down.
// As long as we're still negotiating substreams, shutdown is always postponed.
if self.negotiating_in.is_empty() && self.negotiating_out.is_empty() {
match self.shutdown {
Shutdown::None => {}
Shutdown::Asap => return Poll::Ready(Err(Error::KeepAliveTimeout)),
Shutdown::Later(ref mut delay, _) => match Future::poll(Pin::new(delay), cx) {
Poll::Ready(_) => return Poll::Ready(Err(Error::KeepAliveTimeout)),
Poll::Pending => {}
},
}
}
Poll::Pending
}
}
/// Event produced by a [`HandlerWrapper`].
#[derive(Debug, Copy, Clone, PartialEq, Eq)]
pub enum Event<TOutboundOpenInfo, TCustom> {
/// Require a new outbound substream to be opened with the remote.
OutboundSubstreamRequest(TOutboundOpenInfo),
/// Other event.
Custom(TCustom),
}
#[cfg(test)]
mod tests {
use super::*;
use crate::handler::PendingConnectionHandler;
use quickcheck::*;
use std::sync::Arc;
#[test]
fn max_negotiating_inbound_streams() {
fn prop(max_negotiating_inbound_streams: u8) {
let max_negotiating_inbound_streams: usize = max_negotiating_inbound_streams.into();
let mut wrapper = HandlerWrapper::new(
PeerId::random(),
ConnectedPoint::Listener {
local_addr: Multiaddr::empty(),
send_back_addr: Multiaddr::empty(),
},
PendingConnectionHandler::new("test".to_string()),
None,
max_negotiating_inbound_streams,
);
let alive_substreams_counter = Arc::new(());
for _ in 0..max_negotiating_inbound_streams {
let substream =
SubstreamBox::new(PendingSubstream(alive_substreams_counter.clone()));
wrapper.inject_substream(substream, SubstreamEndpoint::Listener);
}
assert_eq!(
Arc::strong_count(&alive_substreams_counter),
max_negotiating_inbound_streams + 1,
"Expect none of the substreams up to the limit to be dropped."
);
let substream = SubstreamBox::new(PendingSubstream(alive_substreams_counter.clone()));
wrapper.inject_substream(substream, SubstreamEndpoint::Listener);
assert_eq!(
Arc::strong_count(&alive_substreams_counter),
max_negotiating_inbound_streams + 1,
"Expect substream exceeding the limit to be dropped."
);
}
QuickCheck::new().quickcheck(prop as fn(_));
}
struct PendingSubstream(Arc<()>);
impl AsyncRead for PendingSubstream {
fn poll_read(
self: Pin<&mut Self>,
_cx: &mut Context<'_>,
_buf: &mut [u8],
) -> Poll<std::io::Result<usize>> {
Poll::Pending
}
}
impl AsyncWrite for PendingSubstream {
fn poll_write(
self: Pin<&mut Self>,
_cx: &mut Context<'_>,
_buf: &[u8],
) -> Poll<std::io::Result<usize>> {
Poll::Pending
}
fn poll_flush(self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<std::io::Result<()>> {
Poll::Pending
}
fn poll_close(self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<std::io::Result<()>> {
Poll::Pending
}
}
}

View File

@ -19,6 +19,7 @@
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
use crate::connection::Connection;
use crate::{
behaviour::{THandlerInEvent, THandlerOutEvent},
connection::{
@ -89,7 +90,7 @@ where
/// The maximum number of inbound streams concurrently negotiating on a connection.
///
/// See [`super::handler_wrapper::HandlerWrapper::max_negotiating_inbound_streams`].
/// See [`Connection::max_negotiating_inbound_streams`].
max_negotiating_inbound_streams: usize,
/// The executor to use for running the background tasks. If `None`,
@ -746,11 +747,9 @@ where
},
);
let connection = super::Connection::new(
obtained_peer_id,
endpoint,
let connection = Connection::new(
muxer,
handler,
handler.into_handler(&obtained_peer_id, &endpoint),
self.substream_upgrade_protocol_override,
self.max_negotiating_inbound_streams,
);
@ -1165,7 +1164,7 @@ pub struct PoolConfig {
/// The maximum number of inbound streams concurrently negotiating on a connection.
///
/// See [super::handler_wrapper::HandlerWrapper::max_negotiating_inbound_streams].
/// See [`Connection::max_negotiating_inbound_streams`].
max_negotiating_inbound_streams: usize,
}
@ -1240,7 +1239,7 @@ impl PoolConfig {
/// The maximum number of inbound streams concurrently negotiating on a connection.
///
/// See [`super::handler_wrapper::HandlerWrapper::max_negotiating_inbound_streams`].
/// See [`Connection::max_negotiating_inbound_streams`].
pub fn with_max_negotiating_inbound_streams(mut self, v: usize) -> Self {
self.max_negotiating_inbound_streams = v;
self