Merge pull request #2176 from TheBlueMatt/2023-04-expose-success-prob
[rust-lightning] / lightning-net-tokio / src / lib.rs
index a513e603efe54d2654bdce1a59a74b59fa9e9b93..5527d85adf6f819e0b02e3ad05e18cc7c4426ae6 100644 (file)
@@ -8,64 +8,19 @@
 // licenses.
 
 //! A socket handling library for those running in Tokio environments who wish to use
-//! rust-lightning with native TcpStreams.
+//! rust-lightning with native [`TcpStream`]s.
 //!
 //! Designed to be as simple as possible, the high-level usage is almost as simple as "hand over a
-//! TcpStream and a reference to a PeerManager and the rest is handled", except for the
-//! [Event](../lightning/util/events/enum.Event.html) handling mechanism; see example below.
+//! [`TcpStream`] and a reference to a [`PeerManager`] and the rest is handled".
 //!
-//! The PeerHandler, due to the fire-and-forget nature of this logic, must be an Arc, and must use
-//! the SocketDescriptor provided here as the PeerHandler's SocketDescriptor.
+//! The [`PeerManager`], due to the fire-and-forget nature of this logic, must be a reference,
+//! (e.g. an [`Arc`]) and must use the [`SocketDescriptor`] provided here as the [`PeerManager`]'s
+//! `SocketDescriptor` implementation.
 //!
-//! Three methods are exposed to register a new connection for handling in tokio::spawn calls; see
-//! their individual docs for details.
+//! Three methods are exposed to register a new connection for handling in [`tokio::spawn`] calls;
+//! see their individual docs for details.
 //!
-//! # Example
-//! ```
-//! use std::net::TcpStream;
-//! use bitcoin::secp256k1::PublicKey;
-//! use lightning::util::events::{Event, EventHandler, EventsProvider};
-//! use std::net::SocketAddr;
-//! use std::sync::Arc;
-//!
-//! // Define concrete types for our high-level objects:
-//! type TxBroadcaster = dyn lightning::chain::chaininterface::BroadcasterInterface + Send + Sync;
-//! type FeeEstimator = dyn lightning::chain::chaininterface::FeeEstimator + Send + Sync;
-//! type Logger = dyn lightning::util::logger::Logger + Send + Sync;
-//! type NodeSigner = dyn lightning::chain::keysinterface::NodeSigner + Send + Sync;
-//! type UtxoLookup = dyn lightning::routing::utxo::UtxoLookup + Send + Sync;
-//! type ChainFilter = dyn lightning::chain::Filter + Send + Sync;
-//! type DataPersister = dyn lightning::chain::chainmonitor::Persist<lightning::chain::keysinterface::InMemorySigner> + Send + Sync;
-//! type ChainMonitor = lightning::chain::chainmonitor::ChainMonitor<lightning::chain::keysinterface::InMemorySigner, Arc<ChainFilter>, Arc<TxBroadcaster>, Arc<FeeEstimator>, Arc<Logger>, Arc<DataPersister>>;
-//! type ChannelManager = Arc<lightning::ln::channelmanager::SimpleArcChannelManager<ChainMonitor, TxBroadcaster, FeeEstimator, Logger>>;
-//! type PeerManager = Arc<lightning::ln::peer_handler::SimpleArcPeerManager<lightning_net_tokio::SocketDescriptor, ChainMonitor, TxBroadcaster, FeeEstimator, UtxoLookup, Logger>>;
-//!
-//! // Connect to node with pubkey their_node_id at addr:
-//! async fn connect_to_node(peer_manager: PeerManager, chain_monitor: Arc<ChainMonitor>, channel_manager: ChannelManager, their_node_id: PublicKey, addr: SocketAddr) {
-//!    lightning_net_tokio::connect_outbound(peer_manager, their_node_id, addr).await;
-//!    loop {
-//!            let event_handler = |event: Event| {
-//!                    // Handle the event!
-//!            };
-//!            channel_manager.await_persistable_update();
-//!            channel_manager.process_pending_events(&event_handler);
-//!            chain_monitor.process_pending_events(&event_handler);
-//!    }
-//! }
-//!
-//! // Begin reading from a newly accepted socket and talk to the peer:
-//! async fn accept_socket(peer_manager: PeerManager, chain_monitor: Arc<ChainMonitor>, channel_manager: ChannelManager, socket: TcpStream) {
-//!    lightning_net_tokio::setup_inbound(peer_manager, socket);
-//!    loop {
-//!            let event_handler = |event: Event| {
-//!                    // Handle the event!
-//!            };
-//!            channel_manager.await_persistable_update();
-//!            channel_manager.process_pending_events(&event_handler);
-//!            chain_monitor.process_pending_events(&event_handler);
-//!    }
-//! }
-//! ```
+//! [`PeerManager`]: lightning::ln::peer_handler::PeerManager
 
 // Prefix these with `rustdoc::` when we update our MSRV to be >= 1.52 to remove warnings.
 #![deny(broken_intra_doc_links)]
 use bitcoin::secp256k1::PublicKey;
 
 use tokio::net::TcpStream;
-use tokio::{io, time};
+use tokio::time;
 use tokio::sync::mpsc;
-use tokio::io::{AsyncReadExt, AsyncWrite, AsyncWriteExt};
 
-use lightning::chain::keysinterface::NodeSigner;
 use lightning::ln::peer_handler;
 use lightning::ln::peer_handler::SocketDescriptor as LnSocketTrait;
-use lightning::ln::peer_handler::CustomMessageHandler;
-use lightning::ln::msgs::{ChannelMessageHandler, NetAddress, OnionMessageHandler, RoutingMessageHandler};
-use lightning::util::logger::Logger;
+use lightning::ln::peer_handler::APeerManager;
+use lightning::ln::msgs::SocketAddress;
 
 use std::ops::Deref;
-use std::task;
+use std::task::{self, Poll};
+use std::future::Future;
 use std::net::SocketAddr;
 use std::net::TcpStream as StdTcpStream;
 use std::sync::{Arc, Mutex};
 use std::sync::atomic::{AtomicU64, Ordering};
 use std::time::Duration;
+use std::pin::Pin;
 use std::hash::Hash;
 
 static ID_COUNTER: AtomicU64 = AtomicU64::new(0);
 
+// We only need to select over multiple futures in one place, and taking on the full `tokio/macros`
+// dependency tree in order to do so (which has broken our MSRV before) is excessive. Instead, we
+// define a trivial two- and three- select macro with the specific types we need and just use that.
+
+pub(crate) enum SelectorOutput {
+       A(Option<()>), B(Option<()>), C(tokio::io::Result<()>),
+}
+
+pub(crate) struct TwoSelector<
+       A: Future<Output=Option<()>> + Unpin, B: Future<Output=Option<()>> + Unpin
+> {
+       pub a: A,
+       pub b: B,
+}
+
+impl<
+       A: Future<Output=Option<()>> + Unpin, B: Future<Output=Option<()>> + Unpin
+> Future for TwoSelector<A, B> {
+       type Output = SelectorOutput;
+       fn poll(mut self: Pin<&mut Self>, ctx: &mut task::Context<'_>) -> Poll<SelectorOutput> {
+               match Pin::new(&mut self.a).poll(ctx) {
+                       Poll::Ready(res) => { return Poll::Ready(SelectorOutput::A(res)); },
+                       Poll::Pending => {},
+               }
+               match Pin::new(&mut self.b).poll(ctx) {
+                       Poll::Ready(res) => { return Poll::Ready(SelectorOutput::B(res)); },
+                       Poll::Pending => {},
+               }
+               Poll::Pending
+       }
+}
+
+pub(crate) struct ThreeSelector<
+       A: Future<Output=Option<()>> + Unpin, B: Future<Output=Option<()>> + Unpin, C: Future<Output=tokio::io::Result<()>> + Unpin
+> {
+       pub a: A,
+       pub b: B,
+       pub c: C,
+}
+
+impl<
+       A: Future<Output=Option<()>> + Unpin, B: Future<Output=Option<()>> + Unpin, C: Future<Output=tokio::io::Result<()>> + Unpin
+> Future for ThreeSelector<A, B, C> {
+       type Output = SelectorOutput;
+       fn poll(mut self: Pin<&mut Self>, ctx: &mut task::Context<'_>) -> Poll<SelectorOutput> {
+               match Pin::new(&mut self.a).poll(ctx) {
+                       Poll::Ready(res) => { return Poll::Ready(SelectorOutput::A(res)); },
+                       Poll::Pending => {},
+               }
+               match Pin::new(&mut self.b).poll(ctx) {
+                       Poll::Ready(res) => { return Poll::Ready(SelectorOutput::B(res)); },
+                       Poll::Pending => {},
+               }
+               match Pin::new(&mut self.c).poll(ctx) {
+                       Poll::Ready(res) => { return Poll::Ready(SelectorOutput::C(res)); },
+                       Poll::Pending => {},
+               }
+               Poll::Pending
+       }
+}
+
 /// Connection contains all our internal state for a connection - we hold a reference to the
 /// Connection object (in an Arc<Mutex<>>) in each SocketDescriptor we create as well as in the
 /// read future (which is returned by schedule_read).
 struct Connection {
-       writer: Option<io::WriteHalf<TcpStream>>,
+       writer: Option<Arc<TcpStream>>,
        // Because our PeerManager is templated by user-provided types, and we can't (as far as I can
        // tell) have a const RawWakerVTable built out of templated functions, we need some indirection
        // between being woken up with write-ready and calling PeerManager::write_buffer_space_avail.
@@ -125,53 +140,25 @@ struct Connection {
        id: u64,
 }
 impl Connection {
-       async fn poll_event_process<PM, CMH, RMH, OMH, L, UMH, NS>(
+       async fn poll_event_process<PM: Deref + 'static + Send + Sync>(
                peer_manager: PM,
                mut event_receiver: mpsc::Receiver<()>,
-       ) where
-                       PM: Deref<Target = peer_handler::PeerManager<SocketDescriptor, CMH, RMH, OMH, L, UMH, NS>> + 'static + Send + Sync,
-                       CMH: Deref + 'static + Send + Sync,
-                       RMH: Deref + 'static + Send + Sync,
-                       OMH: Deref + 'static + Send + Sync,
-                       L: Deref + 'static + Send + Sync,
-                       UMH: Deref + 'static + Send + Sync,
-                       NS: Deref + 'static + Send + Sync,
-                       CMH::Target: ChannelMessageHandler + Send + Sync,
-                       RMH::Target: RoutingMessageHandler + Send + Sync,
-                       OMH::Target: OnionMessageHandler + Send + Sync,
-                       L::Target: Logger + Send + Sync,
-                       UMH::Target: CustomMessageHandler + Send + Sync,
-                       NS::Target: NodeSigner + Send + Sync,
-       {
+       ) where PM::Target: APeerManager<Descriptor = SocketDescriptor> {
                loop {
                        if event_receiver.recv().await.is_none() {
                                return;
                        }
-                       peer_manager.process_events();
+                       peer_manager.as_ref().process_events();
                }
        }
 
-       async fn schedule_read<PM, CMH, RMH, OMH, L, UMH, NS>(
+       async fn schedule_read<PM: Deref + 'static + Send + Sync + Clone>(
                peer_manager: PM,
                us: Arc<Mutex<Self>>,
-               mut reader: io::ReadHalf<TcpStream>,
+               reader: Arc<TcpStream>,
                mut read_wake_receiver: mpsc::Receiver<()>,
                mut write_avail_receiver: mpsc::Receiver<()>,
-       ) where
-                       PM: Deref<Target = peer_handler::PeerManager<SocketDescriptor, CMH, RMH, OMH, L, UMH, NS>> + 'static + Send + Sync + Clone,
-                       CMH: Deref + 'static + Send + Sync,
-                       RMH: Deref + 'static + Send + Sync,
-                       OMH: Deref + 'static + Send + Sync,
-                       L: Deref + 'static + Send + Sync,
-                       UMH: Deref + 'static + Send + Sync,
-                       NS: Deref + 'static + Send + Sync,
-                       CMH::Target: ChannelMessageHandler + 'static + Send + Sync,
-                       RMH::Target: RoutingMessageHandler + 'static + Send + Sync,
-                       OMH::Target: OnionMessageHandler + 'static + Send + Sync,
-                       L::Target: Logger + 'static + Send + Sync,
-                       UMH::Target: CustomMessageHandler + 'static + Send + Sync,
-                       NS::Target: NodeSigner + 'static + Send + Sync,
-               {
+       ) where PM::Target: APeerManager<Descriptor = SocketDescriptor> {
                // Create a waker to wake up poll_event_process, above
                let (event_waker, event_receiver) = mpsc::channel(1);
                tokio::spawn(Self::poll_event_process(peer_manager.clone(), event_receiver));
@@ -202,29 +189,49 @@ impl Connection {
                                }
                                us_lock.read_paused
                        };
-                       tokio::select! {
-                               v = write_avail_receiver.recv() => {
+                       // TODO: Drop the Box'ing of the futures once Rust has pin-on-stack support.
+                       let select_result = if read_paused {
+                               TwoSelector {
+                                       a: Box::pin(write_avail_receiver.recv()),
+                                       b: Box::pin(read_wake_receiver.recv()),
+                               }.await
+                       } else {
+                               ThreeSelector {
+                                       a: Box::pin(write_avail_receiver.recv()),
+                                       b: Box::pin(read_wake_receiver.recv()),
+                                       c: Box::pin(reader.readable()),
+                               }.await
+                       };
+                       match select_result {
+                               SelectorOutput::A(v) => {
                                        assert!(v.is_some()); // We can't have dropped the sending end, its in the us Arc!
-                                       if peer_manager.write_buffer_space_avail(&mut our_descriptor).is_err() {
+                                       if peer_manager.as_ref().write_buffer_space_avail(&mut our_descriptor).is_err() {
                                                break Disconnect::CloseConnection;
                                        }
                                },
-                               _ = read_wake_receiver.recv() => {},
-                               read = reader.read(&mut buf), if !read_paused => match read {
-                                       Ok(0) => break Disconnect::PeerDisconnected,
-                                       Ok(len) => {
-                                               let read_res = peer_manager.read_event(&mut our_descriptor, &buf[0..len]);
-                                               let mut us_lock = us.lock().unwrap();
-                                               match read_res {
-                                                       Ok(pause_read) => {
-                                                               if pause_read {
-                                                                       us_lock.read_paused = true;
-                                                               }
-                                                       },
-                                                       Err(_) => break Disconnect::CloseConnection,
-                                               }
-                                       },
-                                       Err(_) => break Disconnect::PeerDisconnected,
+                               SelectorOutput::B(_) => {},
+                               SelectorOutput::C(res) => {
+                                       if res.is_err() { break Disconnect::PeerDisconnected; }
+                                       match reader.try_read(&mut buf) {
+                                               Ok(0) => break Disconnect::PeerDisconnected,
+                                               Ok(len) => {
+                                                       let read_res = peer_manager.as_ref().read_event(&mut our_descriptor, &buf[0..len]);
+                                                       let mut us_lock = us.lock().unwrap();
+                                                       match read_res {
+                                                               Ok(pause_read) => {
+                                                                       if pause_read {
+                                                                               us_lock.read_paused = true;
+                                                                       }
+                                                               },
+                                                               Err(_) => break Disconnect::CloseConnection,
+                                                       }
+                                               },
+                                               Err(e) if e.kind() == std::io::ErrorKind::WouldBlock => {
+                                                       // readable() is allowed to spuriously wake, so we have to handle
+                                                       // WouldBlock here.
+                                               },
+                                               Err(_) => break Disconnect::PeerDisconnected,
+                                       }
                                },
                        }
                        let _ = event_waker.try_send(());
@@ -234,20 +241,16 @@ impl Connection {
                        // our timeslice to another task we may just spin on this peer, starving other peers
                        // and eventually disconnecting them for ping timeouts. Instead, we explicitly yield
                        // here.
-                       tokio::task::yield_now().await;
+                       let _ = tokio::task::yield_now().await;
                };
-               let writer_option = us.lock().unwrap().writer.take();
-               if let Some(mut writer) = writer_option {
-                       // If the socket is already closed, shutdown() will fail, so just ignore it.
-                       let _ = writer.shutdown().await;
-               }
+               us.lock().unwrap().writer.take();
                if let Disconnect::PeerDisconnected = disconnect_type {
-                       peer_manager.socket_disconnected(&our_descriptor);
-                       peer_manager.process_events();
+                       peer_manager.as_ref().socket_disconnected(&our_descriptor);
+                       peer_manager.as_ref().process_events();
                }
        }
 
-       fn new(stream: StdTcpStream) -> (io::ReadHalf<TcpStream>, mpsc::Receiver<()>, mpsc::Receiver<()>, Arc<Mutex<Self>>) {
+       fn new(stream: StdTcpStream) -> (Arc<TcpStream>, mpsc::Receiver<()>, mpsc::Receiver<()>, Arc<Mutex<Self>>) {
                // We only ever need a channel of depth 1 here: if we returned a non-full write to the
                // PeerManager, we will eventually get notified that there is room in the socket to write
                // new bytes, which will generate an event. That event will be popped off the queue before
@@ -259,24 +262,24 @@ impl Connection {
                // false.
                let (read_waker, read_receiver) = mpsc::channel(1);
                stream.set_nonblocking(true).unwrap();
-               let (reader, writer) = io::split(TcpStream::from_std(stream).unwrap());
+               let tokio_stream = Arc::new(TcpStream::from_std(stream).unwrap());
 
-               (reader, write_receiver, read_receiver,
+               (Arc::clone(&tokio_stream), write_receiver, read_receiver,
                Arc::new(Mutex::new(Self {
-                       writer: Some(writer), write_avail, read_waker, read_paused: false,
+                       writer: Some(tokio_stream), write_avail, read_waker, read_paused: false,
                        rl_requested_disconnect: false,
                        id: ID_COUNTER.fetch_add(1, Ordering::AcqRel)
                })))
        }
 }
 
-fn get_addr_from_stream(stream: &StdTcpStream) -> Option<NetAddress> {
+fn get_addr_from_stream(stream: &StdTcpStream) -> Option<SocketAddress> {
        match stream.peer_addr() {
-               Ok(SocketAddr::V4(sockaddr)) => Some(NetAddress::IPv4 {
+               Ok(SocketAddr::V4(sockaddr)) => Some(SocketAddress::TcpIpV4 {
                        addr: sockaddr.ip().octets(),
                        port: sockaddr.port(),
                }),
-               Ok(SocketAddr::V6(sockaddr)) => Some(NetAddress::IPv6 {
+               Ok(SocketAddr::V6(sockaddr)) => Some(SocketAddress::TcpIpV6 {
                        addr: sockaddr.ip().octets(),
                        port: sockaddr.port(),
                }),
@@ -290,30 +293,17 @@ fn get_addr_from_stream(stream: &StdTcpStream) -> Option<NetAddress> {
 /// The returned future will complete when the peer is disconnected and associated handling
 /// futures are freed, though, because all processing futures are spawned with tokio::spawn, you do
 /// not need to poll the provided future in order to make progress.
-pub fn setup_inbound<PM, CMH, RMH, OMH, L, UMH, NS>(
+pub fn setup_inbound<PM: Deref + 'static + Send + Sync + Clone>(
        peer_manager: PM,
        stream: StdTcpStream,
-) -> impl std::future::Future<Output=()> where
-               PM: Deref<Target = peer_handler::PeerManager<SocketDescriptor, CMH, RMH, OMH, L, UMH, NS>> + 'static + Send + Sync + Clone,
-               CMH: Deref + 'static + Send + Sync,
-               RMH: Deref + 'static + Send + Sync,
-               OMH: Deref + 'static + Send + Sync,
-               L: Deref + 'static + Send + Sync,
-               UMH: Deref + 'static + Send + Sync,
-               NS: Deref + 'static + Send + Sync,
-               CMH::Target: ChannelMessageHandler + Send + Sync,
-               RMH::Target: RoutingMessageHandler + Send + Sync,
-               OMH::Target: OnionMessageHandler + Send + Sync,
-               L::Target: Logger + Send + Sync,
-               UMH::Target: CustomMessageHandler + Send + Sync,
-               NS::Target: NodeSigner + Send + Sync,
-{
+) -> impl std::future::Future<Output=()>
+where PM::Target: APeerManager<Descriptor = SocketDescriptor> {
        let remote_addr = get_addr_from_stream(&stream);
        let (reader, write_receiver, read_receiver, us) = Connection::new(stream);
        #[cfg(test)]
        let last_us = Arc::clone(&us);
 
-       let handle_opt = if peer_manager.new_inbound_connection(SocketDescriptor::new(us.clone()), remote_addr).is_ok() {
+       let handle_opt = if peer_manager.as_ref().new_inbound_connection(SocketDescriptor::new(us.clone()), remote_addr).is_ok() {
                Some(tokio::spawn(Connection::schedule_read(peer_manager, us, reader, read_receiver, write_receiver)))
        } else {
                // Note that we will skip socket_disconnected here, in accordance with the PeerManager
@@ -345,30 +335,17 @@ pub fn setup_inbound<PM, CMH, RMH, OMH, L, UMH, NS>(
 /// The returned future will complete when the peer is disconnected and associated handling
 /// futures are freed, though, because all processing futures are spawned with tokio::spawn, you do
 /// not need to poll the provided future in order to make progress.
-pub fn setup_outbound<PM, CMH, RMH, OMH, L, UMH, NS>(
+pub fn setup_outbound<PM: Deref + 'static + Send + Sync + Clone>(
        peer_manager: PM,
        their_node_id: PublicKey,
        stream: StdTcpStream,
-) -> impl std::future::Future<Output=()> where
-               PM: Deref<Target = peer_handler::PeerManager<SocketDescriptor, CMH, RMH, OMH, L, UMH, NS>> + 'static + Send + Sync + Clone,
-               CMH: Deref + 'static + Send + Sync,
-               RMH: Deref + 'static + Send + Sync,
-               OMH: Deref + 'static + Send + Sync,
-               L: Deref + 'static + Send + Sync,
-               UMH: Deref + 'static + Send + Sync,
-               NS: Deref + 'static + Send + Sync,
-               CMH::Target: ChannelMessageHandler + Send + Sync,
-               RMH::Target: RoutingMessageHandler + Send + Sync,
-               OMH::Target: OnionMessageHandler + Send + Sync,
-               L::Target: Logger + Send + Sync,
-               UMH::Target: CustomMessageHandler + Send + Sync,
-               NS::Target: NodeSigner + Send + Sync,
-{
+) -> impl std::future::Future<Output=()>
+where PM::Target: APeerManager<Descriptor = SocketDescriptor> {
        let remote_addr = get_addr_from_stream(&stream);
        let (reader, mut write_receiver, read_receiver, us) = Connection::new(stream);
        #[cfg(test)]
        let last_us = Arc::clone(&us);
-       let handle_opt = if let Ok(initial_send) = peer_manager.new_outbound_connection(their_node_id, SocketDescriptor::new(us.clone()), remote_addr) {
+       let handle_opt = if let Ok(initial_send) = peer_manager.as_ref().new_outbound_connection(their_node_id, SocketDescriptor::new(us.clone()), remote_addr) {
                Some(tokio::spawn(async move {
                        // We should essentially always have enough room in a TCP socket buffer to send the
                        // initial 10s of bytes. However, tokio running in single-threaded mode will always
@@ -387,7 +364,7 @@ pub fn setup_outbound<PM, CMH, RMH, OMH, L, UMH, NS>(
                                                },
                                                _ => {
                                                        eprintln!("Failed to write first full message to socket!");
-                                                       peer_manager.socket_disconnected(&SocketDescriptor::new(Arc::clone(&us)));
+                                                       peer_manager.as_ref().socket_disconnected(&SocketDescriptor::new(Arc::clone(&us)));
                                                        break Err(());
                                                }
                                        }
@@ -430,25 +407,12 @@ pub fn setup_outbound<PM, CMH, RMH, OMH, L, UMH, NS>(
 /// disconnected and associated handling futures are freed, though, because all processing in said
 /// futures are spawned with tokio::spawn, you do not need to poll the second future in order to
 /// make progress.
-pub async fn connect_outbound<PM, CMH, RMH, OMH, L, UMH, NS>(
+pub async fn connect_outbound<PM: Deref + 'static + Send + Sync + Clone>(
        peer_manager: PM,
        their_node_id: PublicKey,
        addr: SocketAddr,
-) -> Option<impl std::future::Future<Output=()>> where
-               PM: Deref<Target = peer_handler::PeerManager<SocketDescriptor, CMH, RMH, OMH, L, UMH, NS>> + 'static + Send + Sync + Clone,
-               CMH: Deref + 'static + Send + Sync,
-               RMH: Deref + 'static + Send + Sync,
-               OMH: Deref + 'static + Send + Sync,
-               L: Deref + 'static + Send + Sync,
-               UMH: Deref + 'static + Send + Sync,
-               NS: Deref + 'static + Send + Sync,
-               CMH::Target: ChannelMessageHandler + Send + Sync,
-               RMH::Target: RoutingMessageHandler + Send + Sync,
-               OMH::Target: OnionMessageHandler + Send + Sync,
-               L::Target: Logger + Send + Sync,
-               UMH::Target: CustomMessageHandler + Send + Sync,
-               NS::Target: NodeSigner + Send + Sync,
-{
+) -> Option<impl std::future::Future<Output=()>>
+where PM::Target: APeerManager<Descriptor = SocketDescriptor> {
        if let Ok(Ok(stream)) = time::timeout(Duration::from_secs(10), async { TcpStream::connect(&addr).await.map(|s| s.into_std().unwrap()) }).await {
                Some(setup_outbound(peer_manager, their_node_id, stream))
        } else { None }
@@ -498,9 +462,9 @@ impl SocketDescriptor {
 }
 impl peer_handler::SocketDescriptor for SocketDescriptor {
        fn send_data(&mut self, data: &[u8], resume_read: bool) -> usize {
-               // To send data, we take a lock on our Connection to access the WriteHalf of the TcpStream,
-               // writing to it if there's room in the kernel buffer, or otherwise create a new Waker with
-               // SocketDescriptor in it which can wake up the write_avail Sender, waking up the
+               // To send data, we take a lock on our Connection to access the TcpStream, writing to it if
+               // there's room in the kernel buffer, or otherwise create a new Waker with a
+               // SocketDescriptor in it which can wake up the write_avail Sender, waking up the
                // processing future which will call write_buffer_space_avail and we'll end up back here.
                let mut us = self.conn.lock().unwrap();
                if us.writer.is_none() {
@@ -520,24 +484,18 @@ impl peer_handler::SocketDescriptor for SocketDescriptor {
                let mut ctx = task::Context::from_waker(&waker);
                let mut written_len = 0;
                loop {
-                       match std::pin::Pin::new(us.writer.as_mut().unwrap()).poll_write(&mut ctx, &data[written_len..]) {
-                               task::Poll::Ready(Ok(res)) => {
-                                       // The tokio docs *seem* to indicate this can't happen, and I certainly don't
-                                       // know how to handle it if it does (cause it should be a Poll::Pending
-                                       // instead):
-                                       assert_ne!(res, 0);
-                                       written_len += res;
-                                       if written_len == data.len() { return written_len; }
-                               },
-                               task::Poll::Ready(Err(e)) => {
-                                       // The tokio docs *seem* to indicate this can't happen, and I certainly don't
-                                       // know how to handle it if it does (cause it should be a Poll::Pending
-                                       // instead):
-                                       assert_ne!(e.kind(), io::ErrorKind::WouldBlock);
-                                       // Probably we've already been closed, just return what we have and let the
-                                       // read thread handle closing logic.
-                                       return written_len;
+                       match us.writer.as_ref().unwrap().poll_write_ready(&mut ctx) {
+                               task::Poll::Ready(Ok(())) => {
+                                       match us.writer.as_ref().unwrap().try_write(&data[written_len..]) {
+                                               Ok(res) => {
+                                                       debug_assert_ne!(res, 0);
+                                                       written_len += res;
+                                                       if written_len == data.len() { return written_len; }
+                                               },
+                                               Err(_) => return written_len,
+                                       }
                                },
+                               task::Poll::Ready(Err(_)) => return written_len,
                                task::Poll::Pending => {
                                        // We're queued up for a write event now, but we need to make sure we also
                                        // pause read given we're now waiting on the remote end to ACK (and in
@@ -586,8 +544,10 @@ mod tests {
        use lightning::ln::peer_handler::{MessageHandler, PeerManager};
        use lightning::ln::features::NodeFeatures;
        use lightning::routing::gossip::NodeId;
-       use lightning::util::events::*;
+       use lightning::events::*;
        use lightning::util::test_utils::TestNodeSigner;
+       use bitcoin::Network;
+       use bitcoin::blockdata::constants::ChainHash;
        use bitcoin::secp256k1::{Secp256k1, SecretKey, PublicKey};
 
        use tokio::sync::mpsc;
@@ -643,6 +603,17 @@ mod tests {
                fn handle_update_fee(&self, _their_node_id: &PublicKey, _msg: &UpdateFee) {}
                fn handle_announcement_signatures(&self, _their_node_id: &PublicKey, _msg: &AnnouncementSignatures) {}
                fn handle_channel_update(&self, _their_node_id: &PublicKey, _msg: &ChannelUpdate) {}
+               fn handle_open_channel_v2(&self, _their_node_id: &PublicKey, _msg: &OpenChannelV2) {}
+               fn handle_accept_channel_v2(&self, _their_node_id: &PublicKey, _msg: &AcceptChannelV2) {}
+               fn handle_tx_add_input(&self, _their_node_id: &PublicKey, _msg: &TxAddInput) {}
+               fn handle_tx_add_output(&self, _their_node_id: &PublicKey, _msg: &TxAddOutput) {}
+               fn handle_tx_remove_input(&self, _their_node_id: &PublicKey, _msg: &TxRemoveInput) {}
+               fn handle_tx_remove_output(&self, _their_node_id: &PublicKey, _msg: &TxRemoveOutput) {}
+               fn handle_tx_complete(&self, _their_node_id: &PublicKey, _msg: &TxComplete) {}
+               fn handle_tx_signatures(&self, _their_node_id: &PublicKey, _msg: &TxSignatures) {}
+               fn handle_tx_init_rbf(&self, _their_node_id: &PublicKey, _msg: &TxInitRbf) {}
+               fn handle_tx_ack_rbf(&self, _their_node_id: &PublicKey, _msg: &TxAckRbf) {}
+               fn handle_tx_abort(&self, _their_node_id: &PublicKey, _msg: &TxAbort) {}
                fn peer_disconnected(&self, their_node_id: &PublicKey) {
                        if *their_node_id == self.expected_pubkey {
                                self.disconnected_flag.store(true, Ordering::SeqCst);
@@ -659,6 +630,9 @@ mod tests {
                fn handle_error(&self, _their_node_id: &PublicKey, _msg: &ErrorMessage) {}
                fn provided_node_features(&self) -> NodeFeatures { NodeFeatures::empty() }
                fn provided_init_features(&self, _their_node_id: &PublicKey) -> InitFeatures { InitFeatures::empty() }
+               fn get_genesis_hashes(&self) -> Option<Vec<ChainHash>> {
+                       Some(vec![ChainHash::using_genesis_block(Network::Testnet)])
+               }
        }
        impl MessageSendEventsProvider for MsgHandler {
                fn get_and_clear_pending_msg_events(&self) -> Vec<MessageSendEvent> {
@@ -704,7 +678,8 @@ mod tests {
                        chan_handler: Arc::clone(&a_handler),
                        route_handler: Arc::clone(&a_handler),
                        onion_message_handler: Arc::new(lightning::ln::peer_handler::IgnoringMessageHandler{}),
-               }, 0, &[1; 32], Arc::new(TestLogger()), Arc::new(lightning::ln::peer_handler::IgnoringMessageHandler{}), Arc::new(TestNodeSigner::new(a_key))));
+                       custom_message_handler: Arc::new(lightning::ln::peer_handler::IgnoringMessageHandler{}),
+               }, 0, &[1; 32], Arc::new(TestLogger()), Arc::new(TestNodeSigner::new(a_key))));
 
                let (b_connected_sender, mut b_connected) = mpsc::channel(1);
                let (b_disconnected_sender, mut b_disconnected) = mpsc::channel(1);
@@ -719,7 +694,8 @@ mod tests {
                        chan_handler: Arc::clone(&b_handler),
                        route_handler: Arc::clone(&b_handler),
                        onion_message_handler: Arc::new(lightning::ln::peer_handler::IgnoringMessageHandler{}),
-               }, 0, &[2; 32], Arc::new(TestLogger()), Arc::new(lightning::ln::peer_handler::IgnoringMessageHandler{}), Arc::new(TestNodeSigner::new(b_key))));
+                       custom_message_handler: Arc::new(lightning::ln::peer_handler::IgnoringMessageHandler{}),
+               }, 0, &[2; 32], Arc::new(TestLogger()), Arc::new(TestNodeSigner::new(b_key))));
 
                // We bind on localhost, hoping the environment is properly configured with a local
                // address. This may not always be the case in containers and the like, so if this test is
@@ -772,7 +748,8 @@ mod tests {
                        chan_handler: Arc::new(lightning::ln::peer_handler::ErroringMessageHandler::new()),
                        onion_message_handler: Arc::new(lightning::ln::peer_handler::IgnoringMessageHandler{}),
                        route_handler: Arc::new(lightning::ln::peer_handler::IgnoringMessageHandler{}),
-               }, 0, &[1; 32], Arc::new(TestLogger()), Arc::new(lightning::ln::peer_handler::IgnoringMessageHandler{}), Arc::new(TestNodeSigner::new(a_key))));
+                       custom_message_handler: Arc::new(lightning::ln::peer_handler::IgnoringMessageHandler{}),
+               }, 0, &[1; 32], Arc::new(TestLogger()), Arc::new(TestNodeSigner::new(a_key))));
 
                // Make two connections, one for an inbound and one for an outbound connection
                let conn_a = {