From: Matt Corallo Date: Sat, 1 Feb 2020 17:27:30 +0000 (-0500) Subject: Rewrite lightning-net-tokio using async/await and tokio 0.2 X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=commitdiff_plain;h=e3892e0ba3ed1c9d7c74107ce186c3fabd263561;p=rust-lightning Rewrite lightning-net-tokio using async/await and tokio 0.2 This is a rather major rewrite, using async/await and tokio 0.2, which cleans up the code a ton as well as adds significantly to readability. --- diff --git a/lightning-net-tokio/Cargo.toml b/lightning-net-tokio/Cargo.toml index 1bd9805a7..758c715e7 100644 --- a/lightning-net-tokio/Cargo.toml +++ b/lightning-net-tokio/Cargo.toml @@ -1,8 +1,9 @@ [package] name = "lightning-net-tokio" -version = "0.0.2" +version = "0.0.3" authors = ["Matt Corallo"] license = "Apache-2.0" +edition = "2018" description = """ Implementation of the rust-lightning network stack using Tokio. For Rust-Lightning clients which wish to make direct connections to Lightning P2P nodes, this is a simple alternative to implementing the nerequired network stack, especially for those already using Tokio. @@ -13,7 +14,4 @@ bitcoin = "0.21" bitcoin_hashes = "0.7" lightning = { version = "0.0.10", path = "../lightning" } secp256k1 = "0.15" -tokio-codec = "0.1" -futures = "0.1" -tokio = "0.1" -bytes = "0.4" +tokio = { version = "0.2", features = [ "io-util", "macros", "rt-core", "sync", "tcp", "time" ] } diff --git a/lightning-net-tokio/src/lib.rs b/lightning-net-tokio/src/lib.rs index ca12cad40..6d992873a 100644 --- a/lightning-net-tokio/src/lib.rs +++ b/lightning-net-tokio/src/lib.rs @@ -1,109 +1,161 @@ -extern crate bytes; -extern crate tokio; -extern crate tokio_codec; -extern crate futures; -extern crate lightning; -extern crate secp256k1; - -use bytes::BufMut; - -use futures::future; -use futures::future::Future; -use futures::{AsyncSink, Stream, Sink}; -use futures::sync::mpsc; - use secp256k1::key::PublicKey; -use tokio::timer::Delay; use tokio::net::TcpStream; +use tokio::{io, time}; +use tokio::sync::{mpsc, oneshot}; +use tokio::io::{AsyncReadExt, AsyncWrite, AsyncWriteExt}; use lightning::ln::peer_handler; use lightning::ln::peer_handler::SocketDescriptor as LnSocketTrait; use lightning::ln::msgs::ChannelMessageHandler; -use std::mem; +use std::task; use std::net::SocketAddr; use std::sync::{Arc, Mutex}; use std::sync::atomic::{AtomicU64, Ordering}; -use std::time::{Duration, Instant}; -use std::vec::Vec; +use std::time::Duration; use std::hash::Hash; static ID_COUNTER: AtomicU64 = AtomicU64::new(0); /// A connection to a remote peer. Can be constructed either as a remote connection using -/// Connection::setup_outbound o +/// Connection::setup_outbound pub struct Connection { - writer: Option>, + writer: Option>, event_notify: mpsc::Sender<()>, - pending_read: Vec, - read_blocker: Option>>, + // 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_event. This provides + // that indirection, with a Sender which gets handed to the PeerManager Arc on the + // schedule_read stack. + // + // An alternative (likely more effecient) approach would involve creating a RawWakerVTable at + // runtime with functions templated by the Arc type, calling write_event directly + // from tokio's write wake, however doing so would require more unsafe voodo than I really feel + // like writing. + write_avail: mpsc::Sender<()>, + // When we are told by rust-lightning to pause read (because we have writes backing up), we do + // so by setting read_paused. If the read thread thereafter reads some data, it will place a + // Sender here and then block on it. + read_blocker: Option>, read_paused: bool, - need_disconnect: bool, + // If we get disconnected via SocketDescriptor::disconnect_socket(), we don't call + // disconnect_event(), but if we get an Err return value out of PeerManager, in general, we do. + // We track here whether we'll need to call disconnect_event() after the socket closes. + need_disconnect_event: bool, + disconnect: bool, id: u64, } impl Connection { - fn schedule_read(peer_manager: Arc, Arc>>, us: Arc>, reader: futures::stream::SplitStream>) { - let us_ref = us.clone(); - let us_close_ref = us.clone(); + async fn schedule_read(peer_manager: Arc>>, us: Arc>, mut reader: io::ReadHalf, mut write_event: mpsc::Receiver<()>) { let peer_manager_ref = peer_manager.clone(); - tokio::spawn(reader.for_each(move |b| { - let pending_read = b.to_vec(); - { - let mut lock = us_ref.lock().unwrap(); - assert!(lock.pending_read.is_empty()); - if lock.read_paused { - lock.pending_read = pending_read; - let (sender, blocker) = futures::sync::oneshot::channel(); - lock.read_blocker = Some(sender); - return future::Either::A(blocker.then(|_| { Ok(()) })); - } + let mut buf = [0; 8192]; + loop { + macro_rules! shutdown_socket { + ($err: expr) => { { + println!("Disconnecting peer due to {}!", $err); + break; + } } } - //TODO: There's a race where we don't meet the requirements of disconnect_socket if its - //called right here, after we release the us_ref lock in the scope above, but before we - //call read_event! - match peer_manager.read_event(&mut SocketDescriptor::new(us_ref.clone(), peer_manager.clone()), &pending_read) { - Ok(pause_read) => { - if pause_read { - let mut lock = us_ref.lock().unwrap(); - lock.read_paused = true; + + // Whenever we want to block, we have to at least select with the write_event Receiver, + // which is used by the SocketDescriptor to wake us up if we need to shut down the + // socket or if we need to generate a write_event. + macro_rules! select_write_ev { + ($v: expr) => { { + assert!($v.is_some()); // We can't have dropped the sending end, its in the us Arc! + if us.lock().unwrap().disconnect { + shutdown_socket!("disconnect_socket() call from RL"); } - }, - Err(e) => { - us_ref.lock().unwrap().need_disconnect = false; - return future::Either::B(future::result(Err(std::io::Error::new(std::io::ErrorKind::InvalidData, e)))); - } + if let Err(e) = peer_manager.write_event(&mut SocketDescriptor::new(us.clone())) { + shutdown_socket!(e); + } + } } } - if let Err(e) = us_ref.lock().unwrap().event_notify.try_send(()) { + tokio::select! { + v = write_event.recv() => select_write_ev!(v), + read = reader.read(&mut buf) => match read { + Ok(0) => { + println!("Connection closed"); + break; + }, + Ok(len) => { + if let Some(blocker) = { + let mut lock = us.lock().unwrap(); + if lock.disconnect { + shutdown_socket!("disconnect_socket() call from RL"); + } + if lock.read_paused { + let (sender, blocker) = oneshot::channel(); + lock.read_blocker = Some(sender); + Some(blocker) + } else { None } + } { + tokio::select! { + res = blocker => { + res.unwrap(); // We should never drop the sender without sending () into it! + if us.lock().unwrap().disconnect { + shutdown_socket!("disconnect_socket() call from RL"); + } + }, + v = write_event.recv() => select_write_ev!(v), + } + } + match peer_manager.read_event(&mut SocketDescriptor::new(Arc::clone(&us)), &buf[0..len]) { + Ok(pause_read) => { + if pause_read { + let mut lock = us.lock().unwrap(); + lock.read_paused = true; + } + + if let Err(mpsc::error::TrySendError::Full(_)) = us.lock().unwrap().event_notify.try_send(()) { + // Ignore full errors as we just need them to poll after this point, so if the user + // hasn't received the last send yet, it doesn't matter. + } else { + panic!(); + } + }, + Err(e) => shutdown_socket!(e), + } + }, + Err(e) => { + println!("Connection closed: {}", e); + break; + }, + }, + } + } + let writer_option = us.lock().unwrap().writer.take(); + if let Some(mut writer) = writer_option { + writer.shutdown().await.expect("We should be able to shutdown() a socket, even if it is already disconnected"); + } + if us.lock().unwrap().need_disconnect_event { + peer_manager_ref.disconnect_event(&SocketDescriptor::new(Arc::clone(&us))); + if let Err(mpsc::error::TrySendError::Full(_)) = us.lock().unwrap().event_notify.try_send(()) { // Ignore full errors as we just need them to poll after this point, so if the user // hasn't received the last send yet, it doesn't matter. - assert!(e.is_full()); - } - - future::Either::B(future::result(Ok(()))) - }).then(move |_| { - if us_close_ref.lock().unwrap().need_disconnect { - peer_manager_ref.disconnect_event(&SocketDescriptor::new(us_close_ref, peer_manager_ref.clone())); - println!("Peer disconnected!"); } else { - println!("We disconnected peer!"); + panic!(); } - Ok(()) - })); + } } - fn new(event_notify: mpsc::Sender<()>, stream: TcpStream) -> (futures::stream::SplitStream>, Arc>) { - let (writer, reader) = tokio_codec::Framed::new(stream, tokio_codec::BytesCodec::new()).split(); - let (send_sink, send_stream) = mpsc::channel(3); - tokio::spawn(writer.send_all(send_stream.map_err(|_| -> std::io::Error { - unreachable!(); - })).then(|_| { - future::result(Ok(())) - })); - let us = Arc::new(Mutex::new(Self { writer: Some(send_sink), event_notify, pending_read: Vec::new(), read_blocker: None, read_paused: false, need_disconnect: true, id: ID_COUNTER.fetch_add(1, Ordering::AcqRel) })); + fn new(event_notify: mpsc::Sender<()>, stream: TcpStream) -> (io::ReadHalf, mpsc::Receiver<()>, Arc>) { + // 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 + // we call write_event, ensuring that we have room to push a new () if, during the + // write_event() call, send_data() returns a non-full write. + let (write_avail, receiver) = mpsc::channel(1); + let (reader, writer) = io::split(stream); - (reader, us) + (reader, receiver, + Arc::new(Mutex::new(Self { + writer: Some(writer), event_notify, write_avail, + read_blocker: None, read_paused: false, need_disconnect_event: true, disconnect: false, + id: ID_COUNTER.fetch_add(1, Ordering::AcqRel) + }))) } /// Process incoming messages and feed outgoing messages on the provided socket generated by @@ -111,11 +163,11 @@ impl Connection { /// /// You should poll the Receive end of event_notify and call get_and_clear_pending_events() on /// ChannelManager and ChannelMonitor objects. - pub fn setup_inbound(peer_manager: Arc, Arc>>, event_notify: mpsc::Sender<()>, stream: TcpStream) { - let (reader, us) = Self::new(event_notify, stream); + pub async fn setup_inbound(peer_manager: Arc>>, event_notify: mpsc::Sender<()>, stream: TcpStream) { + let (reader, receiver, us) = Self::new(event_notify, stream); - if let Ok(_) = peer_manager.new_inbound_connection(SocketDescriptor::new(us.clone(), peer_manager.clone())) { - Self::schedule_read(peer_manager, us, reader); + if let Ok(_) = peer_manager.new_inbound_connection(SocketDescriptor::new(us.clone())) { + tokio::spawn(Self::schedule_read(peer_manager, us, reader, receiver)).await; } } @@ -125,13 +177,15 @@ impl Connection { /// /// You should poll the Receive end of event_notify and call get_and_clear_pending_events() on /// ChannelManager and ChannelMonitor objects. - pub fn setup_outbound(peer_manager: Arc, Arc>>, event_notify: mpsc::Sender<()>, their_node_id: PublicKey, stream: TcpStream) { - let (reader, us) = Self::new(event_notify, stream); + pub async fn setup_outbound(peer_manager: Arc>>, event_notify: mpsc::Sender<()>, their_node_id: PublicKey, stream: TcpStream) { + let (reader, receiver, us) = Self::new(event_notify, stream); - if let Ok(initial_send) = peer_manager.new_outbound_connection(their_node_id, SocketDescriptor::new(us.clone(), peer_manager.clone())) { - if SocketDescriptor::new(us.clone(), peer_manager.clone()).send_data(&initial_send, true) == initial_send.len() { - Self::schedule_read(peer_manager, us, reader); + if let Ok(initial_send) = peer_manager.new_outbound_connection(their_node_id, SocketDescriptor::new(us.clone())) { + if SocketDescriptor::new(us.clone()).send_data(&initial_send, true) == initial_send.len() { + tokio::spawn(Self::schedule_read(peer_manager, us, reader, receiver)).await; } else { + // Note that we will skip disconnect_event here, in accordance with the PeerManager + // requirements, as disconnect_event is called by the schedule_read Future. println!("Failed to write first full message to socket!"); } } @@ -143,135 +197,134 @@ impl Connection { /// /// You should poll the Receive end of event_notify and call get_and_clear_pending_events() on /// ChannelManager and ChannelMonitor objects. - pub fn connect_outbound(peer_manager: Arc, Arc>>, event_notify: mpsc::Sender<()>, their_node_id: PublicKey, addr: SocketAddr) { - let connect_timeout = Delay::new(Instant::now() + Duration::from_secs(10)).then(|_| { - future::err(std::io::Error::new(std::io::ErrorKind::TimedOut, "timeout reached")) - }); - tokio::spawn(TcpStream::connect(&addr).select(connect_timeout) - .and_then(move |stream| { - Connection::setup_outbound(peer_manager, event_notify, their_node_id, stream.0); - future::ok(()) - }).or_else(|_| { - //TODO: return errors somehow - future::ok(()) - })); + pub async fn connect_outbound(peer_manager: Arc>>, event_notify: mpsc::Sender<()>, their_node_id: PublicKey, addr: SocketAddr) { + let connect_timeout = time::delay_for(Duration::from_secs(10)); + let connect_fut = TcpStream::connect(&addr); + tokio::select! { + _ = connect_timeout => { }, + res = connect_fut => { + if let Ok(stream) = res { + Connection::setup_outbound(peer_manager, event_notify, their_node_id, stream).await; + } + }, + }; } } -pub struct SocketDescriptor { +const SOCK_WAKER_VTABLE: task::RawWakerVTable = + task::RawWakerVTable::new(clone_socket_waker, wake_socket_waker, wake_socket_waker_by_ref, drop_socket_waker); + +fn clone_socket_waker(orig_ptr: *const ()) -> task::RawWaker { + descriptor_to_waker(orig_ptr as *const SocketDescriptor) +} +fn wake_socket_waker(orig_ptr: *const ()) { + wake_socket_waker_by_ref(orig_ptr); + drop_socket_waker(orig_ptr); +} +fn wake_socket_waker_by_ref(orig_ptr: *const ()) { + let descriptor = orig_ptr as *const SocketDescriptor; + // An error should be fine. Most likely we got two send_datas in a row, both of which failed to + // fully write, but we only need to provide a write_event() once. Otherwise, the sending thread + // may have already gone away due to a socket close, in which case there's nothing to wake up + // anyway. + let _ = unsafe { (*descriptor).conn.lock() }.unwrap().write_avail.try_send(()); +} +fn drop_socket_waker(orig_ptr: *const ()) { + let _orig_box = unsafe { Box::from_raw(orig_ptr as *mut SocketDescriptor) }; + // _orig_box is now dropped +} +fn descriptor_to_waker(descriptor: *const SocketDescriptor) -> task::RawWaker { + let new_box = Box::leak(Box::new(unsafe { (*descriptor).clone() })); + let new_ptr = new_box as *const SocketDescriptor; + task::RawWaker::new(new_ptr as *const (), &SOCK_WAKER_VTABLE) +} + +pub struct SocketDescriptor { conn: Arc>, id: u64, - peer_manager: Arc, Arc>>, } -impl SocketDescriptor { - fn new(conn: Arc>, peer_manager: Arc, Arc>>) -> Self { +impl SocketDescriptor { + fn new(conn: Arc>) -> Self { let id = conn.lock().unwrap().id; - Self { conn, id, peer_manager } + Self { conn, id } } } -impl peer_handler::SocketDescriptor for SocketDescriptor { +impl peer_handler::SocketDescriptor for SocketDescriptor { fn send_data(&mut self, data: &[u8], resume_read: bool) -> usize { - macro_rules! schedule_read { - ($us_ref: expr) => { - tokio::spawn(future::lazy(move || -> Result<(), ()> { - let mut read_data = Vec::new(); - { - let mut us = $us_ref.conn.lock().unwrap(); - mem::swap(&mut read_data, &mut us.pending_read); - } - if !read_data.is_empty() { - let mut us_clone = $us_ref.clone(); - match $us_ref.peer_manager.read_event(&mut us_clone, &read_data) { - Ok(pause_read) => { - if pause_read { return Ok(()); } - }, - Err(_) => { - //TODO: Not actually sure how to do this - return Ok(()); - } - } - } - let mut us = $us_ref.conn.lock().unwrap(); - if let Some(sender) = us.read_blocker.take() { - sender.send(Ok(())).unwrap(); - } - us.read_paused = false; - if let Err(e) = us.event_notify.try_send(()) { - // Ignore full errors as we just need them to poll after this point, so if the user - // hasn't received the last send yet, it doesn't matter. - assert!(e.is_full()); - } - Ok(()) - })); - } - } - let mut us = self.conn.lock().unwrap(); - if resume_read { - let us_ref = self.clone(); - schedule_read!(us_ref); - } - if data.is_empty() { return 0; } if us.writer.is_none() { - us.read_paused = true; + // The writer gets take()n when its time to shut down, so just fast-return 0 here. return 0; } - let mut bytes = bytes::BytesMut::with_capacity(data.len()); - bytes.put(data); - let write_res = us.writer.as_mut().unwrap().start_send(bytes.freeze()); - match write_res { - Ok(res) => { - match res { - AsyncSink::Ready => { - data.len() - }, - AsyncSink::NotReady(_) => { - us.read_paused = true; - let us_ref = self.clone(); - tokio::spawn(us.writer.take().unwrap().flush().then(move |writer_res| -> Result<(), ()> { - if let Ok(writer) = writer_res { - { - let mut us = us_ref.conn.lock().unwrap(); - us.writer = Some(writer); - } - schedule_read!(us_ref); - } // we'll fire the disconnect event on the socket reader end - Ok(()) - })); - 0 - } - } - }, - Err(_) => { - // We'll fire the disconnected event on the socket reader end - 0 - }, + if resume_read { + if let Some(sender) = us.read_blocker.take() { + sender.send(()).unwrap(); + } + us.read_paused = false; + } + if data.is_empty() { return 0; } + let waker = unsafe { task::Waker::from_raw(descriptor_to_waker(self)) }; + 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; + }, + 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 + // accordance with the send_data() docs). + us.read_paused = true; + return written_len; + }, + } } } fn disconnect_socket(&mut self) { let mut us = self.conn.lock().unwrap(); - us.need_disconnect = true; + us.need_disconnect_event = false; + us.disconnect = true; us.read_paused = true; + // Wake up the sending thread, assuming its still alive + let _ = us.write_avail.try_send(()); + // TODO: There's a race where we don't meet the requirements of disconnect_socket if the + // read task is about to call a PeerManager function (eg read_event or write_event). + // Ideally we need to release the us lock and block until we have confirmation from the + // read task that it has broken out of its main loop. } } -impl Clone for SocketDescriptor { +impl Clone for SocketDescriptor { fn clone(&self) -> Self { Self { conn: Arc::clone(&self.conn), id: self.id, - peer_manager: Arc::clone(&self.peer_manager), } } } -impl Eq for SocketDescriptor {} -impl PartialEq for SocketDescriptor { +impl Eq for SocketDescriptor {} +impl PartialEq for SocketDescriptor { fn eq(&self, o: &Self) -> bool { self.id == o.id } } -impl Hash for SocketDescriptor { +impl Hash for SocketDescriptor { fn hash(&self, state: &mut H) { self.id.hash(state); }