Update tokio requirement from 0.2 to 0.3 (#1796)

* Update tokio requirement from 0.2 to 0.3

Updates the requirements on [tokio](https://github.com/tokio-rs/tokio) to permit the latest version.
- [Release notes](https://github.com/tokio-rs/tokio/releases)
- [Commits](https://github.com/tokio-rs/tokio/compare/tokio-0.2.0...tokio-0.3.0)

Signed-off-by: dependabot[bot] <support@github.com>

* protocols/mdns: Ensure to set non_blocking on tokio udp socket

* transports/tcp: Ensure to set non_blocking on tokio tcp socket

See https://github.com/tokio-rs/tokio/pull/3016 for details.

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Max Inden <mail@max-inden.de>

CHANGELOG.md

@@ -25,7 +25,8 @@
 
 # Version 0.30.0 [unreleased]
 
-- Update `libp2p-core` and all its dependers.
+- Update `libp2p-mdns`, `libp2p-tcp` and `libp2p-uds` as well as `libp2p-core`
+  and all its dependers.
 
 # Version 0.29.1 [2020-10-20]
 

Cargo.toml

@@ -95,7 +95,7 @@ libp2p-websocket = { version = "0.25.0", path = "transports/websocket", optional
 [dev-dependencies]
 async-std = "1.6.2"
 env_logger = "0.8.1"
-tokio = { version = "0.2", features = ["io-util", "io-std", "stream", "macros"] }
+tokio = { version = "0.3", features = ["io-util", "io-std", "stream", "macros", "rt", "rt-multi-thread"] }
 
 [workspace]
 members = [

protocols/mdns/Cargo.toml

@@ -22,9 +22,10 @@ log = "0.4"
 net2 = "0.2"
 rand = "0.7"
 smallvec = "1.0"
-tokio = { version = "0.2", default-features = false, features = ["udp"], optional = true }
+tokio = { version = "0.3", default-features = false, features = ["net"], optional = true }
 void = "1.0"
 wasm-timer = "0.2.4"
 
 [dev-dependencies]
 if-addrs = "0.6.4"
+tokio = { version = "0.3", default-features = false, features = ["rt", "rt-multi-thread"] }

protocols/mdns/src/service.rs

@@ -298,8 +298,9 @@ impl fmt::Debug for $service_name {
 #[cfg(feature = "async-std")]
 codegen!("async-std", MdnsService, async_std::net::UdpSocket, (|socket| Ok::<_, std::io::Error>(async_std::net::UdpSocket::from(socket))));
 
+// Note: Tokio's UdpSocket::from_std does not set the socket into non-blocking mode.
 #[cfg(feature = "tokio")]
-codegen!("tokio", TokioMdnsService, tokio::net::UdpSocket, (|socket| tokio::net::UdpSocket::from_std(socket)));
+codegen!("tokio", TokioMdnsService, tokio::net::UdpSocket, (|socket: std::net::UdpSocket| { socket.set_nonblocking(true); tokio::net::UdpSocket::from_std(socket) }));
 
 
 /// A valid mDNS packet received by the service.

transports/tcp/Cargo.toml

@@ -18,7 +18,7 @@ ipnet = "2.0.0"
 libp2p-core = { version = "0.24.0", path = "../../core" }
 log = "0.4.1"
 socket2 = "0.3.12"
-tokio = { version = "0.2", default-features = false, features = ["tcp"], optional = true }
+tokio = { version = "0.3", default-features = false, features = ["net"], optional = true }
 
 [dev-dependencies]
 libp2p-tcp = { path = ".", features = ["async-std"] }

transports/tcp/src/lib.rs

@@ -123,6 +123,11 @@ impl Transport for $tcp_config {
             socket.bind(&socket_addr.into())?;
             socket.listen(1024)?; // we may want to make this configurable
 
+            // Note: Tokio's TcpListener::from_std, which the TcpListener's TryFrom implementation
+            // uses, does not set the socket into non-blocking mode.
+            #[cfg(feature = "tokio")]
+            socket.set_nonblocking(true);
+
             let listener = <$tcp_listener>::try_from(socket.into_tcp_listener())
                 .map_err(|e| io::Error::new(io::ErrorKind::Other, e))?;
 
@@ -353,7 +358,11 @@ impl AsyncWrite for TcpTransStream {
 #[cfg(feature = "tokio")]
 impl AsyncRead for TokioTcpTransStream {
     fn poll_read(mut self: Pin<&mut Self>, cx: &mut Context, buf: &mut [u8]) -> Poll<Result<usize, io::Error>> {
-        tokio::io::AsyncRead::poll_read(Pin::new(&mut self.inner), cx, buf)
+        // Adapted from
+        // https://github.com/tokio-rs/tokio/blob/6d99e1c7dec4c6a37c4c7bf2801bc82cc210351d/tokio-util/src/compat.rs#L126.
+        let mut read_buf = tokio::io::ReadBuf::new(buf);
+        futures::ready!(tokio::io::AsyncRead::poll_read(Pin::new(&mut self.inner), cx, &mut read_buf))?;
+        Poll::Ready(Ok(read_buf.filled().len()))
     }
 }
 

transports/uds/Cargo.toml

@@ -14,7 +14,7 @@ async-std = { version = "1.6.2", optional = true }
 libp2p-core = { version = "0.24.0", path = "../../core" }
 log = "0.4.1"
 futures = "0.3.1"
-tokio = { version = "0.2", default-features = false, features = ["uds"], optional = true }
+tokio = { version = "0.3", default-features = false, features = ["net"], optional = true }
 
 [target.'cfg(all(unix, not(target_os = "emscripten")))'.dev-dependencies]
 tempfile = "3.0"