Use async-io.

Cargo.toml

@@ -17,7 +17,7 @@ default = [
     "identify",
     "kad",
     "gossipsub",
-    "mdns-async-std",
+    "mdns",
     "mplex",
     "noise",
     "ping",
@@ -37,8 +37,7 @@ floodsub = ["libp2p-floodsub"]
 identify = ["libp2p-identify"]
 kad = ["libp2p-kad"]
 gossipsub = ["libp2p-gossipsub"]
-mdns-async-std = ["libp2p-mdns", "libp2p-mdns/async-std"]
-mdns-tokio = ["libp2p-mdns", "libp2p-mdns/tokio"]
+mdns = ["libp2p-mdns"]
 mplex = ["libp2p-mplex"]
 noise = ["libp2p-noise"]
 ping = ["libp2p-ping"]
@@ -125,4 +124,4 @@ members = [
 
 [[example]]
 name = "chat-tokio"
-required-features = ["tcp-tokio", "mdns-tokio"]
+required-features = ["tcp-tokio", "mdns"]

protocols/mdns/Cargo.toml

@@ -10,10 +10,10 @@ keywords = ["peer-to-peer", "libp2p", "networking"]
 categories = ["network-programming", "asynchronous"]
 
 [dependencies]
-async-std = { version = "1.6.2", optional = true }
+async-io = "1.2.0"
+either = "1.5.3"
 data-encoding = "2.0"
 dns-parser = "0.8"
-either = "1.5.3"
 futures = "0.3.1"
 if-watch = "0.1.2"
 lazy_static = "1.2"
@@ -23,10 +23,10 @@ log = "0.4"
 net2 = "0.2"
 rand = "0.7"
 smallvec = "1.0"
-tokio = { version = "0.3", default-features = false, features = ["net"], optional = true }
 void = "1.0"
 wasm-timer = "0.2.4"
 
 [dev-dependencies]
+async-std = "1.7.0"
 if-addrs = "0.6.4"
 tokio = { version = "0.3", default-features = false, features = ["rt", "rt-multi-thread"] }

protocols/mdns/src/behaviour.rs

@@ -18,7 +18,7 @@
 // FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 // DEALINGS IN THE SOFTWARE.
 
-use crate::service::{MdnsPacket, build_query_response, build_service_discovery_response};
+use crate::service::{MdnsPacket, MdnsService, build_query_response, build_service_discovery_response};
 use futures::prelude::*;
 use libp2p_core::{
     Multiaddr,
@@ -41,14 +41,11 @@ use wasm_timer::{Delay, Instant};
 
 const MDNS_RESPONSE_TTL: std::time::Duration = Duration::from_secs(5 * 60);
 
-macro_rules! codegen {
-    ($feature_name:expr, $behaviour_name:ident, $maybe_busy_wrapper:ident, $service_name:ty) => {
-
 /// A `NetworkBehaviour` for mDNS. Automatically discovers peers on the local network and adds
 /// them to the topology.
-pub struct $behaviour_name {
+pub struct Mdns {
     /// The inner service.
-    service: $maybe_busy_wrapper,
+    service: MdnsBusyWrapper,
 
     /// List of nodes that we have discovered, the address, and when their TTL expires.
     ///
@@ -66,37 +63,37 @@ pub struct $behaviour_name {
 /// and a `MdnsPacket` (similar to the old Tokio socket send style). The two states are thus `Free`
 /// with an `MdnsService` or `Busy` with a future returning the original `MdnsService` and an
 /// `MdnsPacket`.
-enum $maybe_busy_wrapper {
-    Free($service_name),
-    Busy(Pin<Box<dyn Future<Output = ($service_name, MdnsPacket)> + Send>>),
+enum MdnsBusyWrapper {
+    Free(MdnsService),
+    Busy(Pin<Box<dyn Future<Output = (MdnsService, MdnsPacket)> + Send>>),
     Poisoned,
 }
 
-impl fmt::Debug for $maybe_busy_wrapper {
+impl fmt::Debug for MdnsBusyWrapper {
     fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {
-            $maybe_busy_wrapper::Free(service) => {
-                fmt.debug_struct("$maybe_busy_wrapper::Free")
+            Self::Free(service) => {
+                fmt.debug_struct("MdnsBusyWrapper::Free")
                     .field("service", service)
                     .finish()
             },
-            $maybe_busy_wrapper::Busy(_) => {
-                fmt.debug_struct("$maybe_busy_wrapper::Busy")
+            Self::Busy(_) => {
+                fmt.debug_struct("MdnsBusyWrapper::Busy")
                     .finish()
             }
-            $maybe_busy_wrapper::Poisoned => {
-                fmt.debug_struct("$maybe_busy_wrapper::Poisoned")
+            Self::Poisoned => {
+                fmt.debug_struct("MdnsBusyWrapper::Poisoned")
                     .finish()
             }
         }
     }
 }
 
-impl $behaviour_name {
+impl Mdns {
     /// Builds a new `Mdns` behaviour.
-    pub async fn new() -> io::Result<$behaviour_name> {
-        Ok($behaviour_name {
-            service: $maybe_busy_wrapper::Free(<$service_name>::new().await?),
+    pub async fn new() -> io::Result<Self> {
+        Ok(Self {
+            service: MdnsBusyWrapper::Free(MdnsService::new().await?),
             discovered_nodes: SmallVec::new(),
             closest_expiration: None,
         })
@@ -113,7 +110,7 @@ impl $behaviour_name {
     }
 }
 
-impl NetworkBehaviour for $behaviour_name {
+impl NetworkBehaviour for Mdns {
     type ProtocolsHandler = DummyProtocolsHandler;
     type OutEvent = MdnsEvent;
 
@@ -179,32 +176,32 @@ impl NetworkBehaviour for $behaviour_name {
 
         // Polling the mDNS service, and obtain the list of nodes discovered this round.
         let discovered = loop {
-            let service = mem::replace(&mut self.service, $maybe_busy_wrapper::Poisoned);
+            let service = mem::replace(&mut self.service, MdnsBusyWrapper::Poisoned);
 
             let packet = match service {
-                $maybe_busy_wrapper::Free(service) => {
-                    self.service = $maybe_busy_wrapper::Busy(Box::pin(service.next()));
+                MdnsBusyWrapper::Free(service) => {
+                    self.service = MdnsBusyWrapper::Busy(Box::pin(service.next()));
                     continue;
                 },
-                $maybe_busy_wrapper::Busy(mut fut) => {
+                MdnsBusyWrapper::Busy(mut fut) => {
                     match fut.as_mut().poll(cx) {
                         Poll::Ready((service, packet)) => {
-                            self.service = $maybe_busy_wrapper::Free(service);
+                            self.service = MdnsBusyWrapper::Free(service);
                             packet
                         },
                         Poll::Pending => {
-                            self.service = $maybe_busy_wrapper::Busy(fut);
+                            self.service = MdnsBusyWrapper::Busy(fut);
                             return Poll::Pending;
                         }
                     }
                 },
-                $maybe_busy_wrapper::Poisoned => panic!("Mdns poisoned"),
+                MdnsBusyWrapper::Poisoned => panic!("Mdns poisoned"),
             };
 
             match packet {
                 MdnsPacket::Query(query) => {
                     // MaybeBusyMdnsService should always be Free.
-                    if let $maybe_busy_wrapper::Free(ref mut service) = self.service {
+                    if let MdnsBusyWrapper::Free(ref mut service) = self.service {
                         let resp = build_query_response(
                             query.query_id(),
                             params.local_peer_id().clone(),
@@ -256,7 +253,7 @@ impl NetworkBehaviour for $behaviour_name {
                 },
                 MdnsPacket::ServiceDiscovery(disc) => {
                     // MaybeBusyMdnsService should always be Free.
-                    if let $maybe_busy_wrapper::Free(ref mut service) = self.service {
+                    if let MdnsBusyWrapper::Free(ref mut service) = self.service {
                         let resp = build_service_discovery_response(
                             disc.query_id(),
                             MDNS_RESPONSE_TTL,
@@ -281,23 +278,14 @@ impl NetworkBehaviour for $behaviour_name {
     }
 }
 
-impl fmt::Debug for $behaviour_name {
+impl fmt::Debug for Mdns {
     fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
         fmt.debug_struct("Mdns")
             .field("service", &self.service)
             .finish()
     }
 }
 
-};
-}
-
-#[cfg(feature = "async-std")]
-codegen!("async-std", Mdns, MaybeBusyMdnsService, crate::service::MdnsService);
-
-#[cfg(feature = "tokio")]
-codegen!("tokio", TokioMdns, MaybeBusyTokioMdnsService, crate::service::TokioMdnsService);
-
 /// Event that can be produced by the `Mdns` behaviour.
 #[derive(Debug)]
 pub enum MdnsEvent {

protocols/mdns/src/lib.rs

@@ -35,12 +35,10 @@ const SERVICE_NAME: &[u8] = b"_p2p._udp.local";
 /// Hardcoded name of the service used for DNS-SD.
 const META_QUERY_SERVICE: &[u8] = b"_services._dns-sd._udp.local";
 
-#[cfg(feature = "async-std")]
-pub use self::{behaviour::Mdns, service::MdnsService};
-#[cfg(feature = "tokio")]
-pub use self::{behaviour::TokioMdns, service::TokioMdnsService};
-
-pub use self::behaviour::MdnsEvent;
+pub use crate::{
+    behaviour::{Mdns, MdnsEvent},
+    service::MdnsService,
+};
 
 mod behaviour;
 mod dns;

protocols/mdns/src/service.rs

@@ -19,12 +19,13 @@
 // DEALINGS IN THE SOFTWARE.
 
 use crate::{SERVICE_NAME, META_QUERY_SERVICE, dns};
+use async_io::Async;
 use dns_parser::{Packet, RData};
 use either::Either::{Left, Right};
 use futures::{future, prelude::*};
 use libp2p_core::{multiaddr::{Multiaddr, Protocol}, PeerId};
 use log::warn;
-use std::{convert::TryFrom as _, fmt, io, net::Ipv4Addr, net::SocketAddr, str, time::{Duration, Instant}};
+use std::{convert::TryFrom, fmt, io, net::Ipv4Addr, net::{UdpSocket, SocketAddr}, str, time::{Duration, Instant}};
 use wasm_timer::Interval;
 use lazy_static::lazy_static;
 
@@ -37,9 +38,6 @@ lazy_static! {
     ));
 }
 
-macro_rules! codegen {
-    ($feature_name:expr, $service_name:ident, $udp_socket:ty, $udp_socket_from_std:tt) => {
-
 /// A running service that discovers libp2p peers and responds to other libp2p peers' queries on
 /// the local network.
 ///
@@ -71,10 +69,7 @@ macro_rules! codegen {
 /// # let my_peer_id = PeerId::from(identity::Keypair::generate_ed25519().public());
 /// # let my_listened_addrs: Vec<Multiaddr> = vec![];
 /// # async {
-/// # #[cfg(feature = "async-std")]
 /// # let mut service = libp2p_mdns::service::MdnsService::new().await.unwrap();
-/// # #[cfg(feature = "tokio")]
-/// # let mut service = libp2p_mdns::service::TokioMdnsService::new().await.unwrap();
 /// let _future_to_poll = async {
 ///     let (mut service, packet) = service.next().await;
 ///
@@ -108,13 +103,12 @@ macro_rules! codegen {
 /// };
 /// # };
 /// # }
-#[cfg_attr(docsrs, doc(cfg(feature = $feature_name)))]
-pub struct $service_name {
+pub struct MdnsService {
     /// Main socket for listening.
-    socket: $udp_socket,
+    socket: Async<UdpSocket>,
 
     /// Socket for sending queries on the network.
-    query_socket: $udp_socket,
+    query_socket: Async<UdpSocket>,
 
     /// Interval for sending queries.
     query_interval: Interval,
@@ -137,42 +131,41 @@ pub struct $service_name {
     if_watch: if_watch::IfWatcher,
 }
 
-impl $service_name {
+impl MdnsService {
     /// Starts a new mDNS service.
-    pub async fn new() -> io::Result<$service_name> {
+    pub async fn new() -> io::Result<Self> {
         Self::new_inner(false).await
     }
 
     /// Same as `new`, but we don't automatically send queries on the network.
-    pub async fn silent() -> io::Result<$service_name> {
+    pub async fn silent() -> io::Result<Self> {
         Self::new_inner(true).await
     }
 
     /// Starts a new mDNS service.
-    async fn new_inner(silent: bool) -> io::Result<$service_name> {
+    async fn new_inner(silent: bool) -> io::Result<Self> {
         let socket = {
             let builder = net2::UdpBuilder::new_v4()?;
             builder.reuse_address(true)?;
             #[cfg(unix)]
             net2::unix::UnixUdpBuilderExt::reuse_port(&builder, true)?;
             let socket = builder.bind((Ipv4Addr::UNSPECIFIED, 5353))?;
-            let socket = $udp_socket_from_std(socket)?;
             socket.set_multicast_loop_v4(true)?;
             socket.set_multicast_ttl_v4(255)?;
-            socket
+            Async::new(socket)?
         };
 
         // Given that we pass an IP address to bind, which does not need to be resolved, we can
         // use std::net::UdpSocket::bind, instead of its async counterpart from async-std.
         let query_socket = {
             let socket = std::net::UdpSocket::bind((Ipv4Addr::UNSPECIFIED, 0))?;
-            $udp_socket_from_std(socket)?
+            Async::new(socket)?
         };
 
 
         let if_watch = if_watch::IfWatcher::new().await?;
 
-        Ok($service_name {
+        Ok(Self {
             socket,
             query_socket,
             query_interval: Interval::new_at(Instant::now(), Duration::from_secs(20)),
@@ -217,7 +210,8 @@ impl $service_name {
                 if let Ok(if_watch::IfEvent::Up(inet)) = event {
                     if inet.addr().is_ipv4() && !inet.addr().is_loopback() {
                         self.socket
-                            .join_multicast_v4(From::from([224, 0, 0, 251]), Ipv4Addr::UNSPECIFIED)
+                            .get_ref()
+                            .join_multicast_v4(&From::from([224, 0, 0, 251]), &Ipv4Addr::UNSPECIFIED)
                             .ok();
                     }
                 }
@@ -294,25 +288,14 @@ impl $service_name {
     }
 }
 
-impl fmt::Debug for $service_name {
+impl fmt::Debug for MdnsService {
     fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
         fmt.debug_struct("$service_name")
             .field("silent", &self.silent)
             .finish()
     }
 }
 
-};
-}
-
-#[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: std::net::UdpSocket| { socket.set_nonblocking(true); tokio::net::UdpSocket::from_std(socket) }));
-
-
 /// A valid mDNS packet received by the service.
 #[derive(Debug)]
 pub enum MdnsPacket {
@@ -700,17 +683,15 @@ mod tests {
     }
     }
 
-    #[cfg(feature = "async-std")]
     testgen!(
         async_std,
         crate::service::MdnsService,
         (|fut| async_std::task::block_on::<_, ()>(fut))
     );
 
-    #[cfg(feature = "tokio")]
     testgen!(
         tokio,
-        crate::service::TokioMdnsService,
+        crate::service::MdnsService,
         (|fut| tokio::runtime::Runtime::new().unwrap().block_on::<futures::future::BoxFuture<()>>(fut))
     );
 }

src/lib.rs

@@ -196,8 +196,8 @@ pub use libp2p_gossipsub as gossipsub;
 #[cfg_attr(docsrs, doc(cfg(feature = "mplex")))]
 #[doc(inline)]
 pub use libp2p_mplex as mplex;
-#[cfg(any(feature = "mdns-async-std", feature = "mdns-tokio"))]
-#[cfg_attr(docsrs, doc(cfg(any(feature = "mdns-async-std", feature = "mdns-tokio"))))]
+#[cfg(feature = "mdns")]
+#[cfg_attr(docsrs, doc(cfg(feature = "mdns")))]
 #[cfg(not(any(target_os = "emscripten", target_os = "wasi", target_os = "unknown")))]
 #[doc(inline)]
 pub use libp2p_mdns as mdns;