2 files changed, 176 insertions, 0 deletions
diff --git a/karyons_p2p/src/protocols/mod.rs b/karyons_p2p/src/protocols/mod.rs
new file mode 100644
index 0000000..4a8f6b9
--- /dev/null
+++ b/karyons_p2p/src/protocols/mod.rs
@@ -0,0 +1,3 @@
+mod ping;
+
+pub use ping::PingProtocol;
diff --git a/karyons_p2p/src/protocols/ping.rs b/karyons_p2p/src/protocols/ping.rs
new file mode 100644
index 0000000..b337494
--- /dev/null
+++ b/karyons_p2p/src/protocols/ping.rs
@@ -0,0 +1,173 @@
+use std::{sync::Arc, time::Duration};
+
+use async_trait::async_trait;
+use bincode::{Decode, Encode};
+use log::trace;
+use rand::{rngs::OsRng, RngCore};
+use smol::{
+    channel,
+    channel::{Receiver, Sender},
+    stream::StreamExt,
+    Timer,
+};
+
+use karyons_core::{
+    async_utils::{select, timeout, Either, TaskGroup, TaskResult},
+    event::EventListener,
+    utils::decode,
+    Executor,
+};
+
+use karyons_net::NetError;
+
+use crate::{
+    peer::ArcPeer,
+    protocol::{ArcProtocol, Protocol, ProtocolEvent, ProtocolID},
+    utils::Version,
+    Result,
+};
+
+const MAX_FAILUERS: u32 = 3;
+
+#[derive(Clone, Debug, Encode, Decode)]
+enum PingProtocolMsg {
+    Ping([u8; 32]),
+    Pong([u8; 32]),
+}
+
+pub struct PingProtocol {
+    peer: ArcPeer,
+    ping_interval: u64,
+    ping_timeout: u64,
+    task_group: TaskGroup,
+}
+
+impl PingProtocol {
+    #[allow(clippy::new_ret_no_self)]
+    pub fn new(peer: ArcPeer) -> ArcProtocol {
+        let ping_interval = peer.config().ping_interval;
+        let ping_timeout = peer.config().ping_timeout;
+        Arc::new(Self {
+            peer,
+            ping_interval,
+            ping_timeout,
+            task_group: TaskGroup::new(),
+        })
+    }
+
+    async fn recv_loop(
+        &self,
+        listener: &EventListener<ProtocolID, ProtocolEvent>,
+        pong_chan: Sender<[u8; 32]>,
+    ) -> Result<()> {
+        loop {
+            let event = listener.recv().await?;
+            let msg_payload = match event.clone() {
+                ProtocolEvent::Message(m) => m,
+                ProtocolEvent::Shutdown => {
+                    break;
+                }
+            };
+
+            let (msg, _) = decode::<PingProtocolMsg>(&msg_payload)?;
+
+            match msg {
+                PingProtocolMsg::Ping(nonce) => {
+                    trace!("Received Ping message {:?}", nonce);
+                    self.peer
+                        .send(&Self::id(), &PingProtocolMsg::Pong(nonce))
+                        .await?;
+                    trace!("Send back Pong message {:?}", nonce);
+                }
+                PingProtocolMsg::Pong(nonce) => {
+                    pong_chan.send(nonce).await?;
+                }
+            }
+        }
+        Ok(())
+    }
+
+    async fn ping_loop(self: Arc<Self>, chan: Receiver<[u8; 32]>) -> Result<()> {
+        let mut timer = Timer::interval(Duration::from_secs(self.ping_interval));
+        let rng = &mut OsRng;
+        let mut retry = 0;
+
+        while retry < MAX_FAILUERS {
+            timer.next().await;
+
+            let mut ping_nonce: [u8; 32] = [0; 32];
+            rng.fill_bytes(&mut ping_nonce);
+
+            trace!("Send Ping message {:?}", ping_nonce);
+            self.peer
+                .send(&Self::id(), &PingProtocolMsg::Ping(ping_nonce))
+                .await?;
+
+            let d = Duration::from_secs(self.ping_timeout);
+
+            // Wait for Pong message
+            let pong_msg = match timeout(d, chan.recv()).await {
+                Ok(m) => m?,
+                Err(_) => {
+                    retry += 1;
+                    continue;
+                }
+            };
+
+            trace!("Received Pong message {:?}", pong_msg);
+
+            if pong_msg != ping_nonce {
+                retry += 1;
+                continue;
+            }
+        }
+
+        Err(NetError::Timeout.into())
+    }
+}
+
+#[async_trait]
+impl Protocol for PingProtocol {
+    async fn start(self: Arc<Self>, ex: Executor<'_>) -> Result<()> {
+        trace!("Start Ping protocol");
+        let (pong_chan, pong_chan_recv) = channel::bounded(1);
+        let (stop_signal_s, stop_signal) = channel::bounded::<Result<()>>(1);
+
+        let selfc = self.clone();
+        self.task_group.spawn(
+            ex.clone(),
+            selfc.clone().ping_loop(pong_chan_recv.clone()),
+            |res| async move {
+                if let TaskResult::Completed(result) = res {
+                    let _ = stop_signal_s.send(result).await;
+                }
+            },
+        );
+
+        let listener = self.peer.register_listener::<Self>().await;
+
+        let result = select(self.recv_loop(&listener, pong_chan), stop_signal.recv()).await;
+        listener.cancel().await;
+        self.task_group.cancel().await;
+
+        match result {
+            Either::Left(res) => {
+                trace!("Receive loop stopped {:?}", res);
+                res
+            }
+            Either::Right(res) => {
+                let res = res?;
+                trace!("Ping loop stopped {:?}", res);
+                res
+            }
+        }
+    }
+
+    fn version() -> Result<Version> {
+        "0.1.0".parse()
+    }
+
+    fn id() -> ProtocolID {
+        "PING".into()
+    }
+}