Introduced Message 4 sent by Alice to replace message 2 response

swap/src/network/request_response.rs

@@ -1,4 +1,4 @@
-use crate::protocol::{alice, bob, bob::Message5};
+use crate::protocol::{alice, alice::Message4, bob, bob::Message5};
 use async_trait::async_trait;
 use futures::prelude::*;
 use libp2p::{
@@ -42,12 +42,14 @@ pub enum AliceToBob {
 /// All responses are empty
 #[derive(Clone, Debug, Serialize, Deserialize)]
 pub enum Request {
-    Message5(Message5),
+    Message4(Box<Message4>),
+    Message5(Box<Message5>),
 }
 
-#[derive(Clone, Debug, Serialize, Deserialize)]
+#[derive(Clone, Copy, Debug, Serialize, Deserialize)]
 /// Response are only used for acknowledgement purposes.
 pub enum Response {
+    Message4,
     Message5,
 }
 
@@ -63,6 +65,9 @@ pub struct Message1Protocol;
 #[derive(Debug, Clone, Copy, Default)]
 pub struct Message2Protocol;
 
+#[derive(Debug, Clone, Copy, Default)]
+pub struct Message4Protocol;
+
 #[derive(Debug, Clone, Copy, Default)]
 pub struct Message5Protocol;
 
@@ -90,6 +95,12 @@ impl ProtocolName for Message2Protocol {
     }
 }
 
+impl ProtocolName for Message4Protocol {
+    fn protocol_name(&self) -> &[u8] {
+        b"/xmr/btc/message4/1.0.0"
+    }
+}
+
 impl ProtocolName for Message5Protocol {
     fn protocol_name(&self) -> &[u8] {
         b"/xmr/btc/message5/1.0.0"

swap/src/protocol/alice.rs

@@ -5,6 +5,7 @@ pub use self::{
     message0::Message0,
     message1::Message1,
     message2::Message2,
+    message4::Message4,
     state::*,
     swap::{run, run_until},
     swap_response::*,
@@ -37,6 +38,7 @@ pub mod event_loop;
 mod message0;
 mod message1;
 mod message2;
+mod message4;
 mod message5;
 pub mod state;
 mod steps;

swap/src/protocol/alice/message4.rs

@@ -0,0 +1,101 @@
+use crate::{
+    monero,
+    network::request_response::{Message4Protocol, OneShotCodec, Request, Response, TIMEOUT},
+};
+use libp2p::{
+    request_response::{
+        handler::RequestProtocol, ProtocolSupport, RequestResponse, RequestResponseConfig,
+        RequestResponseEvent, RequestResponseMessage,
+    },
+    swarm::{NetworkBehaviourAction, NetworkBehaviourEventProcess, PollParameters},
+    NetworkBehaviour, PeerId,
+};
+use serde::{Deserialize, Serialize};
+use std::{
+    collections::VecDeque,
+    task::{Context, Poll},
+    time::Duration,
+};
+use tracing::error;
+
+#[derive(Clone, Debug, Serialize, Deserialize)]
+pub struct Message4 {
+    pub tx_lock_proof: monero::TransferProof,
+}
+
+#[derive(Debug, Copy, Clone)]
+pub enum OutEvent {
+    Msg,
+}
+
+/// A `NetworkBehaviour` that represents sending message 4 to Bob.
+#[derive(NetworkBehaviour)]
+#[behaviour(out_event = "OutEvent", poll_method = "poll")]
+#[allow(missing_debug_implementations)]
+pub struct Behaviour {
+    rr: RequestResponse<OneShotCodec<Message4Protocol>>,
+    #[behaviour(ignore)]
+    events: VecDeque<OutEvent>,
+}
+
+impl Behaviour {
+    pub fn send(&mut self, bob: PeerId, msg: Message4) {
+        let msg = Request::Message4(Box::new(msg));
+        let _id = self.rr.send_request(&bob, msg);
+    }
+
+    fn poll(
+        &mut self,
+        _: &mut Context<'_>,
+        _: &mut impl PollParameters,
+    ) -> Poll<NetworkBehaviourAction<RequestProtocol<OneShotCodec<Message4Protocol>>, OutEvent>>
+    {
+        if let Some(event) = self.events.pop_front() {
+            return Poll::Ready(NetworkBehaviourAction::GenerateEvent(event));
+        }
+
+        Poll::Pending
+    }
+}
+
+impl Default for Behaviour {
+    fn default() -> Self {
+        let timeout = Duration::from_secs(TIMEOUT);
+        let mut config = RequestResponseConfig::default();
+        config.set_request_timeout(timeout);
+
+        Self {
+            rr: RequestResponse::new(
+                OneShotCodec::default(),
+                vec![(Message4Protocol, ProtocolSupport::Full)],
+                config,
+            ),
+            events: Default::default(),
+        }
+    }
+}
+
+impl NetworkBehaviourEventProcess<RequestResponseEvent<Request, Response>> for Behaviour {
+    fn inject_event(&mut self, event: RequestResponseEvent<Request, Response>) {
+        match event {
+            RequestResponseEvent::Message {
+                message: RequestResponseMessage::Request { .. },
+                ..
+            } => panic!("Alice should never get a message 4 request from Bob"),
+            RequestResponseEvent::Message {
+                message: RequestResponseMessage::Response { response, .. },
+                ..
+            } => {
+                if let Response::Message4 = response {
+                    self.events.push_back(OutEvent::Msg);
+                }
+            }
+            RequestResponseEvent::InboundFailure { error, .. } => {
+                error!("Inbound failure: {:?}", error);
+            }
+            RequestResponseEvent::OutboundFailure { error, .. } => {
+                error!("Outbound failure: {:?}", error);
+            }
+        }
+    }
+}

swap/src/protocol/alice/message5.rs

@@ -74,11 +74,12 @@ impl NetworkBehaviourEventProcess<RequestResponseEvent<Request, Response>> for B
                     },
                 ..
             } => {
-                let Request::Message5(msg) = request;
-                debug!("Received message 5");
-                self.events.push_back(OutEvent::Msg(msg));
-                // Send back empty response so that the request/response protocol completes.
-                let _ = self.rr.send_response(channel, Response::Message5);
+                if let Request::Message5(msg) = request {
+                    debug!("Received message 5");
+                    self.events.push_back(OutEvent::Msg(*msg));
+                    // Send back empty response so that the request/response protocol completes.
+                    let _ = self.rr.send_response(channel, Response::Message5);
+                }
             }
             RequestResponseEvent::Message {
                 message: RequestResponseMessage::Response { .. },

swap/src/protocol/bob/message5.rs

@@ -40,7 +40,7 @@ pub struct Behaviour {
 
 impl Behaviour {
     pub fn send(&mut self, alice: PeerId, msg: Message5) {
-        let msg = Request::Message5(msg);
+        let msg = Request::Message5(Box::new(msg));
         let _id = self.rr.send_request(&alice, msg);
     }
 
@@ -86,8 +86,9 @@ impl NetworkBehaviourEventProcess<RequestResponseEvent<Request, Response>> for B
                 message: RequestResponseMessage::Response { response, .. },
                 ..
             } => {
-                let Response::Message5 = response;
-                self.events.push_back(OutEvent::Msg);
+                if let Response::Message5 = response {
+                    self.events.push_back(OutEvent::Msg);
+                }
             }
             RequestResponseEvent::InboundFailure { error, .. } => {
                 error!("Inbound failure: {:?}", error);