fix(relay): expose Deny reason for circuits and reservations

Fixes: #6066

Pull-Request: #6067.

Author: SaadTalaat

protocols/relay/CHANGELOG.md

@@ -3,6 +3,8 @@
 - Remove duplicated forwarding of pending events to connection handler.
 - Emit `relay::Event::ReservationClosed` when an active reservation is dropped due to the connection closing.
   See [PR 5869](https://github.com/libp2p/rust-libp2p/pull/5869).
+- Include denial reason in `relay::Event::CircuitReqDenied` and `relay::Event::ReservationReqDenied`
+  See [PR 6067](https://github.com/libp2p/rust-libp2p/pull/6067/files).
 
 ## 0.19.0
 

protocols/relay/src/behaviour.rs

@@ -184,7 +184,10 @@ pub enum Event {
         error: inbound_hop::Error,
     },
     /// An inbound reservation request has been denied.
-    ReservationReqDenied { src_peer_id: PeerId },
+    ReservationReqDenied {
+        src_peer_id: PeerId,
+        status: StatusCode,
+    },
     /// Denying an inbound reservation request has failed.
     #[deprecated(
         note = "Will be removed in favor of logging them internally, see <https://github.com/libp2p/rust-libp2p/issues/4757> for details."
@@ -201,6 +204,7 @@ pub enum Event {
     CircuitReqDenied {
         src_peer_id: PeerId,
         dst_peer_id: PeerId,
+        status: StatusCode,
     },
     /// Denying an inbound circuit request failed.
     #[deprecated(
@@ -481,10 +485,11 @@ impl NetworkBehaviour for Behaviour {
                     },
                 ));
             }
-            handler::Event::ReservationReqDenied {} => {
+            handler::Event::ReservationReqDenied { status } => {
                 self.queued_actions.push_back(ToSwarm::GenerateEvent(
                     Event::ReservationReqDenied {
                         src_peer_id: event_source,
+                        status: status.into(),
                     },
                 ));
             }
@@ -592,6 +597,7 @@ impl NetworkBehaviour for Behaviour {
             handler::Event::CircuitReqDenied {
                 circuit_id,
                 dst_peer_id,
+                status,
             } => {
                 if let Some(circuit_id) = circuit_id {
                     self.circuits.remove(circuit_id);
@@ -601,6 +607,7 @@ impl NetworkBehaviour for Behaviour {
                     .push_back(ToSwarm::GenerateEvent(Event::CircuitReqDenied {
                         src_peer_id: event_source,
                         dst_peer_id,
+                        status: status.into(),
                     }));
             }
             handler::Event::CircuitReqDenyFailed {
@@ -809,3 +816,31 @@ impl Add<u64> for CircuitId {
         CircuitId(self.0 + rhs)
     }
 }
+
+/// Status code for a relay reservation request that was denied.
+#[derive(Debug)]
+pub enum StatusCode {
+    OK,
+    ReservationRefused,
+    ResourceLimitExceeded,
+    PermissionDenied,
+    ConnectionFailed,
+    NoReservation,
+    MalformedMessage,
+    UnexpectedMessage,
+}
+
+impl From<proto::Status> for StatusCode {
+    fn from(other: proto::Status) -> Self {
+        match other {
+            proto::Status::OK => Self::OK,
+            proto::Status::RESERVATION_REFUSED => Self::ReservationRefused,
+            proto::Status::RESOURCE_LIMIT_EXCEEDED => Self::ResourceLimitExceeded,
+            proto::Status::PERMISSION_DENIED => Self::PermissionDenied,
+            proto::Status::CONNECTION_FAILED => Self::ConnectionFailed,
+            proto::Status::NO_RESERVATION => Self::NoReservation,
+            proto::Status::MALFORMED_MESSAGE => Self::MalformedMessage,
+            proto::Status::UNEXPECTED_MESSAGE => Self::UnexpectedMessage,
+        }
+    }
+}

protocols/relay/src/behaviour/handler.rs

@@ -159,7 +159,7 @@ pub enum Event {
     /// Accepting an inbound reservation request failed.
     ReservationReqAcceptFailed { error: inbound_hop::Error },
     /// An inbound reservation request has been denied.
-    ReservationReqDenied {},
+    ReservationReqDenied { status: proto::Status },
     /// Denying an inbound reservation request has failed.
     ReservationReqDenyFailed { error: inbound_hop::Error },
     /// An inbound reservation has timed out.
@@ -173,6 +173,7 @@ pub enum Event {
     CircuitReqDenied {
         circuit_id: Option<CircuitId>,
         dst_peer_id: PeerId,
+        status: proto::Status,
     },
     /// Denying an inbound circuit request failed.
     CircuitReqDenyFailed {
@@ -238,9 +239,10 @@ impl fmt::Debug for Event {
                 .debug_struct("Event::ReservationReqAcceptFailed")
                 .field("error", error)
                 .finish(),
-            Event::ReservationReqDenied {} => {
-                f.debug_struct("Event::ReservationReqDenied").finish()
-            }
+            Event::ReservationReqDenied { status } => f
+                .debug_struct("Event::ReservationReqDenied")
+                .field("status", status)
+                .finish(),
             Event::ReservationReqDenyFailed { error } => f
                 .debug_struct("Event::ReservationReqDenyFailed")
                 .field("error", error)
@@ -256,10 +258,12 @@ impl fmt::Debug for Event {
             Event::CircuitReqDenied {
                 circuit_id,
                 dst_peer_id,
+                status,
             } => f
                 .debug_struct("Event::CircuitReqDenied")
                 .field("circuit_id", circuit_id)
                 .field("dst_peer_id", dst_peer_id)
+                .field("status", status)
                 .finish(),
             Event::CircuitReqDenyFailed {
                 circuit_id,
@@ -359,7 +363,12 @@ pub struct Handler {
     /// Futures accepting an inbound circuit request.
     circuit_accept_futures: Futures<Result<CircuitParts, (CircuitId, PeerId, inbound_hop::Error)>>,
     /// Futures denying an inbound circuit request.
-    circuit_deny_futures: Futures<(Option<CircuitId>, PeerId, Result<(), inbound_hop::Error>)>,
+    circuit_deny_futures: Futures<(
+        Option<CircuitId>,
+        PeerId,
+        proto::Status,
+        Result<(), inbound_hop::Error>,
+    )>,
     /// Futures relaying data for circuit between two peers.
     circuits: Futures<(CircuitId, PeerId, Result<(), std::io::Error>)>,
 
@@ -479,7 +488,7 @@ impl Handler {
 
 enum ReservationRequestFuture {
     Accepting(BoxFuture<'static, Result<(), inbound_hop::Error>>),
-    Denying(BoxFuture<'static, Result<(), inbound_hop::Error>>),
+    Denying(BoxFuture<'static, (proto::Status, Result<(), inbound_hop::Error>)>),
 }
 
 type Futures<T> = FuturesUnordered<BoxFuture<'static, T>>;
@@ -519,7 +528,11 @@ impl ConnectionHandler for Handler {
                 if self
                     .reservation_request_future
                     .replace(ReservationRequestFuture::Denying(
-                        inbound_reservation_req.deny(status).err_into().boxed(),
+                        inbound_reservation_req
+                            .deny(status)
+                            .err_into()
+                            .map(move |result| (status, result))
+                            .boxed(),
                     ))
                     .is_some()
                 {
@@ -554,7 +567,7 @@ impl ConnectionHandler for Handler {
                     inbound_circuit_req
                         .deny(status)
                         .err_into()
-                        .map(move |result| (circuit_id, dst_peer_id, result))
+                        .map(move |result| (circuit_id, dst_peer_id, status, result))
                         .boxed(),
                 );
             }
@@ -719,7 +732,7 @@ impl ConnectionHandler for Handler {
         }
 
         // Deny new circuits.
-        if let Poll::Ready(Some((circuit_id, dst_peer_id, result))) =
+        if let Poll::Ready(Some((circuit_id, dst_peer_id, status, result))) =
             self.circuit_deny_futures.poll_next_unpin(cx)
         {
             match result {
@@ -728,6 +741,7 @@ impl ConnectionHandler for Handler {
                         Event::CircuitReqDenied {
                             circuit_id,
                             dst_peer_id,
+                            status,
                         },
                     ));
                 }
@@ -838,13 +852,13 @@ impl ConnectionHandler for Handler {
                 }
             }
             Some(ReservationRequestFuture::Denying(fut)) => {
-                if let Poll::Ready(result) = fut.poll_unpin(cx) {
+                if let Poll::Ready((status, result)) = fut.poll_unpin(cx) {
                     self.reservation_request_future = None;
 
                     match result {
                         Ok(()) => {
                             return Poll::Ready(ConnectionHandlerEvent::NotifyBehaviour(
-                                Event::ReservationReqDenied {},
+                                Event::ReservationReqDenied { status },
                             ))
                         }
                         Err(error) => {

protocols/relay/src/lib.rs

@@ -39,7 +39,7 @@ mod proto {
     };
 }
 
-pub use behaviour::{rate_limiter::RateLimiter, Behaviour, CircuitId, Config, Event};
+pub use behaviour::{rate_limiter::RateLimiter, Behaviour, CircuitId, Config, Event, StatusCode};
 pub use protocol::{HOP_PROTOCOL_NAME, STOP_PROTOCOL_NAME};
 
 /// Types related to the relay protocol inbound.