swarm/src/toggle: Ignore listen upgr errors when disabled (#1945)

* swarm/src/toggle: Ignore listen upgr errors when disabled

A disabled `ToggleProtoHandler` can receive listen upgrade errors in the
following two cases:

1. Protocol negotiation on an incoming stream failed with no protocol being
   agreed on.

2. When combining `ProtocolsHandler` implementations a single `ProtocolsHandler`
   might be notified of an inbound upgrade error unrelated to its own upgrade
   logic. For example when nesting a `ToggleProtoHandler` in a
   `ProtocolsHandlerSelect` the former might receive an inbound upgrade error
   even when disabled.

`ToggleProtoHandler` should ignore the error in both of these cases.

* *: Prepare libp2p-swarm v0.27.2 release

CHANGELOG.md

@@ -45,7 +45,7 @@
 
 - Use `libp2p-swarm-derive`, the former `libp2p-core-derive`.
 
-- Update `libp2p-gossipsub` and `libp2p-request-response`.
+- Update `libp2p-gossipsub`, `libp2p-request-response` and `libp2p-swarm`.
 
 ## Version 0.34.0 [2021-01-12]
 

Cargo.toml

@@ -72,7 +72,7 @@ libp2p-ping = { version = "0.27.0", path = "protocols/ping", optional = true }
 libp2p-plaintext = { version = "0.27.0", path = "transports/plaintext", optional = true }
 libp2p-pnet = { version = "0.20.0", path = "transports/pnet", optional = true }
 libp2p-request-response = { version = "0.9.1", path = "protocols/request-response", optional = true }
-libp2p-swarm = { version = "0.27.1", path = "swarm" }
+libp2p-swarm = { version = "0.27.2", path = "swarm" }
 libp2p-swarm-derive = { version = "0.22.0", path = "swarm-derive" }
 libp2p-uds = { version = "0.27.0", path = "transports/uds", optional = true }
 libp2p-wasm-ext = { version = "0.27.0", path = "transports/wasm-ext", optional = true }

swarm/CHANGELOG.md

@@ -1,3 +1,8 @@
+# 0.27.2 [2021-02-04]
+
+- Have `ToggleProtoHandler` ignore listen upgrade errors when disabled.
+  [PR 1945](https://github.com/libp2p/rust-libp2p/pull/1945/files).
+
 # 0.27.1 [2021-01-27]
 
 - Make `OneShotHandler`s `max_dial_negotiate` limit configurable.

swarm/Cargo.toml

@@ -2,7 +2,7 @@
 name = "libp2p-swarm"
 edition = "2018"
 description = "The libp2p swarm"
-version = "0.27.1"
+version = "0.27.2"
 authors = ["Parity Technologies <[email protected]>"]
 license = "MIT"
 repository = "https://github.com/libp2p/rust-libp2p"

swarm/src/toggle.rs

@@ -271,6 +271,21 @@ where
     }
 
     fn inject_listen_upgrade_error(&mut self, info: Self::InboundOpenInfo, err: ProtocolsHandlerUpgrErr<<Self::InboundProtocol as InboundUpgradeSend>::Error>) {
+        let (inner, info) = match (self.inner.as_mut(), info) {
+            (Some(inner), Either::Left(info)) => (inner, info),
+            // Ignore listen upgrade errors in disabled state.
+            (None, Either::Right(())) => return,
+            (Some(_), Either::Right(())) => panic!(
+                "Unexpected `Either::Right` inbound info through \
+                 `inject_listen_upgrade_error` in enabled state.",
+            ),
+            (None, Either::Left(_)) => panic!(
+                "Unexpected `Either::Left` inbound info through \
+                 `inject_listen_upgrade_error` in disabled state.",
+            ),
+
+        };
+
         let err = match err {
             ProtocolsHandlerUpgrErr::Timeout => ProtocolsHandlerUpgrErr::Timeout,
             ProtocolsHandlerUpgrErr::Timer => ProtocolsHandlerUpgrErr::Timer,
@@ -280,13 +295,8 @@ where
                     EitherError::B(v) => void::unreachable(v)
                 }))
         };
-        if let Either::Left(info) = info {
-            self.inner.as_mut()
-                .expect("Can't receive an inbound substream if disabled; QED")
-                .inject_listen_upgrade_error(info, err)
-        } else {
-            panic!("Unexpected Either::Right on enabled `inject_listen_upgrade_error`.")
-        }
+
+        inner.inject_listen_upgrade_error(info, err)
     }
 
     fn connection_keep_alive(&self) -> KeepAlive {
@@ -307,3 +317,32 @@ where
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::protocols_handler::DummyProtocolsHandler;
+
+    /// A disabled [`ToggleProtoHandler`] can receive listen upgrade errors in
+    /// the following two cases:
+    ///
+    /// 1. Protocol negotiation on an incoming stream failed with no protocol
+    ///    being agreed on.
+    ///
+    /// 2. When combining [`ProtocolsHandler`] implementations a single
+    ///    [`ProtocolsHandler`] might be notified of an inbound upgrade error
+    ///    unrelated to its own upgrade logic. For example when nesting a
+    ///    [`ToggleProtoHandler`] in a
+    ///    [`ProtocolsHandlerSelect`](crate::protocols_handler::ProtocolsHandlerSelect)
+    ///    the former might receive an inbound upgrade error even when disabled.
+    ///
+    /// [`ToggleProtoHandler`] should ignore the error in both of these cases.
+    #[test]
+    fn ignore_listen_upgrade_error_when_disabled() {
+        let mut handler = ToggleProtoHandler::<DummyProtocolsHandler> {
+            inner: None,
+        };
+
+        handler.inject_listen_upgrade_error(Either::Right(()), ProtocolsHandlerUpgrErr::Timeout);
+    }
+}