Throw an error if a bootnode is registered with two different peer ids (#3891)

* Throw an error if a bootnode is registered with two different peer ids

* Rename error

* Fix compilation :(

* Review feedback

substrate/core/network/src/error.rs

@@ -18,16 +18,42 @@
 
 use client;
 
+use libp2p::{PeerId, Multiaddr};
+
+use std::fmt;
+
 /// Result type alias for the network.
 pub type Result<T> = std::result::Result<T, Error>;
 
 /// Error type for the network.
-#[derive(Debug, derive_more::Display, derive_more::From)]
+#[derive(derive_more::Display, derive_more::From)]
 pub enum Error {
 	/// Io error
 	Io(std::io::Error),
 	/// Client error
 	Client(client::error::Error),
+	/// The same bootnode (based on address) is registered with two different peer ids.
+	#[display(
+		fmt = "The same bootnode (`{}`) is registered with two different peer ids: `{}` and `{}`",
+		address,
+		first_id,
+		second_id,
+	)]
+	DuplicateBootnode {
+		/// The address of the bootnode.
+		address: Multiaddr,
+		/// The first peer id that was found for the bootnode.
+		first_id: PeerId,
+		/// The second peer id that was found for the bootnode.
+		second_id: PeerId,
+	},
+}
+
+// Make `Debug` use the `Display` implementation.
+impl fmt::Debug for Error {
+	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+		fmt::Display::fmt(self, f)
+	}
 }
 
 impl std::error::Error for Error {
@@ -35,6 +61,7 @@ impl std::error::Error for Error {
 		match self {
 			Error::Io(ref err) => Some(err),
 			Error::Client(ref err) => Some(err),
+			Error::DuplicateBootnode { .. } => None,
 		}
 	}
 }

substrate/core/network/src/service.rs

@@ -52,14 +52,11 @@ use crate::protocol::specialization::NetworkSpecialization;
 use crate::protocol::sync::SyncState;
 
 /// Minimum Requirements for a Hash within Networking
-pub trait ExHashT:
-	::std::hash::Hash + Eq + ::std::fmt::Debug + Clone + Send + Sync + 'static
-{
-}
+pub trait ExHashT: std::hash::Hash + Eq + std::fmt::Debug + Clone + Send + Sync + 'static {}
+
 impl<T> ExHashT for T where
-	T: ::std::hash::Hash + Eq + ::std::fmt::Debug + Clone + Send + Sync + 'static
-{
-}
+	T: std::hash::Hash + Eq + std::fmt::Debug + Clone + Send + Sync + 'static
+{}
 
 /// Transaction pool interface
 pub trait TransactionPool<H: ExHashT, B: BlockT>: Send + Sync {
@@ -152,6 +149,23 @@ impl<B: BlockT + 'static, S: NetworkSpecialization<B>, H: ExHashT> NetworkWorker
 			}
 		}
 
+		// Check for duplicate bootnodes.
+		known_addresses.iter()
+			.try_for_each(|(peer_id, addr)|
+				if let Some(other) = known_addresses
+					.iter()
+					.find(|o| o.1 == *addr && o.0 != *peer_id)
+				{
+					Err(Error::DuplicateBootnode {
+						address: addr.clone(),
+						first_id: peer_id.clone(),
+						second_id: other.0.clone(),
+					})
+				} else {
+					Ok(())
+				}
+			)?;
+
 		// Initialize the reserved peers.
 		for reserved in params.network_config.reserved_nodes.iter() {
 			if let Ok((peer_id, addr)) = parse_str_addr(reserved) {
@@ -553,8 +567,9 @@ impl<B: BlockT + 'static, S: NetworkSpecialization<B>, H: ExHashT> NetworkServic
 	}
 }
 
-impl<B: BlockT + 'static, S: NetworkSpecialization<B>, H: ExHashT>
-	::consensus::SyncOracle for NetworkService<B, S, H> {
+impl<B: BlockT + 'static, S: NetworkSpecialization<B>, H: ExHashT> consensus::SyncOracle
+	for NetworkService<B, S, H>
+{
 	fn is_major_syncing(&mut self) -> bool {
 		NetworkService::is_major_syncing(self)
 	}
@@ -564,8 +579,9 @@ impl<B: BlockT + 'static, S: NetworkSpecialization<B>, H: ExHashT>
 	}
 }
 
-impl<'a, B: BlockT + 'static, S: NetworkSpecialization<B>, H: ExHashT>
-	::consensus::SyncOracle for &'a NetworkService<B, S, H> {
+impl<'a, B: BlockT + 'static, S: NetworkSpecialization<B>, H: ExHashT> consensus::SyncOracle
+	for &'a NetworkService<B, S, H>
+{
 	fn is_major_syncing(&mut self) -> bool {
 		NetworkService::is_major_syncing(self)
 	}