Polite-grandpa improvements (#2229)

* send neighbor packets in more generic way

* integrate periodic neighbor-packet rebroadcaster

* integrate reporting

* attach callbacks to commit messages for rebroadcasting and reporting

* Tests for commit relay

* crunch up some nice warnings

* exit-scope sub-futures of grandpa

* address small grumbles

* some changes to commit handling

substrate/core/network/src/service.rs

@@ -45,7 +45,6 @@ pub use network_libp2p::PeerId;
 /// Type that represents fetch completion future.
 pub type FetchFuture = oneshot::Receiver<Vec<u8>>;
 
-
 /// Sync status
 pub trait SyncProvider<B: BlockT>: Send + Sync {
 	/// Get a stream of sync statuses.
@@ -129,6 +128,20 @@ impl<B: BlockT, S: NetworkSpecialization<B>> Link<B> for NetworkLink<B, S> {
 	}
 }
 
+/// A cloneable handle for reporting cost/benefits of peers.
+#[derive(Clone)]
+pub struct ReportHandle {
+	inner: PeersetHandle, // wraps it so we don't have to worry about breaking API.
+}
+
+impl ReportHandle {
+	/// Report a given peer as either beneficial (+) or costly (-) according to the
+	/// given scalar.
+	pub fn report_peer(&self, who: PeerId, cost_benefit: i32) {
+		self.inner.report_peer(who, cost_benefit);
+	}
+}
+
 /// Substrate network service. Handles network IO and manages connectivity.
 pub struct Service<B: BlockT + 'static, S: NetworkSpecialization<B>> {
 	/// Sinks to propagate status updates.
@@ -268,6 +281,17 @@ impl<B: BlockT + 'static, S: NetworkSpecialization<B>> Service<B, S> {
 			));
 	}
 
+	/// Return a cloneable handle for reporting peers' benefits or misbehavior.
+	pub fn report_handle(&self) -> ReportHandle {
+		ReportHandle { inner: self.peerset.clone() }
+	}
+
+	/// Report a given peer as either beneficial (+) or costly (-) according to the
+	/// given scalar.
+	pub fn report_peer(&self, who: PeerId, cost_benefit: i32) {
+		self.peerset.report_peer(who, cost_benefit);
+	}
+
 	/// Execute a closure with the chain-specific network specialization.
 	pub fn with_spec<F>(&self, f: F)
 		where F: FnOnce(&mut S, &mut Context<B>) + Send + 'static