refactor/reputation: unify the values used (#2462)

* refactor/reputation: unify the values used

* chore/rep: rename Annoy* to Cost*, make duplicate message Cost*Repeated

* fix/reputation: lost and found, convert at the boundary to substrate

* refactor/rep: move conversion to base reputation one level down, left conversions

* fix/rep: order of magnitude adjustments

Thanks pierre!

* remove spaces

* chore/rep: give rationale for order of magnitude

* refactor/rep: move UnifiedReputationChange to separate file

* fix/rep: order of magnitudes correction

polkadot/node/network/protocol/src/lib.rs

@@ -23,12 +23,14 @@ use polkadot_primitives::v1::{Hash, BlockNumber};
 use parity_scale_codec::{Encode, Decode};
 use std::{fmt, collections::HashMap};
 
-pub use sc_network::{ReputationChange, PeerId};
+pub use sc_network::PeerId;
 #[doc(hidden)]
 pub use polkadot_node_jaeger::JaegerSpan;
 #[doc(hidden)]
 pub use std::sync::Arc;
 
+mod reputation;
+pub use self::reputation::{ReputationChange, UnifiedReputationChange};
 
 /// Peer-sets and protocols used for parachains.
 pub mod peer_set;
@@ -372,7 +374,7 @@ pub mod v1 {
 	}
 
 	impl std::fmt::Debug for CompressedPoV {
-    	fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+		fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 			write!(f, "CompressedPoV({} bytes)", self.0.len())
 		}
 	}

polkadot/node/network/protocol/src/reputation.rs

@@ -0,0 +1,65 @@
+pub use sc_network::ReputationChange;
+
+/// Unified annoyance cost and good behavior benefits.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+#[allow(missing_docs)]
+pub enum UnifiedReputationChange {
+	CostMajor(&'static str),
+	CostMinor(&'static str),
+	CostMajorRepeated(&'static str),
+	CostMinorRepeated(&'static str),
+	Malicious(&'static str),
+	BenefitMinorFirst(&'static str),
+	BenefitMinor(&'static str),
+	BenefitMajorFirst(&'static str),
+	BenefitMajor(&'static str),
+}
+
+impl UnifiedReputationChange {
+	/// Obtain the cost or benefit associated with
+	/// the enum variant.
+	///
+	/// Order of magnitude rationale:
+	///
+	/// * the peerset will not connect to a peer whose reputation is below a fixed value
+	/// * `max(2% *$rep, 1)` is the delta of convergence towards a reputation of 0
+	///
+	/// The whole range of an `i32` should be used, so order of magnitude of
+	/// something malicious should be `1<<20` (give or take).
+	const fn cost_or_benefit(&self) -> i32 {
+		match self {
+			Self::CostMinor(_) => -100_000,
+			Self::CostMajor(_) => -300_000,
+			Self::CostMinorRepeated(_) => -200_000,
+			Self::CostMajorRepeated(_) => -600_000,
+			Self::Malicious(_) => -1_000_000,
+			Self::BenefitMajorFirst(_) => 300_000,
+			Self::BenefitMajor(_) => 200_000,
+			Self::BenefitMinorFirst(_) => 15_000,
+			Self::BenefitMinor(_) => 10_000,
+		}
+	}
+
+	/// Extract the static description.
+	pub const fn description(&self) -> &'static str {
+		match self {
+			Self::CostMinor(description) => description,
+			Self::CostMajor(description) => description,
+			Self::CostMinorRepeated(description) => description,
+			Self::CostMajorRepeated(description) => description,
+			Self::Malicious(description) => description,
+			Self::BenefitMajorFirst(description) => description,
+			Self::BenefitMajor(description) => description,
+			Self::BenefitMinorFirst(description) => description,
+			Self::BenefitMinor(description) => description,
+		}
+	}
+
+	/// Convert into a base reputation as used with substrate.
+	pub const fn into_base_rep(self) -> ReputationChange {
+		ReputationChange::new(
+			self.cost_or_benefit(),
+			self.description()
+		)
+	}
+}