Decrease peer reputation on bad transactions (#4035)

* Decrease reputation on bad transactions

* Don't punish on duplicate transactions

substrate/core/network/src/protocol.rs

@@ -90,7 +90,9 @@ const UNEXPECTED_STATUS_REPUTATION_CHANGE: i32 = -(1 << 20);
 /// Reputation change when we are a light client and a peer is behind us.
 const PEER_BEHIND_US_LIGHT_REPUTATION_CHANGE: i32 = -(1 << 8);
 /// Reputation change when a peer sends us an extrinsic that we didn't know about.
-const NEW_EXTRINSIC_REPUTATION_CHANGE: i32 = 1 << 7;
+const GOOD_EXTRINSIC_REPUTATION_CHANGE: i32 = 1 << 7;
+/// Reputation change when a peer sends us a bad extrinsic.
+const BAD_EXTRINSIC_REPUTATION_CHANGE: i32 = -(1 << 12);
 /// We sent an RPC query to the given node, but it failed.
 const RPC_FAILED_REPUTATION_CHANGE: i32 = -(1 << 12);
 /// We received a message that failed to decode.
@@ -1019,7 +1021,8 @@ impl<B: BlockT, S: NetworkSpecialization<B>, H: ExHashT> Protocol<B, S, H> {
 				self.transaction_pool.import(
 					self.peerset_handle.clone().into(),
 					who.clone(),
-					NEW_EXTRINSIC_REPUTATION_CHANGE,
+					GOOD_EXTRINSIC_REPUTATION_CHANGE,
+					BAD_EXTRINSIC_REPUTATION_CHANGE,
 					t,
 				);
 			}

substrate/core/network/src/service.rs

@@ -71,7 +71,8 @@ pub trait TransactionPool<H: ExHashT, B: BlockT>: Send + Sync {
 		&self,
 		report_handle: ReportHandle,
 		who: PeerId,
-		reputation_change: i32,
+		reputation_change_good: i32,
+		reputation_change_bad: i32,
 		transaction: B::Extrinsic,
 	);
 	/// Notify the pool about transactions broadcast.

substrate/core/network/src/test/mod.rs

@@ -399,7 +399,14 @@ impl TransactionPool<Hash, Block> for EmptyTransactionPool {
 		Hash::default()
 	}
 
-	fn import(&self, _report_handle: ReportHandle, _who: PeerId, _rep_change: i32, _transaction: Extrinsic) {}
+	fn import(
+		&self,
+		_report_handle: ReportHandle,
+		_who: PeerId,
+		_rep_change_good: i32,
+		_rep_change_bad: i32,
+		_transaction: Extrinsic
+	) {}
 
 	fn on_broadcasted(&self, _: HashMap<Hash, Vec<String>>) {}
 }