add relayers_state param to the receive_messages_delivery_proof (#584)

bridges/modules/message-lane/src/lib.rs

@@ -35,11 +35,12 @@ use crate::outbound_lane::{OutboundLane, OutboundLaneStorage};
 use bp_message_lane::{
 	source_chain::{LaneMessageVerifier, MessageDeliveryAndDispatchPayment, TargetHeaderChain},
 	target_chain::{DispatchMessage, MessageDispatch, ProvedLaneMessages, ProvedMessages, SourceHeaderChain},
-	InboundLaneData, LaneId, MessageData, MessageKey, MessageNonce, MessagePayload, OutboundLaneData,
+	total_unrewarded_messages, InboundLaneData, LaneId, MessageData, MessageKey, MessageNonce, MessagePayload,
+	OutboundLaneData, UnrewardedRelayersState,
 };
 use codec::{Decode, Encode};
 use frame_support::{
-	decl_error, decl_event, decl_module, decl_storage,
+	decl_error, decl_event, decl_module, decl_storage, ensure,
 	traits::Get,
 	weights::{DispatchClass, Weight},
 	Parameter, StorageMap,
@@ -156,6 +157,8 @@ decl_error! {
 		InvalidMessagesDispatchWeight,
 		/// Invalid messages delivery proof has been submitted.
 		InvalidMessagesDeliveryProof,
+		/// The relayer has declared invalid unrewarded relayers state in the `receive_messages_delivery_proof` call.
+		InvalidUnrewardedRelayersState,
 	}
 }
 
@@ -408,7 +411,11 @@ decl_module! {
 
 		/// Receive messages delivery proof from bridged chain.
 		#[weight = 0] // TODO: update me (https://github.com/paritytech/parity-bridges-common/issues/78)
-		pub fn receive_messages_delivery_proof(origin, proof: MessagesDeliveryProofOf<T, I>) -> DispatchResult {
+		pub fn receive_messages_delivery_proof(
+			origin,
+			proof: MessagesDeliveryProofOf<T, I>,
+			relayers_state: UnrewardedRelayersState,
+		) -> DispatchResult {
 			ensure_operational::<T, I>()?;
 
 			let confirmation_relayer = ensure_signed(origin)?;
@@ -421,6 +428,14 @@ decl_module! {
 				Error::<T, I>::InvalidMessagesDeliveryProof
 			})?;
 
+			// verify that the relayer has declared correct `lane_data::relayers` state
+			// (we only care about total number of entries and messages, because this affects call weight)
+			ensure!(
+				total_unrewarded_messages(&lane_data.relayers) == relayers_state.total_messages
+					&& lane_data.relayers.len() as MessageNonce == relayers_state.unrewarded_relayer_entries,
+				Error::<T, I>::InvalidUnrewardedRelayersState
+			);
+
 			// mark messages as delivered
 			let mut lane = outbound_lane::<T, I>(lane_id);
 			let received_range = lane.confirm_delivery(lane_data.latest_received_nonce);
@@ -501,6 +516,7 @@ impl<T: Config<I>, I: Instance> Module<T, I> {
 		bp_message_lane::UnrewardedRelayersState {
 			unrewarded_relayer_entries: relayers.len() as _,
 			messages_in_oldest_entry: relayers.front().map(|(begin, end, _)| 1 + end - begin).unwrap_or(0),
+			total_messages: total_unrewarded_messages(&relayers),
 		}
 	}
 }
@@ -754,8 +770,9 @@ mod tests {
 				InboundLaneData {
 					latest_received_nonce: 1,
 					..Default::default()
-				}
+				},
 			)),
+			Default::default(),
 		));
 
 		assert_eq!(
@@ -863,8 +880,9 @@ mod tests {
 						InboundLaneData {
 							latest_received_nonce: 1,
 							..Default::default()
-						}
+						},
 					)),
+					Default::default(),
 				),
 				Error::<TestRuntime, DefaultInstance>::Halted,
 			);
@@ -955,6 +973,7 @@ mod tests {
 				UnrewardedRelayersState {
 					unrewarded_relayer_entries: 2,
 					messages_in_oldest_entry: 1,
+					total_messages: 2,
 				},
 			);
 
@@ -988,6 +1007,7 @@ mod tests {
 				UnrewardedRelayersState {
 					unrewarded_relayer_entries: 2,
 					messages_in_oldest_entry: 1,
+					total_messages: 2,
 				},
 			);
 		});
@@ -1065,6 +1085,11 @@ mod tests {
 						..Default::default()
 					}
 				)),
+				UnrewardedRelayersState {
+					unrewarded_relayer_entries: 1,
+					total_messages: 1,
+					..Default::default()
+				},
 			));
 			assert!(TestMessageDeliveryAndDispatchPayment::is_reward_paid(
 				TEST_RELAYER_A,
@@ -1088,6 +1113,11 @@ mod tests {
 						..Default::default()
 					}
 				)),
+				UnrewardedRelayersState {
+					unrewarded_relayer_entries: 2,
+					total_messages: 2,
+					..Default::default()
+				},
 			));
 			assert!(!TestMessageDeliveryAndDispatchPayment::is_reward_paid(
 				TEST_RELAYER_A,
@@ -1104,12 +1134,63 @@ mod tests {
 	fn receive_messages_delivery_proof_rejects_invalid_proof() {
 		run_test(|| {
 			assert_noop!(
-				Module::<TestRuntime>::receive_messages_delivery_proof(Origin::signed(1), Err(()),),
+				Module::<TestRuntime>::receive_messages_delivery_proof(Origin::signed(1), Err(()), Default::default(),),
 				Error::<TestRuntime, DefaultInstance>::InvalidMessagesDeliveryProof,
 			);
 		});
 	}
 
+	#[test]
+	fn receive_messages_delivery_proof_rejects_proof_if_declared_relayers_state_is_invalid() {
+		run_test(|| {
+			// when number of relayers entires is invalid
+			assert_noop!(
+				Module::<TestRuntime>::receive_messages_delivery_proof(
+					Origin::signed(1),
+					Ok((
+						TEST_LANE_ID,
+						InboundLaneData {
+							relayers: vec![(1, 1, TEST_RELAYER_A), (2, 2, TEST_RELAYER_B)]
+								.into_iter()
+								.collect(),
+							latest_received_nonce: 2,
+							..Default::default()
+						}
+					)),
+					UnrewardedRelayersState {
+						unrewarded_relayer_entries: 1,
+						total_messages: 2,
+						..Default::default()
+					},
+				),
+				Error::<TestRuntime, DefaultInstance>::InvalidUnrewardedRelayersState,
+			);
+
+			// when number of messages is invalid
+			assert_noop!(
+				Module::<TestRuntime>::receive_messages_delivery_proof(
+					Origin::signed(1),
+					Ok((
+						TEST_LANE_ID,
+						InboundLaneData {
+							relayers: vec![(1, 1, TEST_RELAYER_A), (2, 2, TEST_RELAYER_B)]
+								.into_iter()
+								.collect(),
+							latest_received_nonce: 2,
+							..Default::default()
+						}
+					)),
+					UnrewardedRelayersState {
+						unrewarded_relayer_entries: 2,
+						total_messages: 1,
+						..Default::default()
+					},
+				),
+				Error::<TestRuntime, DefaultInstance>::InvalidUnrewardedRelayersState,
+			);
+		});
+	}
+
 	#[test]
 	fn receive_messages_accepts_single_message_with_invalid_payload() {
 		run_test(|| {

bridges/primitives/message-lane/src/lib.rs

@@ -103,13 +103,15 @@ impl<RelayerId> Default for InboundLaneData<RelayerId> {
 }
 
 /// Gist of `InboundLaneData::relayers` field used by runtime APIs.
-#[derive(Clone, Encode, Decode, RuntimeDebug, PartialEq, Eq)]
+#[derive(Clone, Default, Encode, Decode, RuntimeDebug, PartialEq, Eq)]
 pub struct UnrewardedRelayersState {
 	/// Number of entries in the `InboundLaneData::relayers` set.
 	pub unrewarded_relayer_entries: MessageNonce,
 	/// Number of messages in the oldest entry of `InboundLaneData::relayers`. This is the
 	/// minimal number of reward proofs required to push out this entry from the set.
 	pub messages_in_oldest_entry: MessageNonce,
+	/// Total number of messages in the relayers vector.
+	pub total_messages: MessageNonce,
 }
 
 /// Outbound lane data.
@@ -134,3 +136,13 @@ impl Default for OutboundLaneData {
 		}
 	}
 }
+
+/// Returns total number of messages in the `InboundLaneData::relayers` vector.
+pub fn total_unrewarded_messages<RelayerId>(
+	relayers: &VecDeque<(MessageNonce, MessageNonce, RelayerId)>,
+) -> MessageNonce {
+	match (relayers.front(), relayers.back()) {
+		(Some((begin, _, _)), Some((_, end, _))) => end.checked_sub(*begin).and_then(|d| d.checked_add(1)).unwrap_or(0),
+		_ => 0,
+	}
+}

bridges/relays/messages-relay/src/message_lane_loop.rs

@@ -693,6 +693,7 @@ pub(crate) mod tests {
 				UnrewardedRelayersState {
 					unrewarded_relayer_entries: 0,
 					messages_in_oldest_entry: 0,
+					total_messages: 0,
 				},
 			))
 		}

bridges/relays/messages-relay/src/message_race_delivery.rs

@@ -497,6 +497,7 @@ mod tests {
 					unrewarded_relayers: UnrewardedRelayersState {
 						unrewarded_relayer_entries: 0,
 						messages_in_oldest_entry: 0,
+						total_messages: 0,
 					},
 				},
 			}),

bridges/relays/substrate/src/messages_target.rs

@@ -37,7 +37,7 @@ use sp_trie::StorageProof;
 use std::ops::RangeInclusive;
 
 /// Message receiving proof returned by the target Substrate node.
-pub type SubstrateMessagesReceivingProof<C> = (HashOf<C>, StorageProof, LaneId);
+pub type SubstrateMessagesReceivingProof<C> = (UnrewardedRelayersState, (HashOf<C>, StorageProof, LaneId));
 
 /// Substrate client as Substrate messages target.
 pub struct SubstrateMessagesTarget<C: Chain, P> {
@@ -156,12 +156,13 @@ where
 		&self,
 		id: TargetHeaderIdOf<P>,
 	) -> Result<(TargetHeaderIdOf<P>, P::MessagesReceivingProof), Self::Error> {
+		let (id, relayers_state) = self.unrewarded_relayers_state(id).await?;
 		let proof = self
 			.client
 			.prove_messages_delivery(self.instance, self.lane_id, id.1)
 			.await?;
 		let proof = (id.1, proof, self.lane_id);
-		Ok((id, proof))
+		Ok((id, (relayers_state, proof)))
 	}
 
 	async fn submit_messages_proof(

bridges/relays/substrate/src/millau_messages_to_rialto.rs

@@ -59,9 +59,10 @@ impl SubstrateMessageLane for MillauMessagesToRialto {
 		_generated_at_block: RialtoHeaderId,
 		proof: <Self as MessageLane>::MessagesReceivingProof,
 	) -> Result<Self::SourceSignedTransaction, SubstrateError> {
+		let (relayers_state, proof) = proof;
 		let account_id = self.source_sign.signer.public().as_array_ref().clone().into();
 		let nonce = self.source_client.next_account_index(account_id).await?;
-		let call = millau_runtime::MessageLaneCall::receive_messages_delivery_proof(proof).into();
+		let call = millau_runtime::MessageLaneCall::receive_messages_delivery_proof(proof, relayers_state).into();
 		let transaction = Millau::sign_transaction(&self.source_client, &self.source_sign.signer, nonce, call);
 		Ok(transaction)
 	}

bridges/relays/substrate/src/rialto_messages_to_millau.rs

@@ -59,9 +59,10 @@ impl SubstrateMessageLane for RialtoMessagesToMillau {
 		_generated_at_block: MillauHeaderId,
 		proof: <Self as MessageLane>::MessagesReceivingProof,
 	) -> Result<Self::SourceSignedTransaction, SubstrateError> {
+		let (relayers_state, proof) = proof;
 		let account_id = self.source_sign.signer.public().as_array_ref().clone().into();
 		let nonce = self.source_client.next_account_index(account_id).await?;
-		let call = rialto_runtime::MessageLaneCall::receive_messages_delivery_proof(proof).into();
+		let call = rialto_runtime::MessageLaneCall::receive_messages_delivery_proof(proof, relayers_state).into();
 		let transaction = Rialto::sign_transaction(&self.source_client, &self.source_sign.signer, nonce, call);
 		Ok(transaction)
 	}