when messages pallet is halted, relay shall not submit messages deliv…

…ery/confirmation transactions (paritytech#1289)

bridges/modules/messages/src/lib.rs

@@ -1113,7 +1113,11 @@ mod tests {
 		REGULAR_PAYLOAD, TEST_LANE_ID, TEST_RELAYER_A, TEST_RELAYER_B,
 	};
 	use bp_messages::{UnrewardedRelayer, UnrewardedRelayersState};
-	use frame_support::{assert_noop, assert_ok, storage::generator::StorageMap, weights::Weight};
+	use frame_support::{
+		assert_noop, assert_ok,
+		storage::generator::{StorageMap, StorageValue},
+		weights::Weight,
+	};
 	use frame_system::{EventRecord, Pallet as System, Phase};
 	use sp_runtime::DispatchError;
 
@@ -2276,6 +2280,11 @@ mod tests {
 
 	#[test]
 	fn storage_keys_computed_properly() {
+		assert_eq!(
+			PalletOperatingMode::<TestRuntime>::storage_value_final_key().to_vec(),
+			bp_messages::storage_keys::operating_mode_key("Messages").0,
+		);
+
 		assert_eq!(
 			OutboundMessages::<TestRuntime>::storage_map_final_key(MessageKey {
 				lane_id: TEST_LANE_ID,

bridges/primitives/messages/src/storage_keys.rs

@@ -16,6 +16,8 @@
 
 //! Storage keys of bridge messages pallet.
 
+/// Name of the `OPERATING_MODE_VALUE_NAME` storage value.
+pub const OPERATING_MODE_VALUE_NAME: &str = "PalletOperatingMode";
 /// Name of the `OutboundMessages` storage map.
 pub const OUTBOUND_MESSAGES_MAP_NAME: &str = "OutboundMessages";
 /// Name of the `OutboundLanes` storage map.
@@ -29,6 +31,17 @@ use codec::Encode;
 use frame_support::Blake2_128Concat;
 use sp_core::storage::StorageKey;
 
+/// Storage key of the `PalletOperatingMode` value in the runtime storage.
+pub fn operating_mode_key(pallet_prefix: &str) -> StorageKey {
+	StorageKey(
+		bp_runtime::storage_value_final_key(
+			pallet_prefix.as_bytes(),
+			OPERATING_MODE_VALUE_NAME.as_bytes(),
+		)
+		.to_vec(),
+	)
+}
+
 /// Storage key of the outbound message in the runtime storage.
 pub fn message_key(pallet_prefix: &str, lane: &LaneId, nonce: MessageNonce) -> StorageKey {
 	bp_runtime::storage_map_final_key::<Blake2_128Concat>(
@@ -61,6 +74,19 @@ mod tests {
 	use super::*;
 	use hex_literal::hex;
 
+	#[test]
+	fn operating_mode_key_computed_properly() {
+		// If this test fails, then something has been changed in module storage that is possibly
+		// breaking all existing message relays.
+		let storage_key = operating_mode_key("BridgeMessages").0;
+		assert_eq!(
+			storage_key,
+			hex!("dd16c784ebd3390a9bc0357c7511ed010f4cf0917788d791142ff6c1f216e7b3").to_vec(),
+			"Unexpected storage key: {}",
+			hex::encode(&storage_key),
+		);
+	}
+
 	#[test]
 	fn storage_message_key_computed_properly() {
 		// If this test fails, then something has been changed in module storage that is breaking

bridges/relays/lib-substrate-relay/src/messages_source.rs

@@ -29,8 +29,8 @@ use crate::{
 
 use async_trait::async_trait;
 use bp_messages::{
-	storage_keys::outbound_lane_data_key, LaneId, MessageNonce, OutboundLaneData,
-	UnrewardedRelayersState,
+	storage_keys::{operating_mode_key, outbound_lane_data_key},
+	LaneId, MessageNonce, OperatingMode, OutboundLaneData, UnrewardedRelayersState,
 };
 use bridge_runtime_common::messages::{
 	source::FromBridgedChainMessagesDeliveryProof, target::FromBridgedChainMessagesProof,
@@ -99,6 +99,11 @@ impl<P: SubstrateMessageLane> SubstrateMessagesSource<P> {
 			)
 			.await
 	}
+
+	/// Ensure that the messages pallet at source chain is active.
+	async fn ensure_pallet_active(&self) -> Result<(), SubstrateError> {
+		ensure_messages_pallet_active::<P::SourceChain, P::TargetChain>(&self.client).await
+	}
 }
 
 impl<P: SubstrateMessageLane> Clone for SubstrateMessagesSource<P> {
@@ -132,6 +137,8 @@ where
 		// we can't continue to deliver confirmations if source node is out of sync, because
 		// it may have already received confirmations that we're going to deliver
 		self.client.ensure_synced().await?;
+		// we can't relay confirmations if messages pallet at source chain is halted
+		self.ensure_pallet_active().await?;
 
 		read_client_state::<
 			_,
@@ -292,6 +299,25 @@ where
 	}
 }
 
+/// Ensure that the messages pallet at source chain is active.
+pub(crate) async fn ensure_messages_pallet_active<AtChain, WithChain>(
+	client: &Client<AtChain>,
+) -> Result<(), SubstrateError>
+where
+	AtChain: ChainWithMessages,
+	WithChain: ChainWithMessages,
+{
+	let operating_mode = client
+		.storage_value(operating_mode_key(WithChain::WITH_CHAIN_MESSAGES_PALLET_NAME), None)
+		.await?;
+	let is_halted = operating_mode == Some(OperatingMode::Halted);
+	if is_halted {
+		Err(SubstrateError::BridgePalletIsHalted)
+	} else {
+		Ok(())
+	}
+}
+
 /// Make messages delivery proof transaction from given proof.
 fn make_messages_delivery_proof_transaction<P: SubstrateMessageLane>(
 	spec_version: u32,

bridges/relays/lib-substrate-relay/src/messages_target.rs

@@ -21,7 +21,7 @@
 use crate::{
 	messages_lane::{MessageLaneAdapter, ReceiveMessagesProofCallBuilder, SubstrateMessageLane},
 	messages_metrics::StandaloneMessagesMetrics,
-	messages_source::{read_client_state, SubstrateMessagesProof},
+	messages_source::{ensure_messages_pallet_active, read_client_state, SubstrateMessagesProof},
 	on_demand_headers::OnDemandHeadersRelay,
 	TransactionParams,
 };
@@ -100,6 +100,11 @@ impl<P: SubstrateMessageLane> SubstrateMessagesTarget<P> {
 			)
 			.await
 	}
+
+	/// Ensure that the messages pallet at target chain is active.
+	async fn ensure_pallet_active(&self) -> Result<(), SubstrateError> {
+		ensure_messages_pallet_active::<P::TargetChain, P::SourceChain>(&self.client).await
+	}
 }
 
 impl<P: SubstrateMessageLane> Clone for SubstrateMessagesTarget<P> {
@@ -136,6 +141,8 @@ where
 		// we can't continue to deliver messages if target node is out of sync, because
 		// it may have already received (some of) messages that we're going to deliver
 		self.client.ensure_synced().await?;
+		// we can't relay messages if messages pallet at target chain is halted
+		self.ensure_pallet_active().await?;
 
 		read_client_state::<
 			_,