Send messages using xcm pallet (#1518)

* send messages using xcm pallet

* XcmBridge && XcmBridgeAdapter + (untested) config in RialtoParachain

* impl encode_send_xcm for the rest

* remove duplicate code

* some fixes

* cleanup

* some more tests

* cleanup

* cleanup

* send Rialto -> Millau messages using bridge-messages pallet

* fmt

* some clippy fixes

* more clippy

bridges/bin/millau/runtime/src/lib.rs

@@ -88,6 +88,7 @@ pub use pallet_bridge_messages::Call as MessagesCall;
 pub use pallet_bridge_parachains::Call as BridgeParachainsCall;
 pub use pallet_sudo::Call as SudoCall;
 pub use pallet_timestamp::Call as TimestampCall;
+pub use pallet_xcm::Call as XcmCall;
 
 use bridge_runtime_common::generate_bridge_reject_obsolete_headers_and_messages;
 #[cfg(any(feature = "std", test))]

bridges/bin/millau/runtime/src/rialto_messages.rs

@@ -37,6 +37,8 @@ use scale_info::TypeInfo;
 use sp_runtime::{traits::Saturating, FixedPointNumber, FixedU128};
 use sp_std::convert::TryFrom;
 
+/// Default lane that is used to send messages to Rialto.
+pub const DEFAULT_XCM_LANE_TO_RIALTO: LaneId = [0, 0, 0, 0];
 /// Initial value of `RialtoToMillauConversionRate` parameter.
 pub const INITIAL_RIALTO_TO_MILLAU_CONVERSION_RATE: FixedU128 =
 	FixedU128::from_inner(FixedU128::DIV);
@@ -149,7 +151,7 @@ impl messages::ThisChainWithMessages for Millau {
 			},
 		}
 
-		*lane == [0, 0, 0, 0] || *lane == [0, 0, 0, 1]
+		*lane == DEFAULT_XCM_LANE_TO_RIALTO || *lane == [0, 0, 0, 1]
 	}
 
 	fn maximal_pending_messages_at_outbound_lane() -> MessageNonce {

bridges/bin/millau/runtime/src/rialto_parachain_messages.rs

@@ -38,6 +38,8 @@ use scale_info::TypeInfo;
 use sp_runtime::{traits::Saturating, FixedPointNumber, FixedU128};
 use sp_std::convert::TryFrom;
 
+/// Default lane that is used to send messages to Rialto parachain.
+pub const DEFAULT_XCM_LANE_TO_RIALTO_PARACHAIN: LaneId = [0, 0, 0, 0];
 /// Weight of 2 XCM instructions is for simple `Trap(42)` program, coming through bridge
 /// (it is prepended with `UniversalOrigin` instruction). It is used just for simplest manual
 /// tests, confirming that we don't break encoding somewhere between.
@@ -138,7 +140,7 @@ impl messages::ThisChainWithMessages for Millau {
 	>;
 
 	fn is_message_accepted(_send_origin: &Self::Origin, lane: &LaneId) -> bool {
-		*lane == [0, 0, 0, 0] || *lane == [0, 0, 0, 1]
+		*lane == DEFAULT_XCM_LANE_TO_RIALTO_PARACHAIN || *lane == [0, 0, 0, 1]
 	}
 
 	fn maximal_pending_messages_at_outbound_lane() -> MessageNonce {

bridges/bin/millau/runtime/src/xcm_config.rs

@@ -17,22 +17,22 @@
 //! XCM configurations for the Millau runtime.
 
 use super::{
-	rialto_messages::WithRialtoMessageBridge, AccountId, AllPalletsWithSystem, Balances,
-	BridgeRialtoMessages, Call, Event, Origin, Runtime, XcmPallet,
+	rialto_messages::{WithRialtoMessageBridge, DEFAULT_XCM_LANE_TO_RIALTO},
+	rialto_parachain_messages::{
+		WithRialtoParachainMessageBridge, DEFAULT_XCM_LANE_TO_RIALTO_PARACHAIN,
+	},
+	AccountId, AllPalletsWithSystem, Balances, Call, Event, Origin, Runtime,
+	WithRialtoMessagesInstance, WithRialtoParachainMessagesInstance, XcmPallet,
 };
-use bp_messages::source_chain::MessagesBridge;
-use bp_millau::{Balance, WeightToFee};
-use bridge_runtime_common::messages::{
-	source::{estimate_message_dispatch_and_delivery_fee, FromThisChainMessagePayload},
-	MessageBridge,
-};
-use codec::Encode;
+use bp_messages::LaneId;
+use bp_millau::WeightToFee;
+use bp_rialto_parachain::RIALTO_PARACHAIN_ID;
+use bridge_runtime_common::messages::source::{XcmBridge, XcmBridgeAdapter};
 use frame_support::{
 	parameter_types,
 	traits::{Everything, Nothing},
 	weights::Weight,
 };
-use sp_std::marker::PhantomData;
 use xcm::latest::prelude::*;
 use xcm_builder::{
 	AccountId32Aliases, AllowKnownQueryResponses, AllowTopLevelPaidExecutionFrom,
@@ -49,6 +49,8 @@ parameter_types! {
 	pub const ThisNetwork: NetworkId = Kusama;
 	/// The Rialto network ID, associated with Polkadot.
 	pub const RialtoNetwork: NetworkId = Polkadot;
+	/// The RialtoParachain network ID, associated with Westend.
+	pub const RialtoParachainNetwork: NetworkId = Westend;
 
 	/// Our XCM location ancestry - i.e. our location within the Consensus Universe.
 	///
@@ -105,7 +107,9 @@ parameter_types! {
 /// individual routers.
 pub type XcmRouter = (
 	// Router to send messages to Rialto.
-	ToRialtoBridge<BridgeRialtoMessages>,
+	XcmBridgeAdapter<ToRialtoBridge>,
+	// Router to send messages to RialtoParachains.
+	XcmBridgeAdapter<ToRialtoParachainBridge>,
 );
 
 parameter_types! {
@@ -189,60 +193,56 @@ impl pallet_xcm::Config for Runtime {
 	type MaxLockers = frame_support::traits::ConstU32<8>;
 }
 
-/// With-rialto bridge.
-pub struct ToRialtoBridge<MB>(PhantomData<MB>);
+/// With-Rialto bridge.
+pub struct ToRialtoBridge;
 
-impl<MB: MessagesBridge<Origin, AccountId, Balance, FromThisChainMessagePayload>> SendXcm
-	for ToRialtoBridge<MB>
-{
-	type Ticket = (Balance, FromThisChainMessagePayload);
+impl XcmBridge for ToRialtoBridge {
+	type MessageBridge = WithRialtoMessageBridge;
+	type MessageSender = pallet_bridge_messages::Pallet<Runtime, WithRialtoMessagesInstance>;
 
-	fn validate(
-		dest: &mut Option<MultiLocation>,
-		msg: &mut Option<Xcm<()>>,
-	) -> SendResult<Self::Ticket> {
-		let d = dest.take().ok_or(SendError::MissingArgument)?;
-		if !matches!(d, MultiLocation { parents: 1, interior: X1(GlobalConsensus(r)) } if r == RialtoNetwork::get())
-		{
-			*dest = Some(d);
-			return Err(SendError::NotApplicable)
-		};
-
-		let dest: InteriorMultiLocation = RialtoNetwork::get().into();
-		let here = UniversalLocation::get();
-		let route = dest.relative_to(&here);
-		let msg = (route, msg.take().unwrap()).encode();
-
-		let fee = estimate_message_dispatch_and_delivery_fee::<WithRialtoMessageBridge>(
-			&msg,
-			WithRialtoMessageBridge::RELAYER_FEE_PERCENT,
-			None,
-		)
-		.map_err(SendError::Transport)?;
-		let fee_assets = MultiAssets::from((Here, fee));
-
-		Ok(((fee, msg), fee_assets))
+	fn universal_location() -> InteriorMultiLocation {
+		UniversalLocation::get()
 	}
 
-	fn deliver(ticket: Self::Ticket) -> Result<XcmHash, SendError> {
-		let lane = [0, 0, 0, 0];
-		let (fee, msg) = ticket;
-		let result = MB::send_message(
-			pallet_xcm::Origin::from(MultiLocation::from(UniversalLocation::get())).into(),
-			lane,
-			msg,
-			fee,
-		);
-		result
-			.map(|artifacts| {
-				let hash = (lane, artifacts.nonce).using_encoded(sp_io::hashing::blake2_256);
-				log::debug!(target: "runtime::bridge", "Sent XCM message {:?}/{} to Millau: {:?}", lane, artifacts.nonce, hash);
-				hash
-			})
-			.map_err(|e| {
-				log::debug!(target: "runtime::bridge", "Failed to send XCM message over lane {:?} to Millau: {:?}", lane, e);
-				SendError::Transport("Bridge has rejected the message")
-			})
+	fn verify_destination(dest: &MultiLocation) -> bool {
+		matches!(*dest, MultiLocation { parents: 1, interior: X1(GlobalConsensus(r)) } if r == RialtoNetwork::get())
+	}
+
+	fn build_destination() -> MultiLocation {
+		let dest: InteriorMultiLocation = RialtoNetwork::get().into();
+		let here = UniversalLocation::get();
+		dest.relative_to(&here)
+	}
+
+	fn xcm_lane() -> LaneId {
+		DEFAULT_XCM_LANE_TO_RIALTO
+	}
+}
+
+/// With-RialtoParachain bridge.
+pub struct ToRialtoParachainBridge;
+
+impl XcmBridge for ToRialtoParachainBridge {
+	type MessageBridge = WithRialtoParachainMessageBridge;
+	type MessageSender =
+		pallet_bridge_messages::Pallet<Runtime, WithRialtoParachainMessagesInstance>;
+
+	fn universal_location() -> InteriorMultiLocation {
+		UniversalLocation::get()
+	}
+
+	fn verify_destination(dest: &MultiLocation) -> bool {
+		matches!(*dest, MultiLocation { parents: 1, interior: X2(GlobalConsensus(r), Parachain(RIALTO_PARACHAIN_ID)) } if r == RialtoNetwork::get())
+	}
+
+	fn build_destination() -> MultiLocation {
+		let dest: InteriorMultiLocation = RialtoParachainNetwork::get().into();
+		let here = UniversalLocation::get();
+		dest.relative_to(&here)
+	}
+
+	fn xcm_lane() -> LaneId {
+		DEFAULT_XCM_LANE_TO_RIALTO_PARACHAIN
 	}
 }
 
@@ -255,6 +255,7 @@ mod tests {
 	};
 	use bp_runtime::messages::MessageDispatchResult;
 	use bridge_runtime_common::messages::target::FromBridgedChainMessageDispatch;
+	use codec::Encode;
 
 	fn new_test_ext() -> sp_io::TestExternalities {
 		sp_io::TestExternalities::new(
@@ -263,17 +264,23 @@ mod tests {
 	}
 
 	#[test]
-	fn xcm_messages_to_rialto_are_sent() {
+	fn xcm_messages_are_sent_using_bridge_router() {
 		new_test_ext().execute_with(|| {
-			// the encoded message (origin ++ xcm) is 0x010109020419A8
-			let dest = (Parent, X1(GlobalConsensus(RialtoNetwork::get())));
 			let xcm: Xcm<()> = vec![Instruction::Trap(42)].into();
-
-			let send_result = send_xcm::<XcmRouter>(dest.into(), xcm);
 			let expected_fee = MultiAssets::from((Here, 4_345_002_552_u64));
 			let expected_hash =
 				([0u8, 0u8, 0u8, 0u8], 1u64).using_encoded(sp_io::hashing::blake2_256);
-			assert_eq!(send_result, Ok((expected_hash, expected_fee)),);
+
+			// message 1 to Rialto
+			let dest = (Parent, X1(GlobalConsensus(RialtoNetwork::get())));
+			let send_result = send_xcm::<XcmRouter>(dest.into(), xcm.clone());
+			assert_eq!(send_result, Ok((expected_hash, expected_fee.clone())));
+
+			// message 2 to RialtoParachain (expected hash is the same, since other lane is used)
+			let dest =
+				(Parent, X2(GlobalConsensus(RialtoNetwork::get()), Parachain(RIALTO_PARACHAIN_ID)));
+			let send_result = send_xcm::<XcmRouter>(dest.into(), xcm);
+			assert_eq!(send_result, Ok((expected_hash, expected_fee)));
 		})
 	}
 

bridges/bin/rialto-parachain/runtime/src/lib.rs

@@ -26,10 +26,13 @@
 #[cfg(feature = "std")]
 include!(concat!(env!("OUT_DIR"), "/wasm_binary.rs"));
 
-use crate::millau_messages::{ToMillauMessagePayload, WithMillauMessageBridge};
+use crate::millau_messages::{
+	ToMillauMessagePayload, WithMillauMessageBridge, DEFAULT_XCM_LANE_TO_MILLAU,
+};
 
 use bridge_runtime_common::messages::{
-	source::estimate_message_dispatch_and_delivery_fee, MessageBridge,
+	source::{estimate_message_dispatch_and_delivery_fee, XcmBridge, XcmBridgeAdapter},
+	MessageBridge,
 };
 use sp_api::impl_runtime_apis;
 use sp_core::{crypto::KeyTypeId, OpaqueMetadata};
@@ -71,6 +74,7 @@ pub use bp_rialto_parachain::{
 
 pub use pallet_bridge_grandpa::Call as BridgeGrandpaCall;
 pub use pallet_bridge_messages::Call as MessagesCall;
+pub use pallet_xcm::Call as XcmCall;
 
 // Polkadot & XCM imports
 use pallet_xcm::XcmPassthrough;
@@ -302,6 +306,10 @@ parameter_types! {
 	pub const RelayNetwork: NetworkId = NetworkId::Polkadot;
 	pub RelayOrigin: Origin = cumulus_pallet_xcm::Origin::Relay.into();
 	pub UniversalLocation: InteriorMultiLocation = X1(Parachain(ParachainInfo::parachain_id().into()));
+	/// The Millau network ID, associated with Kusama.
+	pub const MillauNetwork: NetworkId = Kusama;
+	/// The RialtoParachain network ID, associated with Westend.
+	pub const ThisNetwork: NetworkId = Westend;
 }
 
 /// Type for specifying how a `MultiLocation` can be converted into an `AccountId`. This is used
@@ -417,12 +425,36 @@ pub type LocalOriginToLocation = SignedToAccountId32<Origin, AccountId, RelayNet
 /// The means for routing XCM messages which are not for local execution into the right message
 /// queues.
 pub type XcmRouter = (
-	// Two routers - use UMP to communicate with the relay chain:
-	cumulus_primitives_utility::ParentAsUmp<ParachainSystem, (), ()>,
-	// ..and XCMP to communicate with the sibling chains.
-	XcmpQueue,
+	// Bridge is used to communicate with other relay chain (Millau).
+	XcmBridgeAdapter<ToMillauBridge>,
 );
 
+/// With-Millau bridge.
+pub struct ToMillauBridge;
+
+impl XcmBridge for ToMillauBridge {
+	type MessageBridge = WithMillauMessageBridge;
+	type MessageSender = pallet_bridge_messages::Pallet<Runtime, WithMillauMessagesInstance>;
+
+	fn universal_location() -> InteriorMultiLocation {
+		UniversalLocation::get()
+	}
+
+	fn verify_destination(dest: &MultiLocation) -> bool {
+		matches!(*dest, MultiLocation { parents: 1, interior: X1(GlobalConsensus(r)) } if r == MillauNetwork::get())
+	}
+
+	fn build_destination() -> MultiLocation {
+		let dest: InteriorMultiLocation = MillauNetwork::get().into();
+		let here = UniversalLocation::get();
+		dest.relative_to(&here)
+	}
+
+	fn xcm_lane() -> bp_messages::LaneId {
+		DEFAULT_XCM_LANE_TO_MILLAU
+	}
+}
+
 impl pallet_xcm::Config for Runtime {
 	type Event = Event;
 	type SendXcmOrigin = EnsureXcmOrigin<Origin, LocalOriginToLocation>;
@@ -800,3 +832,72 @@ cumulus_pallet_parachain_system::register_validate_block!(
 	BlockExecutor = cumulus_pallet_aura_ext::BlockExecutor::<Runtime, Executive>,
 	CheckInherents = CheckInherents,
 );
+
+#[cfg(test)]
+mod tests {
+	use super::*;
+	use bp_messages::{
+		target_chain::{DispatchMessage, DispatchMessageData, MessageDispatch},
+		MessageKey,
+	};
+	use bp_runtime::messages::MessageDispatchResult;
+	use bridge_runtime_common::messages::target::FromBridgedChainMessageDispatch;
+	use codec::Encode;
+
+	fn new_test_ext() -> sp_io::TestExternalities {
+		sp_io::TestExternalities::new(
+			frame_system::GenesisConfig::default().build_storage::<Runtime>().unwrap(),
+		)
+	}
+
+	#[test]
+	fn xcm_messages_to_millau_are_sent() {
+		new_test_ext().execute_with(|| {
+			// the encoded message (origin ++ xcm) is 0x010109020419A8
+			let dest = (Parent, X1(GlobalConsensus(MillauNetwork::get())));
+			let xcm: Xcm<()> = vec![Instruction::Trap(42)].into();
+
+			let send_result = send_xcm::<XcmRouter>(dest.into(), xcm);
+			let expected_fee = MultiAssets::from((Here, Fungibility::Fungible(4_345_002_552_u128)));
+			let expected_hash =
+				([0u8, 0u8, 0u8, 0u8], 1u64).using_encoded(sp_io::hashing::blake2_256);
+			assert_eq!(send_result, Ok((expected_hash, expected_fee)),);
+		})
+	}
+
+	#[test]
+	fn xcm_messages_from_millau_are_dispatched() {
+		type XcmExecutor = xcm_executor::XcmExecutor<XcmConfig>;
+		type MessageDispatcher = FromBridgedChainMessageDispatch<
+			WithMillauMessageBridge,
+			XcmExecutor,
+			XcmWeigher,
+			frame_support::traits::ConstU64<BASE_XCM_WEIGHT>,
+		>;
+
+		new_test_ext().execute_with(|| {
+			let location: MultiLocation =
+				(Parent, X1(GlobalConsensus(MillauNetwork::get()))).into();
+			let xcm: Xcm<Call> = vec![Instruction::Trap(42)].into();
+
+			let mut incoming_message = DispatchMessage {
+				key: MessageKey { lane_id: [0, 0, 0, 0], nonce: 1 },
+				data: DispatchMessageData { payload: Ok((location, xcm).into()), fee: 0 },
+			};
+
+			let dispatch_weight = MessageDispatcher::dispatch_weight(&mut incoming_message);
+			assert_eq!(dispatch_weight, 1_000_000_000);
+
+			let dispatch_result =
+				MessageDispatcher::dispatch(&AccountId::from([0u8; 32]), incoming_message);
+			assert_eq!(
+				dispatch_result,
+				MessageDispatchResult {
+					dispatch_result: true,
+					unspent_weight: 0,
+					dispatch_fee_paid_during_dispatch: false,
+				}
+			);
+		})
+	}
+}

bridges/bin/rialto-parachain/runtime/src/millau_messages.rs

@@ -19,7 +19,7 @@
 // TODO: this is almost exact copy of `millau_messages.rs` from Rialto runtime.
 // Should be extracted to a separate crate and reused here.
 
-use crate::Runtime;
+use crate::{OriginCaller, Runtime};
 
 use bp_messages::{
 	source_chain::{SenderOrigin, TargetHeaderChain},
@@ -40,6 +40,8 @@ use scale_info::TypeInfo;
 use sp_runtime::{traits::Saturating, FixedPointNumber, FixedU128};
 use sp_std::convert::TryFrom;
 
+/// Default lane that is used to send messages to Millau.
+pub const DEFAULT_XCM_LANE_TO_MILLAU: LaneId = [0, 0, 0, 0];
 /// Initial value of `MillauToRialtoParachainConversionRate` parameter.
 pub const INITIAL_MILLAU_TO_RIALTO_PARACHAIN_CONVERSION_RATE: FixedU128 =
 	FixedU128::from_inner(FixedU128::DIV);
@@ -137,7 +139,22 @@ impl messages::ThisChainWithMessages for RialtoParachain {
 	>;
 
 	fn is_message_accepted(send_origin: &Self::Origin, lane: &LaneId) -> bool {
-		send_origin.linked_account().is_some() && (*lane == [0, 0, 0, 0] || *lane == [0, 0, 0, 1])
+		let here_location = xcm::v3::MultiLocation::from(crate::UniversalLocation::get());
+		match send_origin.caller {
+			OriginCaller::PolkadotXcm(pallet_xcm::Origin::Xcm(ref location))
+				if *location == here_location =>
+			{
+				log::trace!(target: "runtime::bridge", "Verifying message sent using XCM pallet to Millau");
+			},
+			_ => {
+				// keep in mind that in this case all messages are free (in term of fees)
+				// => it's just to keep testing bridge on our test deployments until we'll have a
+				// better option
+				log::trace!(target: "runtime::bridge", "Verifying message sent using messages pallet to Millau");
+			},
+		}
+
+		*lane == [0, 0, 0, 0] || *lane == [0, 0, 0, 1]
 	}
 
 	fn maximal_pending_messages_at_outbound_lane() -> MessageNonce {

bridges/bin/rialto/runtime/src/lib.rs

@@ -73,6 +73,7 @@ pub use pallet_bridge_grandpa::Call as BridgeGrandpaMillauCall;
 pub use pallet_bridge_messages::Call as MessagesCall;
 pub use pallet_sudo::Call as SudoCall;
 pub use pallet_timestamp::Call as TimestampCall;
+pub use pallet_xcm::Call as XcmCall;
 
 #[cfg(any(feature = "std", test))]
 pub use sp_runtime::BuildStorage;

bridges/bin/rialto/runtime/src/xcm_config.rs

@@ -17,22 +17,16 @@
 //! XCM configurations for the Rialto runtime.
 
 use super::{
-	millau_messages::WithMillauMessageBridge, AccountId, AllPalletsWithSystem, Balances,
-	BridgeMillauMessages, Call, Event, Origin, Runtime, XcmPallet,
+	millau_messages::WithMillauMessageBridge, AccountId, AllPalletsWithSystem, Balances, Call,
+	Event, Origin, Runtime, WithMillauMessagesInstance, XcmPallet,
 };
-use bp_messages::source_chain::MessagesBridge;
-use bp_rialto::{Balance, WeightToFee};
-use bridge_runtime_common::messages::{
-	source::{estimate_message_dispatch_and_delivery_fee, FromThisChainMessagePayload},
-	MessageBridge,
-};
-use codec::Encode;
+use bp_rialto::WeightToFee;
+use bridge_runtime_common::messages::source::{XcmBridge, XcmBridgeAdapter};
 use frame_support::{
 	parameter_types,
 	traits::{Everything, Nothing},
 	weights::Weight,
 };
-use sp_std::marker::PhantomData;
 use xcm::latest::prelude::*;
 use xcm_builder::{
 	AccountId32Aliases, AllowKnownQueryResponses, AllowTopLevelPaidExecutionFrom,
@@ -105,7 +99,7 @@ parameter_types! {
 /// individual routers.
 pub type XcmRouter = (
 	// Router to send messages to Millau.
-	ToMillauBridge<BridgeMillauMessages>,
+	XcmBridgeAdapter<ToMillauBridge>,
 );
 
 parameter_types! {
@@ -189,60 +183,29 @@ impl pallet_xcm::Config for Runtime {
 	type MaxLockers = frame_support::traits::ConstU32<8>;
 }
 
-/// With-rialto bridge.
-pub struct ToMillauBridge<MB>(PhantomData<MB>);
+/// With-Millau bridge.
+pub struct ToMillauBridge;
 
-impl<MB: MessagesBridge<Origin, AccountId, Balance, FromThisChainMessagePayload>> SendXcm
-	for ToMillauBridge<MB>
-{
-	type Ticket = (Balance, FromThisChainMessagePayload);
+impl XcmBridge for ToMillauBridge {
+	type MessageBridge = WithMillauMessageBridge;
+	type MessageSender = pallet_bridge_messages::Pallet<Runtime, WithMillauMessagesInstance>;
 
-	fn validate(
-		dest: &mut Option<MultiLocation>,
-		msg: &mut Option<Xcm<()>>,
-	) -> SendResult<Self::Ticket> {
-		let d = dest.take().ok_or(SendError::MissingArgument)?;
-		if !matches!(d, MultiLocation { parents: 1, interior: X1(GlobalConsensus(r)) } if r == MillauNetwork::get())
-		{
-			*dest = Some(d);
-			return Err(SendError::NotApplicable)
-		};
-
-		let dest: InteriorMultiLocation = MillauNetwork::get().into();
-		let here = UniversalLocation::get();
-		let route = dest.relative_to(&here);
-		let msg = (route, msg.take().unwrap()).encode();
-
-		let fee = estimate_message_dispatch_and_delivery_fee::<WithMillauMessageBridge>(
-			&msg,
-			WithMillauMessageBridge::RELAYER_FEE_PERCENT,
-			None,
-		)
-		.map_err(SendError::Transport)?;
-		let fee_assets = MultiAssets::from((Here, fee));
-
-		Ok(((fee, msg), fee_assets))
+	fn universal_location() -> InteriorMultiLocation {
+		UniversalLocation::get()
 	}
 
-	fn deliver(ticket: Self::Ticket) -> Result<XcmHash, SendError> {
-		let lane = [0, 0, 0, 0];
-		let (fee, msg) = ticket;
-		let result = MB::send_message(
-			pallet_xcm::Origin::from(MultiLocation::from(UniversalLocation::get())).into(),
-			lane,
-			msg,
-			fee,
-		);
-		result
-			.map(|artifacts| {
-				let hash = (lane, artifacts.nonce).using_encoded(sp_io::hashing::blake2_256);
-				log::debug!(target: "runtime::bridge", "Sent XCM message {:?}/{} to Rialto: {:?}", lane, artifacts.nonce, hash);
-				hash
-			})
-			.map_err(|e| {
-				log::debug!(target: "runtime::bridge", "Failed to send XCM message over lane {:?} to Rialto: {:?}", lane, e);
-				SendError::Transport("Bridge has rejected the message")
-			})
+	fn verify_destination(dest: &MultiLocation) -> bool {
+		matches!(*dest, MultiLocation { parents: 1, interior: X1(GlobalConsensus(r)) } if r == MillauNetwork::get())
+	}
+
+	fn build_destination() -> MultiLocation {
+		let dest: InteriorMultiLocation = MillauNetwork::get().into();
+		let here = UniversalLocation::get();
+		dest.relative_to(&here)
+	}
+
+	fn xcm_lane() -> bp_messages::LaneId {
+		[0, 0, 0, 0]
 	}
 }
 
@@ -255,6 +218,7 @@ mod tests {
 	};
 	use bp_runtime::messages::MessageDispatchResult;
 	use bridge_runtime_common::messages::target::FromBridgedChainMessageDispatch;
+	use codec::Encode;
 
 	fn new_test_ext() -> sp_io::TestExternalities {
 		sp_io::TestExternalities::new(

bridges/bin/runtime-common/Cargo.toml

@@ -41,6 +41,7 @@ sp-version = { git = "https://github.com/paritytech/substrate", branch = "master
 
 # Polkadot dependencies
 
+pallet-xcm = { git = "https://github.com/paritytech/polkadot", branch = "gav-xcm-v3", default-features = false }
 xcm = { git = "https://github.com/paritytech/polkadot", branch = "gav-xcm-v3", default-features = false }
 xcm-builder = { git = "https://github.com/paritytech/polkadot", branch = "gav-xcm-v3", default-features = false }
 xcm-executor = { git = "https://github.com/paritytech/polkadot", branch = "gav-xcm-v3", default-features = false }
@@ -65,6 +66,7 @@ std = [
 	"pallet-bridge-messages/std",
 	"pallet-bridge-parachains/std",
 	"pallet-transaction-payment/std",
+	"pallet-xcm/std",
 	"scale-info/std",
 	"sp-api/std",
 	"sp-core/std",

bridges/bin/runtime-common/src/messages.rs

@@ -37,6 +37,7 @@ use sp_runtime::{
 };
 use sp_std::{cmp::PartialOrd, convert::TryFrom, fmt::Debug, marker::PhantomData, vec::Vec};
 use sp_trie::StorageProof;
+use xcm::latest::prelude::*;
 
 /// Bidirectional message bridge.
 pub trait MessageBridge {
@@ -524,6 +525,111 @@ pub mod source {
 
 		Ok((lane, inbound_lane_data))
 	}
+
+	/// XCM bridge.
+	pub trait XcmBridge {
+		/// Runtime message bridge configuration.
+		type MessageBridge: MessageBridge;
+		/// Runtime message sender adapter.
+		type MessageSender: bp_messages::source_chain::MessagesBridge<
+			OriginOf<ThisChain<Self::MessageBridge>>,
+			AccountIdOf<ThisChain<Self::MessageBridge>>,
+			BalanceOf<ThisChain<Self::MessageBridge>>,
+			FromThisChainMessagePayload,
+		>;
+
+		/// Our location within the Consensus Universe.
+		fn universal_location() -> InteriorMultiLocation;
+		/// Verify that the adapter is responsible for handling given XCM destination.
+		fn verify_destination(dest: &MultiLocation) -> bool;
+		/// Build route from this chain to the XCM destination.
+		fn build_destination() -> MultiLocation;
+		/// Return message lane used to deliver XCM messages.
+		fn xcm_lane() -> LaneId;
+	}
+
+	/// XCM bridge adapter for `bridge-messages` pallet.
+	pub struct XcmBridgeAdapter<T>(PhantomData<T>);
+
+	impl<T: XcmBridge> SendXcm for XcmBridgeAdapter<T>
+	where
+		BalanceOf<ThisChain<T::MessageBridge>>: Into<Fungibility>,
+		OriginOf<ThisChain<T::MessageBridge>>: From<pallet_xcm::Origin>,
+	{
+		type Ticket = (BalanceOf<ThisChain<T::MessageBridge>>, FromThisChainMessagePayload);
+
+		fn validate(
+			dest: &mut Option<MultiLocation>,
+			msg: &mut Option<Xcm<()>>,
+		) -> SendResult<Self::Ticket> {
+			let d = dest.take().ok_or(SendError::MissingArgument)?;
+			if !T::verify_destination(&d) {
+				*dest = Some(d);
+				return Err(SendError::NotApplicable)
+			}
+
+			let route = T::build_destination();
+			let msg = (route, msg.take().unwrap()).encode();
+
+			let fee = estimate_message_dispatch_and_delivery_fee::<T::MessageBridge>(
+				&msg,
+				T::MessageBridge::RELAYER_FEE_PERCENT,
+				None,
+			);
+			let fee = match fee {
+				Ok(fee) => fee,
+				Err(e) => {
+					log::trace!(
+						target: "runtime::bridge",
+						"Failed to comupte fee for XCM message to {:?}: {:?}",
+						T::MessageBridge::BRIDGED_CHAIN_ID,
+						e,
+					);
+					*dest = Some(d);
+					return Err(SendError::Transport(e))
+				},
+			};
+			let fee_assets = MultiAssets::from((Here, fee));
+
+			Ok(((fee, msg), fee_assets))
+		}
+
+		fn deliver(ticket: Self::Ticket) -> Result<XcmHash, SendError> {
+			use bp_messages::source_chain::MessagesBridge;
+
+			let lane = T::xcm_lane();
+			let (fee, msg) = ticket;
+			let result = T::MessageSender::send_message(
+				pallet_xcm::Origin::from(MultiLocation::from(T::universal_location())).into(),
+				lane,
+				msg,
+				fee,
+			);
+			result
+				.map(|artifacts| {
+					let hash = (lane, artifacts.nonce).using_encoded(sp_io::hashing::blake2_256);
+					log::debug!(
+						target: "runtime::bridge",
+						"Sent XCM message {:?}/{} to {:?}: {:?}",
+						lane,
+						artifacts.nonce,
+						T::MessageBridge::BRIDGED_CHAIN_ID,
+						hash,
+					);
+					hash
+				})
+				.map_err(|e| {
+					log::debug!(
+						target: "runtime::bridge",
+						"Failed to send XCM message over lane {:?} to {:?}: {:?}",
+						lane,
+						T::MessageBridge::BRIDGED_CHAIN_ID,
+						e,
+					);
+					SendError::Transport("Bridge has rejected the message")
+				})
+		}
+	}
 }
 
 /// Sub-module that is declaring types required for processing Bridged -> This chain messages.
@@ -641,8 +747,6 @@ pub mod target {
 			_relayer_account: &AccountIdOf<ThisChain<B>>,
 			message: DispatchMessage<Self::DispatchPayload, BalanceOf<BridgedChain<B>>>,
 		) -> MessageDispatchResult {
-			use xcm::latest::*;
-
 			let message_id = (message.key.lane_id, message.key.nonce);
 			let do_dispatch = move || -> sp_std::result::Result<Outcome, codec::Error> {
 				let FromBridgedChainMessagePayload { xcm: (location, xcm), weight: weight_limit } =