Adds Snowbridge to Rococo runtime (#2522)

# Description

Adds Snowbridge to the Rococo bridge hub runtime. Includes config
changes required in Rococo asset hub.

---------

Co-authored-by: Alistair Singh <alistair.singh7@gmail.com>
Co-authored-by: ron <yrong1997@gmail.com>
Co-authored-by: Vincent Geddes <vincent.geddes@hey.com>
Co-authored-by: claravanstaden <Cats 4 life!>

cumulus/parachains/runtimes/bridge-hubs/common/src/digest_item.rs

@@ -0,0 +1,34 @@
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//! Custom digest items
+
+use codec::{Decode, Encode};
+use sp_core::{RuntimeDebug, H256};
+use sp_runtime::generic::DigestItem;
+
+/// Custom header digest items, inserted as DigestItem::Other
+#[derive(Encode, Decode, Copy, Clone, Eq, PartialEq, RuntimeDebug)]
+pub enum CustomDigestItem {
+	#[codec(index = 0)]
+	/// Merkle root of outbound Snowbridge messages.
+	Snowbridge(H256),
+}
+
+/// Convert custom application digest item into a concrete digest item
+impl From<CustomDigestItem> for DigestItem {
+	fn from(val: CustomDigestItem) -> Self {
+		DigestItem::Other(val.encode())
+	}
+}

cumulus/parachains/runtimes/bridge-hubs/common/src/lib.rs

@@ -0,0 +1,21 @@
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+#![cfg_attr(not(feature = "std"), no_std)]
+
+pub mod digest_item;
+pub mod message_queue;
+
+pub use digest_item::CustomDigestItem;
+pub use message_queue::{AggregateMessageOrigin, BridgeHubMessageRouter};

cumulus/parachains/runtimes/bridge-hubs/common/src/message_queue.rs

@@ -0,0 +1,146 @@
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//! Runtime configuration for MessageQueue pallet
+use codec::{Decode, Encode, MaxEncodedLen};
+use cumulus_primitives_core::{AggregateMessageOrigin as CumulusAggregateMessageOrigin, ParaId};
+use frame_support::{
+	traits::{ProcessMessage, ProcessMessageError, QueueFootprint, QueuePausedQuery},
+	weights::WeightMeter,
+};
+use pallet_message_queue::OnQueueChanged;
+use scale_info::TypeInfo;
+use snowbridge_core::ChannelId;
+use sp_std::{marker::PhantomData, prelude::*};
+use xcm::v3::{Junction, MultiLocation};
+
+/// The aggregate origin of an inbound message.
+/// This is specialized for BridgeHub, as the snowbridge-outbound-queue pallet is also using
+/// the shared MessageQueue pallet.
+#[derive(Encode, Decode, Copy, MaxEncodedLen, Clone, Eq, PartialEq, TypeInfo, Debug)]
+pub enum AggregateMessageOrigin {
+	/// The message came from the para-chain itself.
+	Here,
+	/// The message came from the relay-chain.
+	///
+	/// This is used by the DMP queue.
+	Parent,
+	/// The message came from a sibling para-chain.
+	///
+	/// This is used by the HRMP queue.
+	Sibling(ParaId),
+	/// The message came from a snowbridge channel.
+	///
+	/// This is used by Snowbridge inbound queue.
+	Snowbridge(ChannelId),
+}
+
+impl From<AggregateMessageOrigin> for MultiLocation {
+	fn from(origin: AggregateMessageOrigin) -> Self {
+		use AggregateMessageOrigin::*;
+		match origin {
+			Here => MultiLocation::here(),
+			Parent => MultiLocation::parent(),
+			Sibling(id) => MultiLocation::new(1, Junction::Parachain(id.into())),
+			// NOTE: We don't need this conversion for Snowbridge. However we have to
+			// implement it anyway as xcm_builder::ProcessXcmMessage requires it.
+			Snowbridge(_) => MultiLocation::default(),
+		}
+	}
+}
+
+impl From<CumulusAggregateMessageOrigin> for AggregateMessageOrigin {
+	fn from(origin: CumulusAggregateMessageOrigin) -> Self {
+		match origin {
+			CumulusAggregateMessageOrigin::Here => Self::Here,
+			CumulusAggregateMessageOrigin::Parent => Self::Parent,
+			CumulusAggregateMessageOrigin::Sibling(id) => Self::Sibling(id),
+		}
+	}
+}
+
+#[cfg(feature = "runtime-benchmarks")]
+impl From<u32> for AggregateMessageOrigin {
+	fn from(x: u32) -> Self {
+		match x {
+			0 => Self::Here,
+			1 => Self::Parent,
+			p => Self::Sibling(ParaId::from(p)),
+		}
+	}
+}
+
+/// Routes messages to either the XCMP or Snowbridge processor.
+pub struct BridgeHubMessageRouter<XcmpProcessor, SnowbridgeProcessor>(
+	PhantomData<(XcmpProcessor, SnowbridgeProcessor)>,
+)
+where
+	XcmpProcessor: ProcessMessage<Origin = AggregateMessageOrigin>,
+	SnowbridgeProcessor: ProcessMessage<Origin = AggregateMessageOrigin>;
+
+impl<XcmpProcessor, SnowbridgeProcessor> ProcessMessage
+	for BridgeHubMessageRouter<XcmpProcessor, SnowbridgeProcessor>
+where
+	XcmpProcessor: ProcessMessage<Origin = AggregateMessageOrigin>,
+	SnowbridgeProcessor: ProcessMessage<Origin = AggregateMessageOrigin>,
+{
+	type Origin = AggregateMessageOrigin;
+
+	fn process_message(
+		message: &[u8],
+		origin: Self::Origin,
+		meter: &mut WeightMeter,
+		id: &mut [u8; 32],
+	) -> Result<bool, ProcessMessageError> {
+		use AggregateMessageOrigin::*;
+		match origin {
+			Here | Parent | Sibling(_) =>
+				XcmpProcessor::process_message(message, origin, meter, id),
+			Snowbridge(_) => SnowbridgeProcessor::process_message(message, origin, meter, id),
+		}
+	}
+}
+
+/// Narrow the scope of the `Inner` query from `AggregateMessageOrigin` to `ParaId`.
+///
+/// All non-`Sibling` variants will be ignored.
+pub struct NarrowOriginToSibling<Inner>(PhantomData<Inner>);
+impl<Inner: QueuePausedQuery<ParaId>> QueuePausedQuery<AggregateMessageOrigin>
+	for NarrowOriginToSibling<Inner>
+{
+	fn is_paused(origin: &AggregateMessageOrigin) -> bool {
+		match origin {
+			AggregateMessageOrigin::Sibling(id) => Inner::is_paused(id),
+			_ => false,
+		}
+	}
+}
+
+impl<Inner: OnQueueChanged<ParaId>> OnQueueChanged<AggregateMessageOrigin>
+	for NarrowOriginToSibling<Inner>
+{
+	fn on_queue_changed(origin: AggregateMessageOrigin, fp: QueueFootprint) {
+		if let AggregateMessageOrigin::Sibling(id) = origin {
+			Inner::on_queue_changed(id, fp)
+		}
+	}
+}
+
+/// Convert a sibling `ParaId` to an `AggregateMessageOrigin`.
+pub struct ParaIdToSibling;
+impl sp_runtime::traits::Convert<ParaId, AggregateMessageOrigin> for ParaIdToSibling {
+	fn convert(para_id: ParaId) -> AggregateMessageOrigin {
+		AggregateMessageOrigin::Sibling(para_id)
+	}
+}