Parachains finality relay (paritytech#1199)

bridges/bin/millau/runtime/Cargo.toml

@@ -26,6 +26,7 @@ bp-westend = { path = "../../../primitives/chain-westend", default-features = fa
 bridge-runtime-common = { path = "../../runtime-common", default-features = false }
 pallet-bridge-grandpa = { path = "../../../modules/grandpa", default-features = false }
 pallet-bridge-messages = { path = "../../../modules/messages", default-features = false }
+pallet-bridge-parachains = { path = "../../../modules/parachains", default-features = false }
 pallet-shift-session-manager = { path = "../../../modules/shift-session-manager", default-features = false }
 
 # Substrate Dependencies
@@ -102,6 +103,7 @@ std = [
 	"pallet-beefy-mmr/std",
 	"pallet-bridge-grandpa/std",
 	"pallet-bridge-messages/std",
+	"pallet-bridge-parachains/std",
 	"pallet-grandpa/std",
 	"pallet-mmr/std",
 	"pallet-randomness-collective-flip/std",

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

@@ -73,6 +73,7 @@ pub use frame_system::Call as SystemCall;
 pub use pallet_balances::Call as BalancesCall;
 pub use pallet_bridge_grandpa::Call as BridgeGrandpaCall;
 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;
 
@@ -461,6 +462,19 @@ impl pallet_bridge_messages::Config<WithRialtoMessagesInstance> for Runtime {
 	type BridgedChainId = RialtoChainId;
 }
 
+parameter_types! {
+	pub const RialtoParasPalletName: &'static str = bp_rialto::PARAS_PALLET_NAME;
+}
+
+/// Instance of the with-Rialto parachains token swap pallet.
+pub type WitRialtoParachainsInstance = ();
+
+impl pallet_bridge_parachains::Config<WitRialtoParachainsInstance> for Runtime {
+	type BridgesGrandpaPalletInstance = RialtoGrandpaInstance;
+	type ParasPalletName = RialtoParasPalletName;
+	type HeadsToKeep = HeadersToKeep;
+}
+
 construct_runtime!(
 	pub enum Runtime where
 		Block = Block,
@@ -495,6 +509,9 @@ construct_runtime!(
 		// Westend bridge modules.
 		BridgeWestendGrandpa: pallet_bridge_grandpa::<Instance1>::{Pallet, Call, Config<T>, Storage},
 
+		// Rialto parachains bridge modules.
+		BridgeRialtoParachains: pallet_bridge_parachains::{Pallet, Call, Storage},
+
 		// Pallet for sending XCM.
 		XcmPallet: pallet_xcm::{Pallet, Call, Storage, Event<T>, Origin, Config} = 99,
 	}

bridges/modules/parachains/Cargo.toml

@@ -13,6 +13,7 @@ serde = { version = "1.0.101", optional = true }
 
 # Bridge Dependencies
 
+bp-parachains = { path = "../../primitives/parachains", default-features = false }
 bp-polkadot-core = { path = "../../primitives/polkadot-core", default-features = false }
 bp-runtime = { path = "../../primitives/runtime", default-features = false }
 pallet-bridge-grandpa = { path = "../grandpa", default-features = false }
@@ -34,6 +35,7 @@ sp-io = { git = "https://github.com/paritytech/substrate", branch = "master" }
 [features]
 default = ["std"]
 std = [
+	"bp-parachains/std",
 	"bp-polkadot-core/std",
 	"bp-runtime/std",
 	"codec/std",

bridges/modules/parachains/src/lib.rs

@@ -23,7 +23,8 @@
 
 #![cfg_attr(not(feature = "std"), no_std)]
 
-use bp_polkadot_core::parachains::{ParaHash, ParaHead, ParaId, ParachainHeadsProof};
+use bp_parachains::parachain_head_storage_key_at_source;
+use bp_polkadot_core::parachains::{ParaHash, ParaHead, ParaHeadsProof, ParaId};
 use codec::{Decode, Encode};
 use frame_support::RuntimeDebug;
 use scale_info::TypeInfo;
@@ -73,12 +74,16 @@ pub mod pallet {
 	pub trait Config<I: 'static = ()>:
 		pallet_bridge_grandpa::Config<Self::BridgesGrandpaPalletInstance>
 	{
-		/// Instance of bridges GRANDPA pallet that this pallet is linked to.
+		/// Instance of bridges GRANDPA pallet (within this runtime) that this pallet is linked to.
 		///
 		/// The GRANDPA pallet instance must be configured to import headers of relay chain that
 		/// we're interested in.
 		type BridgesGrandpaPalletInstance: 'static;
 
+		/// Name of the `paras` pallet in the `construct_runtime!()` call at the bridged chain.
+		#[pallet::constant]
+		type ParasPalletName: Get<&'static str>;
+
 		/// Maximal number of single parachain heads to keep in the storage.
 		///
 		/// The setting is there to prevent growing the on-chain state indefinitely. Note
@@ -129,7 +134,7 @@ pub mod pallet {
 			_origin: OriginFor<T>,
 			relay_block_hash: RelayBlockHash,
 			parachains: Vec<ParaId>,
-			parachain_heads_proof: ParachainHeadsProof,
+			parachain_heads_proof: ParaHeadsProof,
 		) -> DispatchResult {
 			// we'll need relay chain header to verify that parachains heads are always increasing.
 			let relay_block = pallet_bridge_grandpa::ImportedHeaders::<
@@ -190,7 +195,8 @@ pub mod pallet {
 			storage: &bp_runtime::StorageProofChecker<RelayBlockHasher>,
 			parachain: ParaId,
 		) -> Option<ParaHead> {
-			let parachain_head_key = storage_keys::parachain_head_key(parachain);
+			let parachain_head_key =
+				parachain_head_storage_key_at_source(T::ParasPalletName::get(), parachain);
 			let parachain_head = storage.read_value(parachain_head_key.0.as_ref()).ok()??;
 			let parachain_head = ParaHead::decode(&mut &parachain_head[..]).ok()?;
 			Some(parachain_head)
@@ -257,6 +263,12 @@ pub mod pallet {
 				updated_head_hash,
 			);
 			ImportedParaHeads::<T, I>::insert(parachain, updated_head_hash, updated_head);
+			log::trace!(
+				target: "runtime::bridge-parachains",
+				"Updated head of parachain {:?} to {}",
+				parachain,
+				updated_head_hash,
+			);
 
 			// remove old head
 			if let Ok(head_hash_to_prune) = head_hash_to_prune {
@@ -274,22 +286,10 @@ pub mod pallet {
 	}
 }
 
-pub mod storage_keys {
-	use super::*;
-	use bp_runtime::storage_map_final_key;
-	use frame_support::Twox64Concat;
-	use sp_core::storage::StorageKey;
-
-	/// Storage key of the parachain head in the runtime storage of relay chain.
-	pub fn parachain_head_key(parachain: ParaId) -> StorageKey {
-		storage_map_final_key::<Twox64Concat>("Paras", "Heads", &parachain.encode())
-	}
-}
-
 #[cfg(test)]
 mod tests {
 	use super::*;
-	use crate::mock::{run_test, test_relay_header, Origin, TestRuntime};
+	use crate::mock::{run_test, test_relay_header, Origin, TestRuntime, PARAS_PALLET_NAME};
 
 	use bp_test_utils::{authority_list, make_default_justification};
 	use frame_support::{assert_noop, assert_ok, traits::OnInitialize};
@@ -330,13 +330,14 @@ mod tests {
 
 	fn prepare_parachain_heads_proof(
 		heads: Vec<(ParaId, ParaHead)>,
-	) -> (RelayBlockHash, ParachainHeadsProof) {
+	) -> (RelayBlockHash, ParaHeadsProof) {
 		let mut root = Default::default();
 		let mut mdb = MemoryDB::default();
 		{
 			let mut trie = TrieDBMutV1::<RelayBlockHasher>::new(&mut mdb, &mut root);
 			for (parachain, head) in heads {
-				let storage_key = storage_keys::parachain_head_key(parachain);
+				let storage_key =
+					parachain_head_storage_key_at_source(PARAS_PALLET_NAME, parachain);
 				trie.insert(&storage_key.0, &head.encode())
 					.map_err(|_| "TrieMut::insert has failed")
 					.expect("TrieMut::insert should not fail in tests");
@@ -372,7 +373,7 @@ mod tests {
 	fn import_parachain_1_head(
 		relay_chain_block: RelayBlockNumber,
 		relay_state_root: RelayBlockHash,
-		proof: ParachainHeadsProof,
+		proof: ParaHeadsProof,
 	) -> sp_runtime::DispatchResult {
 		Pallet::<TestRuntime>::submit_parachain_heads(
 			Origin::signed(1),

bridges/modules/parachains/src/mock.rs

@@ -33,6 +33,8 @@ pub type RelayBlockHeader =
 type Block = frame_system::mocking::MockBlock<TestRuntime>;
 type UncheckedExtrinsic = frame_system::mocking::MockUncheckedExtrinsic<TestRuntime>;
 
+pub const PARAS_PALLET_NAME: &str = "Paras";
+
 construct_runtime! {
 	pub enum TestRuntime where
 		Block = Block,
@@ -103,10 +105,12 @@ impl pallet_bridge_grandpa::Config<pallet_bridge_grandpa::Instance2> for TestRun
 
 parameter_types! {
 	pub const HeadsToKeep: u32 = 4;
+	pub const ParasPalletName: &'static str = PARAS_PALLET_NAME;
 }
 
 impl pallet_bridge_parachains::Config for TestRuntime {
 	type BridgesGrandpaPalletInstance = pallet_bridge_grandpa::Instance1;
+	type ParasPalletName = ParasPalletName;
 	type HeadsToKeep = HeadsToKeep;
 }
 

bridges/primitives/chain-millau/src/lib.rs

@@ -269,6 +269,9 @@ pub const WITH_MILLAU_MESSAGES_PALLET_NAME: &str = "BridgeMillauMessages";
 /// Name of the Rialto->Millau (actually DOT->KSM) conversion rate stored in the Millau runtime.
 pub const RIALTO_TO_MILLAU_CONVERSION_RATE_PARAMETER_NAME: &str = "RialtoToMillauConversionRate";
 
+/// Name of the With-Rialto parachains bridge pallet name in the Millau runtime.
+pub const BRIDGE_PARAS_PALLET_NAME: &str = "BridgeRialtoParachains";
+
 /// Name of the `MillauFinalityApi::best_finalized` runtime method.
 pub const BEST_FINALIZED_MILLAU_HEADER_METHOD: &str = "MillauFinalityApi_best_finalized";
 

bridges/primitives/parachains/Cargo.toml

@@ -0,0 +1,34 @@
+[package]
+name = "bp-parachains"
+description = "Primitives of parachains module."
+version = "0.1.0"
+authors = ["Parity Technologies <admin@parity.io>"]
+edition = "2018"
+license = "GPL-3.0-or-later WITH Classpath-exception-2.0"
+
+[dependencies]
+codec = { package = "parity-scale-codec", version = "3.0.0", default-features = false, features = ["derive"] }
+scale-info = { version = "2.1.1", default-features = false, features = ["derive"] }
+serde = { version = "1.0", optional = true, features = ["derive"] }
+
+# Bridge dependencies
+
+bp-polkadot-core = { path = "../polkadot-core", default-features = false }
+bp-runtime = { path = "../runtime", default-features = false }
+
+# Substrate dependencies
+
+frame-support = { git = "https://github.com/paritytech/substrate", branch = "master", default-features = false }
+sp-core = { git = "https://github.com/paritytech/substrate", branch = "master", default-features = false }
+
+[features]
+default = ["std"]
+std = [
+	"bp-polkadot-core/std",
+	"bp-runtime/std",
+	"codec/std",
+	"frame-support/std",
+	"scale-info/std",
+	"serde",
+	"sp-core/std",
+]

bridges/primitives/parachains/src/lib.rs

@@ -0,0 +1,68 @@
+// Copyright 2019-2021 Parity Technologies (UK) Ltd.
+// This file is part of Parity Bridges Common.
+
+// Parity Bridges Common is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Parity Bridges Common is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Parity Bridges Common.  If not, see <http://www.gnu.org/licenses/>.
+
+//! Primitives of parachains module.
+
+#![cfg_attr(not(feature = "std"), no_std)]
+
+use bp_polkadot_core::{
+	parachains::{ParaHash, ParaId},
+	BlockNumber as RelayBlockNumber,
+};
+use codec::{Decode, Encode};
+use frame_support::{Blake2_128Concat, RuntimeDebug, Twox64Concat};
+use scale_info::TypeInfo;
+use sp_core::storage::StorageKey;
+
+/// Best known parachain head hash.
+#[derive(Clone, Decode, Encode, PartialEq, RuntimeDebug, TypeInfo)]
+pub struct BestParaHeadHash {
+	/// Number of relay block where this head has been read.
+	///
+	/// Parachain head is opaque to relay chain. So we can't simply decode it as a header of
+	/// parachains and call `block_number()` on it. Instead, we're using the fact that parachain
+	/// head is always built on top of previous head (because it is blockchain) and relay chain
+	/// always imports parachain heads in order. What it means for us is that at any given
+	/// **finalized** relay block `B`, head of parachain will be ancestor (or the same) of all
+	/// parachain heads available at descendants of `B`.
+	pub at_relay_block_number: RelayBlockNumber,
+	/// Hash of parachain head.
+	pub head_hash: ParaHash,
+}
+
+/// Returns runtime storage key of given parachain head at the source chain.
+///
+/// The head is stored by the `paras` pallet in the `Heads` map.
+pub fn parachain_head_storage_key_at_source(
+	paras_pallet_name: &str,
+	para_id: ParaId,
+) -> StorageKey {
+	bp_runtime::storage_map_final_key::<Twox64Concat>(paras_pallet_name, "Heads", &para_id.encode())
+}
+
+/// Returns runtime storage key of best known parachain head at the target chain.
+///
+/// The head is stored by the `pallet-bridge-parachains` pallet in the `BestParaHeads` map.
+pub fn parachain_head_storage_key_at_target(
+	bridge_parachains_pallet_name: &str,
+	para_id: ParaId,
+) -> StorageKey {
+	bp_runtime::storage_map_final_key::<Blake2_128Concat>(
+		bridge_parachains_pallet_name,
+		"BestParaHeads",
+		&para_id.encode(),
+	)
+}

bridges/primitives/polkadot-core/src/parachains.rs

@@ -79,4 +79,4 @@ impl ParaHead {
 pub type ParaHash = crate::Hash;
 
 /// Raw storage proof of parachain heads, stored in polkadot-like chain runtime.
-pub type ParachainHeadsProof = Vec<Vec<u8>>;
+pub type ParaHeadsProof = Vec<Vec<u8>>;

bridges/relays/bin-substrate/Cargo.toml

@@ -27,6 +27,7 @@ bp-kusama = { path = "../../primitives/chain-kusama" }
 bp-messages = { path = "../../primitives/messages" }
 bp-millau = { path = "../../primitives/chain-millau" }
 bp-polkadot = { path = "../../primitives/chain-polkadot" }
+bp-polkadot-core = { path = "../../primitives/polkadot-core" }
 bp-rialto = { path = "../../primitives/chain-rialto" }
 bp-rialto-parachain = { path = "../../primitives/chain-rialto-parachain" }
 bp-rococo = { path = "../../primitives/chain-rococo" }
@@ -39,6 +40,7 @@ messages-relay = { path = "../messages" }
 millau-runtime = { path = "../../bin/millau/runtime" }
 pallet-bridge-grandpa = { path = "../../modules/grandpa" }
 pallet-bridge-messages = { path = "../../modules/messages" }
+parachains-relay = { path = "../parachains" }
 relay-kusama-client = { path = "../client-kusama" }
 relay-millau-client = { path = "../client-millau" }
 relay-polkadot-client = { path = "../client-polkadot" }

bridges/relays/bin-substrate/src/chains/mod.rs

@@ -24,6 +24,7 @@ pub mod polkadot_headers_to_kusama;
 pub mod polkadot_messages_to_kusama;
 pub mod rialto_headers_to_millau;
 pub mod rialto_messages_to_millau;
+pub mod rialto_parachains_to_millau;
 pub mod rococo_headers_to_wococo;
 pub mod rococo_messages_to_wococo;
 pub mod westend_headers_to_millau;

bridges/relays/bin-substrate/src/chains/rialto_parachains_to_millau.rs

@@ -0,0 +1,39 @@
+// Copyright 2019-2021 Parity Technologies (UK) Ltd.
+// This file is part of Parity Bridges Common.
+
+// Parity Bridges Common is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Parity Bridges Common is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Parity Bridges Common.  If not, see <http://www.gnu.org/licenses/>.
+
+//! Rialto-to-Millau parachains sync entrypoint.
+
+use parachains_relay::ParachainsPipeline;
+use relay_millau_client::Millau;
+use relay_rialto_client::Rialto;
+use substrate_relay_helper::parachains_target::DirectSubmitParachainHeadsCallBuilder;
+
+/// Rialto-to-Millau parachains sync description.
+#[derive(Clone, Debug)]
+pub struct RialtoToMillauParachains;
+
+impl ParachainsPipeline for RialtoToMillauParachains {
+	type SourceChain = Rialto;
+	type TargetChain = Millau;
+}
+
+/// `submit_parachain_heads` call builder for Rialto-to-Millau parachains sync pipeline.
+pub type RialtoToMillauParachainsSubmitParachainHeadsCallBuilder =
+	DirectSubmitParachainHeadsCallBuilder<
+		RialtoToMillauParachains,
+		millau_runtime::Runtime,
+		millau_runtime::WitRialtoParachainsInstance,
+	>;