Add BEEFY finality pallet with basic functionality (#1606)

* pallet-bridge-beefy: initial commit

bridges/primitives/beefy/src/lib.rs

@@ -0,0 +1,152 @@
+// 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 that are used to interact with BEEFY bridge pallet.
+
+#![cfg_attr(not(feature = "std"), no_std)]
+#![warn(missing_docs)]
+
+pub use beefy_merkle_tree::{merkle_root, Keccak256 as BeefyKeccak256};
+pub use beefy_primitives::{
+	crypto::{AuthorityId as EcdsaValidatorId, AuthoritySignature as EcdsaValidatorSignature},
+	known_payloads::MMR_ROOT_ID as MMR_ROOT_PAYLOAD_ID,
+	mmr::{BeefyAuthoritySet, MmrLeafVersion},
+	BeefyAuthorityId, BeefyVerify, Commitment, Payload as BeefyPayload, SignedCommitment,
+	ValidatorSet, ValidatorSetId, BEEFY_ENGINE_ID,
+};
+pub use pallet_beefy_mmr::BeefyEcdsaToEthereum;
+pub use pallet_mmr::{
+	primitives::{DataOrHash as MmrDataOrHash, Proof as MmrProof},
+	verify_leaves_proof as verify_mmr_leaves_proof,
+};
+
+use bp_runtime::{BasicOperatingMode, BlockNumberOf, Chain, HashOf};
+use codec::{Decode, Encode};
+use frame_support::Parameter;
+use scale_info::TypeInfo;
+use sp_runtime::{
+	traits::{Convert, MaybeSerializeDeserialize},
+	RuntimeDebug,
+};
+use sp_std::prelude::*;
+
+/// Substrate-based chain with BEEFY && MMR pallets deployed.
+///
+/// Both BEEFY and MMR pallets and their clients may be configured to use different
+/// primitives. Some of types can be configured in low-level pallets, but are constrained
+/// when BEEFY+MMR bundle is used.
+pub trait ChainWithBeefy: Chain {
+	/// The hashing algorithm used to compute the digest of the BEEFY commitment.
+	///
+	/// Corresponds to the hashing algorithm, used by `beefy_gadget::BeefyKeystore`.
+	type CommitmentHasher: sp_runtime::traits::Hash;
+
+	/// The hashing algorithm used to build the MMR.
+	///
+	/// The same algorithm is also used to compute merkle roots in BEEFY
+	/// (e.g. validator addresses root in leaf data).
+	///
+	/// Corresponds to the `Hashing` field of the `pallet-mmr` configuration.
+	type MmrHashing: sp_runtime::traits::Hash<Output = Self::MmrHash>;
+
+	/// The output type of the hashing algorithm used to build the MMR.
+	///
+	/// This type is actually stored in the MMR.
+
+	/// Corresponds to the `Hash` field of the `pallet-mmr` configuration.
+	type MmrHash: sp_std::hash::Hash
+		+ Parameter
+		+ Copy
+		+ AsRef<[u8]>
+		+ Default
+		+ MaybeSerializeDeserialize;
+
+	/// The type expected for the MMR leaf extra data.
+	type BeefyMmrLeafExtra: Parameter;
+
+	/// A way to identify a BEEFY validator.
+	///
+	/// Corresponds to the `BeefyId` field of the `pallet-beefy` configuration.
+	type AuthorityId: BeefyAuthorityId + Parameter;
+
+	/// The signature type used by BEEFY.
+	///
+	/// Corresponds to the `BeefyId` field of the `pallet-beefy` configuration.
+	type Signature: BeefyVerify<Self::CommitmentHasher, Signer = Self::AuthorityId> + Parameter;
+
+	/// A way to convert validator id to its raw representation in the BEEFY merkle tree.
+	///
+	/// Corresponds to the `BeefyAuthorityToMerkleLeaf` field of the `pallet-beefy-mmr`
+	/// configuration.
+	type AuthorityIdToMerkleLeaf: Convert<Self::AuthorityId, Vec<u8>>;
+}
+
+/// BEEFY validator id used by given Substrate chain.
+pub type BeefyAuthorityIdOf<C> = <C as ChainWithBeefy>::AuthorityId;
+/// BEEFY validator set, containing both validator identifiers and the numeric set id.
+pub type BeefyAuthoritySetOf<C> = ValidatorSet<BeefyAuthorityIdOf<C>>;
+/// BEEFY authority set, containing both validator identifiers and the numeric set id.
+pub type BeefyAuthoritySetInfoOf<C> = beefy_primitives::mmr::BeefyAuthoritySet<MmrHashOf<C>>;
+/// BEEFY validator signature used by given Substrate chain.
+pub type BeefyValidatorSignatureOf<C> = <C as ChainWithBeefy>::Signature;
+/// Signed BEEFY commitment used by given Substrate chain.
+pub type BeefySignedCommitmentOf<C> =
+	SignedCommitment<BlockNumberOf<C>, BeefyValidatorSignatureOf<C>>;
+/// Hash algorithm, used to compute the digest of the BEEFY commitment before signing it.
+pub type BeefyCommitmentHasher<C> = <C as ChainWithBeefy>::CommitmentHasher;
+/// Hash algorithm used in Beefy MMR construction by given Substrate chain.
+pub type MmrHashingOf<C> = <C as ChainWithBeefy>::MmrHashing;
+/// Hash type, used in MMR construction by given Substrate chain.
+pub type MmrHashOf<C> = <C as ChainWithBeefy>::MmrHash;
+/// BEEFY MMR proof type used by the given Substrate chain.
+pub type MmrProofOf<C> = MmrProof<MmrHashOf<C>>;
+/// The type of the MMR leaf extra data used by the given Substrate chain.
+pub type BeefyMmrLeafExtraOf<C> = <C as ChainWithBeefy>::BeefyMmrLeafExtra;
+/// A way to convert a validator id to its raw representation in the BEEFY merkle tree, used by
+/// the given Substrate chain.
+pub type BeefyAuthorityIdToMerkleLeafOf<C> = <C as ChainWithBeefy>::AuthorityIdToMerkleLeaf;
+/// Actual type of leafs in the BEEFY MMR.
+pub type BeefyMmrLeafOf<C> = beefy_primitives::mmr::MmrLeaf<
+	BlockNumberOf<C>,
+	HashOf<C>,
+	MmrHashOf<C>,
+	BeefyMmrLeafExtraOf<C>,
+>;
+
+/// Data required for initializing the BEEFY pallet.
+///
+/// Provides the initial context that the bridge needs in order to know
+/// where to start the sync process from.
+#[derive(Encode, Decode, RuntimeDebug, PartialEq, Clone, TypeInfo)]
+#[cfg_attr(feature = "std", derive(serde::Serialize, serde::Deserialize))]
+pub struct InitializationData<BlockNumber, Hash> {
+	/// Pallet operating mode.
+	pub operating_mode: BasicOperatingMode,
+	/// Number of the best block, finalized by BEEFY.
+	pub best_block_number: BlockNumber,
+	/// BEEFY authority set that will be finalizing descendants of the `best_beefy_block_number`
+	/// block.
+	pub authority_set: BeefyAuthoritySet<Hash>,
+}
+
+/// Basic data, stored by the pallet for every imported commitment.
+#[derive(Encode, Decode, RuntimeDebug, PartialEq, TypeInfo)]
+pub struct ImportedCommitment<BlockNumber, BlockHash, MmrHash> {
+	/// Block number and hash of the finalized block parent.
+	pub parent_number_and_hash: (BlockNumber, BlockHash),
+	/// MMR root at the imported block.
+	pub mmr_root: MmrHash,
+}