Add BEEFY finality pallet with basic functionality (#1606)

* pallet-bridge-beefy: initial commit

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

@@ -20,6 +20,7 @@
 
 mod millau_hash;
 
+use bp_beefy::ChainWithBeefy;
 use bp_messages::{
 	InboundMessageDetails, LaneId, MessageNonce, MessagePayload, OutboundMessageDetails,
 };
@@ -41,6 +42,7 @@ use sp_trie::{LayoutV0, LayoutV1, TrieConfiguration};
 
 #[cfg(feature = "std")]
 use serde::{Deserialize, Serialize};
+use sp_runtime::traits::Keccak256;
 
 pub use millau_hash::MillauHash;
 
@@ -155,6 +157,16 @@ impl Chain for Millau {
 	}
 }
 
+impl ChainWithBeefy for Millau {
+	type CommitmentHasher = Keccak256;
+	type MmrHashing = Keccak256;
+	type MmrHash = <Keccak256 as sp_runtime::traits::Hash>::Output;
+	type BeefyMmrLeafExtra = ();
+	type AuthorityId = bp_beefy::EcdsaValidatorId;
+	type Signature = bp_beefy::EcdsaValidatorSignature;
+	type AuthorityIdToMerkleLeaf = bp_beefy::BeefyEcdsaToEthereum;
+}
+
 /// Millau Hasher (Blake2-256 ++ Keccak-256) implementation.
 #[derive(PartialEq, Eq, Clone, Copy, RuntimeDebug, TypeInfo)]
 #[cfg_attr(feature = "std", derive(Serialize, Deserialize))]