Add BEEFY finality pallet with basic functionality (#1606)

* pallet-bridge-beefy: initial commit

bridges/primitives/chain-millau/Cargo.toml

@@ -10,6 +10,7 @@ license = "GPL-3.0-or-later WITH Classpath-exception-2.0"
 
 # Bridge Dependencies
 
+bp-beefy = { path = "../beefy", default-features = false }
 bp-messages = { path = "../messages", default-features = false }
 bp-runtime = { path = "../runtime", default-features = false }
 fixed-hash = { version = "0.7.0", default-features = false }
@@ -34,6 +35,7 @@ sp-trie = { git = "https://github.com/paritytech/substrate", branch = "master",
 [features]
 default = ["std"]
 std = [
+	"bp-beefy/std",
 	"bp-messages/std",
 	"bp-runtime/std",
 	"fixed-hash/std",

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))]