messages bridge between RialtoParachain and Millau (#1218)

bridges/primitives/chain-rialto-parachain/src/lib.rs

@@ -18,19 +18,32 @@
 // RuntimeApi generated functions
 #![allow(clippy::too_many_arguments)]
 
+use bp_messages::{LaneId, MessageDetails, MessageNonce};
 use bp_runtime::Chain;
 use frame_support::{
 	weights::{constants::WEIGHT_PER_SECOND, DispatchClass, IdentityFee, Weight},
-	RuntimeDebug,
+	Parameter, RuntimeDebug,
 };
 use frame_system::limits;
 use sp_core::Hasher as HasherT;
 use sp_runtime::{
-	traits::{BlakeTwo256, IdentifyAccount, Verify},
-	MultiSignature, MultiSigner, Perbill,
+	traits::{BlakeTwo256, Convert, IdentifyAccount, Verify},
+	FixedU128, MultiSignature, MultiSigner, Perbill,
 };
+use sp_std::vec::Vec;
 
-/// Maximal weight of single Rialto parachain block.
+/// Number of extra bytes (excluding size of storage value itself) of storage proof, built at
+/// RialtoParachain chain. This mostly depends on number of entries (and their density) in the
+/// storage trie. Some reserve is reserved to account future chain growth.
+pub const EXTRA_STORAGE_PROOF_SIZE: u32 = 1024;
+
+/// Can be computed by subtracting encoded call size from raw transaction size.
+pub const TX_EXTRA_BYTES: u32 = 104;
+
+/// Maximal size (in bytes) of encoded (using `Encode::encode()`) account id.
+pub const MAXIMAL_ENCODED_ACCOUNT_ID_SIZE: u32 = 32;
+
+/// Maximal weight of single RialtoParachain block.
 ///
 /// This represents two seconds of compute assuming a target block time of six seconds.
 pub const MAXIMUM_BLOCK_WEIGHT: Weight = 2 * WEIGHT_PER_SECOND;
@@ -42,6 +55,44 @@ pub const AVERAGE_ON_INITIALIZE_RATIO: Perbill = Perbill::from_percent(10);
 /// Represents the portion of a block that will be used by Normal extrinsics.
 pub const NORMAL_DISPATCH_RATIO: Perbill = Perbill::from_percent(75);
 
+/// Maximal number of unrewarded relayer entries in Rialto confirmation transaction.
+pub const MAX_UNREWARDED_RELAYERS_IN_CONFIRMATION_TX: MessageNonce = 1024;
+
+/// Maximal number of unconfirmed messages in Rialto confirmation transaction.
+pub const MAX_UNCONFIRMED_MESSAGES_IN_CONFIRMATION_TX: MessageNonce = 1024;
+
+/// Weight of single regular message delivery transaction on RialtoParachain chain.
+///
+/// This value is a result of `pallet_bridge_messages::Pallet::receive_messages_proof_weight()` call
+/// for the case when single message of `pallet_bridge_messages::EXPECTED_DEFAULT_MESSAGE_LENGTH`
+/// bytes is delivered. The message must have dispatch weight set to zero. The result then must be
+/// rounded up to account possible future runtime upgrades.
+pub const DEFAULT_MESSAGE_DELIVERY_TX_WEIGHT: Weight = 1_500_000_000;
+
+/// Increase of delivery transaction weight on RialtoParachain chain with every additional message
+/// byte.
+///
+/// This value is a result of
+/// `pallet_bridge_messages::WeightInfoExt::storage_proof_size_overhead(1)` call. The result then
+/// must be rounded up to account possible future runtime upgrades.
+pub const ADDITIONAL_MESSAGE_BYTE_DELIVERY_WEIGHT: Weight = 25_000;
+
+/// Maximal weight of single message delivery confirmation transaction on RialtoParachain chain.
+///
+/// This value is a result of `pallet_bridge_messages::Pallet::receive_messages_delivery_proof`
+/// weight formula computation for the case when single message is confirmed. The result then must
+/// be rounded up to account possible future runtime upgrades.
+pub const MAX_SINGLE_MESSAGE_DELIVERY_CONFIRMATION_TX_WEIGHT: Weight = 2_000_000_000;
+
+/// Weight of pay-dispatch-fee operation for inbound messages at Rialto chain.
+///
+/// This value corresponds to the result of
+/// `pallet_bridge_messages::WeightInfoExt::pay_inbound_dispatch_fee_overhead()` call for your
+/// chain. Don't put too much reserve there, because it is used to **decrease**
+/// `DEFAULT_MESSAGE_DELIVERY_TX_WEIGHT` cost. So putting large reserve would make delivery
+/// transactions cheaper.
+pub const PAY_INBOUND_DISPATCH_FEE_WEIGHT: Weight = 600_000_000;
+
 /// Block number type used in Rialto.
 pub type BlockNumber = u32;
 
@@ -103,6 +154,15 @@ impl Chain for RialtoParachain {
 	}
 }
 
+/// Convert a 256-bit hash into an AccountId.
+pub struct AccountIdConverter;
+
+impl Convert<sp_core::H256, AccountId> for AccountIdConverter {
+	fn convert(hash: sp_core::H256) -> AccountId {
+		hash.to_fixed_bytes().into()
+	}
+}
+
 frame_support::parameter_types! {
 	pub BlockLength: limits::BlockLength =
 		limits::BlockLength::max_with_normal_ratio(5 * 1024 * 1024, NORMAL_DISPATCH_RATIO);
@@ -122,3 +182,93 @@ frame_support::parameter_types! {
 		.avg_block_initialization(AVERAGE_ON_INITIALIZE_RATIO)
 		.build_or_panic();
 }
+
+/// Name of the With-Rialto-Parachain messages pallet instance that is deployed at bridged chains.
+pub const WITH_RIALTO_PARACHAIN_MESSAGES_PALLET_NAME: &str = "BridgeRialtoParachainMessages";
+
+/// Name of the Millau->Rialto (actually KSM->DOT) conversion rate stored in the Rialto parachain
+/// runtime.
+pub const MILLAU_TO_RIALTO_CONVERSION_RATE_PARAMETER_NAME: &str = "MillauToRialtoConversionRate";
+
+/// Name of the `RialtoParachainFinalityApi::best_finalized` runtime method.
+pub const BEST_FINALIZED_RIALTO_PARACHAIN_HEADER_METHOD: &str =
+	"RialtoParachainFinalityApi_best_finalized";
+
+/// Name of the `ToRialtoParachainOutboundLaneApi::estimate_message_delivery_and_dispatch_fee`
+/// runtime method.
+pub const TO_RIALTO_PARACHAIN_ESTIMATE_MESSAGE_FEE_METHOD: &str =
+	"ToRialtoParachainOutboundLaneApi_estimate_message_delivery_and_dispatch_fee";
+/// Name of the `ToRialtoParachainOutboundLaneApi::message_details` runtime method.
+pub const TO_RIALTO_PARACHAIN_MESSAGE_DETAILS_METHOD: &str =
+	"ToRialtoParachainOutboundLaneApi_message_details";
+
+// We use this to get the account on RialtoParachain (target) which is derived from Millau's
+// (source) account. We do this so we can fund the derived account on RialtoParachain at Genesis to
+// it can pay transaction fees.
+//
+// The reason we can use the same `AccountId` type for both chains is because they share the same
+// development seed phrase.
+//
+// Note that this should only be used for testing.
+pub fn derive_account_from_millau_id(id: bp_runtime::SourceAccount<AccountId>) -> AccountId {
+	let encoded_id = bp_runtime::derive_account_id(bp_runtime::MILLAU_CHAIN_ID, id);
+	AccountIdConverter::convert(encoded_id)
+}
+
+sp_api::decl_runtime_apis! {
+	/// API for querying information about the finalized RialtoParachain headers.
+	///
+	/// This API is implemented by runtimes that are bridging with the RialtoParachain chain, not the
+	/// RialtoParachain runtime itself.
+	pub trait RialtoParachainFinalityApi {
+		/// Returns number and hash of the best finalized header known to the bridge module.
+		fn best_finalized() -> (BlockNumber, Hash);
+	}
+
+	/// Outbound message lane API for messages that are sent to RialtoParachain chain.
+	///
+	/// This API is implemented by runtimes that are sending messages to RialtoParachain chain, not the
+	/// RialtoParachain runtime itself.
+	pub trait ToRialtoParachainOutboundLaneApi<OutboundMessageFee: Parameter, OutboundPayload: Parameter> {
+		/// Estimate message delivery and dispatch fee that needs to be paid by the sender on
+		/// this chain.
+		///
+		/// Returns `None` if message is too expensive to be sent to RialtoParachain from this chain.
+		///
+		/// Please keep in mind that this method returns the lowest message fee required for message
+		/// to be accepted to the lane. It may be good idea to pay a bit over this price to account
+		/// future exchange rate changes and guarantee that relayer would deliver your message
+		/// to the target chain.
+		fn estimate_message_delivery_and_dispatch_fee(
+			lane_id: LaneId,
+			payload: OutboundPayload,
+			rialto_parachain_to_this_conversion_rate: Option<FixedU128>,
+		) -> Option<OutboundMessageFee>;
+		/// Returns dispatch weight, encoded payload size and delivery+dispatch fee of all
+		/// messages in given inclusive range.
+		///
+		/// If some (or all) messages are missing from the storage, they'll also will
+		/// be missing from the resulting vector. The vector is ordered by the nonce.
+		fn message_details(
+			lane: LaneId,
+			begin: MessageNonce,
+			end: MessageNonce,
+		) -> Vec<MessageDetails<OutboundMessageFee>>;
+	}
+}
+
+#[cfg(test)]
+mod tests {
+	use super::*;
+	use sp_runtime::codec::Encode;
+
+	#[test]
+	fn maximal_account_size_does_not_overflow_constant() {
+		assert!(
+			MAXIMAL_ENCODED_ACCOUNT_ID_SIZE as usize >= AccountId::from([0u8; 32]).encode().len(),
+			"Actual maximal size of encoded AccountId ({}) overflows expected ({})",
+			AccountId::from([0u8; 32]).encode().len(),
+			MAXIMAL_ENCODED_ACCOUNT_ID_SIZE,
+		);
+	}
+}