only store header state root (pallet-bridge-grandpa) (#1699)

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

@@ -413,13 +413,8 @@ parameter_types! {
 }
 
 parameter_types! {
-	/// Maximal size of SCALE-encoded Rialto header.
-	pub const MaxRialtoHeaderSize: u32 = bp_rialto::MAX_HEADER_SIZE;
-
 	/// Maximal number of authorities at Westend.
 	pub const MaxAuthoritiesAtWestend: u32 = bp_westend::MAX_AUTHORITIES_COUNT;
-	/// Maximal size of SCALE-encoded Westend header.
-	pub const MaxWestendHeaderSize: u32 = bp_westend::MAX_HEADER_SIZE;
 }
 
 pub type RialtoGrandpaInstance = ();
@@ -432,7 +427,6 @@ impl pallet_bridge_grandpa::Config for Runtime {
 	type MaxRequests = ConstU32<50>;
 	type HeadersToKeep = HeadersToKeep;
 	type MaxBridgedAuthorities = MaxAuthoritiesAtRialto;
-	type MaxBridgedHeaderSize = MaxRialtoHeaderSize;
 
 	type WeightInfo = pallet_bridge_grandpa::weights::BridgeWeight<Runtime>;
 }
@@ -443,7 +437,6 @@ impl pallet_bridge_grandpa::Config<WestendGrandpaInstance> for Runtime {
 	type MaxRequests = ConstU32<50>;
 	type HeadersToKeep = HeadersToKeep;
 	type MaxBridgedAuthorities = MaxAuthoritiesAtWestend;
-	type MaxBridgedHeaderSize = MaxWestendHeaderSize;
 
 	type WeightInfo = pallet_bridge_grandpa::weights::BridgeWeight<Runtime>;
 }
@@ -871,13 +864,13 @@ impl_runtime_apis! {
 
 	impl bp_rialto::RialtoFinalityApi<Block> for Runtime {
 		fn best_finalized() -> Option<HeaderId<bp_rialto::Hash, bp_rialto::BlockNumber>> {
-			BridgeRialtoGrandpa::best_finalized().map(|header| header.id())
+			BridgeRialtoGrandpa::best_finalized()
 		}
 	}
 
 	impl bp_westend::WestendFinalityApi<Block> for Runtime {
 		fn best_finalized() -> Option<HeaderId<bp_westend::Hash, bp_westend::BlockNumber>> {
-			BridgeWestendGrandpa::best_finalized().map(|header| header.id())
+			BridgeWestendGrandpa::best_finalized()
 		}
 	}
 

bridges/bin/rialto-parachain/runtime/src/lib.rs

@@ -45,7 +45,7 @@ use sp_version::NativeVersion;
 use sp_version::RuntimeVersion;
 
 // A few exports that help ease life for downstream crates.
-use bp_runtime::{HeaderId, HeaderIdProvider};
+use bp_runtime::HeaderId;
 pub use frame_support::{
 	construct_runtime,
 	dispatch::DispatchClass,
@@ -525,8 +525,6 @@ parameter_types! {
 
 	/// Maximal number of authorities at Millau.
 	pub const MaxAuthoritiesAtMillau: u32 = bp_millau::MAX_AUTHORITIES_COUNT;
-	/// Maximal size of SCALE-encoded Millau header.
-	pub const MaxMillauHeaderSize: u32 = bp_millau::MAX_HEADER_SIZE;
 }
 
 pub type MillauGrandpaInstance = ();
@@ -539,7 +537,6 @@ impl pallet_bridge_grandpa::Config for Runtime {
 	type MaxRequests = ConstU32<50>;
 	type HeadersToKeep = HeadersToKeep;
 	type MaxBridgedAuthorities = MaxAuthoritiesAtMillau;
-	type MaxBridgedHeaderSize = MaxMillauHeaderSize;
 	type WeightInfo = pallet_bridge_grandpa::weights::BridgeWeight<Runtime>;
 }
 
@@ -728,7 +725,7 @@ impl_runtime_apis! {
 
 	impl bp_millau::MillauFinalityApi<Block> for Runtime {
 		fn best_finalized() -> Option<HeaderId<bp_millau::Hash, bp_millau::BlockNumber>> {
-			BridgeMillauGrandpa::best_finalized().map(|header| header.id())
+			BridgeMillauGrandpa::best_finalized()
 		}
 	}
 

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

@@ -33,7 +33,7 @@ pub mod parachains;
 pub mod xcm_config;
 
 use beefy_primitives::{crypto::AuthorityId as BeefyId, mmr::MmrLeafVersion, ValidatorSet};
-use bp_runtime::{HeaderId, HeaderIdProvider};
+use bp_runtime::HeaderId;
 use pallet_grandpa::{
 	fg_primitives, AuthorityId as GrandpaId, AuthorityList as GrandpaAuthorityList,
 };
@@ -410,8 +410,6 @@ parameter_types! {
 
 	/// Maximal number of authorities at Millau.
 	pub const MaxAuthoritiesAtMillau: u32 = bp_millau::MAX_AUTHORITIES_COUNT;
-	/// Maximal size of SCALE-encoded Millau header.
-	pub const MaxMillauHeaderSize: u32 = bp_millau::MAX_HEADER_SIZE;
 }
 
 pub type MillauGrandpaInstance = ();
@@ -424,7 +422,6 @@ impl pallet_bridge_grandpa::Config for Runtime {
 	type MaxRequests = ConstU32<50>;
 	type HeadersToKeep = HeadersToKeep;
 	type MaxBridgedAuthorities = MaxAuthoritiesAtMillau;
-	type MaxBridgedHeaderSize = MaxMillauHeaderSize;
 	type WeightInfo = pallet_bridge_grandpa::weights::BridgeWeight<Runtime>;
 }
 
@@ -721,7 +718,7 @@ impl_runtime_apis! {
 
 	impl bp_millau::MillauFinalityApi<Block> for Runtime {
 		fn best_finalized() -> Option<HeaderId<bp_millau::Hash, bp_millau::BlockNumber>> {
-			BridgeMillauGrandpa::best_finalized().map(|header| header.id())
+			BridgeMillauGrandpa::best_finalized()
 		}
 	}
 

bridges/bin/runtime-common/src/messages.rs

@@ -705,7 +705,6 @@ mod tests {
 	use crate::messages_generation::{
 		encode_all_messages, encode_lane_data, prepare_messages_storage_proof,
 	};
-	use bp_runtime::HeaderOf;
 	use codec::{Decode, Encode};
 	use frame_support::weights::Weight;
 	use sp_core::H256;
@@ -881,17 +880,17 @@ mod tests {
 	struct BridgedHeaderChain;
 
 	impl HeaderChain<BridgedUnderlyingChain> for BridgedHeaderChain {
-		fn finalized_header(
+		fn finalized_header_state_root(
 			_hash: HashOf<BridgedChain>,
-		) -> Option<HeaderOf<BridgedUnderlyingChain>> {
-			TEST_BRIDGED_HEADER.with(|h| h.borrow().clone())
+		) -> Option<HashOf<BridgedChain>> {
+			TEST_BRIDGED_HEADER.with(|h| h.borrow().clone()).map(|h| *h.state_root())
 		}
 	}
 
 	struct ThisHeaderChain;
 
 	impl HeaderChain<ThisUnderlyingChain> for ThisHeaderChain {
-		fn finalized_header(_hash: HashOf<ThisChain>) -> Option<HeaderOf<ThisUnderlyingChain>> {
+		fn finalized_header_state_root(_hash: HashOf<ThisChain>) -> Option<HashOf<ThisChain>> {
 			unreachable!()
 		}
 	}

bridges/modules/grandpa/src/extension.rs

@@ -40,7 +40,7 @@ impl<
 
 		let best_finalized = crate::BestFinalized::<T, I>::get();
 		let best_finalized_number = match best_finalized {
-			Some((best_finalized_number, _)) => best_finalized_number,
+			Some(best_finalized_id) => best_finalized_id.number(),
 			None => return InvalidTransaction::Call.into(),
 		};
 
@@ -66,6 +66,7 @@ mod tests {
 		mock::{run_test, test_header, RuntimeCall, TestNumber, TestRuntime},
 		BestFinalized,
 	};
+	use bp_runtime::HeaderId;
 	use bp_test_utils::make_default_justification;
 
 	fn validate_block_submit(num: TestNumber) -> bool {
@@ -81,7 +82,7 @@ mod tests {
 
 	fn sync_to_header_10() {
 		let header10_hash = sp_core::H256::default();
-		BestFinalized::<TestRuntime, ()>::put((10, header10_hash));
+		BestFinalized::<TestRuntime, ()>::put(HeaderId(10, header10_hash));
 	}
 
 	#[test]

bridges/modules/grandpa/src/lib.rs

@@ -38,10 +38,11 @@
 
 use storage_types::StoredAuthoritySet;
 
-use bp_header_chain::{justification::GrandpaJustification, HeaderChain, InitializationData};
-use bp_runtime::{
-	BlockNumberOf, BoundedStorageValue, Chain, HashOf, HasherOf, HeaderOf, OwnedBridgeModule,
+use bp_header_chain::{
+	justification::GrandpaJustification, HeaderChain, InitializationData, StoredHeaderData,
+	StoredHeaderDataBuilder,
 };
+use bp_runtime::{BlockNumberOf, Chain, HashOf, HasherOf, HeaderId, HeaderOf, OwnedBridgeModule};
 use finality_grandpa::voter_set::VoterSet;
 use frame_support::{ensure, fail};
 use frame_system::ensure_signed;
@@ -73,13 +74,15 @@ pub type BridgedChain<T, I> = <T as Config<I>>::BridgedChain;
 pub type BridgedBlockNumber<T, I> = BlockNumberOf<<T as Config<I>>::BridgedChain>;
 /// Block hash of the bridged chain.
 pub type BridgedBlockHash<T, I> = HashOf<<T as Config<I>>::BridgedChain>;
+/// Block id of the bridged chain.
+pub type BridgedBlockId<T, I> = HeaderId<BridgedBlockHash<T, I>, BridgedBlockNumber<T, I>>;
 /// Hasher of the bridged chain.
 pub type BridgedBlockHasher<T, I> = HasherOf<<T as Config<I>>::BridgedChain>;
 /// Header of the bridged chain.
 pub type BridgedHeader<T, I> = HeaderOf<<T as Config<I>>::BridgedChain>;
-/// Stored header of the bridged chain.
-pub type StoredBridgedHeader<T, I> =
-	BoundedStorageValue<<T as Config<I>>::MaxBridgedHeaderSize, BridgedHeader<T, I>>;
+/// Header data of the bridged chain that is stored at this chain by this pallet.
+pub type BridgedStoredHeaderData<T, I> =
+	StoredHeaderData<BridgedBlockNumber<T, I>, BridgedBlockHash<T, I>>;
 
 #[frame_support::pallet]
 pub mod pallet {
@@ -115,15 +118,6 @@ pub mod pallet {
 		/// Max number of authorities at the bridged chain.
 		#[pallet::constant]
 		type MaxBridgedAuthorities: Get<u32>;
-		/// Maximal size (in bytes) of the SCALE-encoded bridged chain header.
-		///
-		/// This constant must be selected with care. The pallet requires mandatory headers to be
-		/// submitted to be able to proceed. Mandatory headers contain public keys of all GRANDPA
-		/// authorities. E.g. for 1024 authorities, the size of encoded keys will be at least 32 KB.
-		/// The same header may also contain other digest items as well, so some reserve here
-		/// is required.
-		#[pallet::constant]
-		type MaxBridgedHeaderSize: Get<u32>;
 
 		/// Weights gathered through benchmarking.
 		type WeightInfo: WeightInfo;
@@ -178,11 +172,8 @@ pub mod pallet {
 				finality_target
 			);
 
-			let best_finalized = BestFinalized::<T, I>::get();
-			let best_finalized =
-				best_finalized.and_then(|(_, hash)| ImportedHeaders::<T, I>::get(hash));
-			let best_finalized = match best_finalized {
-				Some(best_finalized) => best_finalized,
+			let best_finalized_number = match BestFinalized::<T, I>::get() {
+				Some(best_finalized_id) => best_finalized_id.number(),
 				None => {
 					log::error!(
 						target: LOG_TARGET,
@@ -196,7 +187,7 @@ pub mod pallet {
 			// We do a quick check here to ensure that our header chain is making progress and isn't
 			// "travelling back in time" (which could be indicative of something bad, e.g a
 			// hard-fork).
-			ensure!(best_finalized.number() < number, <Error<T, I>>::OldHeader);
+			ensure!(best_finalized_number < *number, <Error<T, I>>::OldHeader);
 
 			let authority_set = <CurrentAuthoritySet<T, I>>::get();
 			let set_id = authority_set.set_id;
@@ -204,20 +195,8 @@ pub mod pallet {
 
 			let is_authorities_change_enacted =
 				try_enact_authority_change::<T, I>(&finality_target, set_id)?;
-			let finality_target = StoredBridgedHeader::<T, I>::try_from_inner(*finality_target)
-				.map_err(|e| {
-					log::error!(
-						target: LOG_TARGET,
-						"Size of header {:?} ({}) is larger that the configured value {}",
-						hash,
-						e.value_size,
-						e.maximal_size,
-					);
-
-					Error::<T, I>::TooLargeHeader
-				})?;
 			<RequestCount<T, I>>::mutate(|count| *count += 1);
-			insert_header::<T, I>(finality_target, hash);
+			insert_header::<T, I>(*finality_target, hash);
 			log::info!(
 				target: LOG_TARGET,
 				"Successfully imported finalized header with hash {:?}!",
@@ -302,8 +281,9 @@ pub mod pallet {
 
 	/// Hash of the best finalized header.
 	#[pallet::storage]
+	#[pallet::getter(fn best_finalized)]
 	pub type BestFinalized<T: Config<I>, I: 'static = ()> =
-		StorageValue<_, (BridgedBlockNumber<T, I>, BridgedBlockHash<T, I>), OptionQuery>;
+		StorageValue<_, BridgedBlockId<T, I>, OptionQuery>;
 
 	/// A ring buffer of imported hashes. Ordered by the insertion time.
 	#[pallet::storage]
@@ -315,10 +295,10 @@ pub mod pallet {
 	pub(super) type ImportedHashesPointer<T: Config<I>, I: 'static = ()> =
 		StorageValue<_, u32, ValueQuery>;
 
-	/// Headers which have been imported into the pallet.
+	/// Relevant fields of imported headers.
 	#[pallet::storage]
 	pub type ImportedHeaders<T: Config<I>, I: 'static = ()> =
-		StorageMap<_, Identity, BridgedBlockHash<T, I>, StoredBridgedHeader<T, I>>;
+		StorageMap<_, Identity, BridgedBlockHash<T, I>, BridgedStoredHeaderData<T, I>>;
 
 	/// The current GRANDPA Authority set.
 	#[pallet::storage]
@@ -394,8 +374,6 @@ pub mod pallet {
 		AlreadyInitialized,
 		/// Too many authorities in the set.
 		TooManyAuthoritiesInSet,
-		/// Too large header.
-		TooLargeHeader,
 		/// Error generated by the `OwnedBridgeModule` trait.
 		BridgeModule(bp_runtime::OwnedBridgeModuleError),
 	}
@@ -489,13 +467,13 @@ pub mod pallet {
 	/// Note this function solely takes care of updating the storage and pruning old entries,
 	/// but does not verify the validity of such import.
 	pub(crate) fn insert_header<T: Config<I>, I: 'static>(
-		header: StoredBridgedHeader<T, I>,
+		header: BridgedHeader<T, I>,
 		hash: BridgedBlockHash<T, I>,
 	) {
 		let index = <ImportedHashesPointer<T, I>>::get();
 		let pruning = <ImportedHashes<T, I>>::try_get(index);
-		<BestFinalized<T, I>>::put((*header.number(), hash));
-		<ImportedHeaders<T, I>>::insert(hash, header);
+		<BestFinalized<T, I>>::put(HeaderId(*header.number(), hash));
+		<ImportedHeaders<T, I>>::insert(hash, header.build());
 		<ImportedHashes<T, I>>::insert(index, hash);
 
 		// Update ring buffer pointer and remove old header.
@@ -526,21 +504,10 @@ pub mod pallet {
 				Error::TooManyAuthoritiesInSet
 			})?;
 		let initial_hash = header.hash();
-		let header = StoredBridgedHeader::<T, I>::try_from_inner(*header).map_err(|e| {
-			log::error!(
-					target: LOG_TARGET,
-					"Failed to initialize bridge. Size of header {:?} ({}) is larger that the configured value {}",
-					initial_hash,
-					e.value_size,
-					e.maximal_size,
-				);
-
-			Error::<T, I>::TooLargeHeader
-		})?;
 
 		<InitialHash<T, I>>::put(initial_hash);
 		<ImportedHashesPointer<T, I>>::put(0);
-		insert_header::<T, I>(header, initial_hash);
+		insert_header::<T, I>(*header, initial_hash);
 
 		<CurrentAuthoritySet<T, I>>::put(authority_set);
 
@@ -568,34 +535,19 @@ pub mod pallet {
 				Default::default(),
 			);
 			let hash = header.hash();
-			insert_header::<T, I>(
-				StoredBridgedHeader::<T, I>::try_from_inner(header)
-					.expect("only used from benchmarks; benchmarks are correct; qed"),
-				hash,
-			);
+			insert_header::<T, I>(header, hash);
 		}
 	}
 }
 
-impl<T: Config<I>, I: 'static> Pallet<T, I> {
-	/// Get the best finalized header the pallet knows of.
-	pub fn best_finalized() -> Option<BridgedHeader<T, I>> {
-		let (_, hash) = <BestFinalized<T, I>>::get()?;
-		<ImportedHeaders<T, I>>::get(hash).map(|h| h.into_inner())
-	}
-
-	/// Check if a particular header is known to the bridge pallet.
-	pub fn is_known_header(hash: BridgedBlockHash<T, I>) -> bool {
-		<ImportedHeaders<T, I>>::contains_key(hash)
-	}
-}
-
 /// Bridge GRANDPA pallet as header chain.
 pub type GrandpaChainHeaders<T, I> = Pallet<T, I>;
 
 impl<T: Config<I>, I: 'static> HeaderChain<BridgedChain<T, I>> for GrandpaChainHeaders<T, I> {
-	fn finalized_header(hash: HashOf<BridgedChain<T, I>>) -> Option<HeaderOf<BridgedChain<T, I>>> {
-		ImportedHeaders::<T, I>::get(hash).map(|h| h.into_inner())
+	fn finalized_header_state_root(
+		header_hash: HashOf<BridgedChain<T, I>>,
+	) -> Option<HashOf<BridgedChain<T, I>>> {
+		ImportedHeaders::<T, I>::get(header_hash).map(|h| h.state_root)
 	}
 }
 
@@ -653,7 +605,7 @@ mod tests {
 	use super::*;
 	use crate::mock::{
 		run_test, test_header, RuntimeOrigin, TestHeader, TestNumber, TestRuntime,
-		MAX_BRIDGED_AUTHORITIES, MAX_HEADER_SIZE,
+		MAX_BRIDGED_AUTHORITIES,
 	};
 	use bp_runtime::BasicOperatingMode;
 	use bp_test_utils::{
@@ -742,10 +694,6 @@ mod tests {
 		Digest { logs: vec![DigestItem::Consensus(GRANDPA_ENGINE_ID, consensus_log.encode())] }
 	}
 
-	fn large_digest() -> Digest {
-		Digest { logs: vec![DigestItem::Other(vec![42; MAX_HEADER_SIZE as _])] }
-	}
-
 	#[test]
 	fn init_root_or_owner_origin_can_initialize_pallet() {
 		run_test(|| {
@@ -808,25 +756,6 @@ mod tests {
 		});
 	}
 
-	#[test]
-	fn init_fails_if_header_is_too_large() {
-		run_test(|| {
-			let mut genesis = test_header(0);
-			genesis.digest = large_digest();
-			let init_data = InitializationData {
-				header: Box::new(genesis),
-				authority_list: authority_list(),
-				set_id: 1,
-				operating_mode: BasicOperatingMode::Normal,
-			};
-
-			assert_noop!(
-				Pallet::<TestRuntime>::initialize(RuntimeOrigin::root(), init_data),
-				Error::<TestRuntime>::TooLargeHeader,
-			);
-		});
-	}
-
 	#[test]
 	fn pallet_rejects_transactions_if_halted() {
 		run_test(|| {
@@ -1073,31 +1002,6 @@ mod tests {
 		});
 	}
 
-	#[test]
-	fn importing_header_rejects_header_if_it_is_too_large() {
-		run_test(|| {
-			initialize_substrate_bridge();
-
-			// Need to update the header digest to indicate that our header signals an authority set
-			// change. However, the change doesn't happen until the next block.
-			let mut header = test_header(2);
-			header.digest = large_digest();
-
-			// Create a valid justification for the header
-			let justification = make_default_justification(&header);
-
-			// Should not be allowed to import this header
-			assert_err!(
-				Pallet::<TestRuntime>::submit_finality_proof(
-					RuntimeOrigin::signed(1),
-					Box::new(header),
-					justification
-				),
-				<Error<TestRuntime>>::TooLargeHeader
-			);
-		});
-	}
-
 	#[test]
 	fn parse_finalized_storage_proof_rejects_proof_on_unknown_header() {
 		run_test(|| {
@@ -1121,11 +1025,8 @@ mod tests {
 			header.set_state_root(state_root);
 
 			let hash = header.hash();
-			<BestFinalized<TestRuntime>>::put((2, hash));
-			<ImportedHeaders<TestRuntime>>::insert(
-				hash,
-				StoredBridgedHeader::<TestRuntime, ()>::try_from_inner(header).unwrap(),
-			);
+			<BestFinalized<TestRuntime>>::put(HeaderId(2, hash));
+			<ImportedHeaders<TestRuntime>>::insert(hash, header.build());
 
 			assert_ok!(
 				Pallet::<TestRuntime>::parse_finalized_storage_proof(hash, storage_proof, |_| (),),
@@ -1220,7 +1121,7 @@ mod tests {
 		run_test(|| {
 			initialize_substrate_bridge();
 			assert_ok!(submit_finality_proof(1));
-			let first_header = Pallet::<TestRuntime>::best_finalized().unwrap();
+			let first_header_hash = Pallet::<TestRuntime>::best_finalized().unwrap().hash();
 			next_block();
 
 			assert_ok!(submit_finality_proof(2));
@@ -1235,8 +1136,8 @@ mod tests {
 			assert_ok!(submit_finality_proof(6));
 
 			assert!(
-				!Pallet::<TestRuntime>::is_known_header(first_header.hash()),
-				"First header should be pruned."
+				!ImportedHeaders::<TestRuntime, ()>::contains_key(first_header_hash),
+				"First header should be pruned.",
 			);
 		})
 	}

bridges/modules/grandpa/src/mock.rs

@@ -34,7 +34,6 @@ type Block = frame_system::mocking::MockBlock<TestRuntime>;
 type UncheckedExtrinsic = frame_system::mocking::MockUncheckedExtrinsic<TestRuntime>;
 
 pub const MAX_BRIDGED_AUTHORITIES: u32 = 2048;
-pub const MAX_HEADER_SIZE: u32 = 65536;
 
 use crate as grandpa;
 
@@ -94,7 +93,6 @@ impl grandpa::Config for TestRuntime {
 	type MaxRequests = MaxRequests;
 	type HeadersToKeep = HeadersToKeep;
 	type MaxBridgedAuthorities = frame_support::traits::ConstU32<MAX_BRIDGED_AUTHORITIES>;
-	type MaxBridgedHeaderSize = frame_support::traits::ConstU32<MAX_HEADER_SIZE>;
 	type WeightInfo = ();
 }
 

bridges/modules/parachains/src/lib.rs

@@ -275,7 +275,7 @@ pub mod pallet {
 			>::get(relay_block_hash)
 			.ok_or(Error::<T, I>::UnknownRelayChainBlock)?;
 			ensure!(
-				*relay_block.number() == relay_block_number,
+				relay_block.number == relay_block_number,
 				Error::<T, I>::InvalidRelayChainBlockNumber,
 			);
 
@@ -604,9 +604,10 @@ pub struct ParachainHeaders<T, I, C>(PhantomData<(T, I, C)>);
 impl<T: Config<I>, I: 'static, C: Parachain<Hash = ParaHash>> HeaderChain<C>
 	for ParachainHeaders<T, I, C>
 {
-	fn finalized_header(hash: HashOf<C>) -> Option<HeaderOf<C>> {
+	fn finalized_header_state_root(hash: HashOf<C>) -> Option<HashOf<C>> {
 		Pallet::<T, I>::parachain_head(ParaId(C::PARACHAIN_ID), hash)
-			.and_then(|head| Decode::decode(&mut &head.0[..]).ok())
+			.and_then(|head| HeaderOf::<C>::decode(&mut &head.0[..]).ok())
+			.map(|h| *h.state_root())
 	}
 }
 

bridges/modules/parachains/src/mock.rs

@@ -100,7 +100,6 @@ impl pallet_bridge_grandpa::Config<pallet_bridge_grandpa::Instance1> for TestRun
 	type MaxRequests = ConstU32<2>;
 	type HeadersToKeep = HeadersToKeep;
 	type MaxBridgedAuthorities = frame_support::traits::ConstU32<5>;
-	type MaxBridgedHeaderSize = frame_support::traits::ConstU32<512>;
 	type WeightInfo = ();
 }
 
@@ -109,7 +108,6 @@ impl pallet_bridge_grandpa::Config<pallet_bridge_grandpa::Instance2> for TestRun
 	type MaxRequests = ConstU32<2>;
 	type HeadersToKeep = HeadersToKeep;
 	type MaxBridgedAuthorities = frame_support::traits::ConstU32<5>;
-	type MaxBridgedHeaderSize = frame_support::traits::ConstU32<512>;
 	type WeightInfo = ();
 }
 

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

@@ -81,9 +81,6 @@ pub const SESSION_LENGTH: BlockNumber = 5 * time_units::MINUTES;
 /// Maximal number of GRANDPA authorities at Millau.
 pub const MAX_AUTHORITIES_COUNT: u32 = 5;
 
-/// Maximal SCALE-encoded header size (in bytes) at Millau.
-pub const MAX_HEADER_SIZE: u32 = 1024;
-
 /// Re-export `time_units` to make usage easier.
 pub use time_units::*;
 

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

@@ -70,11 +70,8 @@ pub const SESSION_LENGTH: BlockNumber = 4;
 /// Maximal number of GRANDPA authorities at Rialto.
 pub const MAX_AUTHORITIES_COUNT: u32 = 5;
 
-/// Maximal SCALE-encoded header size (in bytes) at Rialto.
-pub const MAX_HEADER_SIZE: u32 = 1024;
-
 /// Maximal SCALE-encoded size of parachains headers that are stored at Rialto `Paras` pallet.
-pub const MAX_NESTED_PARACHAIN_HEAD_SIZE: u32 = MAX_HEADER_SIZE;
+pub const MAX_NESTED_PARACHAIN_HEAD_SIZE: u32 = 1024;
 
 /// Re-export `time_units` to make usage easier.
 pub use time_units::*;

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

@@ -35,15 +35,12 @@ pub const PARAS_PALLET_NAME: &str = "Paras";
 /// Name of the With-Rococo GRANDPA pallet instance that is deployed at bridged chains.
 pub const WITH_ROCOCO_GRANDPA_PALLET_NAME: &str = "BridgeRococoGrandpa";
 
-/// Maximal SCALE-encoded header size (in bytes) at Rococo.
+/// Maximal SCALE-encoded size of parachains headers that are stored at Rococo `Paras` pallet.
 ///
 /// Let's assume that the largest header is header that enacts new authorities set with
 /// `MAX_AUTHORITES_COUNT`. Every authority means 32-byte key and 8-byte weight. Let's also have
 /// some fixed reserve for other things (digest, block hash and number, ...) as well.
-pub const MAX_HEADER_SIZE: u32 = 4096 + MAX_AUTHORITIES_COUNT * 40;
-
-/// Maximal SCALE-encoded size of parachains headers that are stored at Rococo `Paras` pallet.
-pub const MAX_NESTED_PARACHAIN_HEAD_SIZE: u32 = MAX_HEADER_SIZE;
+pub const MAX_NESTED_PARACHAIN_HEAD_SIZE: u32 = 4096 + MAX_AUTHORITIES_COUNT * 40;
 
 /// Maximal number of GRANDPA authorities at Rococo.
 ///

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

@@ -37,15 +37,12 @@ pub const WITH_WESTEND_BRIDGE_PARAS_PALLET_NAME: &str = "BridgeWestendParachains
 /// Corresponds to the `MaxAuthorities` constant value from the Westend runtime configuration.
 pub const MAX_AUTHORITIES_COUNT: u32 = 100_000;
 
-/// Maximal SCALE-encoded header size (in bytes) at Westend.
+/// Maximal SCALE-encoded size of parachains headers that are stored at Westend `Paras` pallet.
 ///
 /// Let's assume that the largest header is header that enacts new authorities set with
 /// `MAX_AUTHORITES_COUNT`. Every authority means 32-byte key and 8-byte weight. Let's also have
 /// some fixed reserve for other things (digest, block hash and number, ...) as well.
-pub const MAX_HEADER_SIZE: u32 = 4096 + MAX_AUTHORITIES_COUNT * 40;
-
-/// Maximal SCALE-encoded size of parachains headers that are stored at Westend `Paras` pallet.
-pub const MAX_NESTED_PARACHAIN_HEAD_SIZE: u32 = MAX_HEADER_SIZE;
+pub const MAX_NESTED_PARACHAIN_HEAD_SIZE: u32 = 4096 + MAX_AUTHORITIES_COUNT * 40;
 
 /// Identifier of Westmint parachain at the Westend relay chain.
 pub const WESTMINT_PARACHAIN_ID: u32 = 2000;

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

@@ -20,8 +20,7 @@
 
 pub use bp_polkadot_core::*;
 pub use bp_rococo::{
-	SS58Prefix, MAX_AUTHORITIES_COUNT, MAX_HEADER_SIZE, MAX_NESTED_PARACHAIN_HEAD_SIZE,
-	PARAS_PALLET_NAME,
+	SS58Prefix, MAX_AUTHORITIES_COUNT, MAX_NESTED_PARACHAIN_HEAD_SIZE, PARAS_PALLET_NAME,
 };
 use bp_runtime::decl_bridge_finality_runtime_apis;
 

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

@@ -19,8 +19,8 @@
 
 #![cfg_attr(not(feature = "std"), no_std)]
 
-use bp_runtime::{BasicOperatingMode, Chain, HashOf, HasherOf, HeaderOf, StorageProofChecker};
-use codec::{Codec, Decode, Encode, EncodeLike};
+use bp_runtime::{BasicOperatingMode, Chain, HashOf, HasherOf, StorageProofChecker};
+use codec::{Codec, Decode, Encode, EncodeLike, MaxEncodedLen};
 use core::{clone::Clone, cmp::Eq, default::Default, fmt::Debug};
 use frame_support::PalletError;
 use scale_info::TypeInfo;
@@ -52,19 +52,43 @@ impl From<HeaderChainError> for &'static str {
 	}
 }
 
+/// Header data that we're storing on-chain.
+///
+/// Even though we may store full header, our applications (XCM) only use couple of header
+/// fields. Extracting those values makes on-chain storage and PoV smaller, which is good.
+#[derive(Clone, Decode, Encode, Eq, MaxEncodedLen, PartialEq, RuntimeDebug, TypeInfo)]
+pub struct StoredHeaderData<Number, Hash> {
+	/// Header number.
+	pub number: Number,
+	/// Header state root.
+	pub state_root: Hash,
+}
+
+/// Stored header data builder.
+pub trait StoredHeaderDataBuilder<Number, Hash> {
+	/// Build header data from self.
+	fn build(&self) -> StoredHeaderData<Number, Hash>;
+}
+
+impl<H: HeaderT> StoredHeaderDataBuilder<H::Number, H::Hash> for H {
+	fn build(&self) -> StoredHeaderData<H::Number, H::Hash> {
+		StoredHeaderData { number: *self.number(), state_root: *self.state_root() }
+	}
+}
+
 /// Substrate header chain, abstracted from the way it is stored.
 pub trait HeaderChain<C: Chain> {
-	/// Returns finalized header by its hash.
-	fn finalized_header(hash: HashOf<C>) -> Option<HeaderOf<C>>;
+	/// Returns state (storage) root of given finalized header.
+	fn finalized_header_state_root(header_hash: HashOf<C>) -> Option<HashOf<C>>;
 	/// Parse storage proof using finalized header.
 	fn parse_finalized_storage_proof<R>(
-		hash: HashOf<C>,
+		header_hash: HashOf<C>,
 		storage_proof: StorageProof,
 		parse: impl FnOnce(StorageProofChecker<HasherOf<C>>) -> R,
 	) -> Result<R, HeaderChainError> {
-		let header = Self::finalized_header(hash).ok_or(HeaderChainError::UnknownHeader)?;
-		let storage_proof_checker =
-			bp_runtime::StorageProofChecker::new(*header.state_root(), storage_proof)
+		let state_root = Self::finalized_header_state_root(header_hash)
+			.ok_or(HeaderChainError::UnknownHeader)?;
+		let storage_proof_checker = bp_runtime::StorageProofChecker::new(state_root, storage_proof)
 			.map_err(|_| HeaderChainError::StorageRootMismatch)?;
 
 		Ok(parse(storage_proof_checker))

bridges/primitives/runtime/src/lib.rs

@@ -96,10 +96,34 @@ pub const ROOT_ACCOUNT_DERIVATION_PREFIX: &[u8] = b"pallet-bridge/account-deriva
 
 /// Generic header Id.
 #[derive(
-	RuntimeDebug, Default, Clone, Encode, Decode, Copy, Eq, Hash, PartialEq, PartialOrd, Ord,
+	RuntimeDebug,
+	Default,
+	Clone,
+	Encode,
+	Decode,
+	Copy,
+	Eq,
+	Hash,
+	MaxEncodedLen,
+	PartialEq,
+	PartialOrd,
+	Ord,
+	TypeInfo,
 )]
 pub struct HeaderId<Hash, Number>(pub Number, pub Hash);
 
+impl<Hash: Copy, Number: Copy> HeaderId<Hash, Number> {
+	/// Return header number.
+	pub fn number(&self) -> Number {
+		self.0
+	}
+
+	/// Return header hash.
+	pub fn hash(&self) -> Hash {
+		self.1
+	}
+}
+
 /// Generic header id provider.
 pub trait HeaderIdProvider<Header: HeaderT> {
 	// Get the header id.