separate constants for average and worst case relay headers (#2728)

* separate constants for average and worst case relay headers

* fix compilation

Author: svyatonik

bin/runtime-common/src/mock.rs

@@ -378,6 +378,7 @@ impl ChainWithGrandpa for BridgedUnderlyingChain {
 	const REASONABLE_HEADERS_IN_JUSTIFICATON_ANCESTRY: u32 = 8;
 	const MAX_HEADER_SIZE: u32 = 256;
 	const AVERAGE_HEADER_SIZE_IN_JUSTIFICATION: u32 = 64;
+	const WORST_HEADER_SIZE_IN_JUSTIFICATION: u32 = 64;
 }
 
 impl Chain for BridgedUnderlyingParachain {

modules/grandpa/src/mock.rs

@@ -88,6 +88,7 @@ impl ChainWithGrandpa for TestBridgedChain {
 	const REASONABLE_HEADERS_IN_JUSTIFICATON_ANCESTRY: u32 = 8;
 	const MAX_HEADER_SIZE: u32 = 256;
 	const AVERAGE_HEADER_SIZE_IN_JUSTIFICATION: u32 = 64;
+	const WORST_HEADER_SIZE_IN_JUSTIFICATION: u32 = 64;
 }
 
 /// Return test externalities to use in tests.

modules/parachains/src/mock.rs

@@ -254,6 +254,7 @@ impl ChainWithGrandpa for TestBridgedChain {
 	const REASONABLE_HEADERS_IN_JUSTIFICATON_ANCESTRY: u32 = 8;
 	const MAX_HEADER_SIZE: u32 = 256;
 	const AVERAGE_HEADER_SIZE_IN_JUSTIFICATION: u32 = 64;
+	const WORST_HEADER_SIZE_IN_JUSTIFICATION: u32 = 64;
 }
 
 #[derive(Debug)]
@@ -285,6 +286,7 @@ impl ChainWithGrandpa for OtherBridgedChain {
 	const REASONABLE_HEADERS_IN_JUSTIFICATON_ANCESTRY: u32 = 8;
 	const MAX_HEADER_SIZE: u32 = 256;
 	const AVERAGE_HEADER_SIZE_IN_JUSTIFICATION: u32 = 64;
+	const WORST_HEADER_SIZE_IN_JUSTIFICATION: u32 = 64;
 }
 
 /// Return test externalities to use in tests.

primitives/chain-kusama/src/lib.rs

@@ -54,6 +54,7 @@ impl ChainWithGrandpa for Kusama {
 		REASONABLE_HEADERS_IN_JUSTIFICATON_ANCESTRY;
 	const MAX_HEADER_SIZE: u32 = MAX_HEADER_SIZE;
 	const AVERAGE_HEADER_SIZE_IN_JUSTIFICATION: u32 = AVERAGE_HEADER_SIZE_IN_JUSTIFICATION;
+	const WORST_HEADER_SIZE_IN_JUSTIFICATION: u32 = WORST_HEADER_SIZE_IN_JUSTIFICATION;
 }
 
 // The SignedExtension used by Kusama.

primitives/chain-polkadot-bulletin/src/lib.rs

@@ -44,6 +44,7 @@ pub use bp_polkadot_core::{
 	AccountAddress, AccountId, Balance, Block, BlockNumber, Hash, Hasher, Header, Nonce, Signature,
 	SignedBlock, UncheckedExtrinsic, AVERAGE_HEADER_SIZE_IN_JUSTIFICATION,
 	EXTRA_STORAGE_PROOF_SIZE, MAX_HEADER_SIZE, REASONABLE_HEADERS_IN_JUSTIFICATON_ANCESTRY,
+	WORST_HEADER_SIZE_IN_JUSTIFICATION,
 };
 
 /// Maximal number of GRANDPA authorities at Polkadot Bulletin chain.
@@ -209,6 +210,7 @@ impl ChainWithGrandpa for PolkadotBulletin {
 		REASONABLE_HEADERS_IN_JUSTIFICATON_ANCESTRY;
 	const MAX_HEADER_SIZE: u32 = MAX_HEADER_SIZE;
 	const AVERAGE_HEADER_SIZE_IN_JUSTIFICATION: u32 = AVERAGE_HEADER_SIZE_IN_JUSTIFICATION;
+	const WORST_HEADER_SIZE_IN_JUSTIFICATION: u32 = WORST_HEADER_SIZE_IN_JUSTIFICATION;
 }
 
 decl_bridge_finality_runtime_apis!(polkadot_bulletin, grandpa);

primitives/chain-polkadot/src/lib.rs

@@ -54,6 +54,7 @@ impl ChainWithGrandpa for Polkadot {
 		REASONABLE_HEADERS_IN_JUSTIFICATON_ANCESTRY;
 	const MAX_HEADER_SIZE: u32 = MAX_HEADER_SIZE;
 	const AVERAGE_HEADER_SIZE_IN_JUSTIFICATION: u32 = AVERAGE_HEADER_SIZE_IN_JUSTIFICATION;
+	const WORST_HEADER_SIZE_IN_JUSTIFICATION: u32 = WORST_HEADER_SIZE_IN_JUSTIFICATION;
 }
 
 /// The SignedExtension used by Polkadot.

primitives/chain-rococo/src/lib.rs

@@ -54,6 +54,7 @@ impl ChainWithGrandpa for Rococo {
 		REASONABLE_HEADERS_IN_JUSTIFICATON_ANCESTRY;
 	const MAX_HEADER_SIZE: u32 = MAX_HEADER_SIZE;
 	const AVERAGE_HEADER_SIZE_IN_JUSTIFICATION: u32 = AVERAGE_HEADER_SIZE_IN_JUSTIFICATION;
+	const WORST_HEADER_SIZE_IN_JUSTIFICATION: u32 = WORST_HEADER_SIZE_IN_JUSTIFICATION;
 }
 
 parameter_types! {

primitives/chain-westend/src/lib.rs

@@ -54,6 +54,7 @@ impl ChainWithGrandpa for Westend {
 		REASONABLE_HEADERS_IN_JUSTIFICATON_ANCESTRY;
 	const MAX_HEADER_SIZE: u32 = MAX_HEADER_SIZE;
 	const AVERAGE_HEADER_SIZE_IN_JUSTIFICATION: u32 = AVERAGE_HEADER_SIZE_IN_JUSTIFICATION;
+	const WORST_HEADER_SIZE_IN_JUSTIFICATION: u32 = WORST_HEADER_SIZE_IN_JUSTIFICATION;
 }
 
 parameter_types! {

primitives/header-chain/src/lib.rs

@@ -280,9 +280,22 @@ pub trait ChainWithGrandpa: Chain {
 	/// headers that aren't changing the set.
 	///
 	/// This isn't a strict limit. The relay may submit justifications with larger headers in its
+	/// ancestry and the pallet will accept the call. The limit is only used to compute fee, paid
+	/// by the user at the sending chain. It covers most of cases, but if the actual header,
+	/// submitted with the messages transaction will be larger than the
+	/// `AVERAGE_HEADER_SIZE_IN_JUSTIFICATION`, the difference (`WORST_HEADER_SIZE_IN_JUSTIFICATION`
+	/// - `AVERAGE_HEADER_SIZE_IN_JUSTIFICATION`) must be covered by the sending chain.
+	const AVERAGE_HEADER_SIZE_IN_JUSTIFICATION: u32;
+
+	/// Worst-case size of the chain header from justification ancestry. We don't expect to see
+	/// there headers that change GRANDPA authorities set (GRANDPA will probably be able to finalize
+	/// at least one additional header per session on non test chains), so this is the worst-case
+	/// size of headers that aren't changing the set.
+	///
+	/// This isn't a strict limit. The relay may submit justifications with larger headers in its
 	/// ancestry and the pallet will accept the call. The limit is only used to compute maximal
 	/// refund amount and doing calls which exceed the limit, may be costly to submitter.
-	const AVERAGE_HEADER_SIZE_IN_JUSTIFICATION: u32;
+	const WORST_HEADER_SIZE_IN_JUSTIFICATION: u32;
 }
 
 impl<T> ChainWithGrandpa for T
@@ -298,4 +311,6 @@ where
 	const MAX_HEADER_SIZE: u32 = <T::Chain as ChainWithGrandpa>::MAX_HEADER_SIZE;
 	const AVERAGE_HEADER_SIZE_IN_JUSTIFICATION: u32 =
 		<T::Chain as ChainWithGrandpa>::AVERAGE_HEADER_SIZE_IN_JUSTIFICATION;
+	const WORST_HEADER_SIZE_IN_JUSTIFICATION: u32 =
+		<T::Chain as ChainWithGrandpa>::WORST_HEADER_SIZE_IN_JUSTIFICATION;
 }

primitives/polkadot-core/src/lib.rs

@@ -70,7 +70,16 @@ pub const MAX_AUTHORITIES_COUNT: u32 = 1_256;
 /// reserve here.
 pub const REASONABLE_HEADERS_IN_JUSTIFICATON_ANCESTRY: u32 = 2;
 
-/// Approximate average header size in `votes_ancestries` field of justification on Polkadot-like
+/// Average header size in `votes_ancestries` field of justification on Polkadot-like
+/// chains.
+///
+/// See [`bp-header-chain::ChainWithGrandpa`] for more details.
+///
+/// This value comes from recent (February, 2023) Kusama headers. Average is `336` there, but let's
+/// have some reserve and make it 1024.
+pub const AVERAGE_HEADER_SIZE_IN_JUSTIFICATION: u32 = 1024;
+
+/// Worst-case header size in `votes_ancestries` field of justification on Polkadot-like
 /// chains.
 ///
 /// See [`bp-header-chain::ChainWithGrandpa`] for more details.
@@ -79,7 +88,7 @@ pub const REASONABLE_HEADERS_IN_JUSTIFICATON_ANCESTRY: u32 = 2;
 /// non-mandatory headers has size `40kb` (they contain the BABE epoch descriptor with all
 /// authorities - just like our mandatory header). Since we assume `2` headers in justification
 /// votes ancestry, let's set average header to `40kb / 2`.
-pub const AVERAGE_HEADER_SIZE_IN_JUSTIFICATION: u32 = 20 * 1024;
+pub const WORST_HEADER_SIZE_IN_JUSTIFICATION: u32 = 20 * 1024;
 
 /// Approximate maximal header size on Polkadot-like chains.
 ///