separate constants for average and worst case relay headers

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

@@ -209,6 +209,7 @@ 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.
 ///