Bridges: Making relayer compatible with runtime upgrades

bridges/bin/runtime-common/Cargo.toml

@@ -14,6 +14,8 @@ workspace = true
 codec = { package = "parity-scale-codec", version = "3.6.1", default-features = false, features = ["derive"] }
 hash-db = { version = "0.16.0", default-features = false }
 log = { workspace = true }
+const-fnv1a-hash = "1.1"
+const_format = "0.2"
 scale-info = { version = "2.11.1", default-features = false, features = ["derive"] }
 static_assertions = { version = "1.1", optional = true }
 tuplex = { version = "0.1", default-features = false }
@@ -26,6 +28,7 @@ bp-parachains = { path = "../../primitives/parachains", default-features = false
 bp-polkadot-core = { path = "../../primitives/polkadot-core", default-features = false }
 bp-relayers = { path = "../../primitives/relayers", default-features = false }
 bp-runtime = { path = "../../primitives/runtime", default-features = false }
+bp-test-utils = { path = "../../primitives/test-utils", default-features = false, optional = true }
 bp-xcm-bridge-hub = { path = "../../primitives/xcm-bridge-hub", default-features = false }
 bp-xcm-bridge-hub-router = { path = "../../primitives/xcm-bridge-hub-router", default-features = false }
 pallet-bridge-grandpa = { path = "../../modules/grandpa", default-features = false }
@@ -63,6 +66,7 @@ std = [
 	"bp-polkadot-core/std",
 	"bp-relayers/std",
 	"bp-runtime/std",
+	"bp-test-utils?/std",
 	"bp-xcm-bridge-hub-router/std",
 	"bp-xcm-bridge-hub/std",
 	"codec/std",
@@ -99,4 +103,4 @@ runtime-benchmarks = [
 	"sp-runtime/runtime-benchmarks",
 	"xcm-builder/runtime-benchmarks",
 ]
-integrity-test = ["static_assertions"]
+integrity-test = ["bp-test-utils", "static_assertions"]

bridges/bin/runtime-common/src/extensions/check_obsolete_extension.rs

@@ -262,7 +262,25 @@ macro_rules! generate_bridge_reject_obsolete_headers_and_messages {
 		#[derive(Clone, codec::Decode, Default, codec::Encode, Eq, PartialEq, sp_runtime::RuntimeDebug, scale_info::TypeInfo)]
 		pub struct BridgeRejectObsoleteHeadersAndMessages;
 		impl sp_runtime::traits::SignedExtension for BridgeRejectObsoleteHeadersAndMessages {
-			const IDENTIFIER: &'static str = "BridgeRejectObsoleteHeadersAndMessages";
+			// What we do here is:
+			// - computing hash of all stringified **types**, passed to the macro
+			// - prefixing it with `BridgeReject_`
+			//
+			// So whenever any type passed to the `generate_bridge_reject_obsolete_headers_and_messages`
+			// changes, the `IDENTIFIER` is also changed. Keep in mind that it may change if the type
+			// stays the same, but e.g. name of type alias, used in type name changes:
+			// ```rust
+			// struct F<T>;
+			// type A = u32;
+			// type B = u32;
+			// ```
+			// Then `IDENTIFIER` of `F<A>` is not equal to `F<B>`, even though the type is the same.
+			const IDENTIFIER: &'static str = $crate::extensions::prelude::const_format::concatcp!(
+				"BridgeReject_",
+				$crate::extensions::prelude::const_fnv1a_hash::fnv1a_hash_str_128(
+					concat!($(stringify!($filter_call), )*)
+				)
+			);
 			type AccountId = $account_id;
 			type Call = $call;
 			type AdditionalSigned = ();
@@ -458,6 +476,11 @@ mod tests {
 			SecondFilterCall
 		);
 
+		assert_eq!(
+			BridgeRejectObsoleteHeadersAndMessages::IDENTIFIER,
+			"BridgeReject_163603100942600502516220926454699703369"
+		);
+
 		run_test(|| {
 			assert_err!(
 				BridgeRejectObsoleteHeadersAndMessages.validate(&42, &MockCall { data: 1 }, &(), 0),

bridges/bin/runtime-common/src/extensions/mod.rs

@@ -16,6 +16,12 @@
 
 //! Bridge-specific transaction extensions.
 
+/// All crates that we use in extensions macro.
+pub mod prelude {
+	pub use const_fnv1a_hash;
+	pub use const_format;
+}
+
 pub mod check_obsolete_extension;
 pub mod priority_calculator;
 pub mod refund_relayer_extension;

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

@@ -32,5 +32,7 @@ mod mock;
 
 #[cfg(feature = "integrity-test")]
 pub mod integrity;
+#[cfg(feature = "integrity-test")]
+pub mod relayer_compatibility;
 
 const LOG_TARGET_BRIDGE_DISPATCH: &str = "runtime::bridge-dispatch";

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

@@ -45,7 +45,7 @@ use frame_support::{
 use pallet_transaction_payment::Multiplier;
 use sp_runtime::{
 	testing::H256,
-	traits::{BlakeTwo256, ConstU32, ConstU64, ConstU8},
+	traits::{BlakeTwo256, ConstU32, ConstU64, ConstU8, GetDefault},
 	FixedPointNumber, Perquintill,
 };
 
@@ -182,6 +182,7 @@ impl pallet_transaction_payment::Config for TestRuntime {
 
 impl pallet_bridge_grandpa::Config for TestRuntime {
 	type RuntimeEvent = RuntimeEvent;
+	type CompatibleWithRelayer = GetDefault;
 	type BridgedChain = BridgedUnderlyingChain;
 	type MaxFreeHeadersPerBlock = ConstU32<4>;
 	type FreeHeadersInterval = ConstU32<1_024>;
@@ -191,6 +192,7 @@ impl pallet_bridge_grandpa::Config for TestRuntime {
 
 impl pallet_bridge_parachains::Config for TestRuntime {
 	type RuntimeEvent = RuntimeEvent;
+	type CompatibleWithRelayer = GetDefault;
 	type BridgesGrandpaPalletInstance = ();
 	type ParasPalletName = BridgedParasPalletName;
 	type ParaStoredHeaderDataBuilder =
@@ -202,6 +204,7 @@ impl pallet_bridge_parachains::Config for TestRuntime {
 
 impl pallet_bridge_messages::Config for TestRuntime {
 	type RuntimeEvent = RuntimeEvent;
+	type CompatibleWithRelayer = GetDefault;
 	type WeightInfo = pallet_bridge_messages::weights::BridgeWeight<TestRuntime>;
 	type ActiveOutboundLanes = ActiveOutboundLanes;
 	type MaxUnrewardedRelayerEntriesAtInboundLane = MaxUnrewardedRelayerEntriesAtInboundLane;