Bridges - revert-back congestion mechanism

bridges/chains/chain-asset-hub-rococo/Cargo.toml

@@ -19,15 +19,21 @@ scale-info = { features = ["derive"], workspace = true }
 
 # Substrate Dependencies
 frame-support = { workspace = true }
+sp-core = { workspace = true }
 
 # Bridge Dependencies
 bp-xcm-bridge-hub-router = { workspace = true }
 
+# Polkadot dependencies
+xcm = { workspace = true }
+
 [features]
 default = ["std"]
 std = [
 	"bp-xcm-bridge-hub-router/std",
 	"codec/std",
 	"frame-support/std",
 	"scale-info/std",
+	"sp-core/std",
+	"xcm/std",
 ]

bridges/chains/chain-asset-hub-rococo/src/lib.rs

@@ -18,10 +18,13 @@
 
 #![cfg_attr(not(feature = "std"), no_std)]
 
+extern crate alloc;
+
 use codec::{Decode, Encode};
 use scale_info::TypeInfo;
 
 pub use bp_xcm_bridge_hub_router::XcmBridgeHubRouterCall;
+use xcm::latest::prelude::*;
 
 /// `AssetHubRococo` Runtime `Call` enum.
 ///
@@ -44,5 +47,27 @@ frame_support::parameter_types! {
 	pub const XcmBridgeHubRouterTransactCallMaxWeight: frame_support::weights::Weight = frame_support::weights::Weight::from_parts(200_000_000, 6144);
 }
 
+/// Builds an (un)congestion XCM program with the `report_bridge_status` call for
+/// `ToWestendXcmRouter`.
+pub fn build_congestion_message<RuntimeCall>(
+	bridge_id: sp_core::H256,
+	is_congested: bool,
+) -> alloc::vec::Vec<Instruction<RuntimeCall>> {
+	alloc::vec![
+		UnpaidExecution { weight_limit: Unlimited, check_origin: None },
+		Transact {
+			origin_kind: OriginKind::Xcm,
+			fallback_max_weight: Some(XcmBridgeHubRouterTransactCallMaxWeight::get()),
+			call: Call::ToWestendXcmRouter(XcmBridgeHubRouterCall::report_bridge_status {
+				bridge_id,
+				is_congested,
+			})
+			.encode()
+			.into(),
+		},
+		ExpectTransactStatus(MaybeErrorCode::Success),
+	]
+}
+
 /// Identifier of AssetHubRococo in the Rococo relay chain.
 pub const ASSET_HUB_ROCOCO_PARACHAIN_ID: u32 = 1000;

bridges/chains/chain-asset-hub-westend/Cargo.toml

@@ -19,15 +19,21 @@ scale-info = { features = ["derive"], workspace = true }
 
 # Substrate Dependencies
 frame-support = { workspace = true }
+sp-core = { workspace = true }
 
 # Bridge Dependencies
 bp-xcm-bridge-hub-router = { workspace = true }
 
+# Polkadot dependencies
+xcm = { workspace = true }
+
 [features]
 default = ["std"]
 std = [
 	"bp-xcm-bridge-hub-router/std",
 	"codec/std",
 	"frame-support/std",
 	"scale-info/std",
+	"sp-core/std",
+	"xcm/std",
 ]

bridges/chains/chain-asset-hub-westend/src/lib.rs

@@ -18,10 +18,13 @@
 
 #![cfg_attr(not(feature = "std"), no_std)]
 
+extern crate alloc;
+
 use codec::{Decode, Encode};
 use scale_info::TypeInfo;
 
 pub use bp_xcm_bridge_hub_router::XcmBridgeHubRouterCall;
+use xcm::latest::prelude::*;
 
 /// `AssetHubWestend` Runtime `Call` enum.
 ///
@@ -44,5 +47,27 @@ frame_support::parameter_types! {
 	pub const XcmBridgeHubRouterTransactCallMaxWeight: frame_support::weights::Weight = frame_support::weights::Weight::from_parts(200_000_000, 6144);
 }
 
+/// Builds an (un)congestion XCM program with the `report_bridge_status` call for
+/// `ToRococoXcmRouter`.
+pub fn build_congestion_message<RuntimeCall>(
+	bridge_id: sp_core::H256,
+	is_congested: bool,
+) -> alloc::vec::Vec<Instruction<RuntimeCall>> {
+	alloc::vec![
+		UnpaidExecution { weight_limit: Unlimited, check_origin: None },
+		Transact {
+			origin_kind: OriginKind::Xcm,
+			fallback_max_weight: Some(XcmBridgeHubRouterTransactCallMaxWeight::get()),
+			call: Call::ToRococoXcmRouter(XcmBridgeHubRouterCall::report_bridge_status {
+				bridge_id,
+				is_congested,
+			})
+			.encode()
+			.into(),
+		},
+		ExpectTransactStatus(MaybeErrorCode::Success),
+	]
+}
+
 /// Identifier of AssetHubWestend in the Westend relay chain.
 pub const ASSET_HUB_WESTEND_PARACHAIN_ID: u32 = 1000;

bridges/modules/xcm-bridge-hub-router/src/benchmarking.rs

@@ -18,9 +18,9 @@
 
 #![cfg(feature = "runtime-benchmarks")]
 
-use crate::{DeliveryFeeFactor, MINIMAL_DELIVERY_FEE_FACTOR};
+use crate::{Bridge, BridgeState, Call, MINIMAL_DELIVERY_FEE_FACTOR};
 use frame_benchmarking::{benchmarks_instance_pallet, BenchmarkError};
-use frame_support::traits::{Get, Hooks};
+use frame_support::traits::{EnsureOrigin, Get, Hooks, UnfilteredDispatchable};
 use sp_runtime::traits::Zero;
 use xcm::prelude::*;
 
@@ -45,16 +45,35 @@ pub trait Config<I: 'static>: crate::Config<I> {
 
 benchmarks_instance_pallet! {
 	on_initialize_when_non_congested {
-		DeliveryFeeFactor::<T, I>::put(MINIMAL_DELIVERY_FEE_FACTOR + MINIMAL_DELIVERY_FEE_FACTOR);
+		Bridge::<T, I>::put(BridgeState {
+			is_congested: false,
+			delivery_fee_factor: MINIMAL_DELIVERY_FEE_FACTOR + MINIMAL_DELIVERY_FEE_FACTOR,
+		});
 	}: {
 		crate::Pallet::<T, I>::on_initialize(Zero::zero())
 	}
 
 	on_initialize_when_congested {
-		DeliveryFeeFactor::<T, I>::put(MINIMAL_DELIVERY_FEE_FACTOR + MINIMAL_DELIVERY_FEE_FACTOR);
+		Bridge::<T, I>::put(BridgeState {
+			is_congested: false,
+			delivery_fee_factor: MINIMAL_DELIVERY_FEE_FACTOR + MINIMAL_DELIVERY_FEE_FACTOR,
+		});
 		let _ = T::ensure_bridged_target_destination()?;
 		T::make_congested();
 	}: {
 		crate::Pallet::<T, I>::on_initialize(Zero::zero())
 	}
+
+	report_bridge_status {
+		Bridge::<T, I>::put(BridgeState::default());
+
+		let origin: T::RuntimeOrigin = T::BridgeHubOrigin::try_successful_origin().expect("expected valid BridgeHubOrigin");
+		let bridge_id = Default::default();
+		let is_congested = true;
+
+		let call = Call::<T, I>::report_bridge_status { bridge_id, is_congested };
+	}: { call.dispatch_bypass_filter(origin)? }
+	verify {
+		assert!(Bridge::<T, I>::get().is_congested);
+	}
 }