asset-hubs: transfer assets via bridge using pallet-xcm

Add xcm routing configuration for bridging between
	Polkadot Asset Hub <-> Kusama Asset Hub.

We explicitly allow only reserve based transfer for KSM/DOT to
cross-consensus AssetHubs and nothing else at first (start defensively).
We can later allow whatever (ETH, TrustBackedAssets, ForeignAssets,
PoolAssets ...).

Add tests for simulation:
- `limited_reserve_transfer_assets` with `pallet_xcm` both ways
- handling `ReserveAssetDeposisted` on both sides

Add local zomienet run for:
- reserve based transfer of KSMs from AHK to AHP
- reserve based transfer of DOTs from AHP to AHK
(check parachains/runtimes/bridge-hubs/README.md in this PR)

Signed-off-by: Branislav Kontur <bkontur@gmail.com>
Signed-off-by: Adrian Catangiu <adrian@parity.io>

cumulus/parachains/common/src/xcm_config.rs

@@ -18,10 +18,12 @@ use core::marker::PhantomData;
 use frame_support::{
 	traits::{fungibles::Inspect, tokens::ConversionToAssetBalance, ContainsPair},
 	weights::Weight,
+	DefaultNoBound,
 };
 use log;
 use sp_runtime::traits::Get;
 use xcm::latest::prelude::*;
+use xcm_builder::ExporterFor;
 
 /// A `ChargeFeeInFungibles` implementation that converts the output of
 /// a given WeightToFee implementation an amount charged in
@@ -78,3 +80,141 @@ impl<Location: Get<MultiLocation>> ContainsPair<MultiAsset, MultiLocation>
 		matches!(asset.id, Concrete(ref id) if id == origin && origin == &Location::get())
 	}
 }
+
+/// Trait for matching `Location`.
+pub trait MatchesLocation<Location> {
+	fn matches(&self, location: &Location) -> bool;
+}
+
+/// Simple `MultiLocation` filter utility.
+#[derive(Debug, DefaultNoBound)]
+pub struct LocationFilter<Location> {
+	/// Requested location equals to `Location`.
+	pub equals_any: sp_std::vec::Vec<Location>,
+	/// Requested location starts with `Location`.
+	pub starts_with_any: sp_std::vec::Vec<Location>,
+}
+
+impl<Location> LocationFilter<Location> {
+	pub fn add_equals(mut self, filter: Location) -> Self {
+		self.equals_any.push(filter);
+		self
+	}
+	pub fn add_starts_with(mut self, filter: Location) -> Self {
+		self.starts_with_any.push(filter);
+		self
+	}
+}
+
+/// `MatchesLocation` implementation which works with `MultiLocation`.
+impl MatchesLocation<MultiLocation> for LocationFilter<MultiLocation> {
+	fn matches(&self, location: &MultiLocation) -> bool {
+		for filter in &self.equals_any {
+			if location.eq(filter) {
+				return true
+			}
+		}
+		for filter in &self.starts_with_any {
+			if location.starts_with(filter) {
+				return true
+			}
+		}
+		false
+	}
+}
+
+/// `MatchesLocation` implementation which works with `InteriorMultiLocation`.
+impl MatchesLocation<InteriorMultiLocation> for LocationFilter<InteriorMultiLocation> {
+	fn matches(&self, location: &InteriorMultiLocation) -> bool {
+		for filter in &self.equals_any {
+			if location.eq(filter) {
+				return true
+			}
+		}
+		for filter in &self.starts_with_any {
+			if location.starts_with(filter) {
+				return true
+			}
+		}
+		false
+	}
+}
+
+/// `FilteredNetworkExportTable` is adapter for `ExporterFor` implementation
+/// which tries to find (`bridge_location`, `fees`) for requested `network` and `remote_location`.
+///
+/// Inspired by `xcm_builder::NetworkExportTable`:
+/// the main difference is that `NetworkExportTable` does not check `remote_location`.
+pub struct FilteredNetworkExportTable<T>(sp_std::marker::PhantomData<T>);
+impl<
+		T: Get<
+			sp_std::vec::Vec<(
+				NetworkId,
+				LocationFilter<InteriorMultiLocation>,
+				MultiLocation,
+				Option<MultiAsset>,
+			)>,
+		>,
+	> ExporterFor for FilteredNetworkExportTable<T>
+{
+	fn exporter_for(
+		network: &NetworkId,
+		remote_location: &InteriorMultiLocation,
+		_: &Xcm<()>,
+	) -> Option<(MultiLocation, Option<MultiAsset>)> {
+		T::get()
+			.into_iter()
+			.find(|(ref j, location_filter, ..)| {
+				j == network && location_filter.matches(remote_location)
+			})
+			.map(|(_, _, bridge_location, p)| (bridge_location, p))
+	}
+}
+
+#[cfg(test)]
+mod tests {
+	use super::*;
+
+	#[test]
+	fn filtered_network_export_table_works() {
+		frame_support::parameter_types! {
+			pub BridgeLocation: MultiLocation = MultiLocation::new(1, X1(Parachain(1234)));
+
+			pub BridgeTable: sp_std::vec::Vec<(NetworkId, LocationFilter<InteriorMultiLocation>, MultiLocation, Option<MultiAsset>)> = sp_std::vec![
+				(
+					Kusama,
+					LocationFilter::default()
+						.add_equals(X1(Parachain(2000)))
+						.add_equals(X1(Parachain(3000)))
+						.add_equals(X1(Parachain(4000))),
+					BridgeLocation::get(),
+					None
+				)
+			];
+		}
+
+		let test_data = vec![
+			(Polkadot, X1(Parachain(1000)), None),
+			(Polkadot, X1(Parachain(2000)), None),
+			(Polkadot, X1(Parachain(3000)), None),
+			(Polkadot, X1(Parachain(4000)), None),
+			(Polkadot, X1(Parachain(5000)), None),
+			(Kusama, X1(Parachain(1000)), None),
+			(Kusama, X1(Parachain(2000)), Some((BridgeLocation::get(), None))),
+			(Kusama, X1(Parachain(3000)), Some((BridgeLocation::get(), None))),
+			(Kusama, X1(Parachain(4000)), Some((BridgeLocation::get(), None))),
+			(Kusama, X1(Parachain(5000)), None),
+		];
+
+		for (network, remote_location, expected_result) in test_data {
+			assert_eq!(
+				FilteredNetworkExportTable::<BridgeTable>::exporter_for(
+					&network,
+					&remote_location,
+					&Xcm::default()
+				),
+				expected_result,
+			)
+		}
+	}
+}

cumulus/parachains/runtimes/assets/asset-hub-kusama/src/lib.rs

@@ -1279,7 +1279,10 @@ impl_runtime_apis! {
 				}
 
 				fn universal_alias() -> Result<(MultiLocation, Junction), BenchmarkError> {
-					Err(BenchmarkError::Skip)
+					match xcm_config::bridging::BridgingBenchmarksHelper::prepare_universal_alias() {
+						Some(alias) => Ok(alias),
+						None => Err(BenchmarkError::Skip)
+					}
 				}
 
 				fn transact_origin_and_runtime_call() -> Result<(MultiLocation, RuntimeCall), BenchmarkError> {

cumulus/parachains/runtimes/assets/asset-hub-kusama/src/weights/xcm/mod.rs

@@ -220,7 +220,7 @@ impl<Call> XcmWeightInfo<Call> for AssetHubKusamaXcmWeight<Call> {
 		XcmGeneric::<Runtime>::clear_transact_status()
 	}
 	fn universal_origin(_: &Junction) -> Weight {
-		Weight::MAX
+		XcmGeneric::<Runtime>::universal_origin()
 	}
 	fn export_message(_: &NetworkId, _: &Junctions, _: &Xcm<()>) -> Weight {
 		Weight::MAX

cumulus/parachains/runtimes/assets/asset-hub-kusama/src/weights/xcm/pallet_xcm_benchmarks_generic.rs

@@ -312,6 +312,16 @@ impl<T: frame_system::Config> WeightInfo<T> {
 		// Minimum execution time: 2_886_000 picoseconds.
 		Weight::from_parts(3_015_000, 0)
 	}
+	// Storage: `ParachainInfo::ParachainId` (r:1 w:0)
+	// Proof: `ParachainInfo::ParachainId` (`max_values`: Some(1), `max_size`: Some(4), added: 499, mode: `MaxEncodedLen`)
+	pub fn universal_origin() -> Weight {
+		// Proof Size summary in bytes:
+		//  Measured:  `0`
+		//  Estimated: `1489`
+		// Minimum execution time: 5_088_000 picoseconds.
+		Weight::from_parts(5_253_000, 1489)
+			.saturating_add(T::DbWeight::get().reads(1))
+	}
 	pub fn set_fees_mode() -> Weight {
 		// Proof Size summary in bytes:
 		//  Measured:  `0`