xcm_config.rs

// Copyright (C) Parity Technologies (UK) Ltd.
// This file is part of Polkadot.

// Polkadot is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// Polkadot is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with Polkadot.  If not, see <http://www.gnu.org/licenses/>.

//! XCM configuration for Polkadot.

use super::{
	parachains_origin, AccountId, AllPalletsWithSystem, Balances, Dmp, FellowshipAdmin,
	GeneralAdmin, ParaId, Runtime, RuntimeCall, RuntimeEvent, RuntimeOrigin, StakingAdmin,
	TransactionByteFee, WeightToFee, XcmPallet,
};
use frame_support::{
	match_types, parameter_types,
	traits::{Contains, Everything, Nothing},
	weights::Weight,
};
use frame_system::EnsureRoot;
use pallet_xcm::XcmPassthrough;
use polkadot_runtime_constants::{
	currency::CENTS, system_parachain::*, xcm::body::FELLOWSHIP_ADMIN_INDEX,
};
use runtime_common::{
	crowdloan, paras_registrar,
	xcm_sender::{ChildParachainRouter, ExponentialPrice},
	ToAuthor,
};
use sp_core::ConstU32;
use xcm::latest::prelude::*;
use xcm_builder::{
	AccountId32Aliases, AllowExplicitUnpaidExecutionFrom, AllowKnownQueryResponses,
	AllowSubscriptionsFrom, AllowTopLevelPaidExecutionFrom, ChildParachainAsNative,
	ChildParachainConvertsVia, CurrencyAdapter as XcmCurrencyAdapter, IsConcrete, MintLocation,
	OriginToPluralityVoice, SignedAccountId32AsNative, SignedToAccountId32,
	SovereignSignedViaLocation, TakeWeightCredit, TrailingSetTopicAsId, UsingComponents,
	WeightInfoBounds, WithComputedOrigin, WithUniqueTopic,
};
use xcm_executor::traits::WithOriginFilter;

parameter_types! {
	/// The location of the DOT token, from the context of this chain. Since this token is native to this
	/// chain, we make it synonymous with it and thus it is the `Here` location, which means "equivalent to
	/// the context".
	pub const TokenLocation: MultiLocation = Here.into_location();
	/// The Polkadot network ID. This is named.
	pub const ThisNetwork: NetworkId = NetworkId::Polkadot;
	/// Our location in the universe of consensus systems.
	pub const UniversalLocation: InteriorMultiLocation = X1(GlobalConsensus(ThisNetwork::get()));
	/// The Checking Account, which holds any native assets that have been teleported out and not back in (yet).
	pub CheckAccount: AccountId = XcmPallet::check_account();
	/// The Checking Account along with the indication that the local chain is able to mint tokens.
	pub LocalCheckAccount: (AccountId, MintLocation) = (CheckAccount::get(), MintLocation::Local);
}

/// The canonical means of converting a `MultiLocation` into an `AccountId`, used when we want to
/// determine the sovereign account controlled by a location.
pub type SovereignAccountOf = (
	// We can convert a child parachain using the standard `AccountId` conversion.
	ChildParachainConvertsVia<ParaId, AccountId>,
	// We can directly alias an `AccountId32` into a local account.
	AccountId32Aliases<ThisNetwork, AccountId>,
);

/// Our asset transactor. This is what allows us to interact with the runtime assets from the point
/// of view of XCM-only concepts like `MultiLocation` and `MultiAsset`.
///
/// Ours is only aware of the Balances pallet, which is mapped to `TokenLocation`.
pub type LocalAssetTransactor = XcmCurrencyAdapter<
	// Use this currency:
	Balances,
	// Use this currency when it is a fungible asset matching the given location or name:
	IsConcrete<TokenLocation>,
	// We can convert the MultiLocations with our converter above:
	SovereignAccountOf,
	// Our chain's account ID type (we can't get away without mentioning it explicitly):
	AccountId,
	// We track our teleports in/out to keep total issuance correct.
	LocalCheckAccount,
>;

/// The means that we convert an XCM origin `MultiLocation` into the runtime's `Origin` type for
/// local dispatch. This is a conversion function from an `OriginKind` type along with the
/// `MultiLocation` value and returns an `Origin` value or an error.
type LocalOriginConverter = (
	// If the origin kind is `Sovereign`, then return a `Signed` origin with the account determined
	// by the `SovereignAccountOf` converter.
	SovereignSignedViaLocation<SovereignAccountOf, RuntimeOrigin>,
	// If the origin kind is `Native` and the XCM origin is a child parachain, then we can express
	// it with the special `parachains_origin::Origin` origin variant.
	ChildParachainAsNative<parachains_origin::Origin, RuntimeOrigin>,
	// If the origin kind is `Native` and the XCM origin is the `AccountId32` location, then it can
	// be expressed using the `Signed` origin variant.
	SignedAccountId32AsNative<ThisNetwork, RuntimeOrigin>,
	// Xcm origins can be represented natively under the Xcm pallet's Xcm origin.
	XcmPassthrough<RuntimeOrigin>,
);

parameter_types! {
	/// The amount of weight an XCM operation takes. This is a safe overestimate.
	pub const BaseXcmWeight: Weight = Weight::from_parts(1_000_000_000, 1024);
	/// Maximum number of instructions in a single XCM fragment. A sanity check against weight
	/// calculations getting too crazy.
	pub const MaxInstructions: u32 = 100;
	/// The asset ID for the asset that we use to pay for message delivery fees.
	pub FeeAssetId: AssetId = Concrete(TokenLocation::get());
	/// The base fee for the message delivery fees.
	pub const BaseDeliveryFee: u128 = CENTS.saturating_mul(3);
}

/// The XCM router. When we want to send an XCM message, we use this type. It amalgamates all of our
/// individual routers.
pub type XcmRouter = WithUniqueTopic<(
	// Only one router so far - use DMP to communicate with child parachains.
	ChildParachainRouter<
		Runtime,
		XcmPallet,
		ExponentialPrice<FeeAssetId, BaseDeliveryFee, TransactionByteFee, Dmp>,
	>,
)>;

parameter_types! {
	pub const Dot: MultiAssetFilter = Wild(AllOf { fun: WildFungible, id: Concrete(TokenLocation::get()) });
	pub const StatemintLocation: MultiLocation = Parachain(STATEMINT_ID).into_location();
	pub const DotForStatemint: (MultiAssetFilter, MultiLocation) = (Dot::get(), StatemintLocation::get());
	pub const CollectivesLocation: MultiLocation = Parachain(COLLECTIVES_ID).into_location();
	pub const DotForCollectives: (MultiAssetFilter, MultiLocation) = (Dot::get(), CollectivesLocation::get());
	pub const MaxAssetsIntoHolding: u32 = 64;
}

/// Polkadot Relay recognizes/respects the Statemint chain as a teleporter.
pub type TrustedTeleporters =
	(xcm_builder::Case<DotForStatemint>, xcm_builder::Case<DotForCollectives>);

match_types! {
	pub type OnlyParachains: impl Contains<MultiLocation> = {
		MultiLocation { parents: 0, interior: X1(Parachain(_)) }
	};
	pub type CollectivesOrFellows: impl Contains<MultiLocation> = {
		MultiLocation { parents: 0, interior: X1(Parachain(COLLECTIVES_ID)) } |
		MultiLocation { parents: 0, interior: X2(Parachain(COLLECTIVES_ID), Plurality { id: BodyId::Technical, .. }) }
	};
}

/// The barriers one of which must be passed for an XCM message to be executed.
pub type Barrier = TrailingSetTopicAsId<(
	// Weight that is paid for may be consumed.
	TakeWeightCredit,
	// Expected responses are OK.
	AllowKnownQueryResponses<XcmPallet>,
	WithComputedOrigin<
		(
			// If the message is one that immediately attemps to pay for execution, then allow it.
			AllowTopLevelPaidExecutionFrom<Everything>,
			// Subscriptions for version tracking are OK.
			AllowSubscriptionsFrom<OnlyParachains>,
			// Collectives and Fellows plurality get free execution.
			AllowExplicitUnpaidExecutionFrom<CollectivesOrFellows>,
		),
		UniversalLocation,
		ConstU32<8>,
	>,
)>;

/// A call filter for the XCM Transact instruction. This is a temporary measure until we
/// properly account for proof size weights.
///
/// Calls that are allowed through this filter must:
/// 1. Have a fixed weight;
/// 2. Cannot lead to another call being made;
/// 3. Have a defined proof size weight, e.g. no unbounded vecs in call parameters.
pub struct SafeCallFilter;
impl Contains<RuntimeCall> for SafeCallFilter {
	fn contains(call: &RuntimeCall) -> bool {
		#[cfg(feature = "runtime-benchmarks")]
		{
			if matches!(call, RuntimeCall::System(frame_system::Call::remark_with_event { .. })) {
				return true
			}
		}

		match call {
			RuntimeCall::System(
				frame_system::Call::kill_prefix { .. } | frame_system::Call::set_heap_pages { .. },
			) |
			RuntimeCall::Babe(..) |
			RuntimeCall::Timestamp(..) |
			RuntimeCall::Indices(..) |
			RuntimeCall::Balances(..) |
			RuntimeCall::Crowdloan(
				crowdloan::Call::create { .. } |
				crowdloan::Call::contribute { .. } |
				crowdloan::Call::withdraw { .. } |
				crowdloan::Call::refund { .. } |
				crowdloan::Call::dissolve { .. } |
				crowdloan::Call::edit { .. } |
				crowdloan::Call::poke { .. } |
				crowdloan::Call::contribute_all { .. },
			) |
			RuntimeCall::Staking(
				pallet_staking::Call::bond { .. } |
				pallet_staking::Call::bond_extra { .. } |
				pallet_staking::Call::unbond { .. } |
				pallet_staking::Call::withdraw_unbonded { .. } |
				pallet_staking::Call::validate { .. } |
				pallet_staking::Call::nominate { .. } |
				pallet_staking::Call::chill { .. } |
				pallet_staking::Call::set_payee { .. } |
				pallet_staking::Call::set_controller { .. } |
				pallet_staking::Call::set_validator_count { .. } |
				pallet_staking::Call::increase_validator_count { .. } |
				pallet_staking::Call::scale_validator_count { .. } |
				pallet_staking::Call::force_no_eras { .. } |
				pallet_staking::Call::force_new_era { .. } |
				pallet_staking::Call::set_invulnerables { .. } |
				pallet_staking::Call::force_unstake { .. } |
				pallet_staking::Call::force_new_era_always { .. } |
				pallet_staking::Call::payout_stakers { .. } |
				pallet_staking::Call::rebond { .. } |
				pallet_staking::Call::reap_stash { .. } |
				pallet_staking::Call::set_staking_configs { .. } |
				pallet_staking::Call::chill_other { .. } |
				pallet_staking::Call::force_apply_min_commission { .. },
			) |
			RuntimeCall::Session(pallet_session::Call::purge_keys { .. }) |
			RuntimeCall::Grandpa(..) |
			RuntimeCall::ImOnline(..) |
			RuntimeCall::Treasury(..) |
			RuntimeCall::ConvictionVoting(..) |
			RuntimeCall::Referenda(
				pallet_referenda::Call::place_decision_deposit { .. } |
				pallet_referenda::Call::refund_decision_deposit { .. } |
				pallet_referenda::Call::cancel { .. } |
				pallet_referenda::Call::kill { .. } |
				pallet_referenda::Call::nudge_referendum { .. } |
				pallet_referenda::Call::one_fewer_deciding { .. },
			) |
			RuntimeCall::Claims(
				super::claims::Call::claim { .. } |
				super::claims::Call::mint_claim { .. } |
				super::claims::Call::move_claim { .. },
			) |
			RuntimeCall::Utility(pallet_utility::Call::as_derivative { .. }) |
			RuntimeCall::Identity(
				pallet_identity::Call::add_registrar { .. } |
				pallet_identity::Call::set_identity { .. } |
				pallet_identity::Call::clear_identity { .. } |
				pallet_identity::Call::request_judgement { .. } |
				pallet_identity::Call::cancel_request { .. } |
				pallet_identity::Call::set_fee { .. } |
				pallet_identity::Call::set_account_id { .. } |
				pallet_identity::Call::set_fields { .. } |
				pallet_identity::Call::provide_judgement { .. } |
				pallet_identity::Call::kill_identity { .. } |
				pallet_identity::Call::add_sub { .. } |
				pallet_identity::Call::rename_sub { .. } |
				pallet_identity::Call::remove_sub { .. } |
				pallet_identity::Call::quit_sub { .. },
			) |
			RuntimeCall::Vesting(..) |
			RuntimeCall::Bounties(
				pallet_bounties::Call::propose_bounty { .. } |
				pallet_bounties::Call::approve_bounty { .. } |
				pallet_bounties::Call::propose_curator { .. } |
				pallet_bounties::Call::unassign_curator { .. } |
				pallet_bounties::Call::accept_curator { .. } |
				pallet_bounties::Call::award_bounty { .. } |
				pallet_bounties::Call::claim_bounty { .. } |
				pallet_bounties::Call::close_bounty { .. },
			) |
			RuntimeCall::ChildBounties(..) |
			RuntimeCall::ElectionProviderMultiPhase(..) |
			RuntimeCall::VoterList(..) |
			RuntimeCall::NominationPools(
				pallet_nomination_pools::Call::join { .. } |
				pallet_nomination_pools::Call::bond_extra { .. } |
				pallet_nomination_pools::Call::claim_payout { .. } |
				pallet_nomination_pools::Call::unbond { .. } |
				pallet_nomination_pools::Call::pool_withdraw_unbonded { .. } |
				pallet_nomination_pools::Call::withdraw_unbonded { .. } |
				pallet_nomination_pools::Call::create { .. } |
				pallet_nomination_pools::Call::create_with_pool_id { .. } |
				pallet_nomination_pools::Call::set_state { .. } |
				pallet_nomination_pools::Call::set_configs { .. } |
				pallet_nomination_pools::Call::update_roles { .. } |
				pallet_nomination_pools::Call::chill { .. },
			) |
			RuntimeCall::Hrmp(..) |
			RuntimeCall::Registrar(
				paras_registrar::Call::deregister { .. } |
				paras_registrar::Call::swap { .. } |
				paras_registrar::Call::remove_lock { .. } |
				paras_registrar::Call::reserve { .. } |
				paras_registrar::Call::add_lock { .. },
			) |
			RuntimeCall::XcmPallet(pallet_xcm::Call::limited_reserve_transfer_assets {
				..
			}) |
			RuntimeCall::Whitelist(pallet_whitelist::Call::whitelist_call { .. }) |
			RuntimeCall::Proxy(..) => true,
			_ => false,
		}
	}
}

pub struct XcmConfig;
impl xcm_executor::Config for XcmConfig {
	type RuntimeCall = RuntimeCall;
	type XcmSender = XcmRouter;
	type AssetTransactor = LocalAssetTransactor;
	type OriginConverter = LocalOriginConverter;
	// Polkadot Relay recognises no chains which act as reserves.
	type IsReserve = ();
	type IsTeleporter = TrustedTeleporters;
	type UniversalLocation = UniversalLocation;
	type Barrier = Barrier;
	type Weigher = WeightInfoBounds<
		crate::weights::xcm::PolkadotXcmWeight<RuntimeCall>,
		RuntimeCall,
		MaxInstructions,
	>;
	// The weight trader piggybacks on the existing transaction-fee conversion logic.
	type Trader =
		UsingComponents<WeightToFee, TokenLocation, AccountId, Balances, ToAuthor<Runtime>>;
	type ResponseHandler = XcmPallet;
	type AssetTrap = XcmPallet;
	type AssetLocker = ();
	type AssetExchanger = ();
	type AssetClaims = XcmPallet;
	type SubscriptionService = XcmPallet;
	type PalletInstancesInfo = AllPalletsWithSystem;
	type MaxAssetsIntoHolding = MaxAssetsIntoHolding;
	type FeeManager = ();
	// No bridges yet...
	type MessageExporter = ();
	type UniversalAliases = Nothing;
	type CallDispatcher = WithOriginFilter<SafeCallFilter>;
	type SafeCallFilter = SafeCallFilter;
	type Aliasers = Nothing;
}

parameter_types! {
	// `GeneralAdmin` pluralistic body.
	pub const GeneralAdminBodyId: BodyId = BodyId::Administration;
	// StakingAdmin pluralistic body.
	pub const StakingAdminBodyId: BodyId = BodyId::Defense;
	// FellowshipAdmin pluralistic body.
	pub const FellowshipAdminBodyId: BodyId = BodyId::Index(FELLOWSHIP_ADMIN_INDEX);
}

#[cfg(feature = "runtime-benchmarks")]
parameter_types! {
	pub ReachableDest: Option<MultiLocation> = Some(Parachain(1000).into());
}

/// Type to convert the `GeneralAdmin` origin to a Plurality `MultiLocation` value.
pub type GeneralAdminToPlurality =
	OriginToPluralityVoice<RuntimeOrigin, GeneralAdmin, GeneralAdminBodyId>;

/// Type to convert an `Origin` type value into a `MultiLocation` value which represents an interior
/// location of this chain.
pub type LocalOriginToLocation = (
	GeneralAdminToPlurality,
	// And a usual Signed origin to be used in XCM as a corresponding AccountId32
	SignedToAccountId32<RuntimeOrigin, AccountId, ThisNetwork>,
);

/// Type to convert the `StakingAdmin` origin to a Plurality `MultiLocation` value.
pub type StakingAdminToPlurality =
	OriginToPluralityVoice<RuntimeOrigin, StakingAdmin, StakingAdminBodyId>;

/// Type to convert the `FellowshipAdmin` origin to a Plurality `MultiLocation` value.
pub type FellowshipAdminToPlurality =
	OriginToPluralityVoice<RuntimeOrigin, FellowshipAdmin, FellowshipAdminBodyId>;

/// Type to convert a pallet `Origin` type value into a `MultiLocation` value which represents an
/// interior location of this chain for a destination chain.
pub type LocalPalletOriginToLocation = (
	// GeneralAdmin origin to be used in XCM as a corresponding Plurality `MultiLocation` value.
	GeneralAdminToPlurality,
	// StakingAdmin origin to be used in XCM as a corresponding Plurality `MultiLocation` value.
	StakingAdminToPlurality,
	// FellowshipAdmin origin to be used in XCM as a corresponding Plurality `MultiLocation` value.
	FellowshipAdminToPlurality,
);

impl pallet_xcm::Config for Runtime {
	type RuntimeEvent = RuntimeEvent;
	// We only allow the root, the general admin, the fellowship admin and the staking admin to send
	// messages.
	type SendXcmOrigin = xcm_builder::EnsureXcmOrigin<RuntimeOrigin, LocalPalletOriginToLocation>;
	type XcmRouter = XcmRouter;
	// Anyone can execute XCM messages locally...
	type ExecuteXcmOrigin = xcm_builder::EnsureXcmOrigin<RuntimeOrigin, LocalOriginToLocation>;
	// ...but they must match our filter, which rejects all.
	type XcmExecuteFilter = Nothing; // == Deny All
	type XcmExecutor = xcm_executor::XcmExecutor<XcmConfig>;
	type XcmTeleportFilter = Everything; // == Allow All
	type XcmReserveTransferFilter = Everything; // == Allow All
	type Weigher = WeightInfoBounds<
		crate::weights::xcm::PolkadotXcmWeight<RuntimeCall>,
		RuntimeCall,
		MaxInstructions,
	>;
	type UniversalLocation = UniversalLocation;
	type RuntimeOrigin = RuntimeOrigin;
	type RuntimeCall = RuntimeCall;
	const VERSION_DISCOVERY_QUEUE_SIZE: u32 = 100;
	type AdvertisedXcmVersion = pallet_xcm::CurrentXcmVersion;
	type Currency = Balances;
	type CurrencyMatcher = ();
	type TrustedLockers = ();
	type SovereignAccountOf = SovereignAccountOf;
	type MaxLockers = ConstU32<8>;
	type MaxRemoteLockConsumers = ConstU32<0>;
	type RemoteLockConsumerIdentifier = ();
	type WeightInfo = crate::weights::pallet_xcm::WeightInfo<Runtime>;
	#[cfg(feature = "runtime-benchmarks")]
	type ReachableDest = ReachableDest;
	type AdminOrigin = EnsureRoot<AccountId>;
}