Kusama origins as xcm multi_location

runtime/kusama/constants/src/lib.rs

@@ -97,6 +97,19 @@ pub mod fee {
 	}
 }
 
+/// XCM protocol related constants.
+pub mod xcm {
+	/// Pluralistic bodies existing within the consensus.
+	pub mod body {
+		// Preallocated for the Root body.
+		#[allow(dead_code)]
+		const ROOT_INDEX: u32 = 0;
+		// The bodies corresponding to the runtime origins representing a plurality voice given via a referendum.
+		pub const STAKING_ADMIN_INDEX: u32 = 1;
+		pub const FELLOWS_INDEX: u32 = 2;
+	}
+}
+
 #[cfg(test)]
 mod tests {
 	use super::{

runtime/kusama/src/xcm_config.rs

@@ -18,18 +18,19 @@
 
 use super::{
 	parachains_origin, AccountId, Balances, CouncilCollective, ParaId, Runtime, RuntimeCall,
-	RuntimeEvent, RuntimeOrigin, WeightToFee, XcmPallet,
+	RuntimeEvent, RuntimeOrigin, StakingAdmin, WeightToFee, XcmPallet,
 };
 use frame_support::{match_types, parameter_types, traits::Everything};
+use kusama_runtime_constants::xcm::body::{FELLOWS_INDEX, STAKING_ADMIN_INDEX};
 use runtime_common::{xcm_sender, ToAuthor};
 use xcm::latest::prelude::*;
 use xcm_builder::{
 	AccountId32Aliases, AllowKnownQueryResponses, AllowSubscriptionsFrom,
 	AllowTopLevelPaidExecutionFrom, AllowUnpaidExecutionFrom, BackingToPlurality,
 	ChildParachainAsNative, ChildParachainConvertsVia, ChildSystemParachainAsSuperuser,
 	CurrencyAdapter as XcmCurrencyAdapter, FixedWeightBounds, IsChildSystemParachain, IsConcrete,
-	LocationInverter, SignedAccountId32AsNative, SignedToAccountId32, SovereignSignedViaLocation,
-	TakeWeightCredit, UsingComponents, WeightInfoBounds,
+	LocationInverter, OriginToPluralityVoice, SignedAccountId32AsNative, SignedToAccountId32,
+	SovereignSignedViaLocation, TakeWeightCredit, UsingComponents, WeightInfoBounds,
 };
 
 parameter_types! {
@@ -154,6 +155,10 @@ impl xcm_executor::Config for XcmConfig {
 
 parameter_types! {
 	pub const CouncilBodyId: BodyId = BodyId::Executive;
+	// StakingAdmin pluralistic body.
+	pub const StakingAdminBodyId: BodyId = BodyId::Index(STAKING_ADMIN_INDEX);
+	// Fellows pluralistic body.
+	pub const FellowsBodyId: BodyId = BodyId::Index(FELLOWS_INDEX);
 }
 
 /// Type to convert the council origin to a Plurality `MultiLocation` value.
@@ -172,13 +177,33 @@ pub type LocalOriginToLocation = (
 	// And a usual Signed origin to be used in XCM as a corresponding AccountId32
 	SignedToAccountId32<RuntimeOrigin, AccountId, KusamaNetwork>,
 );
+
+/// Type to convert the `StakingAdmin` origin to a Plurality `MultiLocation` value.
+pub type StakingAdminToPlurality =
+	OriginToPluralityVoice<RuntimeOrigin, StakingAdmin, StakingAdminBodyId>;
+
+/// Type to convert the Fellows origin to a Plurality `MultiLocation` value.
+pub type FellowsToPlurality = OriginToPluralityVoice<RuntimeOrigin, StakingAdmin, FellowsBodyId>;
+
+/// 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 = (
+	// We allow an origin from the Collective pallet to be used in XCM as a corresponding Plurality of the
+	// `Unit` body.
+	CouncilToPlurality,
+	// StakingAdmin origin to be used in XCM as a corresponding Plurality `MultiLocation` value.
+	StakingAdminToPlurality,
+	// Fellows origin to be used in XCM as a corresponding Plurality `MultiLocation` value.
+	FellowsToPlurality,
+);
+
 impl pallet_xcm::Config for Runtime {
 	type RuntimeEvent = RuntimeEvent;
-	// We only allow the council to send messages. This is basically safe to enable for everyone
-	// (safe the possibility of someone spamming the parachain if they're willing to pay the KSM to
-	// send from the Relay-chain), but it's useless until we bring in XCM v3 which will make
-	// `DescendOrigin` a bit more useful.
-	type SendXcmOrigin = xcm_builder::EnsureXcmOrigin<RuntimeOrigin, CouncilToPlurality>;
+	// We only allow the root, the council, fellows and the staking admin to send messages.
+	// This is basically safe to enable for everyone (safe the possibility of someone spamming the parachain
+	// if they're willing to pay the KSM to send from the Relay-chain), but it's useless until we bring in XCM v3
+	// which will make `DescendOrigin` a bit more useful.
+	type SendXcmOrigin = xcm_builder::EnsureXcmOrigin<RuntimeOrigin, LocalPalletOriginToLocation>;
 	type XcmRouter = XcmRouter;
 	// Anyone can execute XCM messages locally.
 	type ExecuteXcmOrigin = xcm_builder::EnsureXcmOrigin<RuntimeOrigin, LocalOriginToLocation>;

xcm/pallet-xcm/src/lib.rs

@@ -1517,6 +1517,19 @@ impl<Prefix: Get<MultiLocation>, Body: Get<BodyId>> Contains<MultiLocation>
 	}
 }
 
+/// Filter for `MultiLocation` to find those which represent a voice of an identified plurality.
+///
+/// May reasonably be used with `EnsureXcm`.
+pub struct IsVoiceOfBody<Prefix, Body>(PhantomData<(Prefix, Body)>);
+impl<Prefix: Get<MultiLocation>, Body: Get<BodyId>> Contains<MultiLocation>
+	for IsVoiceOfBody<Prefix, Body>
+{
+	fn contains(l: &MultiLocation) -> bool {
+		let maybe_suffix = l.match_and_split(&Prefix::get());
+		matches!(maybe_suffix, Some(Plurality { id, part }) if id == &Body::get() && part == &BodyPart::Voice)
+	}
+}
+
 /// `EnsureOrigin` implementation succeeding with a `MultiLocation` value to recognize and filter the
 /// `Origin::Xcm` item.
 pub struct EnsureXcm<F>(PhantomData<F>);

xcm/xcm-builder/src/lib.rs

@@ -37,7 +37,7 @@ pub use location_conversion::{
 mod origin_conversion;
 pub use origin_conversion::{
 	BackingToPlurality, ChildParachainAsNative, ChildSystemParachainAsSuperuser, EnsureXcmOrigin,
-	ParentAsSuperuser, RelayChainAsNative, SiblingParachainAsNative,
+	OriginToPluralityVoice, ParentAsSuperuser, RelayChainAsNative, SiblingParachainAsNative,
 	SiblingSystemParachainAsSuperuser, SignedAccountId32AsNative, SignedAccountKey20AsNative,
 	SignedToAccountId32, SovereignSignedViaLocation,
 };

xcm/xcm-builder/src/origin_conversion.rs

@@ -321,3 +321,20 @@ where
 		})
 	}
 }
+
+/// `Convert` implementation to convert from an origin which passes the check of an `EnsureOrigin`
+/// into a voice of a given pluralistic `Body`.
+pub struct OriginToPluralityVoice<RuntimeOrigin, EnsureBodyOrigin, Body>(
+	PhantomData<(RuntimeOrigin, EnsureBodyOrigin, Body)>,
+);
+impl<RuntimeOrigin: Clone, EnsureBodyOrigin: EnsureOrigin<RuntimeOrigin>, Body: Get<BodyId>>
+	Convert<RuntimeOrigin, MultiLocation>
+	for OriginToPluralityVoice<RuntimeOrigin, EnsureBodyOrigin, Body>
+{
+	fn convert(o: RuntimeOrigin) -> Result<MultiLocation, RuntimeOrigin> {
+		match EnsureBodyOrigin::try_origin(o) {
+			Ok(_) => Ok(Junction::Plurality { id: Body::get(), part: BodyPart::Voice }.into()),
+			Err(o) => Err(o),
+		}
+	}
+}