Allow Queries and Subscriptions (#4150)

* Allow Queries and Subscriptions

* Formatting

* Formatting

polkadot/runtime/kusama/src/lib.rs

@@ -48,7 +48,7 @@ use runtime_parachains::{
 use authority_discovery_primitives::AuthorityId as AuthorityDiscoveryId;
 use beefy_primitives::crypto::AuthorityId as BeefyId;
 use frame_support::{
-	construct_runtime, parameter_types,
+	construct_runtime, match_type, parameter_types,
 	traits::{Contains, Everything, InstanceFilter, KeyOwnerProofSystem, LockIdentifier, Nothing},
 	weights::Weight,
 	PalletId, RuntimeDebug,
@@ -77,11 +77,12 @@ use sp_version::RuntimeVersion;
 use static_assertions::const_assert;
 use xcm::latest::prelude::*;
 use xcm_builder::{
-	AccountId32Aliases, AllowTopLevelPaidExecutionFrom, AllowUnpaidExecutionFrom,
+	AccountId32Aliases, AllowKnownQueryResponses, AllowSubscriptionsFrom,
-	BackingToPlurality, ChildParachainAsNative, ChildParachainConvertsVia,
+	AllowTopLevelPaidExecutionFrom, AllowUnpaidExecutionFrom, BackingToPlurality,
-	ChildSystemParachainAsSuperuser, CurrencyAdapter as XcmCurrencyAdapter, FixedWeightBounds,
+	ChildParachainAsNative, ChildParachainConvertsVia, ChildSystemParachainAsSuperuser,
-	IsChildSystemParachain, IsConcrete, LocationInverter, SignedAccountId32AsNative,
+	CurrencyAdapter as XcmCurrencyAdapter, FixedWeightBounds, IsChildSystemParachain, IsConcrete,
-	SignedToAccountId32, SovereignSignedViaLocation, TakeWeightCredit, UsingComponents,
+	LocationInverter, SignedAccountId32AsNative, SignedToAccountId32, SovereignSignedViaLocation,
+	TakeWeightCredit, UsingComponents,
 };
 use xcm_executor::XcmExecutor;
 
@@ -1329,6 +1330,12 @@ parameter_types! {
 }
 pub type TrustedTeleporters = (xcm_builder::Case<KusamaForStatemine>,);
 
+match_type! {
+	pub type OnlyParachains: impl Contains<MultiLocation> = {
+		MultiLocation { parents: 0, interior: X1(Parachain(_)) }
+	};
+}
+
 /// The barriers one of which must be passed for an XCM message to be executed.
 pub type Barrier = (
 	// Weight that is paid for may be consumed.
@@ -1337,6 +1344,10 @@ pub type Barrier = (
 	AllowTopLevelPaidExecutionFrom<Everything>,
 	// Messages coming from system parachains need not pay for execution.
 	AllowUnpaidExecutionFrom<IsChildSystemParachain<ParaId>>,
+	// Expected responses are OK.
+	AllowKnownQueryResponses<XcmPallet>,
+	// Subscriptions for version tracking are OK.
+	AllowSubscriptionsFrom<OnlyParachains>,
 );
 
 pub struct XcmConfig;

polkadot/runtime/rococo/src/lib.rs

@@ -84,10 +84,10 @@ use constants::{currency::*, fee::*, time::*};
 use frame_support::traits::InstanceFilter;
 use xcm::latest::prelude::*;
 use xcm_builder::{
-	AccountId32Aliases, BackingToPlurality, ChildParachainAsNative, ChildParachainConvertsVia,
+	AccountId32Aliases, AllowKnownQueryResponses, AllowSubscriptionsFrom, BackingToPlurality,
-	ChildSystemParachainAsSuperuser, CurrencyAdapter as XcmCurrencyAdapter, FixedWeightBounds,
+	ChildParachainAsNative, ChildParachainConvertsVia, ChildSystemParachainAsSuperuser,
-	IsConcrete, LocationInverter, SignedAccountId32AsNative, SignedToAccountId32,
+	CurrencyAdapter as XcmCurrencyAdapter, FixedWeightBounds, IsConcrete, LocationInverter,
-	SovereignSignedViaLocation, UsingComponents,
+	SignedAccountId32AsNative, SignedToAccountId32, SovereignSignedViaLocation, UsingComponents,
 };
 use xcm_executor::XcmExecutor;
 
@@ -672,6 +672,10 @@ pub type Barrier = (
 	TakeWeightCredit,
 	AllowTopLevelPaidExecutionFrom<Everything>,
 	AllowUnpaidExecutionFrom<IsInVec<AllowUnpaidFrom>>, // <- Trusted parachains get free execution
+	// Expected responses are OK.
+	AllowKnownQueryResponses<XcmPallet>,
+	// Subscriptions for version tracking are OK.
+	AllowSubscriptionsFrom<Everything>,
 );
 
 pub struct XcmConfig;

polkadot/runtime/westend/src/lib.rs

@@ -46,8 +46,9 @@ use runtime_parachains::{
 
 use xcm::latest::prelude::*;
 use xcm_builder::{
-	AccountId32Aliases, AllowTopLevelPaidExecutionFrom, AllowUnpaidExecutionFrom,
+	AccountId32Aliases, AllowKnownQueryResponses, AllowSubscriptionsFrom,
-	ChildParachainAsNative, ChildParachainConvertsVia, ChildSystemParachainAsSuperuser,
+	AllowTopLevelPaidExecutionFrom, AllowUnpaidExecutionFrom, ChildParachainAsNative,
+	ChildParachainConvertsVia, ChildSystemParachainAsSuperuser,
 	CurrencyAdapter as XcmCurrencyAdapter, IsChildSystemParachain, IsConcrete, LocationInverter,
 	SignedAccountId32AsNative, SignedToAccountId32, SovereignSignedViaLocation, TakeWeightCredit,
 	UsingComponents, WeightInfoBounds,
@@ -976,6 +977,10 @@ pub type Barrier = (
 	AllowTopLevelPaidExecutionFrom<Everything>,
 	// Messages coming from system parachains need not pay for execution.
 	AllowUnpaidExecutionFrom<IsChildSystemParachain<ParaId>>,
+	// Expected responses are OK.
+	AllowKnownQueryResponses<XcmPallet>,
+	// Subscriptions for version tracking are OK.
+	AllowSubscriptionsFrom<Everything>,
 );
 
 pub struct XcmConfig;