feat: Permissioned collators

runtimes/common/Cargo.toml

@@ -51,13 +51,15 @@ pallet-authorship               = { workspace = true }
 pallet-balances                 = { workspace = true }
 pallet-membership               = { workspace = true }
 pallet-multisig                 = { workspace = true }
+pallet-session                  = { workspace = true }
 pallet-tips                     = { workspace = true }
 pallet-transaction-payment      = { workspace = true }
 pallet-treasury                 = { workspace = true }
 sp-consensus-aura               = { workspace = true }
 sp-core                         = { workspace = true }
 sp-io                           = { workspace = true }
 sp-runtime                      = { workspace = true }
+sp-staking                      = { workspace = true }
 sp-std                          = { workspace = true }
 sp-trie                         = { workspace = true }
 sp-weights                      = { workspace = true }
@@ -128,6 +130,7 @@ std = [
   "pallet-membership/std",
   "pallet-multisig/std",
   "pallet-multisig/std",
+  "pallet-session/std",
   "pallet-tips/std",
   "pallet-transaction-payment/std",
   "pallet-treasury/std",
@@ -164,6 +167,7 @@ try-runtime = [
   "pallet-bonded-coins/try-runtime",
   "pallet-membership/try-runtime",
   "pallet-multisig/try-runtime",
+  "pallet-session/try-runtime",
   "pallet-transaction-payment/try-runtime",
   "pallet-treasury/try-runtime",
   "pallet-treasury/try-runtime",

runtimes/common/src/constants.rs

@@ -278,6 +278,8 @@ pub mod staking {
 
 	pub const NETWORK_REWARD_RATE: Perquintill = Perquintill::from_percent(10);
 
+	pub const MAX_COLLATORS: u32 = 32;
+
 	parameter_types! {
 		/// Minimum round length is 1 hour
 		pub const MinBlocksPerRound: BlockNumber = MIN_BLOCKS_PER_ROUND;
@@ -309,6 +311,8 @@ pub mod staking {
 		pub const NetworkRewardStart: BlockNumber = super::treasury::INITIAL_PERIOD_LENGTH;
 		/// The rate in percent for the network rewards
 		pub const NetworkRewardRate: Perquintill = NETWORK_REWARD_RATE;
+		/// The maximum number of collators
+		pub const MaxCollators: u32 = MAX_COLLATORS;
 	}
 }
 

runtimes/common/src/lib.rs

@@ -55,6 +55,7 @@ pub mod errors;
 pub mod fees;
 pub mod migrations;
 pub mod pallet_id;
+pub mod session;
 pub mod web3_names;
 pub mod xcm_config;
 pub use web3_names::Web3Name;

runtimes/common/src/session.rs

@@ -0,0 +1,81 @@
+// KILT Blockchain – <https://kilt.io>
+// Copyright (C) 2025, KILT Foundation
+
+// The KILT Blockchain 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.
+
+// The KILT Blockchain 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 this program.  If not, see <https://www.gnu.org/licenses/>.
+
+// If you feel like getting in touch with us, you can do so at <hello@kilt.io>
+
+pub use frame_support::weights::constants::{BlockExecutionWeight, ExtrinsicBaseWeight, RocksDbWeight};
+use frame_system::Pallet as SystemPallet;
+use pallet_membership::{Config as MembershipConfig, Instance3, Pallet as MembershipPallet};
+use pallet_session::SessionManager as SessionManagerTrait;
+pub use sp_consensus_aura::sr25519::AuthorityId;
+use sp_core::Get;
+use sp_runtime::SaturatedConversion;
+use sp_staking::SessionIndex;
+use sp_std::{marker::PhantomData, vec::Vec};
+
+use crate::constants::staking::DefaultBlocksPerRound;
+
+type AccountIdOf<Runtime> = <Runtime as frame_system::Config>::AccountId;
+
+/// The session manager for the collator set.
+pub struct SessionManager<Runtime>(PhantomData<Runtime>);
+
+impl<Runtime> SessionManagerTrait<AccountIdOf<Runtime>> for SessionManager<Runtime>
+where
+	Runtime: MembershipConfig<Instance3> + pallet_session::Config,
+	<Runtime as pallet_session::Config>::ValidatorId: From<AccountIdOf<Runtime>>,
+{
+	fn new_session(new_index: SessionIndex) -> Option<Vec<AccountIdOf<Runtime>>> {
+		let collators = MembershipPallet::<Runtime, Instance3>::members().to_vec();
+
+		log::debug!(
+			"assembling new collators for new session {} at #{:?} with {:?}",
+			new_index,
+			SystemPallet::<Runtime>::block_number(),
+			collators
+		);
+
+		let has_collator_keys = collators.iter().any(|collator| {
+			pallet_session::NextKeys::<Runtime>::contains_key(<Runtime as pallet_session::Config>::ValidatorId::from(
+				collator.clone(),
+			))
+		});
+
+		SystemPallet::<Runtime>::register_extra_weight_unchecked(
+			<Runtime as frame_system::Config>::DbWeight::get()
+				.reads(2u64.saturating_add(collators.len().saturated_into::<u64>())),
+			frame_support::pallet_prelude::DispatchClass::Mandatory,
+		);
+
+		if collators.is_empty() || !has_collator_keys {
+			// we never want to pass an empty set of collators. This would brick the chain.
+			log::error!("💥 keeping old session because of empty collator set!");
+			return None;
+		}
+
+		Some(collators)
+	}
+
+	fn start_session(_start_index: SessionIndex) {
+		// We don't care
+	}
+
+	fn end_session(_end_index: SessionIndex) {
+		// We don't care
+	}
+}
+
+pub type FixedLengthSession = pallet_session::PeriodicSessions<DefaultBlocksPerRound, DefaultBlocksPerRound>;

runtimes/peregrine/Cargo.toml

@@ -64,6 +64,7 @@ sp-metadata-ir      = { workspace = true }
 sp-offchain         = { workspace = true }
 sp-runtime          = { workspace = true }
 sp-session          = { workspace = true }
+sp-staking          = { workspace = true }
 sp-std              = { workspace = true }
 sp-transaction-pool = { workspace = true }
 sp-version          = { workspace = true }

runtimes/peregrine/src/benchmarks/mod.rs

@@ -38,10 +38,10 @@ use xcm::v4::{Asset, Assets, Fungibility, Location};
 
 use crate::{
 	xcm::XcmConfig, AllPalletsWithSystem, AssetSwitchPool1, Attestation, Balances, BondedCurrencies, BondedFungibles,
-	Council, Ctype, Delegation, Democracy, DepositStorage, Did, DidLookup, DipProvider, Fungibles, Indices, Inflation,
-	MessageQueue, Migration, Multisig, ParachainStaking, ParachainSystem, Preimage, Proxy, PublicCredentials, Runtime,
-	RuntimeEvent, Scheduler, Sudo, System, TechnicalCommittee, TechnicalMembership, Timestamp, Tips, TipsMembership,
-	Treasury, Utility, Vesting, Web3Names,
+	Collators, Council, Ctype, Delegation, Democracy, DepositStorage, Did, DidLookup, DipProvider, Fungibles, Indices,
+	Inflation, MessageQueue, Migration, Multisig, ParachainStaking, ParachainSystem, Preimage, Proxy,
+	PublicCredentials, Runtime, RuntimeEvent, Scheduler, Sudo, System, TechnicalCommittee, TechnicalMembership,
+	Timestamp, Tips, TipsMembership, Treasury, Utility, Vesting, Web3Names,
 };
 
 pub(crate) mod asset_switch;
@@ -56,11 +56,9 @@ use pallet_assets as pallet_bonded_assets;
 #[allow(unused_imports)]
 use pallet_collective as pallet_technical_committee_collective;
 #[allow(unused_imports)]
-use pallet_did_lookup as pallet_unique_linking;
-#[allow(unused_imports)]
 use pallet_membership as pallet_technical_membership;
 #[allow(unused_imports)]
-use pallet_web3_names as pallet_dot_names;
+use pallet_membership as pallet_collators;
 
 define_benchmarks!(
 	[frame_system, frame_system_benchmarking::Pallet::<Runtime>]
@@ -100,6 +98,7 @@ define_benchmarks!(
 	// pallet_membership instances
 	[pallet_membership, TipsMembership]
 	[pallet_technical_membership, TechnicalMembership]
+	[pallet_collators, Collators]
 	// pallet_did_lookup instances
 	[pallet_did_lookup, DidLookup]
 	// pallet_web3_names instances

runtimes/peregrine/src/governance.rs

@@ -175,7 +175,7 @@ impl pallet_collective::Config<TechnicalCollective> for Runtime {
 	type SetMembersOrigin = EnsureRoot<AccountId>;
 }
 
-type RootOrMoreThanHalfCouncil = RootOrCollectiveProportion<CouncilCollective, 1, 2>;
+pub(crate) type RootOrMoreThanHalfCouncil = RootOrCollectiveProportion<CouncilCollective, 1, 2>;
 
 type TechnicalMembershipProvider = pallet_membership::Instance1;
 impl pallet_membership::Config<TechnicalMembershipProvider> for Runtime {

runtimes/peregrine/src/lib.rs

@@ -116,6 +116,7 @@ construct_runtime! {
 		ParachainStaking: parachain_staking = 21,
 		Authorship: pallet_authorship = 20,
 		AuraExt: cumulus_pallet_aura_ext = 24,
+		Collators: pallet_membership::<Instance3> = 25,
 
 		Democracy: pallet_democracy = 30,
 		Council: pallet_collective::<Instance1> = 31,

runtimes/peregrine/src/system/mod.rs

@@ -18,14 +18,15 @@
 
 use frame_support::{
 	parameter_types,
-	traits::{AsEnsureOriginWithArg, Everything, PrivilegeCmp},
+	traits::{AsEnsureOriginWithArg, Everything, NeverEnsureOrigin, PrivilegeCmp},
 	weights::Weight,
 };
 use frame_system::EnsureRoot;
 use runtime_common::{
 	asset_switch::EnsureRootAsTreasury,
 	constants,
 	fees::{ToAuthorCredit, WeightToFee},
+	session::{FixedLengthSession, SessionManager},
 	AccountId, AuthorityId, Balance, BlockHashCount, BlockLength, BlockWeights, FeeSplit, Hash, Nonce,
 	SendDustAndFeesToTreasury, SlowAdjustingFeeUpdate,
 };
@@ -41,9 +42,9 @@ use sp_weights::ConstantMultiplier;
 use xcm::v4::Location;
 
 use crate::{
-	governance::{CouncilCollective, RootOrCollectiveProportion},
-	weights, Aura, Balances, Block, OriginCaller, PalletInfo, ParachainStaking, Preimage, Runtime, RuntimeCall,
-	RuntimeEvent, RuntimeFreezeReason, RuntimeHoldReason, RuntimeOrigin, RuntimeTask, System, VERSION,
+	governance::{CouncilCollective, RootOrCollectiveProportion, RootOrMoreThanHalfCouncil},
+	weights, Aura, Balances, Block, OriginCaller, PalletInfo, Preimage, Runtime, RuntimeCall, RuntimeEvent,
+	RuntimeFreezeReason, RuntimeHoldReason, RuntimeOrigin, RuntimeTask, System, VERSION,
 };
 
 pub(crate) mod proxy;
@@ -145,9 +146,9 @@ impl pallet_session::Config for Runtime {
 	type RuntimeEvent = RuntimeEvent;
 	type ValidatorId = AccountId;
 	type ValidatorIdOf = ConvertInto;
-	type ShouldEndSession = ParachainStaking;
-	type NextSessionRotation = ParachainStaking;
-	type SessionManager = ParachainStaking;
+	type ShouldEndSession = FixedLengthSession;
+	type NextSessionRotation = FixedLengthSession;
+	type SessionManager = SessionManager<Runtime>;
 	type SessionHandler = <SessionKeys as OpaqueKeys>::KeyTypeIdProviders;
 	type Keys = SessionKeys;
 	type WeightInfo = weights::pallet_session::WeightInfo<Runtime>;
@@ -163,7 +164,7 @@ impl pallet_aura::Config for Runtime {
 
 impl pallet_authorship::Config for Runtime {
 	type FindAuthor = pallet_session::FindAccountFromAuthorIndex<Self, Aura>;
-	type EventHandler = ParachainStaking;
+	type EventHandler = ();
 }
 
 impl pallet_utility::Config for Runtime {
@@ -280,3 +281,21 @@ impl pallet_scheduler::Config for Runtime {
 	type OriginPrivilegeCmp = OriginPrivilegeCmp;
 	type Preimages = Preimage;
 }
+
+type CollatorMembershipProvider = pallet_membership::Instance3;
+impl pallet_membership::Config<CollatorMembershipProvider> for Runtime {
+	type RuntimeEvent = RuntimeEvent;
+	type AddOrigin = RootOrMoreThanHalfCouncil;
+	type RemoveOrigin = RootOrMoreThanHalfCouncil;
+	type SwapOrigin = RootOrMoreThanHalfCouncil;
+	type ResetOrigin = RootOrMoreThanHalfCouncil;
+	type PrimeOrigin = NeverEnsureOrigin<AccountId>;
+	type MembershipInitialized = ();
+
+	#[cfg(feature = "runtime-benchmarks")]
+	type MembershipChanged = crate::benchmarks::governance::MockMembershipChangedForBenchmarks;
+	#[cfg(not(feature = "runtime-benchmarks"))]
+	type MembershipChanged = ();
+	type MaxMembers = constants::staking::MaxCollators;
+	type WeightInfo = weights::pallet_collators::WeightInfo<Runtime>;
+}

runtimes/peregrine/src/weights/mod.rs

@@ -28,6 +28,7 @@ pub mod pallet_assets;
 pub mod pallet_balances;
 pub mod pallet_bonded_assets;
 pub mod pallet_bonded_coins;
+pub mod pallet_collators;
 pub mod pallet_collective;
 pub mod pallet_democracy;
 pub mod pallet_deposit_storage;