babe: secondary blocks with VRF

bin/node/runtime/src/lib.rs

@@ -127,7 +127,7 @@ pub const VERSION: RuntimeVersion = RuntimeVersion {
 	// and set impl_version to 0. If only runtime
 	// implementation changes and behavior does not, then leave spec_version as
 	// is and increment impl_version.
-	spec_version: 243,
+	spec_version: 244,
 	impl_version: 0,
 	apis: RUNTIME_API_VERSIONS,
 	transaction_version: 1,
@@ -789,19 +789,19 @@ impl_runtime_apis! {
 	}
 
 	impl sp_consensus_babe::BabeApi<Block> for Runtime {
-		fn configuration() -> sp_consensus_babe::BabeConfiguration {
+		fn configuration() -> sp_consensus_babe::BabeGenesisConfiguration {
 			// The choice of `c` parameter (where `1 - c` represents the
 			// probability of a slot being empty), is done in accordance to the
 			// slot duration and expected target block time, for safely
 			// resisting network delays of maximum two seconds.
 			// <https://research.web3.foundation/en/latest/polkadot/BABE/Babe/#6-practical-results>
-			sp_consensus_babe::BabeConfiguration {
+			sp_consensus_babe::BabeGenesisConfiguration {
 				slot_duration: Babe::slot_duration(),
 				epoch_length: EpochDuration::get(),
 				c: PRIMARY_PROBABILITY,
 				genesis_authorities: Babe::authorities(),
 				randomness: Babe::randomness(),
-				secondary_slots: true,
+				allowed_slots: sp_consensus_babe::AllowedSlots::PrimaryAndSecondaryPlainSlots,
 			}
 		}
 

client/consensus/babe/rpc/src/lib.rs

@@ -118,14 +118,17 @@ impl<B, C, SC> BabeApi for BabeRPCHandler<B, C, SC>
 
 			for slot_number in epoch_start..epoch_end {
 				let epoch = epoch_data(&shared_epoch, &client, &babe_config, slot_number, &select_chain)?;
-				if let Some((claim, key)) = authorship::claim_slot(slot_number, &epoch, &babe_config, &keystore) {
+				if let Some((claim, key)) = authorship::claim_slot(slot_number, &epoch, &keystore) {
 					match claim {
 						PreDigest::Primary { .. } => {
 							claims.entry(key.public()).or_default().primary.push(slot_number);
 						}
-						PreDigest::Secondary { .. } => {
+						PreDigest::SecondaryPlain { .. } => {
 							claims.entry(key.public()).or_default().secondary.push(slot_number);
 						}
+						PreDigest::SecondaryVRF { .. } => {
+							claims.entry(key.public()).or_default().secondary_vrf.push(slot_number);
+						},
 					};
 				}
 			}
@@ -144,6 +147,8 @@ pub struct EpochAuthorship {
 	primary: Vec<u64>,
 	/// the array of secondary slots that can be claimed
 	secondary: Vec<u64>,
+	/// The array of secondary VRF slots that can be claimed.
+	secondary_vrf: Vec<u64>,
 }
 
 /// Errors encountered by the RPC
@@ -184,7 +189,7 @@ fn epoch_data<B, C, SC>(
 		&parent.hash(),
 		parent.number().clone(),
 		slot_number,
-		|slot| babe_config.genesis_epoch(slot),
+		|slot| Epoch::genesis(&babe_config, slot),
 	)
 		.map_err(|e| Error::Consensus(ConsensusError::ChainLookup(format!("{:?}", e))))?
 		.ok_or(Error::Consensus(ConsensusError::InvalidAuthoritiesSet))
@@ -236,7 +241,7 @@ mod tests {
 
 		io.extend_with(BabeApi::to_delegate(handler));
 		let request = r#"{"jsonrpc":"2.0","method":"babe_epochAuthorship","params": [],"id":1}"#;
-		let response = r#"{"jsonrpc":"2.0","result":{"5GrwvaEF5zXb26Fz9rcQpDWS57CtERHpNehXCPcNoHGKutQY":{"primary":[0],"secondary":[1,2,4]}},"id":1}"#;
+		let response = r#"{"jsonrpc":"2.0","result":{"5GrwvaEF5zXb26Fz9rcQpDWS57CtERHpNehXCPcNoHGKutQY":{"primary":[0],"secondary":[1,2,4],"secondary_vrf":[]}},"id":1}"#;
 
 		assert_eq!(Some(response.into()), io.handle_request_sync(request));
 	}

client/consensus/babe/src/authorship.rs

@@ -19,9 +19,11 @@
 use merlin::Transcript;
 use sp_consensus_babe::{
 	AuthorityId, BabeAuthorityWeight, BABE_ENGINE_ID, BABE_VRF_PREFIX,
-	SlotNumber, AuthorityPair, BabeConfiguration
+	SlotNumber, AuthorityPair,
+};
+use sp_consensus_babe::digests::{
+	PreDigest, PrimaryPreDigest, SecondaryPlainPreDigest, SecondaryVRFPreDigest,
 };
-use sp_consensus_babe::digests::{PreDigest, PrimaryPreDigest, SecondaryPreDigest};
 use sp_consensus_vrf::schnorrkel::{VRFOutput, VRFProof};
 use sp_core::{U256, blake2_256};
 use codec::Encode;
@@ -105,18 +107,20 @@ pub(super) fn make_transcript(
 /// to propose.
 fn claim_secondary_slot(
 	slot_number: SlotNumber,
-	authorities: &[(AuthorityId, BabeAuthorityWeight)],
+	epoch: &Epoch,
 	keystore: &KeyStorePtr,
-	randomness: [u8; 32],
+	author_secondary_vrf: bool,
 ) -> Option<(PreDigest, AuthorityPair)> {
+	let Epoch { authorities, randomness, epoch_index, .. } = epoch;
+
 	if authorities.is_empty() {
 		return None;
 	}
 
 	let expected_author = super::authorship::secondary_slot_author(
 		slot_number,
 		authorities,
-		randomness,
+		*randomness,
 	)?;
 
 	let keystore = keystore.read();
@@ -128,10 +132,27 @@ fn claim_secondary_slot(
 		})
 	{
 		if pair.public() == *expected_author {
-			let pre_digest = PreDigest::Secondary(SecondaryPreDigest {
-				slot_number,
-				authority_index: authority_index as u32,
-			});
+			let pre_digest = if author_secondary_vrf {
+				let transcript = super::authorship::make_transcript(
+					randomness,
+					slot_number,
+					*epoch_index,
+				);
+
+				let s = get_keypair(&pair).vrf_sign(transcript);
+
+				PreDigest::SecondaryVRF(SecondaryVRFPreDigest {
+					slot_number,
+					vrf_output: VRFOutput(s.0.to_output()),
+					vrf_proof: VRFProof(s.1),
+					authority_index: authority_index as u32,
+				})
+			} else {
+				PreDigest::SecondaryPlain(SecondaryPlainPreDigest {
+					slot_number,
+					authority_index: authority_index as u32,
+				})
+			};
 
 			return Some((pre_digest, pair));
 		}
@@ -147,17 +168,18 @@ fn claim_secondary_slot(
 pub fn claim_slot(
 	slot_number: SlotNumber,
 	epoch: &Epoch,
-	config: &BabeConfiguration,
 	keystore: &KeyStorePtr,
 ) -> Option<(PreDigest, AuthorityPair)> {
-	claim_primary_slot(slot_number, epoch, config.c, keystore)
+	claim_primary_slot(slot_number, epoch, epoch.config.c, keystore)
 		.or_else(|| {
-			if config.secondary_slots {
+			if epoch.config.allowed_slots.is_secondary_plain_slots_allowed() ||
+				epoch.config.allowed_slots.is_secondary_vrf_slots_allowed()
+			{
 				claim_secondary_slot(
 					slot_number,
-					&epoch.authorities,
+					&epoch,
 					keystore,
-					epoch.randomness,
+					epoch.config.allowed_slots.is_secondary_vrf_slots_allowed(),
 				)
 			} else {
 				None

client/consensus/babe/src/aux_schema.rs

@@ -24,13 +24,13 @@ use codec::{Decode, Encode};
 use sc_client_api::backend::AuxStore;
 use sp_blockchain::{Result as ClientResult, Error as ClientError};
 use sp_runtime::traits::Block as BlockT;
-use sp_consensus_babe::BabeBlockWeight;
+use sp_consensus_babe::{BabeBlockWeight, BabeGenesisConfiguration};
 use sc_consensus_epochs::{EpochChangesFor, SharedEpochChanges, migration::EpochChangesForV0};
-use crate::Epoch;
+use crate::{Epoch, migration::EpochV0};
 
 const BABE_EPOCH_CHANGES_VERSION: &[u8] = b"babe_epoch_changes_version";
 const BABE_EPOCH_CHANGES_KEY: &[u8] = b"babe_epoch_changes";
-const BABE_EPOCH_CHANGES_CURRENT_VERSION: u32 = 1;
+const BABE_EPOCH_CHANGES_CURRENT_VERSION: u32 = 2;
 
 fn block_weight_key<H: Encode>(block_hash: H) -> Vec<u8> {
 	(b"block_weight", block_hash).encode()
@@ -53,14 +53,19 @@ fn load_decode<B, T>(backend: &B, key: &[u8]) -> ClientResult<Option<T>>
 /// Load or initialize persistent epoch change data from backend.
 pub(crate) fn load_epoch_changes<Block: BlockT, B: AuxStore>(
 	backend: &B,
+	config: &BabeGenesisConfiguration,
 ) -> ClientResult<SharedEpochChanges<Block, Epoch>> {
 	let version = load_decode::<_, u32>(backend, BABE_EPOCH_CHANGES_VERSION)?;
 
 	let maybe_epoch_changes = match version {
-		None => load_decode::<_, EpochChangesForV0<Block, Epoch>>(
+		None => load_decode::<_, EpochChangesForV0<Block, EpochV0>>(
 			backend,
 			BABE_EPOCH_CHANGES_KEY,
-		)?.map(|v0| v0.migrate()),
+		)?.map(|v0| v0.migrate().map(|_, _, epoch| epoch.migrate(config))),
+		Some(1) => load_decode::<_, EpochChangesFor<Block, EpochV0>>(
+			backend,
+			BABE_EPOCH_CHANGES_KEY,
+		)?.map(|v1| v1.map(|_, _, epoch| epoch.migrate(config))),
 		Some(BABE_EPOCH_CHANGES_CURRENT_VERSION) => load_decode::<_, EpochChangesFor<Block, Epoch>>(
 			backend,
 			BABE_EPOCH_CHANGES_KEY,
@@ -131,18 +136,19 @@ pub(crate) fn load_block_weight<H: Encode, B: AuxStore>(
 #[cfg(test)]
 mod test {
 	use super::*;
-	use crate::Epoch;
+	use crate::migration::EpochV0;
 	use fork_tree::ForkTree;
 	use substrate_test_runtime_client;
 	use sp_core::H256;
 	use sp_runtime::traits::NumberFor;
+	use sp_consensus_babe::{AllowedSlots, BabeGenesisConfiguration};
 	use sc_consensus_epochs::{PersistedEpoch, PersistedEpochHeader, EpochHeader};
 	use sp_consensus::Error as ConsensusError;
 	use sc_network_test::Block as TestBlock;
 
 	#[test]
 	fn load_decode_from_v0_epoch_changes() {
-		let epoch = Epoch {
+		let epoch = EpochV0 {
 			start_slot: 0,
 			authorities: vec![],
 			randomness: [0; 32],
@@ -160,7 +166,7 @@ mod test {
 
 		client.insert_aux(
 			&[(BABE_EPOCH_CHANGES_KEY,
-			   &EpochChangesForV0::<TestBlock, Epoch>::from_raw(v0_tree).encode()[..])],
+			   &EpochChangesForV0::<TestBlock, EpochV0>::from_raw(v0_tree).encode()[..])],
 			&[],
 		).unwrap();
 
@@ -169,7 +175,16 @@ mod test {
 			None,
 		);
 
-		let epoch_changes = load_epoch_changes::<TestBlock, _>(&client).unwrap();
+		let epoch_changes = load_epoch_changes::<TestBlock, _>(
+			&client, &BabeGenesisConfiguration {
+				slot_duration: 10,
+				epoch_length: 4,
+				c: (3, 10),
+				genesis_authorities: Vec::new(),
+				randomness: Default::default(),
+				allowed_slots: AllowedSlots::PrimaryAndSecondaryPlainSlots,
+			},
+		).unwrap();
 
 		assert!(
 			epoch_changes.lock()
@@ -192,7 +207,7 @@ mod test {
 
 		assert_eq!(
 			load_decode::<_, u32>(&client, BABE_EPOCH_CHANGES_VERSION).unwrap(),
-			Some(1),
+			Some(2),
 		);
 	}
 }