Remove Parent Hash to Session mapping (#928)

* Adds a SigningContext type

* Bump spec versions

* Fixes requested changes

* Bump ParachainHost api_version and guard signing_context call

* Improve error message

* If there is no signing_context api use default value

Co-authored-by: Robert Habermeier <[email protected]>

Author: montekki

Cargo.lock

@@ -131,9 +131,13 @@ impl View {
 	///
 	/// This will be pruned later on a call to `prune_old_leaves`, when this leaf
 	/// is not a leaf anymore.
-	pub(super) fn new_local_leaf(&mut self, relay_chain_leaf: Hash, validation_data: MessageValidationData) {
+	pub(super) fn new_local_leaf(
+		&mut self,
+		validation_data: MessageValidationData,
+	) {
+		let relay_chain_leaf = validation_data.signing_context.parent_hash.clone();
 		self.leaf_work.push((
-			relay_chain_leaf,
+			validation_data.signing_context.parent_hash.clone(),
 			LeafView {
 				validation_data,
 				knowledge: Default::default(),
@@ -207,7 +211,6 @@ impl View {
 
 				// validate signature.
 				let res = view.validation_data.check_statement(
-					&message.relay_chain_leaf,
 					&message.signed_statement,
 				);
 

network/src/legacy/gossip/attestation.rs

@@ -60,7 +60,7 @@ use sc_network_gossip::{
 use polkadot_validation::{SignedStatement};
 use polkadot_primitives::{Block, Hash};
 use polkadot_primitives::parachain::{
-	ParachainHost, ValidatorId, ErasureChunk as PrimitiveChunk
+	ParachainHost, ValidatorId, ErasureChunk as PrimitiveChunk, SigningContext,
 };
 use polkadot_erasure_coding::{self as erasure};
 use codec::{Decode, Encode};
@@ -377,13 +377,12 @@ impl RegisteredMessageValidator {
 	/// relevant to this leaf.
 	pub(crate) fn new_local_leaf(
 		&self,
-		relay_chain_leaf: Hash,
 		validation: MessageValidationData,
 	) -> NewLeafActions {
 		// add an entry in attestation_view
 		// prune any entries from attestation_view which are no longer leaves
 		let mut inner = self.inner.inner.write();
-		inner.attestation_view.new_local_leaf(relay_chain_leaf, validation);
+		inner.attestation_view.new_local_leaf(validation);
 
 		let mut actions = Vec::new();
 
@@ -460,11 +459,13 @@ impl GossipService for RegisteredMessageValidator {
 pub(crate) struct MessageValidationData {
 	/// The authorities' parachain validation keys at a block.
 	pub(crate) authorities: Vec<ValidatorId>,
+	/// The signing context.
+	pub(crate) signing_context: SigningContext,
 }
 
 impl MessageValidationData {
 	// check a statement's signature.
-	fn check_statement(&self, relay_chain_leaf: &Hash, statement: &SignedStatement) -> Result<(), ()> {
+	fn check_statement(&self, statement: &SignedStatement) -> Result<(), ()> {
 		let sender = match self.authorities.get(statement.sender as usize) {
 			Some(val) => val,
 			None => return Err(()),
@@ -475,7 +476,7 @@ impl MessageValidationData {
 				&statement.statement,
 				&statement.signature,
 				sender.clone(),
-				relay_chain_leaf,
+				&self.signing_context,
 			);
 
 		if good {
@@ -826,7 +827,9 @@ mod tests {
 		let topic_c = attestation_topic(hash_c);
 
 		// topic_a is in all 3 views -> succeed
-		validator.inner.write().attestation_view.new_local_leaf(hash_a, MessageValidationData::default());
+		let mut validation_data = MessageValidationData::default();
+		validation_data.signing_context.parent_hash = hash_a;
+		validator.inner.write().attestation_view.new_local_leaf(validation_data);
 		// topic_b is in the neighbor's view but not ours -> fail
 		// topic_c is not in either -> fail
 
@@ -937,7 +940,9 @@ mod tests {
 			}
 		});
 		let encoded = statement.encode();
-		validator.inner.write().attestation_view.new_local_leaf(hash_a, MessageValidationData::default());
+		let mut validation_data = MessageValidationData::default();
+		validation_data.signing_context.parent_hash = hash_a;
+		validator.inner.write().attestation_view.new_local_leaf(validation_data);
 
 		{
 			let mut message_allowed = validator.message_allowed();

network/src/legacy/gossip/mod.rs

@@ -162,7 +162,6 @@ impl NetworkServiceOps for PolkadotNetworkService {
 trait GossipOps: Clone + Send + crate::legacy::GossipService + 'static {
 	fn new_local_leaf(
 		&self,
-		relay_parent: Hash,
 		validation_data: crate::legacy::gossip::MessageValidationData,
 	) -> crate::legacy::gossip::NewLeafActions;
 
@@ -177,10 +176,12 @@ trait GossipOps: Clone + Send + crate::legacy::GossipService + 'static {
 impl GossipOps for RegisteredMessageValidator {
 	fn new_local_leaf(
 		&self,
-		relay_parent: Hash,
 		validation_data: crate::legacy::gossip::MessageValidationData,
 	) -> crate::legacy::gossip::NewLeafActions {
-		RegisteredMessageValidator::new_local_leaf(self, relay_parent, validation_data)
+		RegisteredMessageValidator::new_local_leaf(
+			self,
+			validation_data,
+		)
 	}
 
 	fn register_availability_store(
@@ -804,7 +805,6 @@ impl<Api, Sp, Gossip> Worker<Api, Sp, Gossip> where
 		authorities: Vec<ValidatorId>,
 	) {
 		// glue: let gossip know about our new local leaf.
-		let relay_parent = table.consensus_parent_hash().clone();
 		let (signal, exit) = exit_future::signal();
 
 		let key = table.session_key();
@@ -814,19 +814,20 @@ impl<Api, Sp, Gossip> Worker<Api, Sp, Gossip> where
 			}
 		}
 
+		let signing_context = table.signing_context().clone();
+		let relay_parent = signing_context.parent_hash.clone();
 		let new_leaf_actions = self.gossip_handle.new_local_leaf(
-			relay_parent,
-			crate::legacy::gossip::MessageValidationData { authorities },
+			crate::legacy::gossip::MessageValidationData { authorities, signing_context },
 		);
 
 		new_leaf_actions.perform(&self.gossip_handle);
 
 		self.protocol_handler.consensus_instances.insert(
-			relay_parent,
+			relay_parent.clone(),
 			ConsensusNetworkingInstance {
 				statement_table: table.clone(),
-				relay_parent,
-				attestation_topic: crate::legacy::gossip::attestation_topic(relay_parent),
+				relay_parent: relay_parent.clone(),
+				attestation_topic: crate::legacy::gossip::attestation_topic(relay_parent.clone()),
 				_drop_signal: signal,
 			},
 		);
@@ -1324,7 +1325,7 @@ impl ParachainNetwork for Service {
 	) -> Self::BuildTableRouter {
 		let authorities = authorities.to_vec();
 		let mut sender = self.sender.clone();
-		let relay_parent = table.consensus_parent_hash().clone();
+		let relay_parent = table.signing_context().parent_hash.clone();
 
 		Box::pin(async move {
 			sender.send(

network/src/protocol/mod.rs

@@ -20,7 +20,7 @@ use polkadot_primitives::{Block, Header, BlockId};
 use polkadot_primitives::parachain::{
 	Id as ParaId, Chain, DutyRoster, ParachainHost, ValidatorId,
 	Retriable, CollatorId, AbridgedCandidateReceipt,
-	GlobalValidationSchedule, LocalValidationData, ErasureChunk,
+	GlobalValidationSchedule, LocalValidationData, ErasureChunk, SigningContext,
 };
 use polkadot_validation::SharedTable;
 
@@ -114,7 +114,6 @@ impl crate::legacy::GossipService for MockGossip {
 impl GossipOps for MockGossip {
 	fn new_local_leaf(
 		&self,
-		_relay_parent: Hash,
 		_validation_data: crate::legacy::gossip::MessageValidationData,
 	) -> crate::legacy::gossip::NewLeafActions {
 		crate::legacy::gossip::NewLeafActions::new()
@@ -294,6 +293,22 @@ impl ParachainHost<Block> for RuntimeApi {
 	) -> ClientResult<NativeOrEncoded<Option<Vec<AbridgedCandidateReceipt>>>> {
 		Ok(NativeOrEncoded::Native(Some(Vec::new())))
 	}
+
+	fn ParachainHost_signing_context_runtime_api_impl(
+		&self,
+		_at: &BlockId,
+		_: ExecutionContext,
+		_: Option<()>,
+		_: Vec<u8>,
+	) -> ClientResult<NativeOrEncoded<SigningContext>> {
+		Ok(NativeOrEncoded::Native(
+				SigningContext {
+					session_index: Default::default(),
+					parent_hash: Default::default(),
+				}
+			)
+		)
+	}
 }
 
 impl super::Service {
@@ -389,11 +404,15 @@ fn consensus_instances_cleaned_up() {
 	let relay_parent = [0; 32].into();
 	let authorities = Vec::new();
 
+	let signing_context = SigningContext {
+		session_index: Default::default(),
+		parent_hash: relay_parent,
+	};
 	let table = Arc::new(SharedTable::new(
 		Vec::new(),
 		HashMap::new(),
 		None,
-		relay_parent,
+		signing_context,
 		AvailabilityStore::new_in_memory(service.clone()),
 		None,
 	));

network/src/protocol/tests.rs

@@ -13,6 +13,7 @@ application-crypto = { package = "sp-application-crypto", git = "https://github.
 sp-api = { git = "https://github.com/paritytech/substrate", branch = "master", default-features = false }
 sp-version = { git = "https://github.com/paritytech/substrate", branch = "master", default-features = false }
 sp-std = { package = "sp-std", git = "https://github.com/paritytech/substrate", branch = "master", default-features = false }
+sp-staking = { git = "https://github.com/paritytech/substrate", branch = "master", default-features = false }
 runtime_primitives = { package = "sp-runtime", git = "https://github.com/paritytech/substrate", branch = "master", default-features = false }
 polkadot-parachain = { path = "../parachain", default-features = false }
 trie = { package = "sp-trie", git = "https://github.com/paritytech/substrate", branch = "master", default-features = false }
@@ -33,6 +34,7 @@ std = [
 	"sp-api/std",
 	"sp-std/std",
 	"sp-version/std",
+	"sp-staking/std",
 	"runtime_primitives/std",
 	"serde",
 	"polkadot-parachain/std",

primitives/Cargo.toml

@@ -608,6 +608,15 @@ pub enum ValidityAttestation {
 	Explicit(ValidatorSignature),
 }
 
+/// A type returned by runtime with current session index and a parent hash.
+#[derive(Clone, Eq, PartialEq, Default, Decode, Encode, RuntimeDebug)]
+pub struct SigningContext {
+	/// Current session index.
+	pub session_index: sp_staking::SessionIndex,
+	/// Hash of the parent.
+	pub parent_hash: Hash,
+}
+
 /// An attested candidate. This is submitted to the relay chain by a block author.
 #[derive(Clone, PartialEq, Decode, Encode, RuntimeDebug)]
 pub struct AttestedCandidate {
@@ -655,7 +664,7 @@ impl FeeSchedule {
 
 sp_api::decl_runtime_apis! {
 	/// The API for querying the state of parachains on-chain.
-	#[api_version(2)]
+	#[api_version(3)]
 	pub trait ParachainHost {
 		/// Get the current validators.
 		fn validators() -> Vec<ValidatorId>;
@@ -673,6 +682,8 @@ sp_api::decl_runtime_apis! {
 		/// Extract the abridged head that was set in the extrinsics.
 		fn get_heads(extrinsics: Vec<<Block as BlockT>::Extrinsic>)
 			-> Option<Vec<AbridgedCandidateReceipt>>;
+		/// Get a `SigningContext` with current `SessionIndex` and parent hash.
+		fn signing_context() -> SigningContext;
 	}
 }