grandpa: rewrite warp sync proof generation (paritytech#8148)

* grandpa: use AuthoritySetChanges to generate warp sync proof

* node: init grandpa warp sync protocol

* grandpa: iterator for AuthoritySetChanges

* grandpa: rewrite warp sync proof generation

* grandpa: remove old code for warp sync generation

* grandpa: fix indentation

* grandpa: fix off by one

* grandpa: use binary search to find start idx when generating warp sync proof

* grandpa: add method to verify warp sync proofs

* grandpa: remove unnecessary code to skip authority set changes

* grandpa: add test for warp sync proof generation and verification

* grandpa: add missing docs

* grandpa: remove trailing comma

bin/node/cli/src/service.rs

@@ -197,9 +197,14 @@ pub fn new_full_base(
 	config.network.extra_sets.push(grandpa::grandpa_peers_set_config());
 
 	#[cfg(feature = "cli")]
-	config.network.request_response_protocols.push(sc_finality_grandpa_warp_sync::request_response_config_for_chain(
-		&config, task_manager.spawn_handle(), backend.clone(),
-	));
+	config.network.request_response_protocols.push(
+		sc_finality_grandpa_warp_sync::request_response_config_for_chain(
+			&config,
+			task_manager.spawn_handle(),
+			backend.clone(),
+			import_setup.1.shared_authority_set().clone(),
+		)
+	);
 
 	let (network, network_status_sinks, system_rpc_tx, network_starter) =
 		sc_service::build_network(sc_service::BuildNetworkParams {

client/finality-grandpa-warp-sync/Cargo.toml

@@ -12,16 +12,25 @@ repository = "https://github.com/paritytech/substrate/"
 targets = ["x86_64-unknown-linux-gnu"]
 
 [dependencies]
-sc-network = { version = "0.9.0", path = "../network" }
-sc-finality-grandpa = { version = "0.9.0", path = "../finality-grandpa" }
-sp-runtime = { version = "3.0.0", path = "../../primitives/runtime" }
-sp-blockchain = { version = "3.0.0", path = "../../primitives/blockchain" }
-sc-client-api = { version = "3.0.0", path = "../api" }
-sc-service = { version = "0.9.0", path = "../service" }
+codec = { package = "parity-scale-codec", version = "2.0.0" }
+derive_more = "0.99.11"
 futures = "0.3.8"
 log = "0.4.11"
-derive_more = "0.99.11"
-codec = { package = "parity-scale-codec", version = "2.0.0" }
-prost = "0.7"
 num-traits = "0.2.14"
 parking_lot = "0.11.1"
+prost = "0.7"
+sc-client-api = { version = "3.0.0", path = "../api" }
+sc-finality-grandpa = { version = "0.9.0", path = "../finality-grandpa" }
+sc-network = { version = "0.9.0", path = "../network" }
+sc-service = { version = "0.9.0", path = "../service" }
+sp-blockchain = { version = "3.0.0", path = "../../primitives/blockchain" }
+sp-finality-grandpa = { version = "3.0.0", path = "../../primitives/finality-grandpa" }
+sp-runtime = { version = "3.0.0", path = "../../primitives/runtime" }
+
+[dev-dependencies]
+finality-grandpa = { version = "0.14.0" }
+rand = "0.8"
+sc-block-builder = { version = "0.9.0", path = "../block-builder" }
+sp-consensus = { version = "0.9.0", path = "../../primitives/consensus/common" }
+sp-keyring = { version = "3.0.0", path = "../../primitives/keyring" }
+substrate-test-runtime-client = { version = "2.0.0",  path = "../../test-utils/runtime/client" }

client/finality-grandpa-warp-sync/src/lib.rs

@@ -16,7 +16,7 @@
 
 //! Helper for handling (i.e. answering) grandpa warp sync requests from a remote peer.
 
-use codec::Decode;
+use codec::{Decode, Encode};
 use sc_network::config::{IncomingRequest, OutgoingResponse, ProtocolId, RequestResponseConfig};
 use sc_client_api::Backend;
 use sp_runtime::traits::NumberFor;
@@ -27,13 +27,18 @@ use sp_runtime::traits::Block as BlockT;
 use std::time::Duration;
 use std::sync::Arc;
 use sc_service::{SpawnTaskHandle, config::{Configuration, Role}};
-use sc_finality_grandpa::WarpSyncFragmentCache;
+use sc_finality_grandpa::SharedAuthoritySet;
+
+mod proof;
+
+pub use proof::{AuthoritySetChangeProof, WarpSyncProof};
 
 /// Generates the appropriate [`RequestResponseConfig`] for a given chain configuration.
 pub fn request_response_config_for_chain<TBlock: BlockT, TBackend: Backend<TBlock> + 'static>(
 	config: &Configuration,
 	spawn_handle: SpawnTaskHandle,
 	backend: Arc<TBackend>,
+	authority_set: SharedAuthoritySet<TBlock::Hash, NumberFor<TBlock>>,
 ) -> RequestResponseConfig
 	where NumberFor<TBlock>: sc_finality_grandpa::BlockNumberOps,
 {
@@ -47,6 +52,7 @@ pub fn request_response_config_for_chain<TBlock: BlockT, TBackend: Backend<TBloc
 		let (handler, request_response_config) = GrandpaWarpSyncRequestHandler::new(
 			protocol_id.clone(),
 			backend.clone(),
+			authority_set,
 		);
 		spawn_handle.spawn("grandpa_warp_sync_request_handler", handler.run());
 		request_response_config
@@ -75,38 +81,40 @@ fn generate_protocol_name(protocol_id: ProtocolId) -> String {
 	s
 }
 
-#[derive(codec::Decode)]
+#[derive(Decode)]
 struct Request<B: BlockT> {
-	begin: B::Hash
+	begin: B::Hash,
 }
 
-/// Setting a large fragment limit, allowing client
-/// to define it is possible.
-const WARP_SYNC_FRAGMENTS_LIMIT: usize = 100;
-
-/// Number of item with justification in warp sync cache.
-/// This should be customizable, but setting it to the max number of fragments
-/// we return seems like a good idea until then.
-const WARP_SYNC_CACHE_SIZE: usize = WARP_SYNC_FRAGMENTS_LIMIT;
-
 /// Handler for incoming grandpa warp sync requests from a remote peer.
 pub struct GrandpaWarpSyncRequestHandler<TBackend, TBlock: BlockT> {
 	backend: Arc<TBackend>,
-	cache: Arc<parking_lot::RwLock<WarpSyncFragmentCache<TBlock::Header>>>,
+	authority_set: SharedAuthoritySet<TBlock::Hash, NumberFor<TBlock>>,
 	request_receiver: mpsc::Receiver<IncomingRequest>,
-	_phantom: std::marker::PhantomData<TBlock>
+	_phantom: std::marker::PhantomData<TBlock>,
 }
 
 impl<TBlock: BlockT, TBackend: Backend<TBlock>> GrandpaWarpSyncRequestHandler<TBackend, TBlock> {
 	/// Create a new [`GrandpaWarpSyncRequestHandler`].
-	pub fn new(protocol_id: ProtocolId, backend: Arc<TBackend>) -> (Self, RequestResponseConfig) {
+	pub fn new(
+		protocol_id: ProtocolId,
+		backend: Arc<TBackend>,
+		authority_set: SharedAuthoritySet<TBlock::Hash, NumberFor<TBlock>>,
+	) -> (Self, RequestResponseConfig) {
 		let (tx, request_receiver) = mpsc::channel(20);
 
 		let mut request_response_config = generate_request_response_config(protocol_id);
 		request_response_config.inbound_queue = Some(tx);
-		let cache = Arc::new(parking_lot::RwLock::new(WarpSyncFragmentCache::new(WARP_SYNC_CACHE_SIZE)));
 
-		(Self { backend, request_receiver, cache, _phantom: std::marker::PhantomData }, request_response_config)
+		(
+			Self {
+				backend,
+				request_receiver,
+				_phantom: std::marker::PhantomData,
+				authority_set,
+			},
+			request_response_config,
+		)
 	}
 
 	fn handle_request(
@@ -118,13 +126,14 @@ impl<TBlock: BlockT, TBackend: Backend<TBlock>> GrandpaWarpSyncRequestHandler<TB
 	{
 		let request = Request::<TBlock>::decode(&mut &payload[..])?;
 
-		let mut cache = self.cache.write();
-		let response = sc_finality_grandpa::prove_warp_sync(
-			self.backend.blockchain(), request.begin, Some(WARP_SYNC_FRAGMENTS_LIMIT), Some(&mut cache)
+		let proof = WarpSyncProof::generate(
+			self.backend.blockchain(),
+			request.begin,
+			&self.authority_set.authority_set_changes(),
 		)?;
 
 		pending_response.send(OutgoingResponse {
-			result: Ok(response),
+			result: Ok(proof.encode()),
 			reputation_changes: Vec::new(),
 		}).map_err(|_| HandleRequestError::SendResponse)
 	}
@@ -148,15 +157,19 @@ impl<TBlock: BlockT, TBackend: Backend<TBlock>> GrandpaWarpSyncRequestHandler<TB
 	}
 }
 
-#[derive(derive_more::Display, derive_more::From)]
-enum HandleRequestError {
+#[derive(Debug, derive_more::Display, derive_more::From)]
+pub enum HandleRequestError {
 	#[display(fmt = "Failed to decode request: {}.", _0)]
 	DecodeProto(prost::DecodeError),
 	#[display(fmt = "Failed to encode response: {}.", _0)]
 	EncodeProto(prost::EncodeError),
 	#[display(fmt = "Failed to decode block hash: {}.", _0)]
 	DecodeScale(codec::Error),
 	Client(sp_blockchain::Error),
+	#[from(ignore)]
+	InvalidRequest(String),
+	#[from(ignore)]
+	InvalidProof(String),
 	#[display(fmt = "Failed to send response.")]
 	SendResponse,
 }