Sync: Propagate block announcement data (#7903)

* Sync: Propagate block announcement data

This pr adds a feature to the sync protocol to propagate the data that
we received alongside a block announcement. This is done by adding a
cache that caches the last X block announcement data where X is set to
the number of `in_peers` (giving every peer the chance to send us a
different block). This will be required by parachains to ensure that
even peers who are not connected to a collator receive the data
alongside the block announcement to properly validate it and request the
block.

* Review comment

* Bring back the code and add new variant to ensure we don't insert block
announce data when something wasn't checked

* Also use out_peers

substrate/client/network/test/src/lib.rs

@@ -51,7 +51,10 @@ use sp_consensus::Error as ConsensusError;
 use sp_consensus::{BlockOrigin, ForkChoiceStrategy, BlockImportParams, BlockCheckParams, JustificationImport};
 use futures::prelude::*;
 use futures::future::BoxFuture;
-use sc_network::{NetworkWorker, NetworkService, config::ProtocolId};
+use sc_network::{
+	NetworkWorker, NetworkService, config::{ProtocolId, MultiaddrWithPeerId, NonReservedPeerMode},
+	Multiaddr,
+};
 use sc_network::config::{NetworkConfiguration, NonDefaultSetConfig, TransportConfig};
 use libp2p::PeerId;
 use parking_lot::Mutex;
@@ -228,6 +231,7 @@ pub struct Peer<D> {
 	network: NetworkWorker<Block, <Block as BlockT>::Hash>,
 	imported_blocks_stream: Pin<Box<dyn Stream<Item = BlockImportNotification<Block>> + Send>>,
 	finality_notification_stream: Pin<Box<dyn Stream<Item = FinalityNotification<Block>> + Send>>,
+	listen_addr: Multiaddr,
 }
 
 impl<D> Peer<D> {
@@ -267,7 +271,7 @@ impl<D> Peer<D> {
 	}
 
 	/// Announces an important block on the network.
-	pub fn announce_block(&self, hash: <Block as BlockT>::Hash, data: Vec<u8>) {
+	pub fn announce_block(&self, hash: <Block as BlockT>::Hash, data: Option<Vec<u8>>) {
 		self.network.service().announce_block(hash, data);
 	}
 
@@ -281,7 +285,7 @@ impl<D> Peer<D> {
 		where F: FnMut(BlockBuilder<Block, PeersFullClient, substrate_test_runtime_client::Backend>) -> Block
 	{
 		let best_hash = self.client.info().best_hash;
-		self.generate_blocks_at(BlockId::Hash(best_hash), count, origin, edit_block, false, true)
+		self.generate_blocks_at(BlockId::Hash(best_hash), count, origin, edit_block, false, true, true)
 	}
 
 	/// Add blocks to the peer -- edit the block before adding. The chain will
@@ -294,6 +298,7 @@ impl<D> Peer<D> {
 		mut edit_block: F,
 		headers_only: bool,
 		inform_sync_about_new_best_block: bool,
+		announce_block: bool,
 	) -> H256 where F: FnMut(BlockBuilder<Block, PeersFullClient, substrate_test_runtime_client::Backend>) -> Block {
 		let full_client = self.client.as_full()
 			.expect("blocks could only be generated by full clients");
@@ -327,7 +332,9 @@ impl<D> Peer<D> {
 			};
 
 			self.block_import.import_block(import_block, cache).expect("block_import failed");
-			self.network.service().announce_block(hash, Vec::new());
+			if announce_block {
+				self.network.service().announce_block(hash, None);
+			}
 			at = hash;
 		}
 
@@ -337,7 +344,6 @@ impl<D> Peer<D> {
 				full_client.header(&BlockId::Hash(at)).ok().flatten().unwrap().number().clone(),
 			);
 		}
-		self.network.service().announce_block(at.clone(), Vec::new());
 		at
 	}
 
@@ -350,13 +356,13 @@ impl<D> Peer<D> {
 	/// Push blocks to the peer (simplified: with or without a TX)
 	pub fn push_headers(&mut self, count: usize) -> H256 {
 		let best_hash = self.client.info().best_hash;
-		self.generate_tx_blocks_at(BlockId::Hash(best_hash), count, false, true, true)
+		self.generate_tx_blocks_at(BlockId::Hash(best_hash), count, false, true, true, true)
 	}
 
 	/// Push blocks to the peer (simplified: with or without a TX) starting from
 	/// given hash.
 	pub fn push_blocks_at(&mut self, at: BlockId<Block>, count: usize, with_tx: bool) -> H256 {
-		self.generate_tx_blocks_at(at, count, with_tx, false, true)
+		self.generate_tx_blocks_at(at, count, with_tx, false, true, true)
 	}
 
 	/// Push blocks to the peer (simplified: with or without a TX) starting from
@@ -367,7 +373,18 @@ impl<D> Peer<D> {
 		count: usize,
 		with_tx: bool,
 	) -> H256 {
-		self.generate_tx_blocks_at(at, count, with_tx, false, false)
+		self.generate_tx_blocks_at(at, count, with_tx, false, false, true)
+	}
+
+	/// Push blocks to the peer (simplified: with or without a TX) starting from
+	/// given hash without announcing the block.
+	pub fn push_blocks_at_without_announcing(
+		&mut self,
+		at: BlockId<Block>,
+		count: usize,
+		with_tx: bool,
+	) -> H256 {
+		self.generate_tx_blocks_at(at, count, with_tx, false, true, false)
 	}
 
 	/// Push blocks/headers to the peer (simplified: with or without a TX) starting from
@@ -379,6 +396,7 @@ impl<D> Peer<D> {
 		with_tx: bool,
 		headers_only: bool,
 		inform_sync_about_new_best_block: bool,
+		announce_block: bool,
 	) -> H256 {
 		let mut nonce = 0;
 		if with_tx {
@@ -398,6 +416,7 @@ impl<D> Peer<D> {
 				},
 				headers_only,
 				inform_sync_about_new_best_block,
+				announce_block,
 			)
 		} else {
 			self.generate_blocks_at(
@@ -407,6 +426,7 @@ impl<D> Peer<D> {
 				|builder| builder.build().unwrap().block,
 				headers_only,
 				inform_sync_about_new_best_block,
+				announce_block,
 			)
 		}
 	}
@@ -585,6 +605,10 @@ pub struct FullPeerConfig {
 	pub block_announce_validator: Option<Box<dyn BlockAnnounceValidator<Block> + Send + Sync>>,
 	/// List of notification protocols that the network must support.
 	pub notifications_protocols: Vec<Cow<'static, str>>,
+	/// The indices of the peers the peer should be connected to.
+	///
+	/// If `None`, it will be connected to all other peers.
+	pub connect_to_peers: Option<Vec<usize>>,
 }
 
 pub trait TestNetFactory: Sized {
@@ -689,6 +713,15 @@ pub trait TestNetFactory: Sized {
 				set_config: Default::default()
 			}
 		}).collect();
+		if let Some(connect_to) = config.connect_to_peers {
+			let addrs = connect_to.iter().map(|v| {
+				let peer_id = self.peer(*v).network_service().local_peer_id().clone();
+				let multiaddr = self.peer(*v).listen_addr.clone();
+				MultiaddrWithPeerId { peer_id, multiaddr }
+			}).collect();
+			network_config.default_peers_set.reserved_nodes = addrs;
+			network_config.default_peers_set.non_reserved_mode = NonReservedPeerMode::Deny;
+		}
 
 		let protocol_id = ProtocolId::from("test-protocol-name");
 
@@ -715,9 +748,12 @@ pub trait TestNetFactory: Sized {
 
 		trace!(target: "test_network", "Peer identifier: {}", network.service().local_peer_id());
 
-		self.mut_peers(|peers| {
+		self.mut_peers(move |peers| {
 			for peer in peers.iter_mut() {
-				peer.network.add_known_address(network.service().local_peer_id().clone(), listen_addr.clone());
+				peer.network.add_known_address(
+					network.service().local_peer_id().clone(),
+					listen_addr.clone(),
+				);
 			}
 
 			let imported_blocks_stream = Box::pin(client.import_notification_stream().fuse());
@@ -733,6 +769,7 @@ pub trait TestNetFactory: Sized {
 				block_import,
 				verifier,
 				network,
+				listen_addr,
 			});
 		});
 	}
@@ -813,6 +850,7 @@ pub trait TestNetFactory: Sized {
 				imported_blocks_stream,
 				finality_notification_stream,
 				network,
+				listen_addr,
 			});
 		});
 	}
@@ -912,7 +950,7 @@ pub trait TestNetFactory: Sized {
 
 				// We poll `imported_blocks_stream`.
 				while let Poll::Ready(Some(notification)) = peer.imported_blocks_stream.as_mut().poll_next(cx) {
-					peer.network.service().announce_block(notification.hash, Vec::new());
+					peer.network.service().announce_block(notification.hash, None);
 				}
 
 				// We poll `finality_notification_stream`, but we only take the last event.