Merge branch 'master' of github.com:ethcore/parity-bitcoin into synchronizer

Cargo.lock

@@ -7,6 +7,7 @@ dependencies = [
  "db 0.1.0",
  "ethcore-devtools 1.3.0",
  "linked-hash-map 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "log 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "primitives 0.1.0",
  "script 0.1.0",
@@ -146,6 +147,7 @@ dependencies = [
  "chain 0.1.0",
  "elastic-array 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "ethcore-devtools 1.3.0",
+ "log 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "primitives 0.1.0",
  "rocksdb 0.4.5 (git+https://github.com/ethcore/rust-rocksdb)",
@@ -204,6 +206,7 @@ dependencies = [
 name = "ethcore-devtools"
 version = "1.3.0"
 dependencies = [
+ "log 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand 0.3.14 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 

db/Cargo.toml

@@ -14,6 +14,7 @@ serialization = { path = "../serialization" }
 parking_lot = "0.3"
 test-data = { path = "../test-data" }
 bit-vec = "0.4"
+log = "0.3"
 
 [features]
 dev = []

db/src/lib.rs

@@ -8,6 +8,7 @@ extern crate byteorder;
 extern crate chain;
 extern crate serialization;
 extern crate bit_vec;
+#[macro_use] extern crate log;
 
 #[cfg(test)]
 extern crate ethcore_devtools as devtools;

db/src/storage.rs

@@ -341,6 +341,8 @@ impl Storage {
 	///   all transaction meta is removed
 	///   DOES NOT update best block
 	fn decanonize_block(&self, context: &mut UpdateContext, hash: &H256) -> Result<(), Error> {
+		trace!(target: "reorg", "Decanonizing block {}", hash);
+
 		// ensure that block is of the main chain
 		try!(self.block_number(hash).ok_or(Error::NotMain(hash.clone())));
 

devtools/Cargo.toml

@@ -8,6 +8,7 @@ authors = ["Ethcore <admin@ethcore.io>"]
 
 [dependencies]
 rand = "0.3"
+log = "0.3"
 
 [features]
 

devtools/src/lib.rs

@@ -18,11 +18,14 @@
 
 
 extern crate rand;
+extern crate log;
 
 mod random_path;
 mod test_socket;
 mod stop_guard;
+mod test_logger;
 
 pub use random_path::*;
 pub use test_socket::*;
 pub use stop_guard::*;
+pub use test_logger::init as test_logger;

devtools/src/test_logger.rs

@@ -0,0 +1,22 @@
+use log::{self, Log, LogRecord, LogLevel, LogMetadata, SetLoggerError, LogLevelFilter};
+
+struct TestLogger;
+
+impl Log for TestLogger {
+    fn enabled(&self, metadata: &LogMetadata) -> bool {
+        metadata.level() <= LogLevel::Info
+    }
+
+    fn log(&self, record: &LogRecord) {
+        if self.enabled(record.metadata()) {
+            println!("{} - {}", record.level(), record.args());
+        }
+    }
+}
+
+pub fn init() -> Result<(), SetLoggerError> {
+    log::set_logger(|max_log_level| {
+        max_log_level.set(LogLevelFilter::Info);
+        Box::new(TestLogger)
+    })
+}

script/src/script.rs

@@ -304,6 +304,104 @@ impl Script {
 			ScriptType::NonStandard
 		}
 	}
+
+	pub fn iter(&self) -> Instructions {
+		Instructions { position: 0, script: self }
+	}
+
+	pub fn opcodes(&self) -> Opcodes {
+		Opcodes { position: 0, script: self }
+	}
+
+	pub fn sigop_count(&self) -> Result<usize, Error> {
+		let mut last_opcode = Opcode::OP_0;
+		let mut result = 0;
+		for opcode in self.opcodes() {
+			let opcode = try!(opcode);
+
+			match opcode {
+				Opcode::OP_CHECKSIG | Opcode::OP_CHECKSIGVERIFY => { result += 1; },
+				Opcode::OP_CHECKMULTISIG | Opcode::OP_CHECKMULTISIGVERIFY => {
+					match last_opcode {
+
+						Opcode::OP_1 |
+						Opcode::OP_2 |
+						Opcode::OP_3 |
+						Opcode::OP_4 |
+						Opcode::OP_5 |
+						Opcode::OP_6 |
+						Opcode::OP_7 |
+						Opcode::OP_8 |
+						Opcode::OP_9 |
+						Opcode::OP_10 |
+						Opcode::OP_11 |
+						Opcode::OP_12 |
+						Opcode::OP_13 |
+						Opcode::OP_14 |
+						Opcode::OP_15 |
+						Opcode::OP_16 => {
+							result += (last_opcode as u8 - (Opcode::OP_1 as u8 - 1)) as usize;
+						},
+						_ => {
+							result += MAX_PUBKEYS_PER_MULTISIG;
+						}
+					}
+				},
+				_ => { }
+			};
+
+			last_opcode = opcode;
+		}
+
+		Ok(result)
+	}
+}
+
+pub struct Instructions<'a> {
+	position: usize,
+	script: &'a Script,
+}
+
+pub struct Opcodes<'a> {
+	position: usize,
+	script: &'a Script,
+}
+
+impl<'a> Iterator for Instructions<'a> {
+	type Item = Result<Instruction<'a>, Error>;
+
+	fn next(&mut self) -> Option<Result<Instruction<'a>, Error>> {
+
+		if self.script.len() <= self.position { return None; }
+
+		let instruction = match self.script.get_instruction(self.position) {
+			Ok(x) => x,
+			Err(e) => return Some(Err(e)),
+		};
+
+		self.position += instruction.step;
+
+		Some(Ok(instruction))
+	}
+}
+
+
+impl<'a> Iterator for Opcodes<'a> {
+	type Item = Result<Opcode, Error>;
+
+	fn next(&mut self) -> Option<Result<Opcode, Error>> {
+
+		if self.script.len() <= self.position { return None; }
+
+		let instruction = match self.script.get_instruction(self.position) {
+			Ok(x) => x,
+			Err(e) => return Some(Err(e)),
+		};
+
+		self.position += instruction.step;
+
+		Some(Ok(instruction.opcode))
+	}
 }
 
 impl ops::Deref for Script {
@@ -428,4 +526,12 @@ OP_ADD
 		assert_eq!(ScriptType::ScriptHash, Script::from("a9146262b64aec1f4a4c1d21b32e9c2811dd2171fd7587").script_type());
 		assert_eq!(ScriptType::PubKey, Script::from("4104ae1a62fe09c5f51b13905f07f06b99a2f7159b2225f374cd378d71302fa28414e7aab37397f554a7df5f142c21c1b7303b8a0626f1baded5c72a704f7e6cd84cac").script_type());
 	}
+
+	#[test]
+	fn test_sigops_count() {
+		assert_eq!(1usize, Script::from("76a914aab76ba4877d696590d94ea3e02948b55294815188ac").sigop_count().unwrap());
+		assert_eq!(2usize, Script::from("522102004525da5546e7603eefad5ef971e82f7dad2272b34e6b3036ab1fe3d299c22f21037d7f2227e6c646707d1c61ecceb821794124363a2cf2c1d2a6f28cf01e5d6abe52ae").sigop_count().unwrap());
+		assert_eq!(0usize, Script::from("a9146262b64aec1f4a4c1d21b32e9c2811dd2171fd7587").sigop_count().unwrap());
+		assert_eq!(1usize, Script::from("4104ae1a62fe09c5f51b13905f07f06b99a2f7159b2225f374cd378d71302fa28414e7aab37397f554a7df5f142c21c1b7303b8a0626f1baded5c72a704f7e6cd84cac").sigop_count().unwrap());
+	}
 }

sync/src/local_node.rs

@@ -112,6 +112,11 @@ impl<T, U, V> LocalNode<T, U, V> where T: SynchronizationTaskExecutor + PeersCon
 	pub fn on_peer_getheaders(&self, peer_index: usize, message: types::GetHeaders, id: u32) {
 		trace!(target: "sync", "Got `getheaders` message from peer#{}", peer_index);
 
+		// do not serve getheaders requests until we are synchronized
+		if self.client.lock().state().is_synchronizing() {
+			return;
+		}
+
 		// simulating bitcoind for passing tests: if we are in nearly-saturated state
 		// and peer, which has just provided a new blocks to us, is asking for headers
 		// => do not serve getheaders until we have fully process his blocks + wait until headers are served before returning

sync/src/synchronization_client.rs

@@ -20,7 +20,8 @@ use synchronization_chain::{Chain, ChainRef, BlockState, HeadersIntersection};
 use synchronization_chain::{Information as ChainInformation};
 use verification::{ChainVerifier, Error as VerificationError, Verify};
 use synchronization_executor::{Task, TaskExecutor};
-use synchronization_manager::{manage_synchronization_peers, manage_unknown_orphaned_blocks, MANAGEMENT_INTERVAL_MS, ManagePeersConfig, ManageUnknownBlocksConfig};
+use synchronization_manager::{manage_synchronization_peers_blocks, manage_synchronization_peers_inventory,
+	manage_unknown_orphaned_blocks, MANAGEMENT_INTERVAL_MS, ManagePeersConfig, ManageUnknownBlocksConfig};
 use hash_queue::HashPosition;
 use time;
 use std::time::Duration;
@@ -184,6 +185,7 @@ enum VerificationTask {
 /// Synchronization client trait
 pub trait Client : Send + 'static {
 	fn best_block(&self) -> db::BestBlock;
+	fn state(&self) -> State;
 	fn on_new_blocks_inventory(&mut self, peer_index: usize, peer_hashes: Vec<H256>);
 	fn on_new_blocks_headers(&mut self, peer_index: usize, blocks_headers: Vec<BlockHeader>);
 	fn on_peer_block(&mut self, peer_index: usize, block: Block);
@@ -289,6 +291,11 @@ impl<T> Client for SynchronizationClient<T> where T: TaskExecutor {
 		self.chain.read().best_block()
 	}
 
+	/// Get synchronization state
+	fn state(&self) -> State {
+		self.state.clone()
+	}
+
 	/// Try to queue synchronization of unknown blocks when new inventory is received.
 	fn on_new_blocks_inventory(&mut self, peer_index: usize, blocks_hashes: Vec<H256>) {
 		// we use headers-first synchronization
@@ -343,6 +350,9 @@ impl<T> Client for SynchronizationClient<T> where T: TaskExecutor {
 			blocks_hashes
 		};
 
+		// update peers to select next tasks
+		self.peers.on_inventory_received(peer_index);
+
 		// now insert unknown blocks to the queue
 		self.process_new_blocks_headers(peer_index, blocks_hashes, blocks_headers);
 		self.execute_synchronization_tasks(None);
@@ -362,8 +372,11 @@ impl<T> Client for SynchronizationClient<T> where T: TaskExecutor {
 	/// Peer disconnected.
 	fn on_peer_disconnected(&mut self, peer_index: usize) {
 		// when last peer is disconnected, reset, but let verifying blocks be verified
-		if self.peers.on_peer_disconnected(peer_index) {
+		let peer_tasks = self.peers.on_peer_disconnected(peer_index);
-			self.switch_to_saturated_state(false);
+		if !self.peers.has_any_useful() {
+			self.switch_to_saturated_state();
+		} else if peer_tasks.is_some() {
+			self.execute_synchronization_tasks(peer_tasks);
 		}
 	}
 
@@ -480,15 +493,12 @@ impl<T> SynchronizationClient<T> where T: TaskExecutor {
 						None => return Ok(()),
 					};
 					let mut client = client.lock();
+					client.print_synchronization_information();
 					if client.state.is_synchronizing() || client.state.is_nearly_saturated() {
-						let blocks_to_request = manage_synchronization_peers(&peers_config, &mut client.peers);
+						let blocks_to_request = manage_synchronization_peers_blocks(&peers_config, &mut client.peers);
-						// if no peers left => we are saturated
-						if !client.peers.any() {
-							client.switch_to_saturated_state(false);
-						} else {
 						client.execute_synchronization_tasks(blocks_to_request);
-						}
 
+						manage_synchronization_peers_inventory(&peers_config, &mut client.peers);
 						if let Some(orphans_to_remove) = manage_unknown_orphaned_blocks(&unknown_config, &mut client.unknown_blocks) {
 							client.remove_orphaned_blocks(orphans_to_remove.into_iter().collect());
 						}
@@ -528,13 +538,13 @@ impl<T> SynchronizationClient<T> where T: TaskExecutor {
 				trace!(target: "sync", "Ignoring {} headers from peer#{}. All blocks are known and in database.", headers.len(), peer_index);
 				if self.state.is_synchronizing() {
 					// remember peer as useful
-					self.peers.insert(peer_index);
+					self.peers.useful_peer(peer_index);
 				}
 			},
 			HeadersIntersection::InMemoryNoNewBlocks => {
 				trace!(target: "sync", "Ignoring {} headers from peer#{}. All blocks are known and in memory.", headers.len(), peer_index);
 				// remember peer as useful
-				self.peers.insert(peer_index);
+				self.peers.useful_peer(peer_index);
 			},
 			HeadersIntersection::InMemoryMainNewBlocks(new_block_index)
 				| HeadersIntersection::InMemoryForkNewBlocks(new_block_index)
@@ -544,9 +554,10 @@ impl<T> SynchronizationClient<T> where T: TaskExecutor {
 				let new_blocks_hashes = hashes.split_off(new_block_index);
 				let new_blocks_headers = headers.split_off(new_block_index);
 				let new_blocks_hashes_len = new_blocks_hashes.len();
+				trace!(target: "sync", "Sch. {} headers from peer#{}. First {:?}, last: {:?}", new_blocks_hashes_len, peer_index, new_blocks_hashes[0], new_blocks_hashes[new_blocks_hashes_len - 1]);
 				chain.schedule_blocks_headers(new_blocks_hashes, new_blocks_headers);
 				// remember peer as useful
-				self.peers.insert(peer_index);
+				self.peers.useful_peer(peer_index);
 				// switch to synchronization state
 				if !self.state.is_synchronizing() {
 					if new_blocks_hashes_len == 1 && !self.state.is_nearly_saturated() {
@@ -567,7 +578,7 @@ impl<T> SynchronizationClient<T> where T: TaskExecutor {
 			match chain.block_state(&block_hash) {
 				BlockState::Verifying | BlockState::Stored => {
 					// remember peer as useful
-					self.peers.insert(peer_index);
+					self.peers.useful_peer(peer_index);
 				},
 				BlockState::Unknown | BlockState::Scheduled | BlockState::Requested => {
 					// check parent block state
@@ -593,7 +604,7 @@ impl<T> SynchronizationClient<T> where T: TaskExecutor {
 						},
 						BlockState::Verifying | BlockState::Stored => {
 							// remember peer as useful
-							self.peers.insert(peer_index);
+							self.peers.useful_peer(peer_index);
 							// forget block
 							chain.forget_leave_header(&block_hash);
 							// schedule verification
@@ -632,7 +643,7 @@ impl<T> SynchronizationClient<T> where T: TaskExecutor {
 						},
 						BlockState::Requested | BlockState::Scheduled => {
 							// remember peer as useful
-							self.peers.insert(peer_index);
+							self.peers.useful_peer(peer_index);
 							// remember as orphan block
 							self.orphaned_blocks
 								.entry(block.block_header.previous_header_hash.clone())
@@ -649,67 +660,67 @@ impl<T> SynchronizationClient<T> where T: TaskExecutor {
 		};
 
 		if switch_to_saturated {
-			self.switch_to_saturated_state(true);
+			self.switch_to_saturated_state();
 		}
 	}
 
 	/// Schedule new synchronization tasks, if any.
 	fn execute_synchronization_tasks(&mut self, forced_blocks_requests: Option<Vec<H256>>) {
 		let mut tasks: Vec<Task> = Vec::new();
-		let idle_peers = self.peers.idle_peers();
+
-		let idle_peers_len = idle_peers.len() as u32;
+		// display information if processed many blocks || enough time has passed since sync start
+		self.print_synchronization_information();
 
 		// if some blocks requests are forced => we should ask peers even if there are no idle peers
 		if let Some(forced_blocks_requests) = forced_blocks_requests {
-			let all_peers = self.peers.all_peers();
+			let useful_peers = self.peers.useful_peers();
-			tasks.extend(self.prepare_blocks_requests_tasks(all_peers, forced_blocks_requests));
+			// if we have to request blocks && there are no useful peers at all => switch to saturated state
+			if useful_peers.is_empty() {
+				warn!(target: "sync", "Last peer was marked as non-useful. Moving to saturated state.");
+				self.switch_to_saturated_state();
+				return;
 			}
 
-		// prepare 'normal' synchronization tasks
+			let forced_tasks = self.prepare_blocks_requests_tasks(useful_peers, forced_blocks_requests);
-		if idle_peers_len != 0 {
+			tasks.extend(forced_tasks);
-			let blocks_to_request = {
-				// display information if processed many blocks || enough time has passed since sync start
-				let mut chain = self.chain.write();
-				if let State::Synchronizing(timestamp, num_of_blocks) = self.state {
-					let new_timestamp = time::precise_time_s();
-					let timestamp_diff = new_timestamp - timestamp;
-					let new_num_of_blocks = chain.best_storage_block().number;
-					let blocks_diff = if new_num_of_blocks > num_of_blocks { new_num_of_blocks - num_of_blocks } else { 0 };
-					if timestamp_diff >= 60.0 || blocks_diff > 1000 {
-						self.state = State::Synchronizing(time::precise_time_s(), new_num_of_blocks);
-
-						use time;
-						info!(target: "sync", "{:?} @ Processed {} blocks in {} seconds. Chain information: {:?}"
-							, time::strftime("%H:%M:%S", &time::now()).unwrap()
-							, blocks_diff, timestamp_diff
-							, chain.information());
-					}
 		}
 
+		let mut blocks_requests: Option<Vec<H256>> = None;
+		let blocks_idle_peers = self.peers.idle_peers_for_blocks();
+		{
 			// check if we can query some blocks hashes
-				let scheduled_hashes_len = chain.length_of_state(BlockState::Scheduled);
+			let inventory_idle_peers = self.peers.idle_peers_for_inventory();
-				if self.state.is_synchronizing() {
+			if !inventory_idle_peers.is_empty() {
+				let scheduled_hashes_len = { self.chain.read().length_of_state(BlockState::Scheduled) };
 				if scheduled_hashes_len < MAX_SCHEDULED_HASHES {
-						tasks.push(Task::RequestBlocksHeaders(idle_peers[0]));
+					for inventory_peer in inventory_idle_peers.iter() {
-						self.peers.on_inventory_requested(idle_peers[0]);
+						self.peers.on_inventory_requested(*inventory_peer);
+					}
+
+					let inventory_tasks = inventory_idle_peers.into_iter().map(|p| Task::RequestBlocksHeaders(p));
+					tasks.extend(inventory_tasks);
 				}
 			}
 
 			// check if we can move some blocks from scheduled to requested queue
+			let blocks_idle_peers_len = blocks_idle_peers.len() as u32;
+			if blocks_idle_peers_len != 0 {
+				let mut chain = self.chain.write();
+				let scheduled_hashes_len = chain.length_of_state(BlockState::Scheduled);
 				let requested_hashes_len = chain.length_of_state(BlockState::Requested);
 				let verifying_hashes_len = chain.length_of_state(BlockState::Verifying);
 				if requested_hashes_len + verifying_hashes_len < MAX_REQUESTED_BLOCKS + MAX_VERIFYING_BLOCKS && scheduled_hashes_len != 0 {
-					let chunk_size = min(MAX_BLOCKS_IN_REQUEST, max(scheduled_hashes_len / idle_peers_len, MIN_BLOCKS_IN_REQUEST));
+					let chunk_size = min(MAX_BLOCKS_IN_REQUEST, max(scheduled_hashes_len / blocks_idle_peers_len, MIN_BLOCKS_IN_REQUEST));
-					let hashes_to_request_len = chunk_size * idle_peers_len;
+					let hashes_to_request_len = chunk_size * blocks_idle_peers_len;
-					Some(chain.request_blocks_hashes(hashes_to_request_len))
+					let hashes_to_request = chain.request_blocks_hashes(hashes_to_request_len);
-				} else {
+					blocks_requests = Some(hashes_to_request);
-					None
+				}
+			}
 		}
-			};
 
-			if let Some(blocks_to_request) = blocks_to_request {
+		// append blocks requests tasks
-				tasks.extend(self.prepare_blocks_requests_tasks(idle_peers, blocks_to_request));
+		if let Some(blocks_requests) = blocks_requests {
-			}
+			tasks.extend(self.prepare_blocks_requests_tasks(blocks_idle_peers, blocks_requests));
 		}
 
 		// execute synchronization tasks
@@ -743,7 +754,7 @@ impl<T> SynchronizationClient<T> where T: TaskExecutor {
 	}
 
 	/// Switch to saturated state
-	fn switch_to_saturated_state(&mut self, ask_for_inventory: bool) {
+	fn switch_to_saturated_state(&mut self) {
 		if self.state.is_saturated() {
 			return;
 		}
@@ -770,11 +781,12 @@ impl<T> SynchronizationClient<T> where T: TaskExecutor {
 				chain.information());
 		}
 
-		if ask_for_inventory {
+		// finally - ask all known peers for their best blocks inventory, in case if some peer 
+		// has lead us to the fork
+		{
 			let mut executor = self.executor.lock();
-			for idle_peer in self.peers.idle_peers() {
+			for peer in self.peers.all_peers() {
-				self.peers.on_inventory_requested(idle_peer);
+				executor.execute(Task::RequestBlocksHeaders(peer));
-				executor.execute(Task::RequestBlocksHeaders(idle_peer));
 			}
 		}
 	}
@@ -850,6 +862,27 @@ impl<T> SynchronizationClient<T> where T: TaskExecutor {
 		}
 	}
 
+	/// Print synchronization information
+	fn print_synchronization_information(&mut self) {
+		if let State::Synchronizing(timestamp, num_of_blocks) = self.state {
+			let chain = self.chain.read();
+
+			let new_timestamp = time::precise_time_s();
+			let timestamp_diff = new_timestamp - timestamp;
+			let new_num_of_blocks = chain.best_storage_block().number;
+			let blocks_diff = if new_num_of_blocks > num_of_blocks { new_num_of_blocks - num_of_blocks } else { 0 };
+			if timestamp_diff >= 60.0 || blocks_diff > 1000 {
+				self.state = State::Synchronizing(time::precise_time_s(), new_num_of_blocks);
+
+				use time;
+				info!(target: "sync", "{:?} @ Processed {} blocks in {} seconds. Chain information: {:?}"
+					, time::strftime("%H:%M:%S", &time::now()).unwrap()
+					, blocks_diff, timestamp_diff
+					, chain.information());
+			}
+		}
+	}
+
 	/// Thread procedure for handling verification tasks
 	fn verification_worker_proc(sync: Arc<Mutex<Self>>, storage: Arc<db::Store>, work_receiver: Receiver<VerificationTask>) {
 		let verifier = ChainVerifier::new(storage);
@@ -942,7 +975,7 @@ pub mod tests {
 
 		sync.on_new_blocks_headers(5, vec![block1.block_header.clone()]);
 		let tasks = executor.lock().take_tasks();
-		assert_eq!(tasks, vec![Task::RequestBlocks(5, vec![block1.hash()])]);
+		assert_eq!(tasks, vec![Task::RequestBlocksHeaders(5), Task::RequestBlocks(5, vec![block1.hash()])]);
 		assert!(sync.information().state.is_nearly_saturated());
 		assert_eq!(sync.information().orphaned, 0);
 		assert_eq!(sync.information().chain.scheduled, 0);
@@ -1010,7 +1043,7 @@ pub mod tests {
 			// synchronization has started && new blocks have been requested
 			let tasks = executor.lock().take_tasks();
 			assert!(sync.information().state.is_nearly_saturated());
-			assert_eq!(tasks, vec![Task::RequestBlocks(1, vec![block1.hash()])]);
+			assert_eq!(tasks, vec![Task::RequestBlocksHeaders(1), Task::RequestBlocks(1, vec![block1.hash()])]);
 		}
 
 		{
@@ -1324,4 +1357,39 @@ pub mod tests {
 		let tasks = executor.lock().take_tasks();
 		assert_eq!(tasks, vec![Task::RequestBlocks(1, vec![test_data::block_h1().hash()])]);
 	}
+
+	#[test]
+	fn blocks_rerequested_on_peer_disconnect() {
+		let (_, _, executor, _, sync) = create_sync(None);
+
+		let block1: Block = test_data::block_h1();
+		let block2: Block = test_data::block_h2();
+
+		{
+			let mut sync = sync.lock();
+			// receive inventory from new peer#1
+			sync.on_new_blocks_headers(1, vec![block1.block_header.clone()]);
+			// synchronization has started && new blocks have been requested
+			let tasks = executor.lock().take_tasks();
+			assert_eq!(tasks, vec![Task::RequestBlocksHeaders(1), Task::RequestBlocks(1, vec![block1.hash()])]);
+		}
+
+		{
+			let mut sync = sync.lock();
+			// receive inventory from new peer#2
+			sync.on_new_blocks_headers(2, vec![block1.block_header.clone(), block2.block_header.clone()]);
+			// synchronization has started && new blocks have been requested
+			let tasks = executor.lock().take_tasks();
+			assert_eq!(tasks, vec![Task::RequestBlocksHeaders(2), Task::RequestBlocks(2, vec![block2.hash()])]);
+		}
+
+		{
+			let mut sync = sync.lock();
+			// peer#1 is disconnected && it has pending blocks requests => ask peer#2
+			sync.on_peer_disconnected(1);
+			// blocks have been requested
+			let tasks = executor.lock().take_tasks();
+			assert_eq!(tasks, vec![Task::RequestBlocks(2, vec![block1.hash()])]);
+		}
+	}
 }

sync/src/synchronization_manager.rs

@@ -5,8 +5,10 @@ use primitives::hash::H256;
 
 /// Management interval (in ms)
 pub const MANAGEMENT_INTERVAL_MS: u64 = 10 * 1000;
-/// Response time to decrease peer score
+/// Response time before getting block to decrease peer score
-const DEFAULT_PEER_FAILURE_INTERVAL_MS: u32 = 5 * 1000;
+const DEFAULT_PEER_BLOCK_FAILURE_INTERVAL_MS: u32 = 5 * 1000;
+/// Response time before getting inventory to decrease peer score
+const DEFAULT_PEER_INVENTORY_FAILURE_INTERVAL_MS: u32 = 5 * 1000;
 /// Unknown orphan block removal time
 const DEFAULT_UNKNOWN_BLOCK_REMOVAL_TIME_MS: u32 = 20 * 60 * 1000;
 /// Maximal number of orphaned blocks
@@ -14,14 +16,17 @@ const DEFAULT_UNKNOWN_BLOCKS_MAX_LEN: usize = 16;
 
 /// Peers management configuration
 pub struct ManagePeersConfig {
-	/// Time interval (in milliseconds) to wait answer from the peer before penalizing && reexecuting tasks
+	/// Time interval (in milliseconds) to wait block from the peer before penalizing && reexecuting tasks
-	pub failure_interval_ms: u32,
+	pub block_failure_interval_ms: u32,
+	/// Time interval (in milliseconds) to wait inventory from the peer before penalizing && reexecuting tasks
+	pub inventory_failure_interval_ms: u32,
 }
 
 impl Default for ManagePeersConfig {
 	fn default() -> Self {
 		ManagePeersConfig {
-			failure_interval_ms: DEFAULT_PEER_FAILURE_INTERVAL_MS,
+			block_failure_interval_ms: DEFAULT_PEER_BLOCK_FAILURE_INTERVAL_MS,
+			inventory_failure_interval_ms: DEFAULT_PEER_INVENTORY_FAILURE_INTERVAL_MS,
 		}
 	}
 }
@@ -43,25 +48,25 @@ impl Default for ManageUnknownBlocksConfig {
 	}
 }
 
-/// Manage stalled synchronization peers tasks
+/// Manage stalled synchronization peers blocks tasks
-pub fn manage_synchronization_peers(config: &ManagePeersConfig, peers: &mut Peers) -> Option<Vec<H256>> {
+pub fn manage_synchronization_peers_blocks(config: &ManagePeersConfig, peers: &mut Peers) -> Option<Vec<H256>> {
 	let mut blocks_to_request: Vec<H256> = Vec::new();
 	let now = precise_time_s();
 	// reset tasks for peers, which has not responded during given period
-	for (worst_peer_index, worst_peer_time) in peers.worst_peers() {
+	for (worst_peer_index, worst_peer_time) in peers.ordered_blocks_requests() {
 		// check if peer has not responded within given time
 		let time_diff = now - worst_peer_time;
-		if time_diff <= config.failure_interval_ms as f64 / 1000f64 {
+		if time_diff <= config.block_failure_interval_ms as f64 / 1000f64 {
 			break;
 		}
 
 		// decrease score && move to the idle queue
-		warn!(target: "sync", "Failed to get response from peer#{} in {} seconds", worst_peer_index, time_diff);
+		warn!(target: "sync", "Failed to get requested block from peer#{} in {} seconds", worst_peer_index, time_diff);
-		let peer_tasks = peers.reset_tasks(worst_peer_index);
+		let peer_tasks = peers.reset_blocks_tasks(worst_peer_index);
 		blocks_to_request.extend(peer_tasks);
 
 		// if peer failed many times => forget it
-		if peers.on_peer_failure(worst_peer_index) {
+		if peers.on_peer_block_failure(worst_peer_index) {
 			warn!(target: "sync", "Too many failures for peer#{}. Excluding from synchronization", worst_peer_index);
 		}
 	}
@@ -69,6 +74,21 @@ pub fn manage_synchronization_peers(config: &ManagePeersConfig, peers: &mut Peer
 	if blocks_to_request.is_empty() { None } else { Some(blocks_to_request) }
 }
 
+/// Manage stalled synchronization peers inventory tasks
+pub fn manage_synchronization_peers_inventory(config: &ManagePeersConfig, peers: &mut Peers) {
+	let now = precise_time_s();
+	// reset tasks for peers, which has not responded during given period
+	for (worst_peer_index, worst_peer_time) in peers.ordered_inventory_requests() {
+		// check if peer has not responded within given time
+		let time_diff = now - worst_peer_time;
+		if time_diff <= config.inventory_failure_interval_ms as f64 / 1000f64 {
+			break;
+		}
+
+		peers.on_peer_inventory_failure(worst_peer_index);
+	}
+}
+
 /// Manage unknown orphaned blocks
 pub fn manage_unknown_orphaned_blocks(config: &ManageUnknownBlocksConfig, unknown_blocks: &mut LinkedHashMap<H256, f64>) -> Option<Vec<H256>> {
 	let mut unknown_to_remove: Vec<H256> = Vec::new();
@@ -102,34 +122,34 @@ pub fn manage_unknown_orphaned_blocks(config: &ManageUnknownBlocksConfig, unknow
 mod tests {
 	use time::precise_time_s;
 	use linked_hash_map::LinkedHashMap;
-	use super::{ManagePeersConfig, ManageUnknownBlocksConfig, manage_synchronization_peers, manage_unknown_orphaned_blocks};
+	use super::{ManagePeersConfig, ManageUnknownBlocksConfig, manage_synchronization_peers_blocks, manage_unknown_orphaned_blocks};
 	use synchronization_peers::Peers;
 	use primitives::hash::H256;
 
 	#[test]
 	fn manage_good_peer() {
-		let config = ManagePeersConfig { failure_interval_ms: 1000, };
+		let config = ManagePeersConfig { block_failure_interval_ms: 1000, ..Default::default() };
 		let mut peers = Peers::new();
 		peers.on_blocks_requested(1, &vec![H256::from(0), H256::from(1)]);
 		peers.on_block_received(1, &H256::from(0));
-		assert_eq!(manage_synchronization_peers(&config, &mut peers), None);
+		assert_eq!(manage_synchronization_peers_blocks(&config, &mut peers), None);
-		assert_eq!(peers.idle_peers(), vec![]);
+		assert_eq!(peers.idle_peers_for_blocks(), vec![]);
 	}
 
 	#[test]
 	fn manage_bad_peers() {
 		use std::thread::sleep;
 		use std::time::Duration;
-		let config = ManagePeersConfig { failure_interval_ms: 0, };
+		let config = ManagePeersConfig { block_failure_interval_ms: 0, ..Default::default() };
 		let mut peers = Peers::new();
 		peers.on_blocks_requested(1, &vec![H256::from(0)]);
 		peers.on_blocks_requested(2, &vec![H256::from(1)]);
 		sleep(Duration::from_millis(1));
 
-		let managed_tasks = manage_synchronization_peers(&config, &mut peers).expect("managed tasks");
+		let managed_tasks = manage_synchronization_peers_blocks(&config, &mut peers).expect("managed tasks");
 		assert!(managed_tasks.contains(&H256::from(0)));
 		assert!(managed_tasks.contains(&H256::from(1)));
-		let idle_peers = peers.idle_peers();
+		let idle_peers = peers.idle_peers_for_blocks();
 		assert_eq!(2, idle_peers.len());
 		assert!(idle_peers.contains(&1));
 		assert!(idle_peers.contains(&2));

sync/src/synchronization_peers.rs

@@ -5,28 +5,36 @@ use linked_hash_map::LinkedHashMap;
 use time::precise_time_s;
 
 /// Max peer failures # before excluding from sync process
-const MAX_PEER_FAILURES: usize = 8;
+const MAX_PEER_FAILURES: usize = 2;
 
 /// Set of peers selected for synchronization.
 #[derive(Debug)]
 pub struct Peers {
-	/// Peers that have no pending requests.
+	/// Peers that are marked as useful for current synchronization session && have no pending requests.
 	idle: HashSet<usize>,
-	/// Pending requests by peer.
+	/// Peers that are marked as non-useful for current synchronization session && have no pending requests.
-	requests: HashMap<usize, HashSet<H256>>,
+	unuseful: HashSet<usize>,
-	/// Peers failures.
+	/// # of failures for given peer.
 	failures: HashMap<usize, usize>,
-	/// Last message time from peer
+	/// Peers that are marked as useful for current synchronization session && have pending blocks requests.
-	times: LinkedHashMap<usize, f64>,
+	blocks_requests: HashMap<usize, HashSet<H256>>,
+	/// Last block message time from peer.
+	blocks_requests_order: LinkedHashMap<usize, f64>,
+	/// Peers that are marked as useful for current synchronization session && have pending requests.
+	inventory_requests: HashSet<usize>,
+	/// Last inventory message time from peer.
+	inventory_requests_order: LinkedHashMap<usize, f64>,
 }
 
 /// Information on synchronization peers
 #[cfg(test)]
 #[derive(Debug)]
 pub struct Information {
-	/// Number of currently idle synchronization peers.
+	/// # of peers that are marked as useful for current synchronization session && have no pending requests.
 	pub idle: usize,
-	/// Number of currently active synchronization peers.
+	/// # of peers that are marked as non-useful for current synchronization session && have no pending requests.
+	pub unuseful: usize,
+	/// # of peers that are marked as useful for current synchronization session && have pending requests.
 	pub active: usize,
 }
 
@@ -34,95 +42,172 @@ impl Peers {
 	pub fn new() -> Peers {
 		Peers {
 			idle: HashSet::new(),
-			requests: HashMap::new(),
+			unuseful: HashSet::new(),
 			failures: HashMap::new(),
-			times: LinkedHashMap::new(),
+			blocks_requests: HashMap::new(),
+			blocks_requests_order: LinkedHashMap::new(),
+			inventory_requests: HashSet::new(),
+			inventory_requests_order: LinkedHashMap::new(),
 		}
 	}
 
 	/// Get information on synchronization peers
 	#[cfg(test)]
 	pub fn information(&self) -> Information {
+		let blocks_requests_peers: HashSet<_> = self.blocks_requests.keys().cloned().collect();
+		let total_unuseful_peers = self.unuseful.difference(&self.inventory_requests).count();
+		let total_active_peers = blocks_requests_peers.union(&self.inventory_requests).count();
 		Information {
 			idle: self.idle.len(),
-			active: self.requests.len(),
+			unuseful: total_unuseful_peers,
+			active: total_active_peers,
 		}
 	}
 
-	/// Has any peers?
+	/// Has any useful peers?
-	pub fn any(&self) -> bool {
+	pub fn has_any_useful(&self) -> bool {
-		!self.idle.is_empty() || !self.requests.is_empty()
+		!self.idle.is_empty()
+			|| !self.blocks_requests.is_empty()
+			|| !self.inventory_requests.is_empty()
 	}
 
-	/// Get idle peer.
+	/// Get all peers
-	#[cfg(test)]
-	pub fn idle_peer(&self) -> Option<usize> {
-		self.idle.iter().cloned().next()
-	}
-
-	/// Get all peers.
 	pub fn all_peers(&self) -> Vec<usize> {
-		self.idle.iter().cloned().chain(self.requests.keys().cloned()).collect()
+		self.idle.iter().cloned()
+			.chain(self.unuseful.iter().cloned())
+			.chain(self.blocks_requests.keys().cloned())
+			.chain(self.inventory_requests.iter().cloned())
+			.collect()
+	}
+
+	/// Get useful peers
+	pub fn useful_peers(&self) -> Vec<usize> {
+		self.idle.iter().cloned()
+			.chain(self.blocks_requests.keys().cloned())
+			.chain(self.inventory_requests.iter().cloned())
+			.collect()
+	}
+
+	/// Get idle peers for inventory request.
+	pub fn idle_peers_for_inventory(&self) -> Vec<usize> {
+		let peers: HashSet<_> = self.idle.iter().cloned()
+			.chain(self.blocks_requests.keys().cloned())
+			.collect();
+		let except: HashSet<_> = self.inventory_requests.iter().cloned().collect();
+		peers.difference(&except).cloned().collect()
 	}
 
 	/// Get idle peers.
-	pub fn idle_peers(&self) -> Vec<usize> {
+	pub fn idle_peers_for_blocks(&self) -> Vec<usize> {
-		self.idle.iter().cloned().collect()
+		let peers: HashSet<_> = self.idle.iter().cloned()
+			.chain(self.inventory_requests.iter().cloned())
+			.collect();
+		let except: HashSet<_> = self.blocks_requests.keys().cloned().collect();
+		peers.difference(&except).cloned().collect()
 	}
 
-	/// Get worst peer.
+	/// Get active blocks requests, sorted by last response time (oldest first).
-	pub fn worst_peers(&self) -> Vec<(usize, f64)> {
+	pub fn ordered_blocks_requests(&self) -> Vec<(usize, f64)> {
-		self.times.iter().map(|(&pi, &t)| (pi, t)).collect()
+		self.blocks_requests_order.iter()
+			.map(|(&pi, &t)| (pi, t))
+			.collect()
 	}
 
-	/// Insert new synchronization peer.
+	/// Get active inventory requests, sorted by last response time (oldest first).
-	pub fn insert(&mut self, peer_index: usize) {
+	pub fn ordered_inventory_requests(&self) -> Vec<(usize, f64)> {
-		if !self.idle.contains(&peer_index) && !self.requests.contains_key(&peer_index) {
+		self.inventory_requests_order.iter()
+			.map(|(&pi, &t)| (pi, t))
+			.collect()
+	}
+
+	/// Mark peer as useful.
+	pub fn useful_peer(&mut self, peer_index: usize) {
+		// if peer is unknown => insert to idle queue
+		// if peer is known && not useful => insert to idle queue
+		if !self.idle.contains(&peer_index)
+			&& !self.blocks_requests.contains_key(&peer_index)
+			&& !self.inventory_requests.contains(&peer_index) {
 			self.idle.insert(peer_index);
+			self.unuseful.remove(&peer_index);
+			self.failures.remove(&peer_index);
 		}
 	}
 
 	/// Peer has been disconnected
-	pub fn on_peer_disconnected(&mut self, peer_index: usize) -> bool {
+	pub fn on_peer_disconnected(&mut self, peer_index: usize) -> Option<Vec<H256>> {
+		// forget this peer without any chances to reuse
 		self.idle.remove(&peer_index);
-		self.requests.remove(&peer_index);
+		self.unuseful.remove(&peer_index);
 		self.failures.remove(&peer_index);
-		self.times.remove(&peer_index);
+		let peer_blocks_requests = self.blocks_requests.remove(&peer_index);
-		(self.idle.len() + self.requests.len()) == 0
+		self.blocks_requests_order.remove(&peer_index);
+		self.inventory_requests.remove(&peer_index);
+		self.inventory_requests_order.remove(&peer_index);
+		peer_blocks_requests
+			.map(|hs| hs.into_iter().collect())
 	}
 
 	/// Block is received from peer.
 	pub fn on_block_received(&mut self, peer_index: usize, block_hash: &H256) {
-		if let Entry::Occupied(mut entry) = self.requests.entry(peer_index) {
+		// if this is requested block && it is last requested block => remove from blocks_requests
-			entry.get_mut().remove(block_hash);
+		let try_mark_as_idle = match self.blocks_requests.entry(peer_index) {
-			if entry.get().is_empty() {
+			Entry::Occupied(mut requests_entry) => { 
-				self.idle.insert(peer_index);
+				requests_entry.get_mut().remove(block_hash);
-				entry.remove_entry();
+				self.blocks_requests_order.remove(&peer_index);
+				if requests_entry.get().is_empty() {
+					requests_entry.remove_entry();
+					true
+				} else {
+					self.blocks_requests_order.insert(peer_index, precise_time_s());
+					false
+				}
+			},
+			_ => false,
+		};
+
+		// try to mark as idle
+		if try_mark_as_idle {
+			self.try_mark_idle(peer_index);
 		}
 	}
-		self.on_peer_message(peer_index);
+
+	/// Inventory received from peer.
+	pub fn on_inventory_received(&mut self, peer_index: usize) {
+		// if we have requested inventory => remove from inventory_requests
+		self.inventory_requests.remove(&peer_index);
+		self.inventory_requests_order.remove(&peer_index);
+
+		// try to mark as idle
+		self.try_mark_idle(peer_index);
 	}
 
 	/// Blocks have been requested from peer.
 	pub fn on_blocks_requested(&mut self, peer_index: usize, blocks_hashes: &[H256]) {
+		// mark peer as active
 		self.idle.remove(&peer_index);
-		self.requests.entry(peer_index).or_insert_with(HashSet::new).extend(blocks_hashes.iter().cloned());
+		self.unuseful.remove(&peer_index);
-		self.times.insert(peer_index, precise_time_s());
+		self.blocks_requests.entry(peer_index).or_insert_with(HashSet::new).extend(blocks_hashes.iter().cloned());
+		self.blocks_requests_order.remove(&peer_index);
+		self.blocks_requests_order.insert(peer_index, precise_time_s());
 	}
 
 	/// Inventory has been requested from peer.
 	pub fn on_inventory_requested(&mut self, peer_index: usize) {
-		// inventory can only be requested from idle peers
+		self.inventory_requests.insert(peer_index);
-		assert!(!self.requests.contains_key(&peer_index));
+		self.inventory_requests_order.remove(&peer_index);
+		self.inventory_requests_order.insert(peer_index, precise_time_s());
 
-		self.idle.remove(&peer_index);
+		// mark peer as active
-		// peer is now out-of-synchronization process, because:
+		if self.idle.remove(&peer_index) {
+			self.unuseful.insert(peer_index);
+		}
+		// peer is now out-of-synchronization process (will not request blocks from him), because:
 		// 1) if it has new blocks, it will respond with `inventory` message && will be inserted back here
 		// 2) if it has no new blocks => either synchronization is completed, or it is behind us in sync
 	}
 
-	/// We have failed to get response from peer during given period
+	/// We have failed to get block from peer during given period
-	pub fn on_peer_failure(&mut self, peer_index: usize) -> bool {
+	pub fn on_peer_block_failure(&mut self, peer_index: usize) -> bool {
 		let peer_failures = match self.failures.entry(peer_index) {
 			Entry::Occupied(mut entry) => {
 				let failures = entry.get() + 1;
@@ -134,35 +219,54 @@ impl Peers {
 
 		let too_much_failures = peer_failures >= MAX_PEER_FAILURES;
 		if too_much_failures {
+			self.idle.remove(&peer_index);
+			self.unuseful.insert(peer_index);
 			self.failures.remove(&peer_index);
-			self.requests.remove(&peer_index);
+			self.blocks_requests.remove(&peer_index);
-			self.times.remove(&peer_index);
+			self.blocks_requests_order.remove(&peer_index);
 		}
 		too_much_failures
 	}
 
-	/// Reset peers state
+	/// We have failed to get inventory from peer during given period
-	pub fn reset(&mut self) {
+	pub fn on_peer_inventory_failure(&mut self, peer_index: usize) {
-		self.idle.extend(self.requests.drain().map(|(k, _)| k));
+		// ignore inventory failures
-		self.failures.clear();
+		self.inventory_requests.remove(&peer_index);
-		self.times.clear();
+		self.inventory_requests_order.remove(&peer_index);
+
+		if !self.blocks_requests.contains_key(&peer_index) {
+			self.idle.insert(peer_index);
+			self.unuseful.remove(&peer_index);
+		}
 	}
 
-	/// Reset peer tasks
+	/// Reset all peers state to the unuseful
-	pub fn reset_tasks(&mut self, peer_index: usize) -> Vec<H256> {
+	pub fn reset(&mut self) {
-		let requests = self.requests.remove(&peer_index);
+		self.unuseful.extend(self.idle.drain());
-		self.times.remove(&peer_index);
+		self.unuseful.extend(self.blocks_requests.drain().map(|(k, _)| k));
-		self.idle.insert(peer_index);
+		self.unuseful.extend(self.inventory_requests.drain());
+		self.failures.clear();
+		self.inventory_requests_order.clear();
+		self.blocks_requests_order.clear();
+	}
+
+	/// Reset peer tasks && move peer to idle state
+	pub fn reset_blocks_tasks(&mut self, peer_index: usize) -> Vec<H256> {
+		let requests = self.blocks_requests.remove(&peer_index);
+		self.blocks_requests_order.remove(&peer_index);
+		self.try_mark_idle(peer_index);
 		requests.expect("empty requests queue is not allowed").into_iter().collect()
 	}
 
-	/// When sync message is received from peer
+	/// Try to mark peer as idle
-	fn on_peer_message(&mut self, peer_index: usize) {
+	fn try_mark_idle(&mut self, peer_index: usize) {
-		self.failures.remove(&peer_index);
+		if self.blocks_requests.contains_key(&peer_index)
-		self.times.remove(&peer_index);
+			|| self.inventory_requests.contains(&peer_index) {
-		if self.requests.contains_key(&peer_index) {
+			return;
-			self.times.insert(peer_index, precise_time_s());
 		}
+
+		self.idle.insert(peer_index);
+		self.unuseful.remove(&peer_index);
 	}
 }
 
@@ -174,8 +278,8 @@ mod tests {
 	#[test]
 	fn peers_empty_on_start() {
 		let peers = Peers::new();
-		assert_eq!(peers.idle_peer(), None);
+		assert_eq!(peers.idle_peers_for_blocks(), vec![]);
-		assert_eq!(peers.idle_peers().len(), 0);
+		assert_eq!(peers.idle_peers_for_inventory(), vec![]);
 
 		let info = peers.information();
 		assert_eq!(info.idle, 0);
@@ -183,87 +287,110 @@ mod tests {
 	}
 
 	#[test]
-	fn peers_all_idle_after_reset() {
+	fn peers_all_unuseful_after_reset() {
 		let mut peers = Peers::new();
 		peers.on_blocks_requested(7, &vec![H256::default()]);
 		peers.on_blocks_requested(8, &vec![H256::default()]);
 		assert_eq!(peers.information().idle, 0);
+		assert_eq!(peers.information().unuseful, 0);
 		assert_eq!(peers.information().active, 2);
 		peers.reset();
-		assert_eq!(peers.information().idle, 2);
+		assert_eq!(peers.information().idle, 0);
+		assert_eq!(peers.information().unuseful, 2);
 		assert_eq!(peers.information().active, 0);
 	}
 
 	#[test]
-	fn peers_removed_after_inventory_request() {
+	fn peer_idle_after_reset_tasks() {
 		let mut peers = Peers::new();
-		peers.insert(5);
+		peers.on_blocks_requested(7, &vec![H256::default()]);
-		peers.insert(7);
+		assert_eq!(peers.information().idle, 0);
+		assert_eq!(peers.information().unuseful, 0);
+		assert_eq!(peers.information().active, 1);
+		assert_eq!(peers.reset_blocks_tasks(7), vec![H256::default()]);
+		assert_eq!(peers.information().idle, 1);
+		assert_eq!(peers.information().unuseful, 0);
+		assert_eq!(peers.information().active, 0);
+	}
+
+	#[test]
+	fn peers_active_after_inventory_request() {
+		let mut peers = Peers::new();
+		peers.useful_peer(5);
+		peers.useful_peer(7);
 		assert_eq!(peers.information().idle, 2);
+		assert_eq!(peers.information().unuseful, 0);
 		assert_eq!(peers.information().active, 0);
 		peers.on_inventory_requested(5);
 		assert_eq!(peers.information().idle, 1);
+		assert_eq!(peers.information().unuseful, 0);
+		assert_eq!(peers.information().active, 1);
 	}
 
 	#[test]
 	fn peers_insert_remove_idle() {
 		let mut peers = Peers::new();
 
-		peers.insert(0);
+		peers.useful_peer(0);
 		assert_eq!(peers.information().idle, 1);
+		assert_eq!(peers.information().unuseful, 0);
 		assert_eq!(peers.information().active, 0);
-		assert_eq!(peers.idle_peer(), Some(0));
+		assert_eq!(peers.idle_peers_for_blocks(), vec![0]);
-		assert_eq!(peers.idle_peers(), vec![0]);
 
-		peers.insert(5);
+		peers.useful_peer(5);
 		assert_eq!(peers.information().idle, 2);
 		assert_eq!(peers.information().active, 0);
-		assert!(peers.idle_peer() == Some(0) || peers.idle_peer() == Some(5));
+		let idle_peers = peers.idle_peers_for_blocks();
-		assert!(peers.idle_peers()[0] == 0 || peers.idle_peers()[0] == 5);
+		assert!(idle_peers[0] == 0 || idle_peers[0] == 5);
-		assert!(peers.idle_peers()[1] == 0 || peers.idle_peers()[1] == 5);
+		assert!(idle_peers[1] == 0 || idle_peers[1] == 5);
 
 		peers.on_peer_disconnected(7);
 		assert_eq!(peers.information().idle, 2);
 		assert_eq!(peers.information().active, 0);
-		assert!(peers.idle_peer() == Some(0) || peers.idle_peer() == Some(5));
+		let idle_peers = peers.idle_peers_for_blocks();
-		assert!(peers.idle_peers()[0] == 0 || peers.idle_peers()[0] == 5);
+		assert!(idle_peers[0] == 0 || idle_peers[0] == 5);
-		assert!(peers.idle_peers()[1] == 0 || peers.idle_peers()[1] == 5);
+		assert!(idle_peers[1] == 0 || idle_peers[1] == 5);
 
 		peers.on_peer_disconnected(0);
 		assert_eq!(peers.information().idle, 1);
 		assert_eq!(peers.information().active, 0);
-		assert_eq!(peers.idle_peer(), Some(5));
+		assert_eq!(peers.idle_peers_for_blocks(), vec![5]);
-		assert_eq!(peers.idle_peers(), vec![5]);
 	}
 
 	#[test]
 	fn peers_request_blocks() {
 		let mut peers = Peers::new();
 
-		peers.insert(5);
+		peers.useful_peer(5);
 
 		peers.on_blocks_requested(7, &vec![H256::default()]);
 		assert_eq!(peers.information().idle, 1);
+		assert_eq!(peers.information().unuseful, 0);
 		assert_eq!(peers.information().active, 1);
 
 		peers.on_blocks_requested(8, &vec![H256::default()]);
 		assert_eq!(peers.information().idle, 1);
+		assert_eq!(peers.information().unuseful, 0);
 		assert_eq!(peers.information().active, 2);
 
 		peers.on_block_received(7, &H256::default());
 		assert_eq!(peers.information().idle, 2);
+		assert_eq!(peers.information().unuseful, 0);
 		assert_eq!(peers.information().active, 1);
 
 		peers.on_block_received(9, &H256::default());
 		assert_eq!(peers.information().idle, 2);
+		assert_eq!(peers.information().unuseful, 0);
 		assert_eq!(peers.information().active, 1);
 
 		peers.on_block_received(8, &"000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8ce26f".into());
 		assert_eq!(peers.information().idle, 2);
+		assert_eq!(peers.information().unuseful, 0);
 		assert_eq!(peers.information().active, 1);
 
 		peers.on_block_received(8, &H256::default());
 		assert_eq!(peers.information().idle, 3);
+		assert_eq!(peers.information().unuseful, 0);
 		assert_eq!(peers.information().active, 0);
 	}
 
@@ -271,36 +398,55 @@ mod tests {
 	fn peers_worst() {
 		let mut peers = Peers::new();
 
-		peers.insert(1);
+		peers.useful_peer(1);
-		peers.insert(2);
+		peers.useful_peer(2);
-		assert_eq!(peers.worst_peers(), vec![]);
+		assert_eq!(peers.ordered_blocks_requests(), vec![]);
 
 		peers.on_blocks_requested(1, &vec![H256::default()]);
-		assert_eq!(peers.worst_peers().len(), 1);
+		assert_eq!(peers.ordered_blocks_requests().len(), 1);
-		assert_eq!(peers.worst_peers()[0].0, 1);
+		assert_eq!(peers.ordered_blocks_requests()[0].0, 1);
 
 		peers.on_blocks_requested(2, &vec![H256::default()]);
-		assert_eq!(peers.worst_peers().len(), 2);
+		assert_eq!(peers.ordered_blocks_requests().len(), 2);
-		assert_eq!(peers.worst_peers()[0].0, 1);
+		assert_eq!(peers.ordered_blocks_requests()[0].0, 1);
-		assert_eq!(peers.worst_peers()[1].0, 2);
+		assert_eq!(peers.ordered_blocks_requests()[1].0, 2);
 
 		assert_eq!(peers.information().idle, 0);
+		assert_eq!(peers.information().unuseful, 0);
 		assert_eq!(peers.information().active, 2);
 
-		peers.reset_tasks(1);
+		peers.reset_blocks_tasks(1);
 
 		assert_eq!(peers.information().idle, 1);
+		assert_eq!(peers.information().unuseful, 0);
 		assert_eq!(peers.information().active, 1);
 
-		assert_eq!(peers.worst_peers().len(), 1);
+		assert_eq!(peers.ordered_blocks_requests().len(), 1);
-		assert_eq!(peers.worst_peers()[0].0, 2);
+		assert_eq!(peers.ordered_blocks_requests()[0].0, 2);
 
 		for _ in 0..MAX_PEER_FAILURES {
-			peers.on_peer_failure(2);
+			peers.on_peer_block_failure(2);
 		}
 
-		assert_eq!(peers.worst_peers().len(), 0);
+		assert_eq!(peers.ordered_blocks_requests().len(), 0);
 		assert_eq!(peers.information().idle, 1);
+		assert_eq!(peers.information().unuseful, 1);
 		assert_eq!(peers.information().active, 0);
 	}
+
+	#[test]
+	fn peer_not_inserted_when_known() {
+		let mut peers = Peers::new();
+		peers.useful_peer(1);
+		peers.useful_peer(1);
+		assert_eq!(peers.information().active + peers.information().idle + peers.information().unuseful, 1);
+		peers.on_blocks_requested(1, &vec![H256::default()]);
+		peers.useful_peer(1);
+		assert_eq!(peers.information().active + peers.information().idle + peers.information().unuseful, 1);
+		for _ in 0..MAX_PEER_FAILURES {
+			peers.on_peer_block_failure(1);
+		}
+		peers.useful_peer(1);
+		assert_eq!(peers.information().active + peers.information().idle + peers.information().unuseful, 1);
+	}
 }

test-data/src/block.rs

@@ -331,6 +331,11 @@ impl<F> TransactionInputBuilder<F> where F: Invoke<chain::TransactionInput> {
 		self
 	}
 
+	pub fn signature_bytes(mut self, sig: Bytes) -> Self {
+		self.signature = sig;
+		self
+	}
+
 	pub fn hash(mut self, hash: H256) -> Self {
 		let mut output = self.output.unwrap_or(chain::OutPoint { hash: hash.clone(), index: 0 });
 		output.hash = hash;
@@ -387,6 +392,11 @@ impl<F> TransactionOutputBuilder<F> where F: Invoke<chain::TransactionOutput> {
 		self
 	}
 
+	pub fn signature_bytes(mut self, sig: Bytes) -> Self {
+		self.signature = sig;
+		self
+	}
+
 	pub fn build(self) -> F::Result {
 		self.callback.invoke(
 			chain::TransactionOutput {

verification/Cargo.toml

@@ -14,6 +14,7 @@ test-data = { path = "../test-data" }
 byteorder = "0.5"
 time = "0.1"
 script = { path = "../script" }
+log = "0.3"
 
 [dependencies.db]
 path = "../db"

verification/src/chain_verifier.rs

@@ -9,6 +9,7 @@ use utils;
 
 const BLOCK_MAX_FUTURE: i64 = 2 * 60 * 60; // 2 hours
 const COINBASE_MATURITY: u32 = 100; // 2 hours
+const MAX_BLOCK_SIGOPS: usize = 20000;
 
 pub struct ChainVerifier {
 	store: Arc<db::Store>,
@@ -117,7 +118,6 @@ impl ChainVerifier {
 				return Err(TransactionError::Input(input_index));
 			}
 
-			if self.skip_sig { continue; }
 			// signature verification
 			let signer: TransactionInputSigner = transaction.clone().into();
 			let paired_output = &parent_transaction.outputs[input.previous_output.index as usize];
@@ -127,10 +127,14 @@ impl ChainVerifier {
 			};
 			let input: Script = input.script_sig().to_vec().into();
 			let output: Script = paired_output.script_pubkey.to_vec().into();
+
 			let flags = VerificationFlags::default().verify_p2sh(true);
 
+			// for tests only, skips as late as possible
+			if self.skip_sig { continue; }
+
 			if let Err(e) = verify_script(&input, &output, &flags, &checker) {
-				println!("transaction signature verification failure: {:?}", e);
+				trace!(target: "verification", "transaction signature verification failure: {}", e);
 				// todo: log error here
 				return Err(TransactionError::Signature(input_index))
 			}
@@ -170,10 +174,32 @@ impl Verify for ChainVerifier {
 		}
 
 		// verify transactions (except coinbase)
+		let mut block_sigops = try!(
+			utils::transaction_sigops(&block.transactions()[0])
+				.map_err(|e| Error::Transaction(1, TransactionError::SignatureMallformed(format!("{}", e))))
+		);
+
 		for (idx, transaction) in block.transactions().iter().skip(1).enumerate() {
+
+			block_sigops += try!(
+				utils::transaction_sigops(transaction)
+					.map_err(|e| Error::Transaction(idx+1, TransactionError::SignatureMallformed(format!("{}", e))))
+			);
+
+			if block_sigops > MAX_BLOCK_SIGOPS {
+				return Err(Error::MaximumSigops);
+			}
+
 			try!(self.verify_transaction(block, transaction).map_err(|e| Error::Transaction(idx+1, e)));
 		}
 
+		trace!(
+			target: "verification", "Block {} (transactons: {}, sigops: {}) verification finished",
+			&hash,
+			block.transactions().len(),
+			&block_sigops
+		);
+
 		// todo: pre-process projected block number once verification is parallel!
 		match self.store.accepted_location(block.header()) {
 			None => {
@@ -220,6 +246,7 @@ mod tests {
 	use std::sync::Arc;
 	use devtools::RandomTempPath;
 	use chain::RepresentH256;
+	use script;
 
 	#[test]
 	fn verify_orphan() {
@@ -454,6 +481,57 @@ mod tests {
 		assert_eq!(expected, verifier.verify(&block))
 	}
 
+	#[test]
+	fn sigops_overflow_block() {
+		let path = RandomTempPath::create_dir();
+		let storage = Storage::new(path.as_path()).unwrap();
+
+		let genesis = test_data::block_builder()
+			.transaction()
+				.coinbase()
+				.build()
+			.transaction()
+				.output().value(50).build()
+				.build()
+			.merkled_header().build()
+			.build();
+
+		storage.insert_block(&genesis).unwrap();
+		let reference_tx = genesis.transactions()[1].hash();
+
+		let mut builder_tx1 = script::Builder::default();
+		for _ in 0..11000 {
+			builder_tx1 = builder_tx1.push_opcode(script::Opcode::OP_CHECKSIG)
+		}
+
+		let mut builder_tx2 = script::Builder::default();
+		for _ in 0..11000 {
+			builder_tx2 = builder_tx2.push_opcode(script::Opcode::OP_CHECKSIG)
+		}
+
+		let block = test_data::block_builder()
+			.transaction().coinbase().build()
+			.transaction()
+				.input()
+					.hash(reference_tx.clone())
+					.signature_bytes(builder_tx1.into_script().to_bytes())
+					.build()
+				.build()
+			.transaction()
+				.input()
+					.hash(reference_tx)
+					.signature_bytes(builder_tx2.into_script().to_bytes())
+					.build()
+				.build()
+			.merkled_header().parent(genesis.hash()).build()
+			.build();
+
+		let verifier = ChainVerifier::new(Arc::new(storage)).pow_skip().signatures_skip();
+
+		let expected = Err(Error::MaximumSigops);
+		assert_eq!(expected, verifier.verify(&block));
+	}
+
 	#[test]
 	fn coinbase_overspend() {
 

verification/src/lib.rs

@@ -9,6 +9,8 @@ extern crate linked_hash_map;
 extern crate byteorder;
 extern crate time;
 extern crate script;
+#[macro_use]
+extern crate log;
 
 #[cfg(test)]
 extern crate ethcore_devtools as devtools;
@@ -45,6 +47,9 @@ pub enum Error {
 	MerkleRoot,
 	/// Coinbase spends too much
 	CoinbaseOverspend { expected_max: u64, actual: u64 },
+	/// Maximum sigops operations exceeded - will not provide how much it was in total
+	/// since it stops counting once `MAX_BLOCK_SIGOPS` is reached
+	MaximumSigops,
 }
 
 #[derive(Debug, PartialEq)]
@@ -62,6 +67,8 @@ pub enum TransactionError {
 	UnknownReference(H256),
 	/// Spends more than claims
 	Overspend,
+	/// Signature script can't be properly parsed
+	SignatureMallformed(String),
 }
 
 #[derive(PartialEq, Debug)]

verification/src/queue.rs

@@ -157,7 +157,7 @@ impl Queue {
 				items.push_front(hash, ScheduleItem::Continued(item.block(), num));
 			},
 			Err(e) => {
-				println!("Verification failed: {:?}", e);
+				trace!(target: "verification", "Verification of block {} failed: {:?}", &hash, e);
 				let mut invalid = self.invalid.write();
 				let mut processing = self.processing.write();
 

verification/src/utils.rs

@@ -1,6 +1,8 @@
 //! Verification utilities
 use primitives::hash::H256;
 use byteorder::{BigEndian, ByteOrder};
+use chain;
+use script::{self, Script};
 
 pub fn check_nbits(hash: &H256, n_bits: u32) -> bool {
 	let hash_bytes: &[u8] = &**hash;
@@ -52,6 +54,25 @@ pub fn block_reward_satoshi(block_height: u32) -> u64 {
 	res
 }
 
+pub fn transaction_sigops(transaction: &chain::Transaction) -> Result<usize, script::Error> {
+	let mut result = 0usize;
+
+	for output in transaction.outputs.iter() {
+		let output_script: Script = output.script_pubkey.to_vec().into();
+		// todo: not always allow malformed output?
+		result += output_script.sigop_count().unwrap_or(0);
+	}
+
+	if transaction.is_coinbase() { return Ok(result); }
+
+	for input in transaction.inputs.iter() {
+		let input_script: Script = input.script_sig().to_vec().into();
+		result += try!(input_script.sigop_count());
+	}
+
+	Ok(result)
+}
+
 #[cfg(test)]
 mod tests {