diff --git a/.travis.yml b/.travis.yml
new file mode 100644
index 000000000..1efef4f21
--- /dev/null
+++ b/.travis.yml
@@ -0,0 +1,16 @@
+language: rust
+
+rust:
+    - nightly
+
+os:
+    - osx
+
+before_script:
+    - brew update
+    - brew install rocksdb
+
+cache:
+  directories:
+  - $TRAVIS_BUILD_DIR/target
+  - $HOME/.cargo
\ No newline at end of file
diff --git a/Cargo.toml b/Cargo.toml
index 75f983253..82658c6ac 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -21,10 +21,13 @@ evmjit = { path = "rust-evmjit", optional = true }
 ethash = { path = "ethash" }
 num_cpus = "0.2"
 docopt = "0.6"
+ctrlc = "1.0"
+clippy = "0.0.37"
 
 [features]
 jit = ["evmjit"]
-evm_debug = []
+test-heavy = []
+evm-debug = []
 
 [[bin]]
 name = "client"
diff --git a/README.md b/README.md
index 216ac8091..48172bb60 100644
--- a/README.md
+++ b/README.md
@@ -1 +1,5 @@
 # ethcore
+
+
+# Running clippy
+
diff --git a/ethash/src/lib.rs b/ethash/src/lib.rs
index f7b6d2308..e87ee1a03 100644
--- a/ethash/src/lib.rs
+++ b/ethash/src/lib.rs
@@ -30,11 +30,13 @@ impl EthashManager {
 	/// `nonce` - The nonce to pack into the mix
 	pub fn compute_light(&self, block_number: u64, header_hash: &H256, nonce: u64) -> ProofOfWork {
 		let epoch = block_number / ETHASH_EPOCH_LENGTH;
-		if !self.lights.read().unwrap().contains_key(&epoch) {
-			let mut lights = self.lights.write().unwrap(); // obtain write lock
-			if !lights.contains_key(&epoch) {
-				let light = Light::new(block_number);
-				lights.insert(epoch, light);
+		while !self.lights.read().unwrap().contains_key(&epoch) {
+			if let Ok(mut lights) = self.lights.try_write()
+			{
+				if !lights.contains_key(&epoch) {
+					let light = Light::new(block_number);
+					lights.insert(epoch, light);
+				}
 			}
 		}
 		self.lights.read().unwrap().get(&epoch).unwrap().compute(header_hash, nonce)
diff --git a/hook.sh b/hook.sh
new file mode 100755
index 000000000..a82f926b9
--- /dev/null
+++ b/hook.sh
@@ -0,0 +1,3 @@
+#!/bin/sh
+echo "#!/bin/sh\ncargo test" >> ./.git/hooks/pre-push
+chmod +x ./.git/hooks/pre-push
diff --git a/src/account.rs b/src/account.rs
index c6c4136df..b0fbf3f85 100644
--- a/src/account.rs
+++ b/src/account.rs
@@ -103,7 +103,7 @@ impl Account {
 	/// Get (and cache) the contents of the trie's storage at `key`.
 	pub fn storage_at(&self, db: &HashDB, key: &H256) -> H256 {
 		self.storage_overlay.borrow_mut().entry(key.clone()).or_insert_with(||{
-			(Filth::Clean, H256::from(SecTrieDB::new(db, &self.storage_root).get(key.bytes()).map(|v| -> U256 {decode(v)}).unwrap_or(U256::zero())))
+			(Filth::Clean, H256::from(SecTrieDB::new(db, &self.storage_root).get(key.bytes()).map_or(U256::zero(), |v| -> U256 {decode(v)})))
 		}).1.clone()
 	}
 
@@ -149,7 +149,7 @@ impl Account {
 	/// Provide a database to lookup `code_hash`. Should not be called if it is a contract without code.
 	pub fn cache_code(&mut self, db: &HashDB) -> bool {
 		// TODO: fill out self.code_cache;
-		return self.is_cached() ||
+		self.is_cached() ||
 			match self.code_hash {
 				Some(ref h) => match db.lookup(h) {
 					Some(x) => { self.code_cache = x.to_vec(); true },
@@ -248,8 +248,8 @@ mod tests {
 
 		let a = Account::from_rlp(&rlp);
 		assert_eq!(a.storage_root().unwrap().hex(), "c57e1afb758b07f8d2c8f13a3b6e44fa5ff94ab266facc5a4fd3f062426e50b2");
-		assert_eq!(a.storage_at(&mut db, &H256::from(&U256::from(0x00u64))), H256::from(&U256::from(0x1234u64)));
-		assert_eq!(a.storage_at(&mut db, &H256::from(&U256::from(0x01u64))), H256::new());
+		assert_eq!(a.storage_at(&db, &H256::from(&U256::from(0x00u64))), H256::from(&U256::from(0x1234u64)));
+		assert_eq!(a.storage_at(&db, &H256::from(&U256::from(0x01u64))), H256::new());
 	}
 
 	#[test]
diff --git a/src/account_diff.rs b/src/account_diff.rs
index 06315db95..1843c4381 100644
--- a/src/account_diff.rs
+++ b/src/account_diff.rs
@@ -15,10 +15,10 @@ pub enum Existance {
 
 impl fmt::Display for Existance {
 	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-		match self {
-			&Existance::Born => try!(write!(f, "+++")),
-			&Existance::Alive => try!(write!(f, "***")),
-			&Existance::Died => try!(write!(f, "XXX")),
+		match *self {
+			Existance::Born => try!(write!(f, "+++")),
+			Existance::Alive => try!(write!(f, "***")),
+			Existance::Died => try!(write!(f, "XXX")),
 		}
 		Ok(())
 	}
@@ -72,11 +72,11 @@ impl AccountDiff {
 					code: Diff::new(pre.code.clone(), post.code.clone()),
 					storage: storage.into_iter().map(|k|
 						(k.clone(), Diff::new(
-							pre.storage.get(&k).cloned().unwrap_or(H256::new()),
-							post.storage.get(&k).cloned().unwrap_or(H256::new())
+							pre.storage.get(&k).cloned().unwrap_or_else(H256::new),
+							post.storage.get(&k).cloned().unwrap_or_else(H256::new)
 						))).collect(),
 				};
-				if r.balance.is_same() && r.nonce.is_same() && r.code.is_same() && r.storage.len() == 0 {
+				if r.balance.is_same() && r.nonce.is_same() && r.code.is_same() && r.storage.is_empty() {
 					None
 				} else {
 					Some(r)
@@ -112,16 +112,15 @@ impl fmt::Display for AccountDiff {
 			Diff::Changed(ref pre, ref post) => try!(write!(f, "${} ({} {} {})", post, pre, if pre > post {"-"} else {"+"}, *max(pre, post) - *min(pre, post))),
 			_ => {},
 		}
-		match self.code {
-			Diff::Born(ref x) => try!(write!(f, "  code {}", x.pretty())),
-			_ => {},
+		if let Diff::Born(ref x) = self.code {
+			try!(write!(f, "  code {}", x.pretty()));
 		}
 		try!(write!(f, "\n"));
-		for (k, dv) in self.storage.iter() {
-			match dv {
-				&Diff::Born(ref v) => try!(write!(f, "    +  {} => {}\n", interpreted_hash(k), interpreted_hash(v))),
-				&Diff::Changed(ref pre, ref post) => try!(write!(f, "    *  {} => {} (was {})\n", interpreted_hash(k), interpreted_hash(post), interpreted_hash(pre))),
-				&Diff::Died(_) => try!(write!(f, "    X  {}\n", interpreted_hash(k))),
+		for (k, dv) in &self.storage {
+			match *dv {
+				Diff::Born(ref v) => try!(write!(f, "    +  {} => {}\n", interpreted_hash(k), interpreted_hash(v))),
+				Diff::Changed(ref pre, ref post) => try!(write!(f, "    *  {} => {} (was {})\n", interpreted_hash(k), interpreted_hash(post), interpreted_hash(pre))),
+				Diff::Died(_) => try!(write!(f, "    X  {}\n", interpreted_hash(k))),
 				_ => {},
 			}
 		}
diff --git a/src/bin/client/main.rs b/src/bin/client/main.rs
index 0d0368480..30f320e9d 100644
--- a/src/bin/client/main.rs
+++ b/src/bin/client/main.rs
@@ -7,17 +7,18 @@ extern crate ethcore_util as util;
 extern crate ethcore;
 extern crate log;
 extern crate env_logger;
+extern crate ctrlc;
 
-use std::io::stdin;
 use std::env;
 use log::{LogLevelFilter};
 use env_logger::LogBuilder;
+use ctrlc::CtrlC;
 use util::*;
 use ethcore::client::*;
-use ethcore::service::ClientService;
+use ethcore::service::{ClientService, NetSyncMessage};
 use ethcore::ethereum;
 use ethcore::blockchain::CacheSize;
-use ethcore::sync::*;
+use ethcore::sync::EthSync;
 use docopt::Docopt;
 
 const USAGE: &'static str = "
@@ -66,42 +67,57 @@ fn main() {
 	};
 
 	let mut service = ClientService::start(spec, &init_nodes).unwrap();
-	let io_handler  = Box::new(ClientIoHandler { client: service.client(), timer: 0, info: Default::default() });
-
+	let io_handler  = Arc::new(ClientIoHandler { client: service.client(), info: Default::default(), sync: service.sync() });
 	service.io().register_handler(io_handler).expect("Error registering IO handler");
-	loop {
-		let mut cmd = String::new();
-		stdin().read_line(&mut cmd).unwrap();
-		if cmd == "quit\n" || cmd == "exit\n" || cmd == "q\n" {
-			break;
+
+	let exit = Arc::new(Condvar::new());
+	let e = exit.clone();
+	CtrlC::set_handler(move || { e.notify_all(); });
+	let mutex = Mutex::new(());
+	let _ = exit.wait(mutex.lock().unwrap()).unwrap();
+}
+
+struct Informant {
+	chain_info: RwLock<Option<BlockChainInfo>>,
+	cache_info: RwLock<Option<CacheSize>>,
+	report: RwLock<Option<ClientReport>>,
+}
+
+impl Default for Informant {
+	fn default() -> Self {
+		Informant {
+			chain_info: RwLock::new(None),
+			cache_info: RwLock::new(None),
+			report: RwLock::new(None),
 		}
 	}
 }
 
-#[derive(Default, Debug)]
-struct Informant {
-	chain_info: Option<BlockChainInfo>,
-	cache_info: Option<CacheSize>,
-	report: Option<ClientReport>,
-}
-
 impl Informant {
-	pub fn tick(&mut self, client: &Client) {
+	pub fn tick(&self, client: &Client, sync: &EthSync) {
 		// 5 seconds betwen calls. TODO: calculate this properly.
 		let dur = 5usize;
 
 		let chain_info = client.chain_info();
+		let queue_info = client.queue_info();
 		let cache_info = client.cache_info();
 		let report = client.report();
+		let sync_info = sync.status();
 
-		if let (_, &Some(ref last_cache_info), &Some(ref last_report)) = (&self.chain_info, &self.cache_info, &self.report) {
-			println!("[ {} {} ]---[ {} blk/s | {} tx/s | {} gas/s  //···{}···//  {} ({}) bl  {} ({}) ex ]",
+		if let (_, &Some(ref last_cache_info), &Some(ref last_report)) = (self.chain_info.read().unwrap().deref(), self.cache_info.read().unwrap().deref(), self.report.read().unwrap().deref()) {
+			println!("[ {} {} ]---[ {} blk/s | {} tx/s | {} gas/s  //··· {}/{} peers, {} downloaded, {}+{} queued ···//  {} ({}) bl  {} ({}) ex ]",
 				chain_info.best_block_number,
 				chain_info.best_block_hash,
 				(report.blocks_imported - last_report.blocks_imported) / dur,
 				(report.transactions_applied - last_report.transactions_applied) / dur,
 				(report.gas_processed - last_report.gas_processed) / From::from(dur),
-				0, // TODO: peers
+
+				sync_info.num_active_peers,
+				sync_info.num_peers,
+				sync_info.blocks_received,
+				queue_info.unverified_queue_size,
+				queue_info.verified_queue_size,
+
 				cache_info.blocks,
 				cache_info.blocks as isize - last_cache_info.blocks as isize,
 				cache_info.block_details,
@@ -109,28 +125,28 @@ impl Informant {
 			);
 		}
 
-		self.chain_info = Some(chain_info);
-		self.cache_info = Some(cache_info);
-		self.report = Some(report);
+		*self.chain_info.write().unwrap().deref_mut() = Some(chain_info);
+		*self.cache_info.write().unwrap().deref_mut() = Some(cache_info);
+		*self.report.write().unwrap().deref_mut() = Some(report);
 	}
 }
 
+const INFO_TIMER: TimerToken = 0;
+
 struct ClientIoHandler {
-	client: Arc<RwLock<Client>>,
-	timer: TimerToken,
+	client: Arc<Client>,
+	sync: Arc<EthSync>,
 	info: Informant,
 }
 
 impl IoHandler<NetSyncMessage> for ClientIoHandler {
-	fn initialize<'s>(&'s mut self, io: &mut IoContext<'s, NetSyncMessage>) { 
-		self.timer = io.register_timer(5000).expect("Error registering timer");
+	fn initialize(&self, io: &IoContext<NetSyncMessage>) { 
+		io.register_timer(INFO_TIMER, 5000).expect("Error registering timer");
 	}
 
-	fn timeout<'s>(&'s mut self, _io: &mut IoContext<'s, NetSyncMessage>, timer: TimerToken) {
-		if self.timer == timer {
-			let client = self.client.read().unwrap();
-			client.tick();
-			self.info.tick(client.deref());
+	fn timeout(&self, _io: &IoContext<NetSyncMessage>, timer: TimerToken) {
+		if INFO_TIMER == timer {
+			self.info.tick(&self.client, &self.sync);
 		}
 	}
 }
diff --git a/src/block.rs b/src/block.rs
index ac0ef7f89..1ff326430 100644
--- a/src/block.rs
+++ b/src/block.rs
@@ -1,3 +1,5 @@
+#![allow(ptr_arg)] // Because of &LastHashes -> &Vec<_>
+
 use common::*;
 use engine::*;
 use state::*;
@@ -173,7 +175,7 @@ impl<'x, 'y> OpenBlock<'x, 'y> {
 			timestamp: self.block.header.timestamp,
 			difficulty: self.block.header.difficulty.clone(),
 			last_hashes: self.last_hashes.clone(),		// TODO: should be a reference.
-			gas_used: self.block.archive.last().map(|t| t.receipt.gas_used).unwrap_or(U256::from(0)),
+			gas_used: self.block.archive.last().map_or(U256::zero(), |t| t.receipt.gas_used),
 			gas_limit: self.block.header.gas_limit.clone(),
 		}
 	}
@@ -204,7 +206,7 @@ impl<'x, 'y> OpenBlock<'x, 'y> {
 		s.block.header.state_root = s.block.state.root().clone();
 		s.block.header.receipts_root = ordered_trie_root(s.block.archive.iter().map(|ref e| e.receipt.rlp_bytes()).collect());
 		s.block.header.log_bloom = s.block.archive.iter().fold(LogBloom::zero(), |mut b, e| {b |= &e.receipt.log_bloom; b});
-		s.block.header.gas_used = s.block.archive.last().map(|t| t.receipt.gas_used).unwrap_or(U256::from(0));
+		s.block.header.gas_used = s.block.archive.last().map_or(U256::zero(), |t| t.receipt.gas_used);
 		s.block.header.note_dirty();
 
 		ClosedBlock::new(s, uncle_bytes)
@@ -255,7 +257,7 @@ impl SealedBlock {
 		let mut block_rlp = RlpStream::new_list(3);
 		self.block.header.stream_rlp(&mut block_rlp, Seal::With);
 		block_rlp.append_list(self.block.archive.len());
-		for e in self.block.archive.iter() { e.transaction.rlp_append(&mut block_rlp); }
+		for e in &self.block.archive { e.transaction.rlp_append(&mut block_rlp); }
 		block_rlp.append_raw(&self.uncle_bytes, 1);
 		block_rlp.out()
 	}
diff --git a/src/queue.rs b/src/block_queue.rs
similarity index 85%
rename from src/queue.rs
rename to src/block_queue.rs
index 7c74b56d7..239c559c5 100644
--- a/src/queue.rs
+++ b/src/block_queue.rs
@@ -1,12 +1,25 @@
+//! A queue of blocks. Sits between network or other I/O and the BlockChain.
+//! Sorts them ready for blockchain insertion.
 use std::thread::{JoinHandle, self};
 use std::sync::atomic::{AtomicBool, Ordering as AtomicOrdering};
 use util::*;
 use verification::*;
 use error::*;
 use engine::Engine;
-use sync::*;
 use views::*;
 use header::*;
+use service::*;
+
+/// Block queue status
+#[derive(Debug)]
+pub struct BlockQueueInfo {
+	/// Indicates that queue is full
+	pub full: bool,
+	/// Number of queued blocks pending verification
+	pub unverified_queue_size: usize,
+	/// Number of verified queued blocks pending import
+	pub verified_queue_size: usize,
+}
 
 /// A queue of blocks. Sits between network or other I/O and the BlockChain.
 /// Sorts them ready for blockchain insertion.
@@ -63,14 +76,15 @@ impl BlockQueue {
 		let deleting = Arc::new(AtomicBool::new(false));
 
 		let mut verifiers: Vec<JoinHandle<()>> = Vec::new();
-		let thread_count = max(::num_cpus::get(), 2) - 1;
-		for _ in 0..thread_count {
+		let thread_count = max(::num_cpus::get(), 3) - 2;
+		for i in 0..thread_count {
 			let verification = verification.clone();
 			let engine = engine.clone();
 			let more_to_verify = more_to_verify.clone();
 			let ready_signal = ready_signal.clone();
 			let deleting = deleting.clone();
-			verifiers.push(thread::spawn(move || BlockQueue::verify(verification, engine, more_to_verify, ready_signal,  deleting)));
+			verifiers.push(thread::Builder::new().name(format!("Verifier #{}", i)).spawn(move || BlockQueue::verify(verification, engine, more_to_verify, ready_signal,  deleting))
+				.expect("Error starting block verification thread"));
 		}
 		BlockQueue {
 			engine: engine,
@@ -204,7 +218,7 @@ impl BlockQueue {
 		verification.verified = new_verified;
 	}
 
-	/// TODO [arkpar] Please document me
+	/// Removes up to `max` verified blocks from the queue
 	pub fn drain(&mut self, max: usize) -> Vec<PreVerifiedBlock> {
 		let mut verification = self.verification.lock().unwrap();
 		let count = min(max, verification.verified.len());
@@ -215,8 +229,21 @@ impl BlockQueue {
 			result.push(block);
 		}
 		self.ready_signal.reset();
+		if !verification.verified.is_empty() {
+			self.ready_signal.set();
+		}
 		result
 	}
+
+	/// Get queue status.
+	pub fn queue_info(&self) -> BlockQueueInfo {
+		let verification = self.verification.lock().unwrap();
+		BlockQueueInfo {
+			full: false,
+			verified_queue_size: verification.verified.len(),
+			unverified_queue_size: verification.unverified.len(),
+		}
+	}
 }
 
 impl Drop for BlockQueue {
@@ -234,7 +261,7 @@ impl Drop for BlockQueue {
 mod tests {
 	use util::*;
 	use spec::*;
-	use queue::*;
+	use block_queue::*;
 
 	#[test]
 	fn test_block_queue() {
diff --git a/src/blockchain.rs b/src/blockchain.rs
index 27abe9ee3..39390de97 100644
--- a/src/blockchain.rs
+++ b/src/blockchain.rs
@@ -153,9 +153,8 @@ impl BlockProvider for BlockChain {
 	fn block(&self, hash: &H256) -> Option<Bytes> {
 		{
 			let read = self.blocks.read().unwrap();
-			match read.get(hash) {
-				Some(v) => return Some(v.clone()),
-				None => ()
+			if let Some(v) = read.get(hash) {
+				return Some(v.clone());
 			}
 		}
 
@@ -188,7 +187,7 @@ impl BlockProvider for BlockChain {
 
 const COLLECTION_QUEUE_SIZE: usize = 2;
 const MIN_CACHE_SIZE: usize = 1;
-const MAX_CACHE_SIZE: usize = 1024 * 1024 * 1;
+const MAX_CACHE_SIZE: usize = 1024 * 1024;
 
 impl BlockChain {
 	/// Create new instance of blockchain from given Genesis
@@ -342,19 +341,19 @@ impl BlockChain {
 			Some(h) => h,
 			None => return None,
 		};
-		Some(self._tree_route((from_details, from), (to_details, to)))
+		Some(self._tree_route((&from_details, &from), (&to_details, &to)))
 	}
 
 	/// Similar to `tree_route` function, but can be used to return a route
 	/// between blocks which may not be in database yet.
-	fn _tree_route(&self, from: (BlockDetails, H256), to: (BlockDetails, H256)) -> TreeRoute {
+	fn _tree_route(&self, from: (&BlockDetails, &H256), to: (&BlockDetails, &H256)) -> TreeRoute {
 		let mut from_branch = vec![];
 		let mut to_branch = vec![];
 
-		let mut from_details = from.0;
-		let mut to_details = to.0;
-		let mut current_from = from.1;
-		let mut current_to = to.1;
+		let mut from_details = from.0.clone();
+		let mut to_details = to.0.clone();
+		let mut current_from = from.1.clone();
+		let mut current_to = to.1.clone();
 
 		// reset from && to to the same level
 		while from_details.number > to_details.number {
@@ -409,7 +408,7 @@ impl BlockChain {
 
 		// store block in db
 		self.blocks_db.put(&hash, &bytes).unwrap();
-		let (batch, new_best) = self.block_to_extras_insert_batch(bytes);
+		let (batch, new_best, details) = self.block_to_extras_insert_batch(bytes);
 
 		// update best block
 		let mut best_block = self.best_block.write().unwrap();
@@ -420,6 +419,8 @@ impl BlockChain {
 		// update caches
 		let mut write = self.block_details.write().unwrap();
 		write.remove(&header.parent_hash());
+		write.insert(hash.clone(), details);
+		self.note_used(CacheID::Block(hash));
 
 		// update extras database
 		self.extras_db.write(batch).unwrap();
@@ -427,7 +428,7 @@ impl BlockChain {
 
 	/// Transforms block into WriteBatch that may be written into database
 	/// Additionally, if it's new best block it returns new best block object.
-	fn block_to_extras_insert_batch(&self, bytes: &[u8]) -> (WriteBatch, Option<BestBlock>) {
+	fn block_to_extras_insert_batch(&self, bytes: &[u8]) -> (WriteBatch, Option<BestBlock>, BlockDetails) {
 		// create views onto rlp
 		let block = BlockView::new(bytes);
 		let header = block.header_view();
@@ -459,7 +460,7 @@ impl BlockChain {
 
 		// if it's not new best block, just return
 		if !is_new_best {
-			return (batch, None);
+			return (batch, None, details);
 		}
 
 		// if its new best block we need to make sure that all ancestors
@@ -467,7 +468,7 @@ impl BlockChain {
 		// find the route between old best block and the new one
 		let best_hash = self.best_block_hash();
 		let best_details = self.block_details(&best_hash).expect("best block hash is invalid!");
-		let route = self._tree_route((best_details, best_hash), (details, hash.clone()));
+		let route = self._tree_route((&best_details, &best_hash), (&details, &hash));
 
 		match route.blocks.len() {
 			// its our parent
@@ -494,7 +495,7 @@ impl BlockChain {
 			total_difficulty: total_difficulty
 		};
 
-		(batch, Some(best_block))
+		(batch, Some(best_block), details)
 	}
 
 	/// Returns true if transaction is known.
@@ -527,9 +528,8 @@ impl BlockChain {
 		K: ExtrasSliceConvertable + Eq + Hash + Clone {
 		{
 			let read = cache.read().unwrap();
-			match read.get(hash) {
-				Some(v) => return Some(v.clone()),
-				None => ()
+			if let Some(v) = read.get(hash) {
+				return Some(v.clone());
 			}
 		}
 
@@ -549,9 +549,8 @@ impl BlockChain {
 		T: ExtrasIndexable {
 		{
 			let read = cache.read().unwrap();
-			match read.get(hash) {
-				Some(_) => return true,
-				None => ()
+			if let Some(_) = read.get(hash) {
+				return true;
 			}
 		}
 
@@ -670,6 +669,7 @@ mod tests {
 	}
 
 	#[test]
+	#[allow(cyclomatic_complexity)]
 	fn test_small_fork() {
 		let genesis = "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".from_hex().unwrap();
 		let b1 = "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".from_hex().unwrap();
diff --git a/src/builtin.rs b/src/builtin.rs
index 1835eda97..00d0bbeb5 100644
--- a/src/builtin.rs
+++ b/src/builtin.rs
@@ -94,16 +94,13 @@ pub fn new_builtin_exec(name: &str) -> Option<Box<Fn(&[u8], &mut [u8])>> {
 			if it.v == H256::from(&U256::from(27)) || it.v == H256::from(&U256::from(28)) {
 				let s = Signature::from_rsv(&it.r, &it.s, it.v[31] - 27);
 				if ec::is_valid(&s) {
-					match ec::recover(&s, &it.hash) {
-						Ok(p) => {
-							let r = p.as_slice().sha3();
-							// NICE: optimise and separate out into populate-like function
-							for i in 0..min(32, output.len()) {
-								output[i] = if i < 12 {0} else {r[i]};
-							}
+					if let Ok(p) = ec::recover(&s, &it.hash) {
+						let r = p.as_slice().sha3();
+						// NICE: optimise and separate out into populate-like function
+						for i in 0..min(32, output.len()) {
+							output[i] = if i < 12 {0} else {r[i]};
 						}
-						_ => {}
-					};
+					}
 				}
 			}
 		})),
diff --git a/src/client.rs b/src/client.rs
index b0801f097..6f47d0601 100644
--- a/src/client.rs
+++ b/src/client.rs
@@ -6,8 +6,8 @@ use error::*;
 use header::BlockNumber;
 use spec::Spec;
 use engine::Engine;
-use queue::BlockQueue;
-use sync::NetSyncMessage;
+use block_queue::{BlockQueue, BlockQueueInfo};
+use service::NetSyncMessage;
 use env_info::LastHashes;
 use verification::*;
 use block::*;
@@ -46,13 +46,6 @@ impl fmt::Display for BlockChainInfo {
 	}
 }
 
-/// Block queue status
-#[derive(Debug)]
-pub struct BlockQueueStatus {
-	/// TODO [arkpar] Please document me
-	pub full: bool,
-}
-
 /// TODO [arkpar] Please document me
 pub type TreeRoute = ::blockchain::TreeRoute;
 
@@ -95,13 +88,13 @@ pub trait BlockChainClient : Sync + Send {
 	fn block_receipts(&self, hash: &H256) -> Option<Bytes>;
 
 	/// Import a block into the blockchain.
-	fn import_block(&mut self, bytes: Bytes) -> ImportResult;
+	fn import_block(&self, bytes: Bytes) -> ImportResult;
 
 	/// Get block queue information.
-	fn queue_status(&self) -> BlockQueueStatus;
+	fn queue_info(&self) -> BlockQueueInfo;
 
 	/// Clear block queue and abort all import activity.
-	fn clear_queue(&mut self);
+	fn clear_queue(&self);
 
 	/// Get blockchain information.
 	fn chain_info(&self) -> BlockChainInfo;
@@ -132,19 +125,21 @@ pub struct Client {
 	chain: Arc<RwLock<BlockChain>>,
 	engine: Arc<Box<Engine>>,
 	state_db: JournalDB,
-	queue: BlockQueue,
-	report: ClientReport,
+	block_queue: RwLock<BlockQueue>,
+	report: RwLock<ClientReport>,
+	uncommited_states: RwLock<HashMap<H256, JournalDB>>,
+	import_lock: Mutex<()>
 }
 
 const HISTORY: u64 = 1000;
 
 impl Client {
 	/// Create a new client with given spec and DB path.
-	pub fn new(spec: Spec, path: &Path, message_channel: IoChannel<NetSyncMessage> ) -> Result<Client, Error> {
+	pub fn new(spec: Spec, path: &Path, message_channel: IoChannel<NetSyncMessage> ) -> Result<Arc<Client>, Error> {
 		let chain = Arc::new(RwLock::new(BlockChain::new(&spec.genesis_block(), path)));
 		let mut opts = Options::new();
-		opts.create_if_missing(true);
 		opts.set_max_open_files(256);
+		opts.create_if_missing(true);
 		/*opts.set_use_fsync(false);
 		opts.set_bytes_per_sync(8388608);
 		opts.set_disable_data_sync(false);
@@ -164,37 +159,40 @@ impl Client {
 
 		let mut state_path = path.to_path_buf();
 		state_path.push("state");
-		let db = DB::open(&opts, state_path.to_str().unwrap()).unwrap();
-		let mut state_db = JournalDB::new(db);
+		let db = Arc::new(DB::open(&opts, state_path.to_str().unwrap()).unwrap());
 		
 		let engine = Arc::new(try!(spec.to_engine()));
-		if engine.spec().ensure_db_good(&mut state_db) {
-			state_db.commit(0, &engine.spec().genesis_header().hash(), None).expect("Error commiting genesis state to state DB");
+		{
+			let mut state_db = JournalDB::new_with_arc(db.clone());
+			if engine.spec().ensure_db_good(&mut state_db) {
+				state_db.commit(0, &engine.spec().genesis_header().hash(), None).expect("Error commiting genesis state to state DB");
+			}
 		}
+		let state_db = JournalDB::new_with_arc(db);
 
-//		chain.write().unwrap().ensure_good(&state_db);
-
-		Ok(Client {
+		Ok(Arc::new(Client {
 			chain: chain,
 			engine: engine.clone(),
 			state_db: state_db,
-			queue: BlockQueue::new(engine, message_channel),
-			report: Default::default(),
-		})
+			block_queue: RwLock::new(BlockQueue::new(engine, message_channel)),
+			report: RwLock::new(Default::default()),
+			uncommited_states: RwLock::new(HashMap::new()),
+			import_lock: Mutex::new(()),
+		}))
 	}
 
 	/// This is triggered by a message coming from a block queue when the block is ready for insertion
-	pub fn import_verified_blocks(&mut self) {
-		
+	pub fn import_verified_blocks(&self, _io: &IoChannel<NetSyncMessage>) {
 		let mut bad = HashSet::new();
-		let blocks = self.queue.drain(128); 
+		let _import_lock = self.import_lock.lock();
+		let blocks = self.block_queue.write().unwrap().drain(128); 
 		if blocks.is_empty() {
 			return;
 		}
 
 		for block in blocks {
 			if bad.contains(&block.header.parent_hash) {
-				self.queue.mark_as_bad(&block.header.hash());
+				self.block_queue.write().unwrap().mark_as_bad(&block.header.hash());
 				bad.insert(block.header.hash());
 				continue;
 			}
@@ -202,7 +200,7 @@ impl Client {
 			let header = &block.header;
 			if let Err(e) = verify_block_family(&header, &block.bytes, self.engine.deref().deref(), self.chain.read().unwrap().deref()) {
 				warn!(target: "client", "Stage 3 block verification failed for #{} ({})\nError: {:?}", header.number(), header.hash(), e);
-				self.queue.mark_as_bad(&header.hash());
+				self.block_queue.write().unwrap().mark_as_bad(&header.hash());
 				bad.insert(block.header.hash());
 				return;
 			};
@@ -210,7 +208,7 @@ impl Client {
 				Some(p) => p,
 				None => {
 					warn!(target: "client", "Block import failed for #{} ({}): Parent not found ({}) ", header.number(), header.hash(), header.parent_hash);
-					self.queue.mark_as_bad(&header.hash());
+					self.block_queue.write().unwrap().mark_as_bad(&header.hash());
 					bad.insert(block.header.hash());
 					return;
 				},
@@ -228,18 +226,19 @@ impl Client {
 				}
 			}
 
-			let result = match enact_verified(&block, self.engine.deref().deref(), self.state_db.clone(), &parent, &last_hashes) {
+			let db = self.state_db.clone();
+			let result = match enact_verified(&block, self.engine.deref().deref(), db, &parent, &last_hashes) {
 				Ok(b) => b,
 				Err(e) => {
 					warn!(target: "client", "Block import failed for #{} ({})\nError: {:?}", header.number(), header.hash(), e);
 				bad.insert(block.header.hash());
-					self.queue.mark_as_bad(&header.hash());
+					self.block_queue.write().unwrap().mark_as_bad(&header.hash());
 					return;
 				}
 			};
 			if let Err(e) = verify_block_final(&header, result.block().header()) {
 				warn!(target: "client", "Stage 4 block verification failed for #{} ({})\nError: {:?}", header.number(), header.hash(), e);
-				self.queue.mark_as_bad(&header.hash());
+				self.block_queue.write().unwrap().mark_as_bad(&header.hash());
 				return;
 			}
 
@@ -252,12 +251,16 @@ impl Client {
 					return;
 				}
 			}
-			self.report.accrue_block(&block);
-
+			self.report.write().unwrap().accrue_block(&block);
 			trace!(target: "client", "Imported #{} ({})", header.number(), header.hash());
 		}
 	}
 
+	/// Clear cached state overlay 
+	pub fn clear_state(&self, hash: &H256) {
+		self.uncommited_states.write().unwrap().remove(hash);
+	}
+
 	/// Get info on the cache.
 	pub fn cache_info(&self) -> CacheSize {
 		self.chain.read().unwrap().cache_size()
@@ -265,7 +268,7 @@ impl Client {
 
 	/// Get the report.
 	pub fn report(&self) -> ClientReport {
-		self.report.clone()
+		self.report.read().unwrap().clone()
 	}
 
 	/// Tick the client.
@@ -328,21 +331,20 @@ impl BlockChainClient for Client {
 		unimplemented!();
 	}
 
-	fn import_block(&mut self, bytes: Bytes) -> ImportResult {
+	fn import_block(&self, bytes: Bytes) -> ImportResult {
 		let header = BlockView::new(&bytes).header();
 		if self.chain.read().unwrap().is_known(&header.hash()) {
 			return Err(ImportError::AlreadyInChain);
 		}
-		self.queue.import_block(bytes)
+		self.block_queue.write().unwrap().import_block(bytes)
 	}
 
-	fn queue_status(&self) -> BlockQueueStatus {
-		BlockQueueStatus {
-			full: false
-		}
+	fn queue_info(&self) -> BlockQueueInfo {
+		self.block_queue.read().unwrap().queue_info()
 	}
 
-	fn clear_queue(&mut self) {
+	fn clear_queue(&self) {
+		self.block_queue.write().unwrap().clear();
 	}
 
 	fn chain_info(&self) -> BlockChainInfo {
diff --git a/src/env_info.rs b/src/env_info.rs
index 1246234ff..76d33cd5a 100644
--- a/src/env_info.rs
+++ b/src/env_info.rs
@@ -25,8 +25,14 @@ pub struct EnvInfo {
 }
 
 impl EnvInfo {
-	/// TODO [debris] Please document me
+	/// Create empty env_info initialized with zeros
 	pub fn new() -> EnvInfo {
+		EnvInfo::default()
+	}
+}
+
+impl Default for EnvInfo {
+	fn default() -> Self {
 		EnvInfo {
 			number: 0,
 			author: Address::new(),
@@ -53,11 +59,3 @@ impl FromJson for EnvInfo {
 		}
 	}
 }
-
-/// TODO: it should be the other way around.
-/// `new` should call `default`.
-impl Default for EnvInfo {
-	fn default() -> Self {
-		EnvInfo::new()
-	}
-}
diff --git a/src/ethereum/ethash.rs b/src/ethereum/ethash.rs
index ecfdb0541..aebee1e92 100644
--- a/src/ethereum/ethash.rs
+++ b/src/ethereum/ethash.rs
@@ -32,13 +32,13 @@ impl Ethash {
 	}
 
 	fn u64_param(&self, name: &str) -> u64 {
-		*self.u64_params.write().unwrap().entry(name.to_string()).or_insert_with(||
-			self.spec().engine_params.get(name).map(|a| decode(&a)).unwrap_or(0u64))
+		*self.u64_params.write().unwrap().entry(name.to_owned()).or_insert_with(||
+			self.spec().engine_params.get(name).map_or(0u64, |a| decode(&a)))
 	}
 
 	fn u256_param(&self, name: &str) -> U256 {
-		*self.u256_params.write().unwrap().entry(name.to_string()).or_insert_with(||
-			self.spec().engine_params.get(name).map(|a| decode(&a)).unwrap_or(x!(0)))
+		*self.u256_params.write().unwrap().entry(name.to_owned()).or_insert_with(||
+			self.spec().engine_params.get(name).map_or(x!(0), |a| decode(&a)))
 	}
 }
 
@@ -84,7 +84,7 @@ impl Engine for Ethash {
 	/// Apply the block reward on finalisation of the block.
 	/// This assumes that all uncles are valid uncles (i.e. of at least one generation before the current).
 	fn on_close_block(&self, block: &mut Block) {
-		let reward = self.spec().engine_params.get("blockReward").map(|a| decode(&a)).unwrap_or(U256::from(0u64));
+		let reward = self.spec().engine_params.get("blockReward").map_or(U256::from(0u64), |a| decode(&a));
 		let fields = block.fields();
 
 		// Bestow block reward
@@ -153,6 +153,7 @@ impl Engine for Ethash {
 	}
 }
 
+#[allow(wrong_self_convention)] // to_ethash should take self
 impl Ethash {
 	fn calculate_difficuty(&self, header: &Header, parent: &Header) -> U256 {
 		const EXP_DIFF_PERIOD: u64 = 100000;
diff --git a/src/evm/factory.rs b/src/evm/factory.rs
index 439bee5da..9f76d25ec 100644
--- a/src/evm/factory.rs
+++ b/src/evm/factory.rs
@@ -68,10 +68,11 @@ impl Factory {
 	fn jit() -> Box<Evm> {
 		unimplemented!()
 	}
-
+}
+impl Default for Factory {
 	/// Returns jitvm factory
 	#[cfg(feature = "jit")]
-	pub fn default() -> Factory {
+	fn default() -> Factory {
 		Factory {
 			evm: VMType::Jit
 		}
@@ -79,7 +80,7 @@ impl Factory {
 
 	/// Returns native rust evm factory
 	#[cfg(not(feature = "jit"))]
-	pub fn default() -> Factory {
+	fn default() -> Factory {
 		Factory {
 			evm: VMType::Interpreter
 		}
diff --git a/src/evm/interpreter.rs b/src/evm/interpreter.rs
index 88823cbea..ba151825e 100644
--- a/src/evm/interpreter.rs
+++ b/src/evm/interpreter.rs
@@ -7,19 +7,19 @@ use super::instructions::Instruction;
 use std::marker::Copy;
 use evm::{MessageCallResult, ContractCreateResult};
 
-#[cfg(not(feature = "evm_debug"))]
+#[cfg(not(feature = "evm-debug"))]
 macro_rules! evm_debug {
 	($x: expr) => {}
 }
 
-#[cfg(feature = "evm_debug")]
+#[cfg(feature = "evm-debug")]
 macro_rules! evm_debug {
 	($x: expr) => {
 		$x
 	}
 }
 
-#[cfg(feature = "evm_debug")]
+#[cfg(feature = "evm-debug")]
 fn color(instruction: Instruction, name: &'static str) -> String {
 	let c = instruction as usize % 6;
 	let colors = [31, 34, 33, 32, 35, 36];
@@ -72,7 +72,7 @@ impl<S : Copy> VecStack<S> {
 
 impl<S : fmt::Display> Stack<S> for VecStack<S> {
 	fn peek(&self, no_from_top: usize) -> &S {
-		return &self.stack[self.stack.len() - no_from_top - 1];
+		&self.stack[self.stack.len() - no_from_top - 1]
 	}
 
 	fn swap_with_top(&mut self, no_from_top: usize) {
@@ -157,7 +157,7 @@ impl Memory for Vec<u8> {
 	}
 
 	fn size(&self) -> usize {
-		return self.len()
+		self.len()
 	}
 
 	fn read_slice(&self, init_off_u: U256, init_size_u: U256) -> &[u8] {
@@ -228,6 +228,7 @@ struct CodeReader<'a> {
 	code: &'a Bytes
 }
 
+#[allow(len_without_is_empty)]
 impl<'a> CodeReader<'a> {
 	/// Get `no_of_bytes` from code and convert to U256. Move PC
 	fn read(&mut self, no_of_bytes: usize) -> U256 {
@@ -330,6 +331,7 @@ impl evm::Evm for Interpreter {
 }
 
 impl Interpreter {
+	#[allow(cyclomatic_complexity)]
 	fn get_gas_cost_mem(&self,
 						ext: &evm::Ext,
 						instruction: Instruction,
@@ -716,7 +718,7 @@ impl Interpreter {
 				let big_id = stack.pop_back();
 				let id = big_id.low_u64() as usize;
 				let max = id.wrapping_add(32);
-				let data = params.data.clone().unwrap_or(vec![]);
+				let data = params.data.clone().unwrap_or_else(|| vec![]);
 				let bound = cmp::min(data.len(), max);
 				if id < bound && big_id < U256::from(data.len()) {
 					let mut v = data[id..bound].to_vec();
@@ -727,7 +729,7 @@ impl Interpreter {
 				}
 			},
 			instructions::CALLDATASIZE => {
-				stack.push(U256::from(params.data.clone().unwrap_or(vec![]).len()));
+				stack.push(U256::from(params.data.clone().map_or(0, |l| l.len())));
 			},
 			instructions::CODESIZE => {
 				stack.push(U256::from(code.len()));
@@ -738,10 +740,10 @@ impl Interpreter {
 				stack.push(U256::from(len));
 			},
 			instructions::CALLDATACOPY => {
-				self.copy_data_to_memory(mem, stack, &params.data.clone().unwrap_or(vec![]));
+				self.copy_data_to_memory(mem, stack, &params.data.clone().unwrap_or_else(|| vec![]));
 			},
 			instructions::CODECOPY => {
-				self.copy_data_to_memory(mem, stack, &params.code.clone().unwrap_or(vec![]));
+				self.copy_data_to_memory(mem, stack, &params.code.clone().unwrap_or_else(|| vec![]));
 			},
 			instructions::EXTCODECOPY => {
 				let address = u256_to_address(&stack.pop_back());
@@ -781,7 +783,7 @@ impl Interpreter {
 	fn copy_data_to_memory(&self,
 						   mem: &mut Memory,
 						   stack: &mut Stack<U256>,
-						   data: &Bytes) {
+						   data: &[u8]) {
 		let offset = stack.pop_back();
 		let index = stack.pop_back();
 		let size = stack.pop_back();
@@ -1051,7 +1053,7 @@ impl Interpreter {
 		Ok(())
 	}
 
-	fn find_jump_destinations(&self, code: &Bytes) -> HashSet<CodePosition> {
+	fn find_jump_destinations(&self, code: &[u8]) -> HashSet<CodePosition> {
 		let mut jump_dests = HashSet::new();
 		let mut position = 0;
 
@@ -1066,7 +1068,7 @@ impl Interpreter {
 			position += 1;
 		}
 
-		return jump_dests;
+		jump_dests
 	}
 }
 
diff --git a/src/evm/tests.rs b/src/evm/tests.rs
index 8e1b5eff4..ef5987285 100644
--- a/src/evm/tests.rs
+++ b/src/evm/tests.rs
@@ -19,7 +19,7 @@ struct FakeExt {
 	logs: Vec<FakeLogEntry>,
 	_suicides: HashSet<Address>,
 	info: EnvInfo,
-	_schedule: Schedule
+	schedule: Schedule
 }
 
 impl FakeExt {
@@ -89,7 +89,7 @@ impl Ext for FakeExt {
 	}
 
 	fn schedule(&self) -> &Schedule {
-		&self._schedule
+		&self.schedule
 	}
 
 	fn env_info(&self) -> &EnvInfo {
@@ -122,7 +122,7 @@ fn test_stack_underflow() {
 	};
 	
 	match err {
-		evm::Error::StackUnderflow {instruction: _, wanted, on_stack} => {
+		evm::Error::StackUnderflow {wanted, on_stack, ..} => {
 			assert_eq!(wanted, 2);
 			assert_eq!(on_stack, 0);
 		}
diff --git a/src/executive.rs b/src/executive.rs
index 6c2b29e3f..7671f3cc9 100644
--- a/src/executive.rs
+++ b/src/executive.rs
@@ -75,7 +75,7 @@ impl<'a> Executive<'a> {
 	}
 
 	/// Creates `Externalities` from `Executive`.
-	pub fn to_externalities<'_>(&'_ mut self, origin_info: OriginInfo, substate: &'_ mut Substate, output: OutputPolicy<'_>) -> Externalities {
+	pub fn as_externalities<'_>(&'_ mut self, origin_info: OriginInfo, substate: &'_ mut Substate, output: OutputPolicy<'_>) -> Externalities {
 		Externalities::new(self.state, self.info, self.engine, self.depth, origin_info, substate, output)
 	}
 
@@ -123,8 +123,8 @@ impl<'a> Executive<'a> {
 
 		let mut substate = Substate::new();
 
-		let res = match t.action() {
-			&Action::Create => {
+		let res = match *t.action() {
+			Action::Create => {
 				let new_address = contract_address(&sender, &nonce);
 				let params = ActionParams {
 					code_address: new_address.clone(),
@@ -139,7 +139,7 @@ impl<'a> Executive<'a> {
 				};
 				self.create(params, &mut substate)
 			},
-			&Action::Call(ref address) => {
+			Action::Call(ref address) => {
 				let params = ActionParams {
 					code_address: address.clone(),
 					address: address.clone(),
@@ -177,7 +177,7 @@ impl<'a> Executive<'a> {
 			// if destination is builtin, try to execute it
 			
 			let default = [];
-			let data = if let &Some(ref d) = &params.data { d as &[u8] } else { &default as &[u8] };
+			let data = if let Some(ref d) = params.data { d as &[u8] } else { &default as &[u8] };
 
 			let cost = self.engine.cost_of_builtin(&params.code_address, data);
 			match cost <= params.gas {
@@ -198,7 +198,7 @@ impl<'a> Executive<'a> {
 			let mut unconfirmed_substate = Substate::new();
 
 			let res = {
-				let mut ext = self.to_externalities(OriginInfo::from(&params), &mut unconfirmed_substate, OutputPolicy::Return(output));
+				let mut ext = self.as_externalities(OriginInfo::from(&params), &mut unconfirmed_substate, OutputPolicy::Return(output));
 				self.engine.vm_factory().create().exec(params, &mut ext)
 			};
 
@@ -230,7 +230,7 @@ impl<'a> Executive<'a> {
 		self.state.transfer_balance(&params.sender, &params.address, &params.value);
 
 		let res = {
-			let mut ext = self.to_externalities(OriginInfo::from(&params), &mut unconfirmed_substate, OutputPolicy::InitContract);
+			let mut ext = self.as_externalities(OriginInfo::from(&params), &mut unconfirmed_substate, OutputPolicy::InitContract);
 			self.engine.vm_factory().create().exec(params, &mut ext)
 		};
 		self.enact_result(&res, substate, unconfirmed_substate, backup);
@@ -248,7 +248,7 @@ impl<'a> Executive<'a> {
 		let refunds_bound = sstore_refunds + suicide_refunds;
 
 		// real ammount to refund
-		let gas_left_prerefund = match &result { &Ok(x) => x, _ => x!(0) };
+		let gas_left_prerefund = match result { Ok(x) => x, _ => x!(0) };
 		let refunded = cmp::min(refunds_bound, (t.gas - gas_left_prerefund) / U256::from(2));
 		let gas_left = gas_left_prerefund + refunded;
 
@@ -265,7 +265,7 @@ impl<'a> Executive<'a> {
 		self.state.add_balance(&self.info.author, &fees_value);
 
 		// perform suicides
-		for address in substate.suicides.iter() {
+		for address in &substate.suicides {
 			trace!("Killing {}", address);
 			self.state.kill_account(address);
 		}
@@ -273,11 +273,7 @@ impl<'a> Executive<'a> {
 		match result { 
 			Err(evm::Error::Internal) => Err(ExecutionError::Internal),
 			// TODO [ToDr] BadJumpDestination @debris - how to handle that?
-			Err(evm::Error::OutOfGas) 
-				| Err(evm::Error::BadJumpDestination { destination: _ }) 
-				| Err(evm::Error::BadInstruction { instruction: _ }) 
-				| Err(evm::Error::StackUnderflow {instruction: _, wanted: _, on_stack: _})
-				| Err(evm::Error::OutOfStack {instruction: _, wanted: _, limit: _}) => {
+			Err(_) => {
 				Ok(Executed {
 					gas: t.gas,
 					gas_used: t.gas,
@@ -302,15 +298,15 @@ impl<'a> Executive<'a> {
 
 	fn enact_result(&mut self, result: &evm::Result, substate: &mut Substate, un_substate: Substate, backup: State) {
 		// TODO: handle other evm::Errors same as OutOfGas once they are implemented
-		match result {
-			&Err(evm::Error::OutOfGas)
-				| &Err(evm::Error::BadJumpDestination { destination: _ }) 
-				| &Err(evm::Error::BadInstruction { instruction: _ }) 
-				| &Err(evm::Error::StackUnderflow {instruction: _, wanted: _, on_stack: _})
-				| &Err(evm::Error::OutOfStack {instruction: _, wanted: _, limit: _}) => {
+		match *result {
+			Err(evm::Error::OutOfGas)
+				| Err(evm::Error::BadJumpDestination {..}) 
+				| Err(evm::Error::BadInstruction {.. }) 
+				| Err(evm::Error::StackUnderflow {..})
+				| Err(evm::Error::OutOfStack {..}) => {
 				self.state.revert(backup);
 			},
-			&Ok(_) | &Err(evm::Error::Internal) => substate.accrue(un_substate)
+			Ok(_) | Err(evm::Error::Internal) => substate.accrue(un_substate)
 		}
 	}
 }
diff --git a/src/externalities.rs b/src/externalities.rs
index 8b16cc72b..b2d716d37 100644
--- a/src/externalities.rs
+++ b/src/externalities.rs
@@ -158,9 +158,10 @@ impl<'a> Ext for Externalities<'a> {
 	}
 
 	fn extcode(&self, address: &Address) -> Bytes {
-		self.state.code(address).unwrap_or(vec![])
+		self.state.code(address).unwrap_or_else(|| vec![])
 	}
 
+	#[allow(match_ref_pats)]
 	fn ret(&mut self, gas: &U256, data: &[u8]) -> Result<U256, evm::Error> {
 		match &mut self.output {
 			&mut OutputPolicy::Return(BytesRef::Fixed(ref mut slice)) => unsafe {
diff --git a/src/header.rs b/src/header.rs
index 28ed458fb..68526d8c6 100644
--- a/src/header.rs
+++ b/src/header.rs
@@ -2,7 +2,7 @@ use util::*;
 use basic_types::*;
 use time::now_utc;
 
-/// TODO [Gav Wood] Please document me
+/// Type for Block number
 pub type BlockNumber = u64;
 
 /// A block header.
@@ -171,9 +171,10 @@ impl Header {
 		s.append(&self.gas_used);
 		s.append(&self.timestamp);
 		s.append(&self.extra_data);
-		match with_seal {
-			Seal::With => for b in self.seal.iter() { s.append_raw(&b, 1); },
-			_ => {}
+		if let Seal::With = with_seal {
+			for b in &self.seal { 
+				s.append_raw(&b, 1); 
+			}
 		}
 	}
 
@@ -236,7 +237,7 @@ impl Encodable for Header {
 			self.timestamp.encode(e);
 			self.extra_data.encode(e);
 
-			for b in self.seal.iter() {
+			for b in &self.seal {
 				e.emit_raw(&b);
 			}
 		})
diff --git a/src/lib.rs b/src/lib.rs
index a25fa9338..262f8682f 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,8 +1,11 @@
 #![warn(missing_docs)]
 #![feature(cell_extras)]
 #![feature(augmented_assignments)]
-//#![feature(plugin)]
+#![feature(plugin)]
 //#![plugin(interpolate_idents)]
+#![plugin(clippy)]
+#![allow(needless_range_loop, match_bool)]
+
 //! Ethcore's ethereum implementation
 //!
 //! ### Rust version
@@ -73,7 +76,6 @@
 //!       sudo make install
 //!       sudo ldconfig
 //!       ```
-
 #[macro_use]
 extern crate log;
 extern crate rustc_serialize;
@@ -151,6 +153,5 @@ pub mod sync;
 pub mod block;
 /// TODO [arkpar] Please document me
 pub mod verification;
-/// TODO [debris] Please document me
-pub mod queue;
+pub mod block_queue;
 pub mod ethereum;
diff --git a/src/null_engine.rs b/src/null_engine.rs
index 3b03508a2..3c829606c 100644
--- a/src/null_engine.rs
+++ b/src/null_engine.rs
@@ -11,7 +11,7 @@ pub struct NullEngine {
 }
 
 impl NullEngine {
-	/// TODO [Tomusdrw] Please document me
+	/// Returns new instance of NullEngine with default VM Factory
 	pub fn new_boxed(spec: Spec) -> Box<Engine> {
 		Box::new(NullEngine{
 			spec: spec,
diff --git a/src/pod_state.rs b/src/pod_state.rs
index 2ab27ef1d..1ea8382a5 100644
--- a/src/pod_state.rs
+++ b/src/pod_state.rs
@@ -26,10 +26,10 @@ impl FromJson for PodState {
 			let code = acc.find("code").map(&Bytes::from_json);
 			if balance.is_some() || nonce.is_some() || storage.is_some() || code.is_some() {
 				state.insert(address_from_hex(address), PodAccount{
-					balance: balance.unwrap_or(U256::zero()),
-					nonce: nonce.unwrap_or(U256::zero()),
-					storage: storage.unwrap_or(BTreeMap::new()),
-					code: code.unwrap_or(Vec::new())
+					balance: balance.unwrap_or_else(U256::zero),
+					nonce: nonce.unwrap_or_else(U256::zero),
+					storage: storage.unwrap_or_else(BTreeMap::new),
+					code: code.unwrap_or_else(Vec::new)
 				});
 			}
 			state
diff --git a/src/receipt.rs b/src/receipt.rs
index 82620cfcd..403915fdc 100644
--- a/src/receipt.rs
+++ b/src/receipt.rs
@@ -36,7 +36,7 @@ impl RlpStandard for Receipt {
 		// TODO: make work:
 		//s.append(&self.logs);
 		s.append_list(self.logs.len());
-		for l in self.logs.iter() {
+		for l in &self.logs {
 			l.rlp_append(s);
 		}
 	}
diff --git a/src/service.rs b/src/service.rs
index 07ff4873c..7e9c3ae41 100644
--- a/src/service.rs
+++ b/src/service.rs
@@ -5,24 +5,37 @@ use error::*;
 use std::env;
 use client::Client;
 
+/// Message type for external and internal events
+#[derive(Clone)]
+pub enum SyncMessage {
+	/// New block has been imported into the blockchain
+	NewChainBlock(Bytes), //TODO: use Cow
+	/// A block is ready 
+	BlockVerified,
+}
+
+/// TODO [arkpar] Please document me
+pub type NetSyncMessage = NetworkIoMessage<SyncMessage>;
+
 /// Client service setup. Creates and registers client and network services with the IO subsystem.
 pub struct ClientService {
 	net_service: NetworkService<SyncMessage>,
-	client: Arc<RwLock<Client>>,
+	client: Arc<Client>,
+	sync: Arc<EthSync>,
 }
 
 impl ClientService {
 	/// Start the service in a separate thread.
-	pub fn start(spec: Spec, init_nodes: &Vec<String>) -> Result<ClientService, Error> {
+	pub fn start(spec: Spec, init_nodes: &[String]) -> Result<ClientService, Error> {
 		let mut net_service = try!(NetworkService::start(init_nodes));
 		info!("Starting {}", net_service.host_info());
 		info!("Configured for {} using {} engine", spec.name, spec.engine_name);
 		let mut dir = env::home_dir().unwrap();
 		dir.push(".parity");
 		dir.push(H64::from(spec.genesis_header().hash()).hex());
-		let client = Arc::new(RwLock::new(try!(Client::new(spec, &dir, net_service.io().channel()))));
-		EthSync::register(&mut net_service, client.clone());
-		let client_io = Box::new(ClientIoHandler {
+		let client = try!(Client::new(spec, &dir, net_service.io().channel()));
+		let sync = EthSync::register(&mut net_service, client.clone());
+		let client_io = Arc::new(ClientIoHandler {
 			client: client.clone()
 		});
 		try!(net_service.io().register_handler(client_io));
@@ -30,6 +43,7 @@ impl ClientService {
 		Ok(ClientService {
 			net_service: net_service,
 			client: client,
+			sync: sync,
 		})
 	}
 
@@ -44,34 +58,47 @@ impl ClientService {
 	}
 
 	/// TODO [arkpar] Please document me
-	pub fn client(&self) -> Arc<RwLock<Client>> {
+	pub fn client(&self) -> Arc<Client> {
 		self.client.clone()
+	
+	}
+	
+	/// Get shared sync handler
+	pub fn sync(&self) -> Arc<EthSync> {
+		self.sync.clone()
 	}
 }
 
 /// IO interface for the Client handler
 struct ClientIoHandler {
-	client: Arc<RwLock<Client>>
+	client: Arc<Client>
 }
 
+const CLIENT_TICK_TIMER: TimerToken = 0;
+const CLIENT_TICK_MS: u64 = 5000;
+
 impl IoHandler<NetSyncMessage> for ClientIoHandler {
-	fn initialize<'s>(&'s mut self, _io: &mut IoContext<'s, NetSyncMessage>) {
+	fn initialize(&self, io: &IoContext<NetSyncMessage>) {
+		io.register_timer(CLIENT_TICK_TIMER, CLIENT_TICK_MS).expect("Error registering client timer");
 	}
 
-	fn message<'s>(&'s mut self, _io: &mut IoContext<'s, NetSyncMessage>, net_message: &'s mut NetSyncMessage) {
-		match net_message {
-			&mut UserMessage(ref mut message) =>  {
-				match message {
-					&mut SyncMessage::BlockVerified => {
-						self.client.write().unwrap().import_verified_blocks();
-					},
-					_ => {}, // ignore other messages
-				}
-
-			}
-			_ => {}, // ignore other messages
+	fn timeout(&self, _io: &IoContext<NetSyncMessage>, timer: TimerToken) {
+		if timer == CLIENT_TICK_TIMER {
+			self.client.tick();
 		}
+	}
 
+	#[allow(match_ref_pats)]
+	#[allow(single_match)]
+	fn message(&self, io: &IoContext<NetSyncMessage>, net_message: &NetSyncMessage) {
+		if let &UserMessage(ref message) = net_message {
+			match message {
+				&SyncMessage::BlockVerified => {
+					self.client.import_verified_blocks(&io.channel());
+				},
+				_ => {}, // ignore other messages
+			}
+		}
 	}
 }
 
diff --git a/src/spec.rs b/src/spec.rs
index bb47edacf..9f98d5e2a 100644
--- a/src/spec.rs
+++ b/src/spec.rs
@@ -10,7 +10,7 @@ pub fn gzip64res_to_json(source: &[u8]) -> Json {
 	let data = source.from_base64().expect("Genesis block is malformed!");
 	let data_ref: &[u8] = &data;
 	let mut decoder = GzDecoder::new(data_ref).expect("Gzip is invalid");
-	let mut s: String = "".to_string();
+	let mut s: String = "".to_owned();
 	decoder.read_to_string(&mut s).expect("Gzip is invalid");
 	Json::from_str(&s).expect("Json is invalid")
 }
@@ -18,14 +18,14 @@ pub fn gzip64res_to_json(source: &[u8]) -> Json {
 /// Convert JSON value to equivlaent RLP representation.
 // TODO: handle container types.
 fn json_to_rlp(json: &Json) -> Bytes {
-	match json {
-		&Json::Boolean(o) => encode(&(if o {1u64} else {0})),
-		&Json::I64(o) => encode(&(o as u64)),
-		&Json::U64(o) => encode(&o),
-		&Json::String(ref s) if s.len() >= 2 && &s[0..2] == "0x" && U256::from_str(&s[2..]).is_ok() => {
+	match *json {
+		Json::Boolean(o) => encode(&(if o {1u64} else {0})),
+		Json::I64(o) => encode(&(o as u64)),
+		Json::U64(o) => encode(&o),
+		Json::String(ref s) if s.len() >= 2 && &s[0..2] == "0x" && U256::from_str(&s[2..]).is_ok() => {
 			encode(&U256::from_str(&s[2..]).unwrap())
 		},
-		&Json::String(ref s) => {
+		Json::String(ref s) => {
 			encode(s)
 		},
 		_ => panic!()
@@ -111,6 +111,7 @@ pub struct Spec {
 	state_root_memo: RwLock<Option<H256>>,
 }
 
+#[allow(wrong_self_convention)] // because to_engine(self) should be to_engine(&self)
 impl Spec {
 	/// Convert this object into a boxed Engine of the right underlying type.
 	// TODO avoid this hard-coded nastiness - use dynamic-linked plugin framework instead.
@@ -191,19 +192,19 @@ impl FromJson for Spec {
 						builtins.insert(addr.clone(), builtin);
 					}
 				}
-				let balance = acc.find("balance").and_then(|x| match x { &Json::String(ref b) => U256::from_dec_str(b).ok(), _ => None });
-				let nonce = acc.find("nonce").and_then(|x| match x { &Json::String(ref b) => U256::from_dec_str(b).ok(), _ => None });
+				let balance = acc.find("balance").and_then(|x| match *x { Json::String(ref b) => U256::from_dec_str(b).ok(), _ => None });
+				let nonce = acc.find("nonce").and_then(|x| match *x { Json::String(ref b) => U256::from_dec_str(b).ok(), _ => None });
 //				let balance = if let Some(&Json::String(ref b)) = acc.find("balance") {U256::from_dec_str(b).unwrap_or(U256::from(0))} else {U256::from(0)};
 //				let nonce = if let Some(&Json::String(ref n)) = acc.find("nonce") {U256::from_dec_str(n).unwrap_or(U256::from(0))} else {U256::from(0)};
 				// TODO: handle code & data if they exist.
 				if balance.is_some() || nonce.is_some() {
-					state.insert(addr, GenesisAccount { balance: balance.unwrap_or(U256::from(0)), nonce: nonce.unwrap_or(U256::from(0)) });
+					state.insert(addr, GenesisAccount { balance: balance.unwrap_or_else(U256::zero), nonce: nonce.unwrap_or_else(U256::zero) });
 				}
 			}
 		}
 
 		let nodes = if let Some(&Json::Array(ref ns)) = json.find("nodes") {
-			ns.iter().filter_map(|n| if let &Json::String(ref s) = n { Some(s.to_string()) } else {None}).collect()
+			ns.iter().filter_map(|n| if let Json::String(ref s) = *n { Some(s.clone()) } else {None}).collect()
 		} else { Vec::new() };
 
 		let genesis = &json["genesis"];//.as_object().expect("No genesis object in JSON");
@@ -224,8 +225,8 @@ impl FromJson for Spec {
 		};
 		
 		Spec {
-			name: json.find("name").map(|j| j.as_string().unwrap()).unwrap_or("unknown").to_string(),
-			engine_name: json["engineName"].as_string().unwrap().to_string(),
+			name: json.find("name").map_or("unknown", |j| j.as_string().unwrap()).to_owned(),
+			engine_name: json["engineName"].as_string().unwrap().to_owned(),
 			engine_params: json_to_rlp_map(&json["params"]),
 			nodes: nodes,
 			builtins: builtins,
@@ -252,7 +253,7 @@ impl Spec {
 			let mut root = H256::new(); 
 			{
 				let mut t = SecTrieDBMut::new(db, &mut root);
-				for (address, account) in self.genesis_state.iter() {
+				for (address, account) in &self.genesis_state {
 					t.insert(address.as_slice(), &account.rlp());
 				}
 			}
diff --git a/src/state.rs b/src/state.rs
index e45347fd2..4b7e5af34 100644
--- a/src/state.rs
+++ b/src/state.rs
@@ -88,22 +88,22 @@ impl State {
 
 	/// Get the balance of account `a`.
 	pub fn balance(&self, a: &Address) -> U256 {
-		self.get(a, false).as_ref().map(|account| account.balance().clone()).unwrap_or(U256::from(0u8))
+		self.get(a, false).as_ref().map_or(U256::zero(), |account| account.balance().clone())
 	}
 
 	/// Get the nonce of account `a`.
 	pub fn nonce(&self, a: &Address) -> U256 {
-		self.get(a, false).as_ref().map(|account| account.nonce().clone()).unwrap_or(U256::from(0u8))
+		self.get(a, false).as_ref().map_or(U256::zero(), |account| account.nonce().clone())
 	}
 
 	/// Mutate storage of account `a` so that it is `value` for `key`.
 	pub fn storage_at(&self, a: &Address, key: &H256) -> H256 {
-		self.get(a, false).as_ref().map(|a|a.storage_at(&self.db, key)).unwrap_or(H256::new())	
+		self.get(a, false).as_ref().map_or(H256::new(), |a|a.storage_at(&self.db, key))	
 	}
 
 	/// Mutate storage of account `a` so that it is `value` for `key`.
 	pub fn code(&self, a: &Address) -> Option<Bytes> {
-		self.get(a, true).as_ref().map(|a|a.code().map(|x|x.to_vec())).unwrap_or(None)
+		self.get(a, true).as_ref().map_or(None, |a|a.code().map(|x|x.to_vec()))
 	}
 
 	/// Add `incr` to the balance of account `a`.
@@ -170,6 +170,7 @@ impl State {
 
 	/// Commit accounts to SecTrieDBMut. This is similar to cpp-ethereum's dev::eth::commit.
 	/// `accounts` is mutable because we may need to commit the code or storage and record that.
+	#[allow(match_ref_pats)]
 	pub fn commit_into(db: &mut HashDB, root: &mut H256, accounts: &mut HashMap<Address, Option<Account>>) {
 		// first, commit the sub trees.
 		// TODO: is this necessary or can we dispense with the `ref mut a` for just `a`?
@@ -186,9 +187,9 @@ impl State {
 		{
 			let mut trie = SecTrieDBMut::from_existing(db, root);
 			for (address, ref a) in accounts.iter() {
-				match a {
-					&&Some(ref account) => trie.insert(address, &account.rlp()),
-					&&None => trie.remove(address),
+				match **a {
+					Some(ref account) => trie.insert(address, &account.rlp()),
+					None => trie.remove(address),
 				}
 			}
 		}
@@ -210,7 +211,7 @@ impl State {
 	pub fn to_hashmap_pod(&self) -> HashMap<Address, PodAccount> {
 		// TODO: handle database rather than just the cache.
 		self.cache.borrow().iter().fold(HashMap::new(), |mut m, (add, opt)| {
-			if let &Some(ref acc) = opt {
+			if let Some(ref acc) = *opt {
 				m.insert(add.clone(), PodAccount::from_account(acc));
 			}
 			m
@@ -221,7 +222,7 @@ impl State {
 	pub fn to_pod(&self) -> PodState {
 		// TODO: handle database rather than just the cache.
 		PodState::new(self.cache.borrow().iter().fold(BTreeMap::new(), |mut m, (add, opt)| {
-			if let &Some(ref acc) = opt {
+			if let Some(ref acc) = *opt {
 				m.insert(add.clone(), PodAccount::from_account(acc));
 			}
 			m
diff --git a/src/state_diff.rs b/src/state_diff.rs
index 28d92e59e..08fccf3ed 100644
--- a/src/state_diff.rs
+++ b/src/state_diff.rs
@@ -15,7 +15,7 @@ impl StateDiff {
 
 impl fmt::Display for StateDiff {
 	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-		for (add, acc) in self.0.iter() {
+		for (add, acc) in &self.0 {
 			try!(write!(f, "{} {}: {}", acc.existance(), add, acc));
 		}
 		Ok(())
diff --git a/src/sync/chain.rs b/src/sync/chain.rs
index dba9ae08d..c55cb0a6e 100644
--- a/src/sync/chain.rs
+++ b/src/sync/chain.rs
@@ -107,6 +107,10 @@ pub struct SyncStatus {
 	pub blocks_total: usize,
 	/// Number of blocks downloaded so far.
 	pub blocks_received: usize,
+	/// Total number of connected peers
+	pub num_peers: usize,
+	/// Total number of active peers
+	pub num_active_peers: usize,
 }
 
 #[derive(PartialEq, Eq, Debug)]
@@ -195,8 +199,10 @@ impl ChainSync {
 			start_block_number: self.starting_block,
 			last_imported_block_number: self.last_imported_block,
 			highest_block_number: self.highest_block,
-			blocks_total: (self.last_imported_block - self.starting_block) as usize,
-			blocks_received: (self.highest_block - self.starting_block) as usize,
+			blocks_received: (self.last_imported_block - self.starting_block) as usize,
+			blocks_total: (self.highest_block - self.starting_block) as usize,
+			num_peers: self.peers.len(),
+			num_active_peers: self.peers.values().filter(|p| p.asking != PeerAsking::Nothing).count(),
 		}
 	}
 
@@ -212,7 +218,7 @@ impl ChainSync {
 		self.downloading_bodies.clear();
 		self.headers.clear();
 		self.bodies.clear();
-		for (_, ref mut p) in self.peers.iter_mut() {
+		for (_, ref mut p) in &mut self.peers {
 			p.asking_blocks.clear();
 		}
 		self.header_ids.clear();
@@ -268,6 +274,7 @@ impl ChainSync {
 		Ok(())
 	}
 
+	#[allow(cyclomatic_complexity)]
 	/// Called by peer once it has new block headers during sync
 	fn on_peer_block_headers(&mut self, io: &mut SyncIo, peer_id: PeerId, r: &UntrustedRlp) -> Result<(), PacketDecodeError> {
 		self.reset_peer_asking(peer_id, PeerAsking::BlockHeaders);
@@ -375,7 +382,7 @@ impl ChainSync {
 				transactions_root: tx_root,
 				uncles: uncles
 			};
-			match self.header_ids.get(&header_id).map(|n| *n) {
+			match self.header_ids.get(&header_id).cloned() {
 				Some(n) => {
 					self.header_ids.remove(&header_id);
 					self.bodies.insert_item(n, body.as_raw().to_vec());
@@ -424,6 +431,10 @@ impl ChainSync {
 			let peer_difficulty = self.peers.get_mut(&peer_id).expect("ChainSync: unknown peer").difficulty;
 			if difficulty > peer_difficulty {
 				trace!(target: "sync", "Received block {:?}  with no known parent. Peer needs syncing...", h);
+				{
+					let peer = self.peers.get_mut(&peer_id).expect("ChainSync: unknown peer");
+					peer.latest = header_view.sha3();
+				}
 				self.sync_peer(io, peer_id, true);
 			}
 		}
@@ -540,7 +551,7 @@ impl ChainSync {
 	fn request_blocks(&mut self, io: &mut SyncIo, peer_id: PeerId) {
 		self.clear_peer_download(peer_id);
 
-		if io.chain().queue_status().full {
+		if io.chain().queue_info().full {
 			self.pause_sync();
 			return;
 		}
@@ -699,16 +710,13 @@ impl ChainSync {
 	/// Used to recover from an error and re-download parts of the chain detected as bad.
 	fn remove_downloaded_blocks(&mut self, start: BlockNumber) {
 		for n in self.headers.get_tail(&start) {
-			match self.headers.find_item(&n) {
-				Some(ref header_data) => {
-					let header_to_delete = HeaderView::new(&header_data.data);
-					let header_id = HeaderId {
-						transactions_root: header_to_delete.transactions_root(),
-						uncles: header_to_delete.uncles_hash()
-					};
-					self.header_ids.remove(&header_id);
-				},
-				None => {}
+			if let Some(ref header_data) = self.headers.find_item(&n) {
+				let header_to_delete = HeaderView::new(&header_data.data);
+				let header_id = HeaderId {
+					transactions_root: header_to_delete.transactions_root(),
+					uncles: header_to_delete.uncles_hash()
+				};
+				self.header_ids.remove(&header_id);
 			}
 			self.downloading_bodies.remove(&n);
 			self.downloading_headers.remove(&n);
@@ -796,12 +804,9 @@ impl ChainSync {
 		packet.append(&chain.best_block_hash);
 		packet.append(&chain.genesis_hash);
 		//TODO: handle timeout for status request
-		match io.send(peer_id, STATUS_PACKET, packet.out()) {
-			Err(e) => {
-				warn!(target:"sync", "Error sending status request: {:?}", e);
-				io.disable_peer(peer_id);
-			}
-			Ok(_) => ()
+		if let Err(e) = io.send(peer_id, STATUS_PACKET, packet.out()) {
+			warn!(target:"sync", "Error sending status request: {:?}", e);
+			io.disable_peer(peer_id);
 		}
 	}
 
@@ -837,12 +842,9 @@ impl ChainSync {
 		let mut data = Bytes::new();
 		let inc = (skip + 1) as BlockNumber;
 		while number <= last && number > 0 && count < max_count {
-			match io.chain().block_header_at(number) {
-				Some(mut hdr) => {
-					data.append(&mut hdr);
-					count += 1;
-				}
-				None => {}
+			if let Some(mut hdr) = io.chain().block_header_at(number) {
+				data.append(&mut hdr);
+				count += 1;
 			}
 			if reverse {
 				if number <= inc {
@@ -874,12 +876,9 @@ impl ChainSync {
 		let mut added = 0usize;
 		let mut data = Bytes::new();
 		for i in 0..count {
-			match io.chain().block_body(&try!(r.val_at::<H256>(i))) {
-				Some(mut hdr) => {
-					data.append(&mut hdr);
-					added += 1;
-				}
-				None => {}
+			if let Some(mut hdr) = io.chain().block_body(&try!(r.val_at::<H256>(i))) {
+				data.append(&mut hdr);
+				added += 1;
 			}
 		}
 		let mut rlp = RlpStream::new_list(added);
@@ -901,12 +900,9 @@ impl ChainSync {
 		let mut added = 0usize;
 		let mut data = Bytes::new();
 		for i in 0..count {
-			match io.chain().state_data(&try!(r.val_at::<H256>(i))) {
-				Some(mut hdr) => {
-					data.append(&mut hdr);
-					added += 1;
-				}
-				None => {}
+			if let Some(mut hdr) = io.chain().state_data(&try!(r.val_at::<H256>(i))) {
+				data.append(&mut hdr);
+				added += 1;
 			}
 		}
 		let mut rlp = RlpStream::new_list(added);
@@ -927,12 +923,9 @@ impl ChainSync {
 		let mut added = 0usize;
 		let mut data = Bytes::new();
 		for i in 0..count {
-			match io.chain().block_receipts(&try!(r.val_at::<H256>(i))) {
-				Some(mut hdr) => {
-					data.append(&mut hdr);
-					added += 1;
-				}
-				None => {}
+			if let Some(mut hdr) = io.chain().block_receipts(&try!(r.val_at::<H256>(i))) {
+				data.append(&mut hdr);
+				added += 1;
 			}
 		}
 		let mut rlp = RlpStream::new_list(added);
@@ -967,7 +960,7 @@ impl ChainSync {
 	}
 
 	/// Maintain other peers. Send out any new blocks and transactions
-	pub fn maintain_sync(&mut self, _io: &mut SyncIo) {
+	pub fn _maintain_sync(&mut self, _io: &mut SyncIo) {
 	}
 }
 
diff --git a/src/sync/io.rs b/src/sync/io.rs
index affcbc0d7..501d36ad2 100644
--- a/src/sync/io.rs
+++ b/src/sync/io.rs
@@ -1,7 +1,7 @@
 use client::BlockChainClient;
 use util::{NetworkContext, PeerId, PacketId,};
 use util::error::UtilError;
-use sync::SyncMessage;
+use service::SyncMessage;
 
 /// IO interface for the syning handler.
 /// Provides peer connection management and an interface to the blockchain client.
@@ -14,7 +14,7 @@ pub trait SyncIo {
 	/// Send a packet to a peer.
 	fn send(&mut self, peer_id: PeerId, packet_id: PacketId, data: Vec<u8>) -> Result<(), UtilError>;
 	/// Get the blockchain
-	fn chain<'s>(&'s mut self) -> &'s mut BlockChainClient;
+	fn chain(&self) -> &BlockChainClient;
 	/// Returns peer client identifier string
 	fn peer_info(&self, peer_id: PeerId) -> String {
 		peer_id.to_string()
@@ -22,14 +22,14 @@ pub trait SyncIo {
 }
 
 /// Wraps `NetworkContext` and the blockchain client
-pub struct NetSyncIo<'s, 'h, 'io> where 'h: 's, 'io: 'h {
-	network: &'s mut NetworkContext<'h, 'io, SyncMessage>,
-	chain: &'s mut BlockChainClient
+pub struct NetSyncIo<'s, 'h> where 'h: 's {
+	network: &'s NetworkContext<'h, SyncMessage>,
+	chain: &'s BlockChainClient
 }
 
-impl<'s, 'h, 'io> NetSyncIo<'s, 'h, 'io> {
+impl<'s, 'h> NetSyncIo<'s, 'h> {
 	/// Creates a new instance from the `NetworkContext` and the blockchain client reference.
-	pub fn new(network: &'s mut NetworkContext<'h, 'io, SyncMessage>, chain: &'s mut BlockChainClient) -> NetSyncIo<'s,'h,'io> {
+	pub fn new(network: &'s NetworkContext<'h, SyncMessage>, chain: &'s BlockChainClient) -> NetSyncIo<'s, 'h> {
 		NetSyncIo {
 			network: network,
 			chain: chain,
@@ -37,7 +37,7 @@ impl<'s, 'h, 'io> NetSyncIo<'s, 'h, 'io> {
 	}
 }
 
-impl<'s, 'h, 'op> SyncIo for NetSyncIo<'s, 'h, 'op> {
+impl<'s, 'h> SyncIo for NetSyncIo<'s, 'h> {
 	fn disable_peer(&mut self, peer_id: PeerId) {
 		self.network.disable_peer(peer_id);
 	}
@@ -50,7 +50,7 @@ impl<'s, 'h, 'op> SyncIo for NetSyncIo<'s, 'h, 'op> {
 		self.network.send(peer_id, packet_id, data)
 	}
 
-	fn chain<'a>(&'a mut self) -> &'a mut BlockChainClient {
+	fn chain(&self) -> &BlockChainClient {
 		self.chain
 	}
 
diff --git a/src/sync/mod.rs b/src/sync/mod.rs
index 1ebc34d28..78a5d7613 100644
--- a/src/sync/mod.rs
+++ b/src/sync/mod.rs
@@ -17,7 +17,7 @@
 /// fn main() {
 /// 	let mut service = NetworkService::start().unwrap();
 /// 	let dir = env::temp_dir();
-/// 	let client = Arc::new(Client::new(ethereum::new_frontier(), &dir).unwrap());
+/// 	let client = Client::new(ethereum::new_frontier(), &dir, service.io().channel()).unwrap();
 /// 	EthSync::register(&mut service, client);
 /// }
 /// ```
@@ -25,10 +25,9 @@
 use std::ops::*;
 use std::sync::*;
 use client::Client;
-use util::network::{NetworkProtocolHandler, NetworkService, NetworkContext, PeerId, NetworkIoMessage};
-use util::TimerToken;
-use util::Bytes;
+use util::network::{NetworkProtocolHandler, NetworkService, NetworkContext, PeerId};
 use sync::chain::ChainSync;
+use service::SyncMessage;
 use sync::io::NetSyncIo;
 
 mod chain;
@@ -38,76 +37,57 @@ mod range_collection;
 #[cfg(test)]
 mod tests;
 
-/// Message type for external events
-pub enum SyncMessage {
-	/// New block has been imported into the blockchain
-	NewChainBlock(Bytes),
-	/// A block is ready 
-	BlockVerified,
-}
-
-/// TODO [arkpar] Please document me
-pub type NetSyncMessage = NetworkIoMessage<SyncMessage>;
-
 /// Ethereum network protocol handler
 pub struct EthSync {
 	/// Shared blockchain client. TODO: this should evetually become an IPC endpoint
-	chain: Arc<RwLock<Client>>,
+	chain: Arc<Client>,
 	/// Sync strategy
-	sync: ChainSync
+	sync: RwLock<ChainSync>
 }
 
 pub use self::chain::SyncStatus;
 
 impl EthSync {
 	/// Creates and register protocol with the network service
-	pub fn register(service: &mut NetworkService<SyncMessage>, chain: Arc<RwLock<Client>>) {
-		let sync = Box::new(EthSync {
+	pub fn register(service: &mut NetworkService<SyncMessage>, chain: Arc<Client>) -> Arc<EthSync> {
+		let sync = Arc::new(EthSync {
 			chain: chain,
-			sync: ChainSync::new(),
+			sync: RwLock::new(ChainSync::new()),
 		});
-		service.register_protocol(sync, "eth", &[62u8, 63u8]).expect("Error registering eth protocol handler");
+		service.register_protocol(sync.clone(), "eth", &[62u8, 63u8]).expect("Error registering eth protocol handler");
+		sync
 	}
 
 	/// Get sync status
 	pub fn status(&self) -> SyncStatus {
-		self.sync.status()
+		self.sync.read().unwrap().status()
 	}
 
 	/// Stop sync
 	pub fn stop(&mut self, io: &mut NetworkContext<SyncMessage>) {
-		self.sync.abort(&mut NetSyncIo::new(io, self.chain.write().unwrap().deref_mut()));
+		self.sync.write().unwrap().abort(&mut NetSyncIo::new(io, self.chain.deref()));
 	}
 
 	/// Restart sync
 	pub fn restart(&mut self, io: &mut NetworkContext<SyncMessage>) {
-		self.sync.restart(&mut NetSyncIo::new(io, self.chain.write().unwrap().deref_mut()));
+		self.sync.write().unwrap().restart(&mut NetSyncIo::new(io, self.chain.deref()));
 	}
 }
 
 impl NetworkProtocolHandler<SyncMessage> for EthSync {
-	fn initialize(&mut self, io: &mut NetworkContext<SyncMessage>) {
-		self.sync.restart(&mut NetSyncIo::new(io, self.chain.write().unwrap().deref_mut()));
-		io.register_timer(1000).unwrap();
+	fn initialize(&self, _io: &NetworkContext<SyncMessage>) {
 	}
 
-	fn read(&mut self, io: &mut NetworkContext<SyncMessage>, peer: &PeerId, packet_id: u8, data: &[u8]) {
-		self.sync.on_packet(&mut NetSyncIo::new(io, self.chain.write().unwrap().deref_mut()) , *peer, packet_id, data);
+	fn read(&self, io: &NetworkContext<SyncMessage>, peer: &PeerId, packet_id: u8, data: &[u8]) {
+		self.sync.write().unwrap().on_packet(&mut NetSyncIo::new(io, self.chain.deref()) , *peer, packet_id, data);
 	}
 
-	fn connected(&mut self, io: &mut NetworkContext<SyncMessage>, peer: &PeerId) {
-		self.sync.on_peer_connected(&mut NetSyncIo::new(io, self.chain.write().unwrap().deref_mut()), *peer);
+	fn connected(&self, io: &NetworkContext<SyncMessage>, peer: &PeerId) {
+		self.sync.write().unwrap().on_peer_connected(&mut NetSyncIo::new(io, self.chain.deref()), *peer);
 	}
 
-	fn disconnected(&mut self, io: &mut NetworkContext<SyncMessage>, peer: &PeerId) {
-		self.sync.on_peer_aborting(&mut NetSyncIo::new(io, self.chain.write().unwrap().deref_mut()), *peer);
-	}
-
-	fn timeout(&mut self, io: &mut NetworkContext<SyncMessage>, _timer: TimerToken) {
-		self.sync.maintain_sync(&mut NetSyncIo::new(io, self.chain.write().unwrap().deref_mut()));
-	}
-
-	fn message(&mut self, _io: &mut NetworkContext<SyncMessage>, _message: &SyncMessage) {
+	fn disconnected(&self, io: &NetworkContext<SyncMessage>, peer: &PeerId) {
+		self.sync.write().unwrap().on_peer_aborting(&mut NetSyncIo::new(io, self.chain.deref()), *peer);
 	}
 }
 
diff --git a/src/sync/range_collection.rs b/src/sync/range_collection.rs
index d212625be..b8186e5a5 100644
--- a/src/sync/range_collection.rs
+++ b/src/sync/range_collection.rs
@@ -29,7 +29,7 @@ pub trait RangeCollection<K, V> {
 	/// Remove all elements >= `tail`
 	fn insert_item(&mut self, key: K, value: V);
 	/// Get an iterator over ranges
-	fn range_iter<'c>(&'c self) -> RangeIterator<'c, K, V>;
+	fn range_iter(& self) -> RangeIterator<K, V>;
 }
 
 /// Range iterator. For each range yelds a key for the first element of the range and a vector of values.
@@ -60,7 +60,7 @@ impl<'c, K:'c, V:'c> Iterator for RangeIterator<'c, K, V> where K: Add<Output =
 }
 
 impl<K, V> RangeCollection<K, V> for Vec<(K, Vec<V>)> where K: Ord + PartialEq + Add<Output = K> + Sub<Output = K> + Copy + FromUsize + ToUsize {
-	fn range_iter<'c>(&'c self) -> RangeIterator<'c, K, V> {
+	fn range_iter(&self) -> RangeIterator<K, V> {
 		RangeIterator {
 			range: self.len(),
 			collection: self
@@ -191,6 +191,7 @@ impl<K, V> RangeCollection<K, V> for Vec<(K, Vec<V>)> where K: Ord + PartialEq +
 }
 
 #[test]
+#[allow(cyclomatic_complexity)]
 fn test_range() {
 	use std::cmp::{Ordering};
 
diff --git a/src/sync/tests.rs b/src/sync/tests.rs
index 05d7ac317..7f8a1748b 100644
--- a/src/sync/tests.rs
+++ b/src/sync/tests.rs
@@ -1,38 +1,40 @@
 use util::*;
-use client::{BlockChainClient, BlockStatus, TreeRoute, BlockQueueStatus, BlockChainInfo};
+use client::{BlockChainClient, BlockStatus, TreeRoute, BlockChainInfo};
+use block_queue::BlockQueueInfo;
 use header::{Header as BlockHeader, BlockNumber};
 use error::*;
 use sync::io::SyncIo;
 use sync::chain::ChainSync;
 
 struct TestBlockChainClient {
-	blocks: HashMap<H256, Bytes>,
- 	numbers: HashMap<usize, H256>,
+	blocks: RwLock<HashMap<H256, Bytes>>,
+ 	numbers: RwLock<HashMap<usize, H256>>,
 	genesis_hash: H256,
-	last_hash: H256,
-	difficulty: U256
+	last_hash: RwLock<H256>,
+	difficulty: RwLock<U256>,
 }
 
 impl TestBlockChainClient {
 	fn new() -> TestBlockChainClient {
 
 		let mut client = TestBlockChainClient {
-			blocks: HashMap::new(),
-			numbers: HashMap::new(),
+			blocks: RwLock::new(HashMap::new()),
+			numbers: RwLock::new(HashMap::new()),
 			genesis_hash: H256::new(),
-			last_hash: H256::new(),
-			difficulty: From::from(0),
+			last_hash: RwLock::new(H256::new()),
+			difficulty: RwLock::new(From::from(0)),
 		};
 		client.add_blocks(1, true); // add genesis block
-		client.genesis_hash = client.last_hash.clone();
+		client.genesis_hash = client.last_hash.read().unwrap().clone();
 		client
 	}
 
 	pub fn add_blocks(&mut self, count: usize, empty: bool) {
-		for n in self.numbers.len()..(self.numbers.len() + count) {
+		let len = self.numbers.read().unwrap().len();
+		for n in len..(len + count) {
 			let mut header = BlockHeader::new();
 			header.difficulty = From::from(n);
-			header.parent_hash = self.last_hash.clone();
+			header.parent_hash = self.last_hash.read().unwrap().clone();
 			header.number = n as BlockNumber;
 			let mut uncles = RlpStream::new_list(if empty {0} else {1});
 			if !empty {
@@ -50,12 +52,12 @@ impl TestBlockChainClient {
 
 impl BlockChainClient for TestBlockChainClient {
 	fn block_header(&self, h: &H256) -> Option<Bytes> {
-		self.blocks.get(h).map(|r| Rlp::new(r).at(0).as_raw().to_vec())
+		self.blocks.read().unwrap().get(h).map(|r| Rlp::new(r).at(0).as_raw().to_vec())
 
 	}
 
 	fn block_body(&self, h: &H256) -> Option<Bytes> {
-		self.blocks.get(h).map(|r| {
+		self.blocks.read().unwrap().get(h).map(|r| {
 			let mut stream = RlpStream::new_list(2);
 			stream.append_raw(Rlp::new(&r).at(1).as_raw(), 1);
 			stream.append_raw(Rlp::new(&r).at(2).as_raw(), 1);
@@ -64,30 +66,30 @@ impl BlockChainClient for TestBlockChainClient {
 	}
 
 	fn block(&self, h: &H256) -> Option<Bytes> {
-		self.blocks.get(h).map(|b| b.clone())
+		self.blocks.read().unwrap().get(h).cloned()
 	}
 
 	fn block_status(&self, h: &H256) -> BlockStatus {
-		match self.blocks.get(h) {
+		match self.blocks.read().unwrap().get(h) {
 			Some(_) => BlockStatus::InChain,
 			None => BlockStatus::Unknown
 		}
 	}
 
 	fn block_header_at(&self, n: BlockNumber) -> Option<Bytes> {
-		self.numbers.get(&(n as usize)).and_then(|h| self.block_header(h))
+		self.numbers.read().unwrap().get(&(n as usize)).and_then(|h| self.block_header(h))
 	}
 
 	fn block_body_at(&self, n: BlockNumber) -> Option<Bytes> {
-		self.numbers.get(&(n as usize)).and_then(|h| self.block_body(h))
+		self.numbers.read().unwrap().get(&(n as usize)).and_then(|h| self.block_body(h))
 	}
 
 	fn block_at(&self, n: BlockNumber) -> Option<Bytes> {
-		self.numbers.get(&(n as usize)).map(|h| self.blocks.get(h).unwrap().clone())
+		self.numbers.read().unwrap().get(&(n as usize)).map(|h| self.blocks.read().unwrap().get(h).unwrap().clone())
 	}
 
 	fn block_status_at(&self, n: BlockNumber) -> BlockStatus {
-		if (n as usize) < self.blocks.len() {
+		if (n as usize) < self.blocks.read().unwrap().len() {
 			BlockStatus::InChain
 		} else {
 			BlockStatus::Unknown
@@ -110,14 +112,14 @@ impl BlockChainClient for TestBlockChainClient {
 		None
 	}
 
-	fn import_block(&mut self, b: Bytes) -> ImportResult {
+	fn import_block(&self, b: Bytes) -> ImportResult {
 		let header = Rlp::new(&b).val_at::<BlockHeader>(0);
 		let number: usize = header.number as usize;
-		if number > self.blocks.len() {
-			panic!("Unexpected block number. Expected {}, got {}", self.blocks.len(), number);
+		if number > self.blocks.read().unwrap().len() {
+			panic!("Unexpected block number. Expected {}, got {}", self.blocks.read().unwrap().len(), number);
 		}
 		if number > 0 {
-			match self.blocks.get(&header.parent_hash) {
+			match self.blocks.read().unwrap().get(&header.parent_hash) {
 				Some(parent) => {
 					let parent = Rlp::new(parent).val_at::<BlockHeader>(0);
 					if parent.number != (header.number - 1) {
@@ -129,43 +131,46 @@ impl BlockChainClient for TestBlockChainClient {
 				}
 			}
 		}
-		if number == self.numbers.len() {
-			self.difficulty = self.difficulty + header.difficulty;
-			self.last_hash = header.hash();
-			self.blocks.insert(header.hash(), b);
-			self.numbers.insert(number, header.hash());
+		let len = self.numbers.read().unwrap().len();
+		if number == len {
+			*self.difficulty.write().unwrap().deref_mut() += header.difficulty;
+			mem::replace(self.last_hash.write().unwrap().deref_mut(), header.hash());
+			self.blocks.write().unwrap().insert(header.hash(), b);
+			self.numbers.write().unwrap().insert(number, header.hash());
 			let mut parent_hash = header.parent_hash;
 			if number > 0 {
 				let mut n = number - 1;
-				while n > 0 && self.numbers[&n] != parent_hash {
-					*self.numbers.get_mut(&n).unwrap() = parent_hash.clone();
+				while n > 0 && self.numbers.read().unwrap()[&n] != parent_hash {
+					*self.numbers.write().unwrap().get_mut(&n).unwrap() = parent_hash.clone();
 					n -= 1;
-					parent_hash = Rlp::new(&self.blocks[&parent_hash]).val_at::<BlockHeader>(0).parent_hash;
+					parent_hash = Rlp::new(&self.blocks.read().unwrap()[&parent_hash]).val_at::<BlockHeader>(0).parent_hash;
 				}
 			}
 		}
 		else {
-			self.blocks.insert(header.hash(), b.to_vec());
+			self.blocks.write().unwrap().insert(header.hash(), b.to_vec());
 		}
 		Ok(())
 	}
 
-	fn queue_status(&self) -> BlockQueueStatus {
-		BlockQueueStatus {
+	fn queue_info(&self) -> BlockQueueInfo {
+		BlockQueueInfo {
 			full: false,
+			verified_queue_size: 0,
+			unverified_queue_size: 0,
 		}
 	}
 
-	fn clear_queue(&mut self) {
+	fn clear_queue(&self) {
 	}
 
 	fn chain_info(&self) -> BlockChainInfo {
 		BlockChainInfo {
-			total_difficulty: self.difficulty,
-			pending_total_difficulty: self.difficulty,
+			total_difficulty: *self.difficulty.read().unwrap(),
+			pending_total_difficulty: *self.difficulty.read().unwrap(),
 			genesis_hash: self.genesis_hash.clone(),
-			best_block_hash: self.last_hash.clone(),
-			best_block_number: self.blocks.len() as BlockNumber - 1,
+			best_block_hash: self.last_hash.read().unwrap().clone(),
+			best_block_number: self.blocks.read().unwrap().len() as BlockNumber - 1,
 		}
 	}
 }
@@ -208,7 +213,7 @@ impl<'p> SyncIo for TestIo<'p> {
 		Ok(())
 	}
 
-	fn chain<'a>(&'a mut self) -> &'a mut BlockChainClient {
+	fn chain(&self) -> &BlockChainClient {
 		self.chain
 	}
 }
@@ -265,17 +270,14 @@ impl TestNet {
 
 	pub fn sync_step(&mut self) {
 		for peer in 0..self.peers.len() {
-			match self.peers[peer].queue.pop_front() {
-				Some(packet) => {
-					let mut p = self.peers.get_mut(packet.recipient).unwrap();
-					trace!("--- {} -> {} ---", peer, packet.recipient);
-					p.sync.on_packet(&mut TestIo::new(&mut p.chain, &mut p.queue, Some(peer as PeerId)), peer as PeerId, packet.packet_id, &packet.data);
-					trace!("----------------");
-				},
-				None => {}
+			if let Some(packet) = self.peers[peer].queue.pop_front() {
+				let mut p = self.peers.get_mut(packet.recipient).unwrap();
+				trace!("--- {} -> {} ---", peer, packet.recipient);
+				p.sync.on_packet(&mut TestIo::new(&mut p.chain, &mut p.queue, Some(peer as PeerId)), peer as PeerId, packet.packet_id, &packet.data);
+				trace!("----------------");
 			}
 			let mut p = self.peers.get_mut(peer).unwrap();
-			p.sync.maintain_sync(&mut TestIo::new(&mut p.chain, &mut p.queue, None));
+			p.sync._maintain_sync(&mut TestIo::new(&mut p.chain, &mut p.queue, None));
 		}
 	}
 
@@ -300,7 +302,7 @@ fn full_sync_two_peers() {
 	net.peer_mut(2).chain.add_blocks(1000, false);
 	net.sync();
 	assert!(net.peer(0).chain.block_at(1000).is_some());
-	assert_eq!(net.peer(0).chain.blocks, net.peer(1).chain.blocks);
+	assert_eq!(net.peer(0).chain.blocks.read().unwrap().deref(), net.peer(1).chain.blocks.read().unwrap().deref());
 }
 
 #[test]
@@ -313,7 +315,7 @@ fn full_sync_empty_blocks() {
 	}
 	net.sync();
 	assert!(net.peer(0).chain.block_at(1000).is_some());
-	assert_eq!(net.peer(0).chain.blocks, net.peer(1).chain.blocks);
+	assert_eq!(net.peer(0).chain.blocks.read().unwrap().deref(), net.peer(1).chain.blocks.read().unwrap().deref());
 }
 
 #[test]
@@ -329,9 +331,9 @@ fn forked_sync() {
 	net.peer_mut(1).chain.add_blocks(100, false); //fork between 1 and 2
 	net.peer_mut(2).chain.add_blocks(10, true);
 	// peer 1 has the best chain of 601 blocks
-	let peer1_chain = net.peer(1).chain.numbers.clone();
+	let peer1_chain = net.peer(1).chain.numbers.read().unwrap().clone();
 	net.sync();
-	assert_eq!(net.peer(0).chain.numbers, peer1_chain);
-	assert_eq!(net.peer(1).chain.numbers, peer1_chain);
-	assert_eq!(net.peer(2).chain.numbers, peer1_chain);
+	assert_eq!(net.peer(0).chain.numbers.read().unwrap().deref(), &peer1_chain);
+	assert_eq!(net.peer(1).chain.numbers.read().unwrap().deref(), &peer1_chain);
+	assert_eq!(net.peer(2).chain.numbers.read().unwrap().deref(), &peer1_chain);
 }
diff --git a/src/tests/executive.rs b/src/tests/executive.rs
index fe428e199..c279e20f6 100644
--- a/src/tests/executive.rs
+++ b/src/tests/executive.rs
@@ -168,7 +168,7 @@ fn do_json_test_for(vm: &VMType, json_data: &[u8]) -> Vec<String> {
 		let mut fail = false;
 		//let mut fail_unless = |cond: bool| if !cond && !fail { failed.push(name.to_string()); fail = true };
 		let mut fail_unless = |cond: bool, s: &str | if !cond && !fail { 
-			failed.push(format!("[{}] {}: {}", vm, name.to_string(), s)); 
+			failed.push(format!("[{}] {}: {}", vm, name, s)); 
 			fail = true 
 		};
 	
@@ -187,15 +187,9 @@ fn do_json_test_for(vm: &VMType, json_data: &[u8]) -> Vec<String> {
 			BTreeMap::from_json(&s["storage"]).into_iter().foreach(|(k, v)| state.set_storage(&address, k, v));
 		});
 
-		let mut info = EnvInfo::new();
-
-		test.find("env").map(|env| {
-			info.author = xjson!(&env["currentCoinbase"]);
-			info.difficulty = xjson!(&env["currentDifficulty"]);
-			info.gas_limit = xjson!(&env["currentGasLimit"]);
-			info.number = xjson!(&env["currentNumber"]);
-			info.timestamp = xjson!(&env["currentTimestamp"]);
-		});
+		let info = test.find("env").map(|env| {
+			EnvInfo::from_json(env)
+		}).unwrap_or_default();
 
 		let engine = TestEngine::new(1, vm.clone());
 
@@ -245,7 +239,7 @@ fn do_json_test_for(vm: &VMType, json_data: &[u8]) -> Vec<String> {
 				test.find("post").map(|pre| for (addr, s) in pre.as_object().unwrap() {
 					let address = Address::from(addr.as_ref());
 
-					fail_unless(state.code(&address).unwrap_or(vec![]) == Bytes::from_json(&s["code"]), "code is incorrect");
+					fail_unless(state.code(&address).unwrap_or_else(|| vec![]) == Bytes::from_json(&s["code"]), "code is incorrect");
 					fail_unless(state.balance(&address) == xjson!(&s["balance"]), "balance is incorrect");
 					fail_unless(state.nonce(&address) == xjson!(&s["nonce"]), "nonce is incorrect");
 					BTreeMap::from_json(&s["storage"]).iter().foreach(|(k, v)| fail_unless(&state.storage_at(&address, &k) == v, "storage is incorrect"));
@@ -266,7 +260,7 @@ fn do_json_test_for(vm: &VMType, json_data: &[u8]) -> Vec<String> {
 	}
 
 
-	for f in failed.iter() {
+	for f in &failed {
 		println!("FAILED: {:?}", f);
 	}
 
@@ -277,11 +271,10 @@ fn do_json_test_for(vm: &VMType, json_data: &[u8]) -> Vec<String> {
 declare_test!{ExecutiveTests_vmArithmeticTest, "VMTests/vmArithmeticTest"}
 declare_test!{ExecutiveTests_vmBitwiseLogicOperationTest, "VMTests/vmBitwiseLogicOperationTest"}
 // this one crashes with some vm internal error. Separately they pass.
-declare_test_ignore!{ExecutiveTests_vmBlockInfoTest, "VMTests/vmBlockInfoTest"}
+declare_test!{ignore => ExecutiveTests_vmBlockInfoTest, "VMTests/vmBlockInfoTest"}
 declare_test!{ExecutiveTests_vmEnvironmentalInfoTest, "VMTests/vmEnvironmentalInfoTest"}
 declare_test!{ExecutiveTests_vmIOandFlowOperationsTest, "VMTests/vmIOandFlowOperationsTest"}
-// this one take way too long.
-declare_test_ignore!{ExecutiveTests_vmInputLimits, "VMTests/vmInputLimits"}
+declare_test!{heavy => ExecutiveTests_vmInputLimits, "VMTests/vmInputLimits"}
 declare_test!{ExecutiveTests_vmLogTest, "VMTests/vmLogTest"}
 declare_test!{ExecutiveTests_vmPerformanceTest, "VMTests/vmPerformanceTest"}
 declare_test!{ExecutiveTests_vmPushDupSwapTest, "VMTests/vmPushDupSwapTest"}
diff --git a/src/tests/state.rs b/src/tests/state.rs
index 119e7037a..75b9b2493 100644
--- a/src/tests/state.rs
+++ b/src/tests/state.rs
@@ -15,7 +15,7 @@ fn do_json_test(json_data: &[u8]) -> Vec<String> {
 		let mut fail = false;
 		{
 			let mut fail_unless = |cond: bool| if !cond && !fail {
-				failed.push(name.to_string());
+				failed.push(name.clone());
 				flush(format!("FAIL\n"));
 				fail = true;
 				true
@@ -73,20 +73,20 @@ fn do_json_test(json_data: &[u8]) -> Vec<String> {
 
 declare_test!{StateTests_stBlockHashTest, "StateTests/stBlockHashTest"}
 declare_test!{StateTests_stCallCodes, "StateTests/stCallCodes"}
-declare_test_ignore!{StateTests_stCallCreateCallCodeTest, "StateTests/stCallCreateCallCodeTest"}	//<< Out of stack
-declare_test!{StateTests_stDelegatecallTest, "StateTests/stDelegatecallTest"}						//<< FAIL - gas too high
+declare_test!{ignore => StateTests_stCallCreateCallCodeTest, "StateTests/stCallCreateCallCodeTest"}	//<< Out of stack
+declare_test!{StateTests_stDelegatecallTest, "StateTests/stDelegatecallTest"}
 declare_test!{StateTests_stExample, "StateTests/stExample"}
 declare_test!{StateTests_stInitCodeTest, "StateTests/stInitCodeTest"}
 declare_test!{StateTests_stLogTests, "StateTests/stLogTests"}
-declare_test!{StateTests_stMemoryStressTest, "StateTests/stMemoryStressTest"}
-declare_test!{StateTests_stMemoryTest, "StateTests/stMemoryTest"}
+declare_test!{heavy => StateTests_stMemoryStressTest, "StateTests/stMemoryStressTest"}
+declare_test!{heavy => StateTests_stMemoryTest, "StateTests/stMemoryTest"}
 declare_test!{StateTests_stPreCompiledContracts, "StateTests/stPreCompiledContracts"}
-declare_test_ignore!{StateTests_stQuadraticComplexityTest, "StateTests/stQuadraticComplexityTest"}	//<< Too long
-declare_test_ignore!{StateTests_stRecursiveCreate, "StateTests/stRecursiveCreate"}					//<< Out of stack 
+declare_test!{heavy => StateTests_stQuadraticComplexityTest, "StateTests/stQuadraticComplexityTest"} //<< Too long
+declare_test!{ignore => StateTests_stRecursiveCreate, "StateTests/stRecursiveCreate"} //<< Out of stack 
 declare_test!{StateTests_stRefundTest, "StateTests/stRefundTest"}
 declare_test!{StateTests_stSolidityTest, "StateTests/stSolidityTest"}
-declare_test_ignore!{StateTests_stSpecialTest, "StateTests/stSpecialTest"}							//<< Signal 11
-declare_test_ignore!{StateTests_stSystemOperationsTest, "StateTests/stSystemOperationsTest"}		//<< Signal 11
+declare_test!{ignore => StateTests_stSpecialTest, "StateTests/stSpecialTest"} //<< Out of Stack
+declare_test!{ignore => StateTests_stSystemOperationsTest, "StateTests/stSystemOperationsTest"} //<< Out of stack
 declare_test!{StateTests_stTransactionTest, "StateTests/stTransactionTest"}
 declare_test!{StateTests_stTransitionTest, "StateTests/stTransitionTest"}
 declare_test!{StateTests_stWalletTest, "StateTests/stWalletTest"}
diff --git a/src/tests/test_common.rs b/src/tests/test_common.rs
index 15c5364c4..87e7b979e 100644
--- a/src/tests/test_common.rs
+++ b/src/tests/test_common.rs
@@ -1,24 +1,34 @@
 pub use common::*;
 
+macro_rules! test {
+	($name: expr) => {
+		assert!(do_json_test(include_bytes!(concat!("../../res/ethereum/tests/", $name, ".json"))).is_empty());
+	}
+}
+
 #[macro_export]
 macro_rules! declare_test {
-	($id: ident, $name: expr) => {
-		#[test]
-		#[allow(non_snake_case)]
-		fn $id() {
-			assert!(do_json_test(include_bytes!(concat!("../../res/ethereum/tests/", $name, ".json"))).len() == 0);
-		}
-	};
-}
-
-#[macro_export]
-macro_rules! declare_test_ignore {
-	($id: ident, $name: expr) => {
-		#[test]
+	(ignore => $id: ident, $name: expr) => {
 		#[ignore]
+		#[test]
 		#[allow(non_snake_case)]
 		fn $id() {
-			assert!(do_json_test(include_bytes!(concat!("../../res/ethereum/tests/", $name, ".json"))).len() == 0);
+			test!($name);
 		}
 	};
+	(heavy => $id: ident, $name: expr) => {
+		#[cfg(feature = "test-heavy")]
+		#[test]
+		#[allow(non_snake_case)]
+		fn $id() {
+			test!($name);
+		}
+	};
+	($id: ident, $name: expr) => {
+		#[test]
+		#[allow(non_snake_case)]
+		fn $id() {
+			test!($name);
+		}
+	}
 }
diff --git a/src/tests/transaction.rs b/src/tests/transaction.rs
index d4836ca84..59a6db7cb 100644
--- a/src/tests/transaction.rs
+++ b/src/tests/transaction.rs
@@ -9,13 +9,13 @@ fn do_json_test(json_data: &[u8]) -> Vec<String> {
 	let ot = RefCell::new(Transaction::new());
 	for (name, test) in json.as_object().unwrap() {
 		let mut fail = false;
-		let mut fail_unless = |cond: bool| if !cond && !fail { failed.push(name.to_string()); println!("Transaction: {:?}", ot.borrow()); fail = true };
+		let mut fail_unless = |cond: bool| if !cond && !fail { failed.push(name.clone()); println!("Transaction: {:?}", ot.borrow()); fail = true };
 		let schedule = match test.find("blocknumber")
 			.and_then(|j| j.as_string())
 			.and_then(|s| BlockNumber::from_str(s).ok())
 			.unwrap_or(0) { x if x < 900000 => &old_schedule, _ => &new_schedule };
 		let rlp = Bytes::from_json(&test["rlp"]);
-		let res = UntrustedRlp::new(&rlp).as_val().map_err(|e| From::from(e)).and_then(|t: Transaction| t.validate(schedule, schedule.have_delegate_call));
+		let res = UntrustedRlp::new(&rlp).as_val().map_err(From::from).and_then(|t: Transaction| t.validate(schedule, schedule.have_delegate_call));
 		fail_unless(test.find("transaction").is_none() == res.is_err());
 		if let (Some(&Json::Object(ref tx)), Some(&Json::String(ref expect_sender))) = (test.find("transaction"), test.find("sender")) {
 			let t = res.unwrap();
@@ -30,11 +30,11 @@ fn do_json_test(json_data: &[u8]) -> Vec<String> {
 				fail_unless(to == &xjson!(&tx["to"]));
 			} else {
 				*ot.borrow_mut() = t.clone();
-				fail_unless(Bytes::from_json(&tx["to"]).len() == 0);
+				fail_unless(Bytes::from_json(&tx["to"]).is_empty());
 			}
 		}
 	}
-	for f in failed.iter() {
+	for f in &failed {
 		println!("FAILED: {:?}", f);
 	}
 	failed
@@ -65,14 +65,14 @@ declare_test!{TransactionTests/ttTransactionTest}
 declare_test!{TransactionTests/tt10mbDataField}
 declare_test!{TransactionTests/ttWrongRLPTransaction}
 declare_test!{TransactionTests/Homestead/ttTransactionTest}
-declare_test!{TransactionTests/Homestead/tt10mbDataField}
+declare_test!{heavy => TransactionTests/Homestead/tt10mbDataField}
 declare_test!{TransactionTests/Homestead/ttWrongRLPTransaction}
 declare_test!{TransactionTests/RandomTests/tr201506052141PYTHON}*/
 
 declare_test!{TransactionTests_ttTransactionTest, "TransactionTests/ttTransactionTest"}
-declare_test_ignore!{TransactionTests_tt10mbDataField, "TransactionTests/tt10mbDataField"}
+declare_test!{heavy => TransactionTests_tt10mbDataField, "TransactionTests/tt10mbDataField"}
 declare_test!{TransactionTests_ttWrongRLPTransaction, "TransactionTests/ttWrongRLPTransaction"}
 declare_test!{TransactionTests_Homestead_ttTransactionTest, "TransactionTests/Homestead/ttTransactionTest"}
-declare_test_ignore!{TransactionTests_Homestead_tt10mbDataField, "TransactionTests/Homestead/tt10mbDataField"}
+declare_test!{heavy => TransactionTests_Homestead_tt10mbDataField, "TransactionTests/Homestead/tt10mbDataField"}
 declare_test!{TransactionTests_Homestead_ttWrongRLPTransaction, "TransactionTests/Homestead/ttWrongRLPTransaction"}
 declare_test!{TransactionTests_RandomTests_tr201506052141PYTHON, "TransactionTests/RandomTests/tr201506052141PYTHON"}
diff --git a/src/transaction.rs b/src/transaction.rs
index 081870e4b..47b8fa91f 100644
--- a/src/transaction.rs
+++ b/src/transaction.rs
@@ -117,9 +117,8 @@ impl Transaction {
 		};
 		s.append(&self.value);
 		s.append(&self.data);
-		match with_seal {
-			Seal::With => { s.append(&(self.v as u16)).append(&self.r).append(&self.s); },
-			_ => {}
+		if let Seal::With = with_seal {
+			s.append(&(self.v as u16)).append(&self.r).append(&self.s);
 		}
 	}
 
@@ -138,7 +137,7 @@ impl FromJson for Transaction {
 			gas_price: xjson!(&json["gasPrice"]),
 			gas: xjson!(&json["gasLimit"]),
 			action: match Bytes::from_json(&json["to"]) {
-				ref x if x.len() == 0 => Action::Create,
+				ref x if x.is_empty() => Action::Create,
 				ref x => Action::Call(Address::from_slice(x)),
 			},
 			value: xjson!(&json["value"]),
@@ -303,4 +302,4 @@ fn signing() {
 	let key = KeyPair::create().unwrap();
 	let t = Transaction::new_create(U256::from(42u64), b"Hello!".to_vec(), U256::from(3000u64), U256::from(50_000u64), U256::from(1u64)).signed(&key.secret());
 	assert_eq!(Address::from(key.public().sha3()), t.sender().unwrap());
-}
\ No newline at end of file
+}
diff --git a/src/verification.rs b/src/verification.rs
index 3d852dc3e..064c0b7d7 100644
--- a/src/verification.rs
+++ b/src/verification.rs
@@ -64,7 +64,7 @@ pub fn verify_block_unordered(header: Header, bytes: Bytes, engine: &Engine) ->
 /// Phase 3 verification. Check block information against parent and uncles.
 pub fn verify_block_family<BC>(header: &Header, bytes: &[u8], engine: &Engine, bc: &BC) -> Result<(), Error> where BC: BlockProvider {
 	// TODO: verify timestamp
-	let parent = try!(bc.block_header(&header.parent_hash).ok_or::<Error>(From::from(BlockError::UnknownParent(header.parent_hash.clone()))));
+	let parent = try!(bc.block_header(&header.parent_hash).ok_or_else(|| Error::from(BlockError::UnknownParent(header.parent_hash.clone()))));
 	try!(verify_parent(&header, &parent));
 	try!(engine.verify_block_family(&header, &parent, Some(bytes)));
 
@@ -122,7 +122,7 @@ pub fn verify_block_family<BC>(header: &Header, bytes: &[u8], engine: &Engine, b
 			// cB.p^7	-------------/
 			// cB.p^8
 			let mut expected_uncle_parent = header.parent_hash.clone();
-			let uncle_parent = try!(bc.block_header(&uncle.parent_hash).ok_or::<Error>(From::from(BlockError::UnknownUncleParent(uncle.parent_hash.clone()))));
+			let uncle_parent = try!(bc.block_header(&uncle.parent_hash).ok_or_else(|| Error::from(BlockError::UnknownUncleParent(uncle.parent_hash.clone()))));
 			for _ in 0..depth {
 				match bc.block_details(&expected_uncle_parent) {
 					Some(details) => { 
@@ -284,7 +284,7 @@ mod tests {
 
 		/// Get raw block data
 		fn block(&self, hash: &H256) -> Option<Bytes> {
-			self.blocks.get(hash).map(|b| b.clone())
+			self.blocks.get(hash).cloned()
 		}
 
 		/// Get the familial details concerning a block.
@@ -302,7 +302,7 @@ mod tests {
 
 		/// Get the hash of given block's number.
 		fn block_hash(&self, index: BlockNumber) -> Option<H256> {
-			self.numbers.get(&index).map(|h| h.clone())
+			self.numbers.get(&index).cloned()
 		}
 	}
 
diff --git a/src/views.rs b/src/views.rs
index a9c723ef2..e1c704625 100644
--- a/src/views.rs
+++ b/src/views.rs
@@ -141,7 +141,7 @@ impl<'a> BlockView<'a> {
 
 	/// Return List of transactions in given block.
 	pub fn transaction_views(&self) -> Vec<TransactionView> {
-		self.rlp.at(1).iter().map(|rlp| TransactionView::new_from_rlp(rlp)).collect()
+		self.rlp.at(1).iter().map(TransactionView::new_from_rlp).collect()
 	}
 
 	/// Return transaction hashes.
@@ -156,7 +156,7 @@ impl<'a> BlockView<'a> {
 
 	/// Return List of transactions in given block.
 	pub fn uncle_views(&self) -> Vec<HeaderView> {
-		self.rlp.at(2).iter().map(|rlp| HeaderView::new_from_rlp(rlp)).collect()
+		self.rlp.at(2).iter().map(HeaderView::new_from_rlp).collect()
 	}
 
 	/// Return list of uncle hashes of given block.
diff --git a/util/Cargo.toml b/util/Cargo.toml
index 02fdad17f..a91bff962 100644
--- a/util/Cargo.toml
+++ b/util/Cargo.toml
@@ -22,8 +22,10 @@ rust-crypto = "0.2.34"
 elastic-array = "0.4"
 heapsize = "0.2"
 itertools = "0.4"
+crossbeam = "0.2"
 slab = { git = "https://github.com/arkpar/slab.git" }
 sha3 = { path = "sha3" }
+clippy = "*" # Always newest, since we use nightly
 
 [dev-dependencies]
 json-tests = { path = "json-tests" }
diff --git a/util/src/bytes.rs b/util/src/bytes.rs
index 8ee98441b..a30581a1f 100644
--- a/util/src/bytes.rs
+++ b/util/src/bytes.rs
@@ -106,18 +106,18 @@ impl<'a> Deref for BytesRef<'a> {
 	type Target = [u8];
 
 	fn deref(&self) -> &[u8] {
-		match self {
-			&BytesRef::Flexible(ref bytes) => bytes,
-			&BytesRef::Fixed(ref bytes) => bytes
+		match *self {
+			BytesRef::Flexible(ref bytes) => bytes,
+			BytesRef::Fixed(ref bytes) => bytes
 		}
 	}
 }
 
 impl <'a> DerefMut for BytesRef<'a> {
 	fn deref_mut(&mut self) -> &mut [u8] {
-		match self {
-			&mut BytesRef::Flexible(ref mut bytes) => bytes,
-			&mut BytesRef::Fixed(ref mut bytes) => bytes
+		match *self {
+			BytesRef::Flexible(ref mut bytes) => bytes,
+			BytesRef::Fixed(ref mut bytes) => bytes
 		}
 	}
 }
@@ -299,7 +299,7 @@ pub trait FromBytes: Sized {
 
 impl FromBytes for String {
 	fn from_bytes(bytes: &[u8]) -> FromBytesResult<String> {
-		Ok(::std::str::from_utf8(bytes).unwrap().to_string())
+		Ok(::std::str::from_utf8(bytes).unwrap().to_owned())
 	}
 }
 
diff --git a/util/src/chainfilter.rs b/util/src/chainfilter.rs
index 41fce8521..64f9e7d39 100644
--- a/util/src/chainfilter.rs
+++ b/util/src/chainfilter.rs
@@ -323,10 +323,9 @@ impl<'a, D> ChainFilter<'a, D> where D: FilterDataSource
 			let offset = level_size * index;
 
 			// go doooown!
-			match self.blocks(bloom, from_block, to_block, max_level, offset) {
-				Some(blocks) => result.extend(blocks),
-				None => ()
-			};
+			if let Some(blocks) = self.blocks(bloom, from_block, to_block, max_level, offset) {
+				result.extend(blocks);
+			}
 		}
 
 		result
diff --git a/util/src/hash.rs b/util/src/hash.rs
index 352efed7d..252877a24 100644
--- a/util/src/hash.rs
+++ b/util/src/hash.rs
@@ -207,11 +207,11 @@ macro_rules! impl_hash {
 
 		impl FromJson for $from {
 			fn from_json(json: &Json) -> Self {
-				match json {
-					&Json::String(ref s) => {
+				match *json {
+					Json::String(ref s) => {
 						match s.len() % 2 {
 							0 => FromStr::from_str(clean_0x(s)).unwrap(),
-							_ => FromStr::from_str(&("0".to_string() + &(clean_0x(s).to_string()))[..]).unwrap()
+							_ => FromStr::from_str(&("0".to_owned() + &(clean_0x(s).to_owned()))[..]).unwrap()
 						}
 					},
 					_ => Default::default(),
@@ -221,7 +221,7 @@ macro_rules! impl_hash {
 
 		impl fmt::Debug for $from {
 			fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-				for i in self.0.iter() {
+				for i in &self.0[..] {
 					try!(write!(f, "{:02x}", i));
 				}
 				Ok(())
@@ -229,11 +229,11 @@ macro_rules! impl_hash {
 		}
 		impl fmt::Display for $from {
 			fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-				for i in self.0[0..2].iter() {
+				for i in &self.0[0..2] {
 					try!(write!(f, "{:02x}", i));
 				}
 				try!(write!(f, "…"));
-				for i in self.0[$size - 4..$size].iter() {
+				for i in &self.0[$size - 4..$size] {
 					try!(write!(f, "{:02x}", i));
 				}
 				Ok(())
@@ -291,36 +291,36 @@ macro_rules! impl_hash {
 		impl Index<usize> for $from {
 			type Output = u8;
 
-			fn index<'a>(&'a self, index: usize) -> &'a u8 {
+			fn index(&self, index: usize) -> &u8 {
 				&self.0[index]
 			}
 		}
 		impl IndexMut<usize> for $from {
-			fn index_mut<'a>(&'a mut self, index: usize) -> &'a mut u8 {
+			fn index_mut(&mut self, index: usize) -> &mut u8 {
 				&mut self.0[index]
 			}
 		}
 		impl Index<ops::Range<usize>> for $from {
 			type Output = [u8];
 
-			fn index<'a>(&'a self, index: ops::Range<usize>) -> &'a [u8] {
+			fn index(&self, index: ops::Range<usize>) -> &[u8] {
 				&self.0[index]
 			}
 		}
 		impl IndexMut<ops::Range<usize>> for $from {
-			fn index_mut<'a>(&'a mut self, index: ops::Range<usize>) -> &'a mut [u8] {
+			fn index_mut(&mut self, index: ops::Range<usize>) -> &mut [u8] {
 				&mut self.0[index]
 			}
 		}
 		impl Index<ops::RangeFull> for $from {
 			type Output = [u8];
 
-			fn index<'a>(&'a self, _index: ops::RangeFull) -> &'a [u8] {
+			fn index(&self, _index: ops::RangeFull) -> &[u8] {
 				&self.0
 			}
 		}
 		impl IndexMut<ops::RangeFull> for $from {
-			fn index_mut<'a>(&'a mut self, _index: ops::RangeFull) -> &'a mut [u8] {
+			fn index_mut(&mut self, _index: ops::RangeFull) -> &mut [u8] {
 				&mut self.0
 			}
 		}
@@ -440,9 +440,9 @@ macro_rules! impl_hash {
 			fn from(s: &'_ str) -> $from {
 				use std::str::FromStr;
 				if s.len() % 2 == 1 {
-					$from::from_str(&("0".to_string() + &(clean_0x(s).to_string()))[..]).unwrap_or($from::new())
+					$from::from_str(&("0".to_owned() + &(clean_0x(s).to_owned()))[..]).unwrap_or_else(|_| $from::new())
 				} else {
-					$from::from_str(clean_0x(s)).unwrap_or($from::new())
+					$from::from_str(clean_0x(s)).unwrap_or_else(|_| $from::new())
 				}
 			}
 		}
@@ -565,6 +565,7 @@ mod tests {
 	use std::str::FromStr;
 
 	#[test]
+	#[allow(eq_op)]
 	fn hash() {
 		let h = H64([0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef]);
 		assert_eq!(H64::from_str("0123456789abcdef").unwrap(), h);
diff --git a/util/src/io/mod.rs b/util/src/io/mod.rs
index c59de0584..48c02f6ee 100644
--- a/util/src/io/mod.rs
+++ b/util/src/io/mod.rs
@@ -8,27 +8,28 @@
 ///
 /// struct MyHandler;
 ///
+/// #[derive(Clone)]
 /// struct MyMessage {
 /// 	data: u32
 /// }
 ///
 ///	impl IoHandler<MyMessage> for MyHandler {
-///		fn initialize(&mut self, io: &mut IoContext<MyMessage>) {
-///			io.register_timer(1000).unwrap();
+///		fn initialize(&self, io: &IoContext<MyMessage>) {
+///			io.register_timer(0, 1000).unwrap();
 ///		}
 ///
-///		fn timeout(&mut self, _io: &mut IoContext<MyMessage>, timer: TimerToken) {
+///		fn timeout(&self, _io: &IoContext<MyMessage>, timer: TimerToken) {
 ///			println!("Timeout {}", timer);
 ///		}
 ///
-///		fn message(&mut self, _io: &mut IoContext<MyMessage>, message: &mut MyMessage) {
+///		fn message(&self, _io: &IoContext<MyMessage>, message: &MyMessage) {
 ///			println!("Message {}", message.data);
 ///		}
 ///	}
 ///
 /// fn main () {
 /// 	let mut service = IoService::<MyMessage>::start().expect("Error creating network service");
-/// 	service.register_handler(Box::new(MyHandler)).unwrap();
+/// 	service.register_handler(Arc::new(MyHandler)).unwrap();
 ///
 /// 	// Wait for quit condition
 /// 	// ...
@@ -36,6 +37,9 @@
 /// }
 /// ```
 mod service;
+mod worker;
+
+use mio::{EventLoop, Token};
 
 #[derive(Debug)]
 /// TODO [arkpar] Please document me
@@ -44,7 +48,7 @@ pub enum IoError {
 	Mio(::std::io::Error),
 }
 
-impl<Message> From<::mio::NotifyError<service::IoMessage<Message>>> for IoError where Message: Send {
+impl<Message> From<::mio::NotifyError<service::IoMessage<Message>>> for IoError where Message: Send + Clone {
 	fn from(_err: ::mio::NotifyError<service::IoMessage<Message>>) -> IoError {
 		IoError::Mio(::std::io::Error::new(::std::io::ErrorKind::ConnectionAborted, "Network IO notification error"))
 	}
@@ -53,54 +57,63 @@ impl<Message> From<::mio::NotifyError<service::IoMessage<Message>>> for IoError
 /// Generic IO handler. 
 /// All the handler function are called from within IO event loop.
 /// `Message` type is used as notification data
-pub trait IoHandler<Message>: Send where Message: Send + 'static {
+pub trait IoHandler<Message>: Send + Sync where Message: Send + Sync + Clone + 'static {
 	/// Initialize the handler
-	fn initialize<'s>(&'s mut self, _io: &mut IoContext<'s, Message>) {}
+	fn initialize(&self, _io: &IoContext<Message>) {}
 	/// Timer function called after a timeout created with `HandlerIo::timeout`.
-	fn timeout<'s>(&'s mut self, _io: &mut IoContext<'s, Message>, _timer: TimerToken) {}
+	fn timeout(&self, _io: &IoContext<Message>, _timer: TimerToken) {}
 	/// Called when a broadcasted message is received. The message can only be sent from a different IO handler.
-	fn message<'s>(&'s mut self, _io: &mut IoContext<'s, Message>, _message: &'s mut Message) {} // TODO: make message immutable and provide internal channel for adding network handler
+	fn message(&self, _io: &IoContext<Message>, _message: &Message) {}
 	/// Called when an IO stream gets closed
-	fn stream_hup<'s>(&'s mut self, _io: &mut IoContext<'s, Message>, _stream: StreamToken) {}
+	fn stream_hup(&self, _io: &IoContext<Message>, _stream: StreamToken) {}
 	/// Called when an IO stream can be read from 
-	fn stream_readable<'s>(&'s mut self, _io: &mut IoContext<'s, Message>, _stream: StreamToken) {}
+	fn stream_readable(&self, _io: &IoContext<Message>, _stream: StreamToken) {}
 	/// Called when an IO stream can be written to
-	fn stream_writable<'s>(&'s mut self, _io: &mut IoContext<'s, Message>, _stream: StreamToken) {}
+	fn stream_writable(&self, _io: &IoContext<Message>, _stream: StreamToken) {}
+	/// Register a new stream with the event loop
+	fn register_stream(&self, _stream: StreamToken, _reg: Token, _event_loop: &mut EventLoop<IoManager<Message>>) {}
+	/// Re-register a stream with the event loop
+	fn update_stream(&self, _stream: StreamToken, _reg: Token, _event_loop: &mut EventLoop<IoManager<Message>>) {}
 }
 
 /// TODO [arkpar] Please document me
-pub type TimerToken = service::TimerToken;
+pub use io::service::TimerToken;
 /// TODO [arkpar] Please document me
-pub type StreamToken = service::StreamToken;
+pub use io::service::StreamToken;
 /// TODO [arkpar] Please document me
-pub type IoContext<'s, M> = service::IoContext<'s, M>;
+pub use io::service::IoContext;
 /// TODO [arkpar] Please document me
-pub type IoService<M> = service::IoService<M>;
+pub use io::service::IoService;
 /// TODO [arkpar] Please document me
-pub type IoChannel<M> = service::IoChannel<M>;
-//pub const USER_TOKEN_START: usize = service::USER_TOKEN; // TODO: ICE in rustc 1.7.0-nightly (49c382779 2016-01-12)
+pub use io::service::IoChannel;
+/// TODO [arkpar] Please document me
+pub use io::service::IoManager;
+/// TODO [arkpar] Please document me
+pub use io::service::TOKENS_PER_HANDLER;
 
 #[cfg(test)]
 mod tests {
 
+	use std::sync::Arc;
 	use io::*;
 
 	struct MyHandler;
 
+	#[derive(Clone)]
 	struct MyMessage {
 		data: u32
 	}
 
 	impl IoHandler<MyMessage> for MyHandler {
-		fn initialize(&mut self, io: &mut IoContext<MyMessage>) {
-			io.register_timer(1000).unwrap();
+		fn initialize(&self, io: &IoContext<MyMessage>) {
+			io.register_timer(0, 1000).unwrap();
 		}
 
-		fn timeout(&mut self, _io: &mut IoContext<MyMessage>, timer: TimerToken) {
+		fn timeout(&self, _io: &IoContext<MyMessage>, timer: TimerToken) {
 			println!("Timeout {}", timer);
 		}
 
-		fn message(&mut self, _io: &mut IoContext<MyMessage>, message: &mut MyMessage) {
+		fn message(&self, _io: &IoContext<MyMessage>, message: &MyMessage) {
 			println!("Message {}", message.data);
 		}
 	}
@@ -108,7 +121,7 @@ mod tests {
 	#[test]
 	fn test_service_register_handler () {
 		let mut service = IoService::<MyMessage>::start().expect("Error creating network service");
-		service.register_handler(Box::new(MyHandler)).unwrap();
+		service.register_handler(Arc::new(MyHandler)).unwrap();
 	}
 
 }
diff --git a/util/src/io/service.rs b/util/src/io/service.rs
index 4a96d19a7..8a1653056 100644
--- a/util/src/io/service.rs
+++ b/util/src/io/service.rs
@@ -1,148 +1,229 @@
+use std::sync::*;
 use std::thread::{self, JoinHandle};
+use std::collections::HashMap;
 use mio::*;
-use mio::util::{Slab};
 use hash::*;
 use rlp::*;
 use error::*;
 use io::{IoError, IoHandler};
+use arrayvec::*;
+use crossbeam::sync::chase_lev;
+use io::worker::{Worker, Work, WorkType};
 
+/// Timer ID
 pub type TimerToken = usize;
+/// Timer ID
 pub type StreamToken = usize;
+/// IO Hadndler ID
+pub type HandlerId = usize;
 
-// Tokens
-const MAX_USER_TIMERS: usize = 32;
-const USER_TIMER: usize = 0;
-const LAST_USER_TIMER: usize = USER_TIMER + MAX_USER_TIMERS - 1;
-//const USER_TOKEN: usize = LAST_USER_TIMER + 1;
+/// Maximum number of tokens a handler can use
+pub const TOKENS_PER_HANDLER: usize = 16384;
 
 /// Messages used to communicate with the event loop from other threads.
-pub enum IoMessage<Message> where Message: Send + Sized {
+#[derive(Clone)]
+pub enum IoMessage<Message> where Message: Send + Clone + Sized {
 	/// Shutdown the event loop
 	Shutdown,
 	/// Register a new protocol handler.
 	AddHandler {
-		handler: Box<IoHandler<Message>+Send>,
+		handler: Arc<IoHandler<Message>+Send>,
+	},
+	AddTimer {
+		handler_id: HandlerId,
+		token: TimerToken,
+		delay: u64,
+	},
+	RemoveTimer {
+		handler_id: HandlerId,
+		token: TimerToken,
+	},
+	RegisterStream {
+		handler_id: HandlerId,
+		token: StreamToken,
+	},
+	UpdateStreamRegistration {
+		handler_id: HandlerId,
+		token: StreamToken,
 	},
 	/// Broadcast a message across all protocol handlers.
 	UserMessage(Message)
 }
 
 /// IO access point. This is passed to all IO handlers and provides an interface to the IO subsystem.
-pub struct IoContext<'s, Message> where Message: Send + 'static {
-	timers: &'s mut Slab<UserTimer>,
-	/// Low leve MIO Event loop for custom handler registration.
-	pub event_loop: &'s mut EventLoop<IoManager<Message>>,
+pub struct IoContext<Message> where Message: Send + Clone + 'static {
+	channel: IoChannel<Message>,
+	handler: HandlerId,
 }
 
-impl<'s, Message> IoContext<'s, Message> where Message: Send + 'static {
+impl<Message> IoContext<Message> where Message: Send + Clone + 'static {
 	/// Create a new IO access point. Takes references to all the data that can be updated within the IO handler.
-	fn new(event_loop: &'s mut EventLoop<IoManager<Message>>, timers: &'s mut Slab<UserTimer>) -> IoContext<'s, Message> {
+	pub fn new(channel: IoChannel<Message>, handler: HandlerId) -> IoContext<Message> {
 		IoContext {
-			event_loop: event_loop,
-			timers: timers,
+			handler: handler,
+			channel: channel,
 		}
 	}
 
-	/// Register a new IO timer. Returns a new timer token. 'IoHandler::timeout' will be called with the token.
-	pub fn register_timer(&mut self, ms: u64) -> Result<TimerToken, UtilError> {
-		match self.timers.insert(UserTimer {
+	/// Register a new IO timer. 'IoHandler::timeout' will be called with the token.
+	pub fn register_timer(&self, token: TimerToken, ms: u64) -> Result<(), UtilError> {
+		try!(self.channel.send_io(IoMessage::AddTimer {
+			token: token,
 			delay: ms,
-		}) {
-			Ok(token) => {
-				self.event_loop.timeout_ms(token, ms).expect("Error registering user timer");
-				Ok(token.as_usize())
-			},
-			_ => { panic!("Max timers reached") }
-		}
+			handler_id: self.handler,
+		}));
+		Ok(())
+	}
+
+	/// Delete a timer.
+	pub fn clear_timer(&self, token: TimerToken) -> Result<(), UtilError> {
+		try!(self.channel.send_io(IoMessage::RemoveTimer {
+			token: token,
+			handler_id: self.handler,
+		}));
+		Ok(())
+	}
+	/// Register a new IO stream.
+	pub fn register_stream(&self, token: StreamToken) -> Result<(), UtilError> {
+		try!(self.channel.send_io(IoMessage::RegisterStream {
+			token: token,
+			handler_id: self.handler,
+		}));
+		Ok(())
+	}
+
+	/// Reregister an IO stream.
+	pub fn update_registration(&self, token: StreamToken) -> Result<(), UtilError> {
+		try!(self.channel.send_io(IoMessage::UpdateStreamRegistration {
+			token: token,
+			handler_id: self.handler,
+		}));
+		Ok(())
 	}
 
 	/// Broadcast a message to other IO clients
-	pub fn message(&mut self, message: Message) {
-		match self.event_loop.channel().send(IoMessage::UserMessage(message)) {
-			Ok(_) => {}
-			Err(e) => { panic!("Error sending io message {:?}", e); }
-		}
+	pub fn message(&self, message: Message) {
+		self.channel.send(message).expect("Error seding message");
+	}
+
+	/// Get message channel
+	pub fn channel(&self) -> IoChannel<Message> {
+		self.channel.clone()
 	}
 }
 
+#[derive(Clone)]
 struct UserTimer {
 	delay: u64,
+	timeout: Timeout,
 }
 
 /// Root IO handler. Manages user handlers, messages and IO timers.
-pub struct IoManager<Message> where Message: Send {
-	timers: Slab<UserTimer>,
-	handlers: Vec<Box<IoHandler<Message>>>,
+pub struct IoManager<Message> where Message: Send + Sync {
+	timers: Arc<RwLock<HashMap<HandlerId, UserTimer>>>,
+	handlers: Vec<Arc<IoHandler<Message>>>,
+	_workers: Vec<Worker>,
+	worker_channel: chase_lev::Worker<Work<Message>>,
+	work_ready: Arc<Condvar>,
 }
 
-impl<Message> IoManager<Message> where Message: Send + 'static {
+impl<Message> IoManager<Message> where Message: Send + Sync + Clone + 'static {
 	/// Creates a new instance and registers it with the event loop.
 	pub fn start(event_loop: &mut EventLoop<IoManager<Message>>) -> Result<(), UtilError> {
+		let (worker, stealer) = chase_lev::deque();
+		let num_workers = 4;
+		let work_ready_mutex =  Arc::new(Mutex::new(()));
+		let work_ready = Arc::new(Condvar::new());
+		let workers = (0..num_workers).map(|i| 
+			Worker::new(i, stealer.clone(), IoChannel::new(event_loop.channel()), work_ready.clone(), work_ready_mutex.clone())).collect();
+
 		let mut io = IoManager {
-			timers: Slab::new_starting_at(Token(USER_TIMER), MAX_USER_TIMERS),
+			timers: Arc::new(RwLock::new(HashMap::new())),
 			handlers: Vec::new(),
+			worker_channel: worker,
+			_workers: workers,
+			work_ready: work_ready,
 		};
 		try!(event_loop.run(&mut io));
 		Ok(())
 	}
 }
 
-impl<Message> Handler for IoManager<Message> where Message: Send + 'static {
+impl<Message> Handler for IoManager<Message> where Message: Send + Clone + Sync + 'static {
 	type Timeout = Token;
 	type Message = IoMessage<Message>;
 
-	fn ready(&mut self, event_loop: &mut EventLoop<Self>, token: Token, events: EventSet) {
+	fn ready(&mut self, _event_loop: &mut EventLoop<Self>, token: Token, events: EventSet) {
+		let handler_index  = token.as_usize() / TOKENS_PER_HANDLER;
+		let token_id  = token.as_usize() % TOKENS_PER_HANDLER;
+		if handler_index >= self.handlers.len() {
+			panic!("Unexpected stream token: {}", token.as_usize());
+		}
+		let handler = self.handlers[handler_index].clone();
+
 		if events.is_hup() {
-			for h in self.handlers.iter_mut() {
-				h.stream_hup(&mut IoContext::new(event_loop, &mut self.timers), token.as_usize());
-			}
-		}
-		else if events.is_readable() {
-			for h in self.handlers.iter_mut() {
-				h.stream_readable(&mut IoContext::new(event_loop, &mut self.timers), token.as_usize());
-			}
-		}
-		else if events.is_writable() {
-			for h in self.handlers.iter_mut() {
-				h.stream_writable(&mut IoContext::new(event_loop, &mut self.timers), token.as_usize());
+			self.worker_channel.push(Work { work_type: WorkType::Hup, token: token_id, handler: handler.clone(), handler_id: handler_index });
+		}
+		else {
+			if events.is_readable() {
+				self.worker_channel.push(Work { work_type: WorkType::Readable, token: token_id, handler: handler.clone(), handler_id: handler_index });
+			}
+			if events.is_writable() {
+				self.worker_channel.push(Work { work_type: WorkType::Writable, token: token_id, handler: handler.clone(), handler_id: handler_index });
 			}
 		}
+		self.work_ready.notify_all();
 	}
 
 	fn timeout(&mut self, event_loop: &mut EventLoop<Self>, token: Token) {
-		match token.as_usize() {
-			USER_TIMER ... LAST_USER_TIMER => {
-				let delay = {
-					let timer = self.timers.get_mut(token).expect("Unknown user timer token");
-					timer.delay
-				};
-				for h in self.handlers.iter_mut() {
-					h.timeout(&mut IoContext::new(event_loop, &mut self.timers), token.as_usize());
-				}
-				event_loop.timeout_ms(token, delay).expect("Error re-registering user timer");
-			}
-			_ => { // Just pass the event down. IoHandler is supposed to re-register it if required.
-				for h in self.handlers.iter_mut() {
-					h.timeout(&mut IoContext::new(event_loop, &mut self.timers), token.as_usize());
-				}
-			}
+		let handler_index  = token.as_usize()  / TOKENS_PER_HANDLER;
+		let token_id  = token.as_usize()  % TOKENS_PER_HANDLER;
+		if handler_index >= self.handlers.len() {
+			panic!("Unexpected timer token: {}", token.as_usize());
+		}
+		if let Some(timer) = self.timers.read().unwrap().get(&token.as_usize()) {
+			event_loop.timeout_ms(token, timer.delay).expect("Error re-registering user timer");
+			let handler = self.handlers[handler_index].clone();
+			self.worker_channel.push(Work { work_type: WorkType::Timeout, token: token_id, handler: handler, handler_id: handler_index });
+			self.work_ready.notify_all();
 		}
 	}
 
 	fn notify(&mut self, event_loop: &mut EventLoop<Self>, msg: Self::Message) {
-		let mut m = msg;
-		match m {
+		match msg {
 			IoMessage::Shutdown => event_loop.shutdown(),
-			IoMessage::AddHandler {
-				handler,
-			} => {
-				self.handlers.push(handler);
-				self.handlers.last_mut().unwrap().initialize(&mut IoContext::new(event_loop, &mut self.timers));
+			IoMessage::AddHandler { handler } => {
+				let handler_id = {
+					self.handlers.push(handler.clone());
+					self.handlers.len() - 1
+				};
+				handler.initialize(&IoContext::new(IoChannel::new(event_loop.channel()), handler_id));
 			},
-			IoMessage::UserMessage(ref mut data) => {
-				for h in self.handlers.iter_mut() {
-					h.message(&mut IoContext::new(event_loop, &mut self.timers), data);
+			IoMessage::AddTimer { handler_id, token, delay } => {
+				let timer_id = token + handler_id * TOKENS_PER_HANDLER;
+				let timeout = event_loop.timeout_ms(Token(timer_id), delay).expect("Error registering user timer");
+				self.timers.write().unwrap().insert(timer_id, UserTimer { delay: delay, timeout: timeout });
+			},
+			IoMessage::RemoveTimer { handler_id, token } => {
+				let timer_id = token + handler_id * TOKENS_PER_HANDLER;
+				if let Some(timer) = self.timers.write().unwrap().remove(&timer_id) {
+					event_loop.clear_timeout(timer.timeout);
 				}
+			},
+			IoMessage::RegisterStream { handler_id, token } => {
+				let handler = self.handlers.get(handler_id).expect("Unknown handler id").clone();
+				handler.register_stream(token, Token(token + handler_id * TOKENS_PER_HANDLER), event_loop);
+			},
+			IoMessage::UpdateStreamRegistration { handler_id, token } => {
+				let handler = self.handlers.get(handler_id).expect("Unknown handler id").clone();
+				handler.update_stream(token, Token(token + handler_id * TOKENS_PER_HANDLER), event_loop);
+			},
+			IoMessage::UserMessage(data) => {
+				for n in 0 .. self.handlers.len() {
+					let handler = self.handlers[n].clone();
+					self.worker_channel.push(Work { work_type: WorkType::Message(data.clone()), token: 0, handler: handler, handler_id: n });
+				}
+				self.work_ready.notify_all();
 			}
 		}
 	}
@@ -150,11 +231,19 @@ impl<Message> Handler for IoManager<Message> where Message: Send + 'static {
 
 /// Allows sending messages into the event loop. All the IO handlers will get the message
 /// in the `message` callback.
-pub struct IoChannel<Message> where Message: Send {
+pub struct IoChannel<Message> where Message: Send + Clone{
 	channel: Option<Sender<IoMessage<Message>>>
 }
 
-impl<Message> IoChannel<Message> where Message: Send {
+impl<Message> Clone for IoChannel<Message> where Message: Send + Clone {
+	fn clone(&self) -> IoChannel<Message> {
+		IoChannel {
+			channel: self.channel.clone()
+		}
+	}
+}
+
+impl<Message> IoChannel<Message> where Message: Send + Clone {
 	/// Send a msessage through the channel
 	pub fn send(&self, message: Message) -> Result<(), IoError> {
 		if let Some(ref channel) = self.channel {
@@ -163,20 +252,31 @@ impl<Message> IoChannel<Message> where Message: Send {
 		Ok(())
 	}
 
+	/// Send low level io message
+	pub fn send_io(&self, message: IoMessage<Message>) -> Result<(), IoError> {
+		if let Some(ref channel) = self.channel {
+			try!(channel.send(message))
+		}
+		Ok(())
+	}
 	/// Create a new channel to connected to event loop.
 	pub fn disconnected() -> IoChannel<Message> {
 		IoChannel { channel: None }
 	}
+
+	fn new(channel: Sender<IoMessage<Message>>) -> IoChannel<Message> {
+		IoChannel { channel: Some(channel) }
+	}
 }
 
 /// General IO Service. Starts an event loop and dispatches IO requests.
 /// 'Message' is a notification message type
-pub struct IoService<Message> where Message: Send + 'static {
+pub struct IoService<Message> where Message: Send + Sync + Clone + 'static {
 	thread: Option<JoinHandle<()>>,
-	host_channel: Sender<IoMessage<Message>>
+	host_channel: Sender<IoMessage<Message>>,
 }
 
-impl<Message> IoService<Message> where Message: Send + 'static {
+impl<Message> IoService<Message> where Message: Send + Sync + Clone + 'static {
 	/// Starts IO event loop
 	pub fn start() -> Result<IoService<Message>, UtilError> {
 		let mut event_loop = EventLoop::new().unwrap();
@@ -191,7 +291,7 @@ impl<Message> IoService<Message> where Message: Send + 'static {
 	}
 
 	/// Regiter a IO hadnler with the event loop.
-	pub fn register_handler(&mut self, handler: Box<IoHandler<Message>+Send>) -> Result<(), IoError> {
+	pub fn register_handler(&mut self, handler: Arc<IoHandler<Message>+Send>) -> Result<(), IoError> {
 		try!(self.host_channel.send(IoMessage::AddHandler {
 			handler: handler,
 		}));
@@ -210,10 +310,10 @@ impl<Message> IoService<Message> where Message: Send + 'static {
 	}
 }
 
-impl<Message> Drop for IoService<Message> where Message: Send {
+impl<Message> Drop for IoService<Message> where Message: Send + Sync + Clone {
 	fn drop(&mut self) {
 		self.host_channel.send(IoMessage::Shutdown).unwrap();
-		self.thread.take().unwrap().join().unwrap();
+		self.thread.take().unwrap().join().ok();
 	}
 }
 
diff --git a/util/src/io/worker.rs b/util/src/io/worker.rs
new file mode 100644
index 000000000..33eff42c5
--- /dev/null
+++ b/util/src/io/worker.rs
@@ -0,0 +1,99 @@
+use std::sync::*;
+use std::mem;
+use std::thread::{JoinHandle, self};
+use std::sync::atomic::{AtomicBool, Ordering as AtomicOrdering};
+use crossbeam::sync::chase_lev;
+use io::service::{HandlerId, IoChannel, IoContext};
+use io::{IoHandler};
+
+pub enum WorkType<Message> {
+	Readable,
+	Writable,
+	Hup,
+	Timeout,
+	Message(Message)
+}
+
+pub struct Work<Message> {
+	pub work_type: WorkType<Message>,
+	pub token: usize,
+	pub handler_id: HandlerId,
+	pub handler: Arc<IoHandler<Message>>,
+}
+
+/// An IO worker thread
+/// Sorts them ready for blockchain insertion.
+pub struct Worker {
+	thread: Option<JoinHandle<()>>,
+	wait: Arc<Condvar>,
+	deleting: Arc<AtomicBool>,
+}
+
+impl Worker {
+	/// Creates a new worker instance.
+	pub fn new<Message>(index: usize, 
+						stealer: chase_lev::Stealer<Work<Message>>, 
+						channel: IoChannel<Message>,
+						wait: Arc<Condvar>,
+						wait_mutex: Arc<Mutex<()>>) -> Worker 
+						where Message: Send + Sync + Clone + 'static {
+		let deleting = Arc::new(AtomicBool::new(false));
+		let mut worker = Worker {
+			thread: None,
+			wait: wait.clone(),
+			deleting: deleting.clone(),
+		};
+		worker.thread = Some(thread::Builder::new().name(format!("IO Worker #{}", index)).spawn(
+			move || Worker::work_loop(stealer, channel.clone(), wait, wait_mutex.clone(), deleting))
+			.expect("Error creating worker thread"));
+		worker
+	}
+
+	fn work_loop<Message>(stealer: chase_lev::Stealer<Work<Message>>,
+						channel: IoChannel<Message>, wait: Arc<Condvar>, 
+						wait_mutex: Arc<Mutex<()>>, 
+						deleting: Arc<AtomicBool>) 
+						where Message: Send + Sync + Clone + 'static {
+		while !deleting.load(AtomicOrdering::Relaxed) {
+			{
+				let lock = wait_mutex.lock().unwrap();
+				let _ = wait.wait(lock).unwrap();
+				if deleting.load(AtomicOrdering::Relaxed) {
+					return;
+				}
+			}
+			while let chase_lev::Steal::Data(work) = stealer.steal() {
+				Worker::do_work(work, channel.clone());
+			}
+		}
+	}
+
+	fn do_work<Message>(work: Work<Message>, channel: IoChannel<Message>) where Message: Send + Sync + Clone + 'static {
+		match work.work_type {
+			WorkType::Readable => {
+				work.handler.stream_readable(&IoContext::new(channel, work.handler_id), work.token);
+			},
+			WorkType::Writable => {
+				work.handler.stream_writable(&IoContext::new(channel, work.handler_id), work.token);
+			}
+			WorkType::Hup => {
+				work.handler.stream_hup(&IoContext::new(channel, work.handler_id), work.token);
+			}
+			WorkType::Timeout => {
+				work.handler.timeout(&IoContext::new(channel, work.handler_id), work.token);
+			}
+			WorkType::Message(message) => {
+				work.handler.message(&IoContext::new(channel, work.handler_id), &message);
+			}
+		}
+	}
+}
+
+impl Drop for Worker {
+	fn drop(&mut self) {
+		self.deleting.store(true, AtomicOrdering::Relaxed);
+		self.wait.notify_all();
+		let thread = mem::replace(&mut self.thread, None).unwrap();
+		thread.join().ok();
+	}
+}
diff --git a/util/src/journaldb.rs b/util/src/journaldb.rs
index ada9c0d2b..ba31efafb 100644
--- a/util/src/journaldb.rs
+++ b/util/src/journaldb.rs
@@ -34,6 +34,16 @@ impl JournalDB {
 		}
 	}
 
+	/// Create a new instance given a shared `backing` database.
+	pub fn new_with_arc(backing: Arc<DB>) -> JournalDB {
+		JournalDB {
+			forward: OverlayDB::new_with_arc(backing.clone()),
+			backing: backing,
+			inserts: vec![],
+			removes: vec![],
+		}
+	}
+
 	/// Create a new instance with an anonymous temporary database.
 	pub fn new_temp() -> JournalDB {
 		let mut dir = env::temp_dir();
@@ -96,7 +106,7 @@ impl JournalDB {
 			})) {
 				let rlp = Rlp::new(&rlp_data);
 				let to_remove: Vec<H256> = rlp.val_at(if canon_id == rlp.val_at(0) {2} else {1});
-				for i in to_remove.iter() {
+				for i in &to_remove {
 					self.forward.remove(i);
 				}
 				try!(self.backing.delete(&last));
diff --git a/util/src/json_aid.rs b/util/src/json_aid.rs
index 595484908..5974c5989 100644
--- a/util/src/json_aid.rs
+++ b/util/src/json_aid.rs
@@ -11,18 +11,18 @@ pub fn clean(s: &str) -> &str {
 
 fn u256_from_str(s: &str) -> U256 {
 	if s.len() >= 2 && &s[0..2] == "0x" {
-		U256::from_str(&s[2..]).unwrap_or(U256::from(0))
+		U256::from_str(&s[2..]).unwrap_or_else(|_| U256::zero())
 	} else {
-		U256::from_dec_str(s).unwrap_or(U256::from(0))
+		U256::from_dec_str(s).unwrap_or_else(|_| U256::zero())
 	}
 }
 
 impl FromJson for Bytes {
 	fn from_json(json: &Json) -> Self {
-		match json {
-			&Json::String(ref s) => match s.len() % 2 {
-				0 => FromHex::from_hex(clean(s)).unwrap_or(vec![]),
-				_ => FromHex::from_hex(&("0".to_string() + &(clean(s).to_string()))[..]).unwrap_or(vec![]),
+		match *json {
+			Json::String(ref s) => match s.len() % 2 {
+				0 => FromHex::from_hex(clean(s)).unwrap_or_else(|_| vec![]),
+				_ => FromHex::from_hex(&("0".to_owned() + &(clean(s).to_owned()))[..]).unwrap_or_else(|_| vec![]),
 			},
 			_ => vec![],
 		}
@@ -31,8 +31,8 @@ impl FromJson for Bytes {
 
 impl FromJson for BTreeMap<H256, H256> {
 	fn from_json(json: &Json) -> Self {
-		match json {
-			&Json::Object(ref o) => o.iter().map(|(key, value)| (x!(&u256_from_str(key)), x!(&U256::from_json(value)))).collect(),
+		match *json {
+			Json::Object(ref o) => o.iter().map(|(key, value)| (x!(&u256_from_str(key)), x!(&U256::from_json(value)))).collect(),
 			_ => BTreeMap::new(),
 		}
 	}
@@ -40,8 +40,8 @@ impl FromJson for BTreeMap<H256, H256> {
 
 impl<T> FromJson for Vec<T> where T: FromJson {
 	fn from_json(json: &Json) -> Self {
-		match json {
-			&Json::Array(ref o) => o.iter().map(|x|T::from_json(x)).collect(),
+		match *json {
+			Json::Array(ref o) => o.iter().map(|x|T::from_json(x)).collect(),
 			_ => Vec::new(),
 		}
 	}
@@ -49,9 +49,9 @@ impl<T> FromJson for Vec<T> where T: FromJson {
 
 impl<T> FromJson for Option<T> where T: FromJson {
 	fn from_json(json: &Json) -> Self {
-		match json {
-			&Json::String(ref o) if o.is_empty() => None,
-			&Json::Null => None,
+		match *json {
+			Json::String(ref o) if o.is_empty() => None,
+			Json::Null => None,
 			_ => Some(FromJson::from_json(json)),
 		}
 	}
@@ -135,4 +135,4 @@ fn option_types() {
 	assert_eq!(None, v);
 	let v: Option<u16> = xjson!(&j["empty"]);
 	assert_eq!(None, v);
-}
\ No newline at end of file
+}
diff --git a/util/src/lib.rs b/util/src/lib.rs
index 1cfa11657..970c0713c 100644
--- a/util/src/lib.rs
+++ b/util/src/lib.rs
@@ -2,6 +2,9 @@
 #![feature(op_assign_traits)]
 #![feature(augmented_assignments)]
 #![feature(associated_consts)]
+#![feature(plugin)]
+#![plugin(clippy)]
+#![allow(needless_range_loop, match_bool)]
 //! Ethcore-util library
 //!
 //! ### Rust version:
@@ -51,6 +54,7 @@ extern crate crypto as rcrypto;
 extern crate secp256k1;
 extern crate arrayvec;
 extern crate elastic_array;
+extern crate crossbeam;
 
 /// TODO [Gav Wood] Please document me
 pub mod standard;
diff --git a/util/src/misc.rs b/util/src/misc.rs
index b28b8df42..316e78a11 100644
--- a/util/src/misc.rs
+++ b/util/src/misc.rs
@@ -18,13 +18,13 @@ impl<T> Diff<T> where T: Eq {
 	pub fn new(pre: T, post: T) -> Self { if pre == post { Diff::Same } else { Diff::Changed(pre, post) } }
 
 	/// Get the before value, if there is one.
-	pub fn pre(&self) -> Option<&T> { match self { &Diff::Died(ref x) | &Diff::Changed(ref x, _) => Some(x), _ => None } }
+	pub fn pre(&self) -> Option<&T> { match *self { Diff::Died(ref x) | Diff::Changed(ref x, _) => Some(x), _ => None } }
 
 	/// Get the after value, if there is one.
-	pub fn post(&self) -> Option<&T> { match self { &Diff::Born(ref x) | &Diff::Changed(_, ref x) => Some(x), _ => None } }
+	pub fn post(&self) -> Option<&T> { match *self { Diff::Born(ref x) | Diff::Changed(_, ref x) => Some(x), _ => None } }
 
 	/// Determine whether there was a change or not.
-	pub fn is_same(&self) -> bool { match self { &Diff::Same => true, _ => false }}
+	pub fn is_same(&self) -> bool { match *self { Diff::Same => true, _ => false }}
 }
 
 #[derive(PartialEq,Eq,Clone,Copy)]
diff --git a/util/src/network/connection.rs b/util/src/network/connection.rs
index f11c10384..33cafd708 100644
--- a/util/src/network/connection.rs
+++ b/util/src/network/connection.rs
@@ -1,5 +1,5 @@
 use std::collections::VecDeque;
-use mio::{Handler, Token, EventSet, EventLoop, Timeout, PollOpt, TryRead, TryWrite};
+use mio::{Handler, Token, EventSet, EventLoop, PollOpt, TryRead, TryWrite};
 use mio::tcp::*;
 use hash::*;
 use sha3::*;
@@ -7,6 +7,7 @@ use bytes::*;
 use rlp::*;
 use std::io::{self, Cursor, Read};
 use error::*;
+use io::{IoContext, StreamToken};
 use network::error::NetworkError;
 use network::handshake::Handshake;
 use crypto;
@@ -17,11 +18,12 @@ use rcrypto::buffer::*;
 use tiny_keccak::Keccak;
 
 const ENCRYPTED_HEADER_LEN: usize = 32;
+const RECIEVE_PAYLOAD_TIMEOUT: u64 = 30000;
 
 /// Low level tcp connection
 pub struct Connection {
 	/// Connection id (token)
-	pub token: Token,
+	pub token: StreamToken,
 	/// Network socket
 	pub socket: TcpStream,
 	/// Receive buffer
@@ -45,14 +47,14 @@ pub enum WriteStatus {
 
 impl Connection {
 	/// Create a new connection with given id and socket.
-	pub fn new(token: Token, socket: TcpStream) -> Connection {
+	pub fn new(token: StreamToken, socket: TcpStream) -> Connection {
 		Connection {
 			token: token,
 			socket: socket,
 			send_queue: VecDeque::new(),
 			rec_buf: Bytes::new(),
 			rec_size: 0,
-			interest: EventSet::hup(),
+			interest: EventSet::hup() | EventSet::readable(),
 		}
 	}
 
@@ -86,7 +88,7 @@ impl Connection {
 
 	/// Add a packet to send queue.
 	pub fn send(&mut self, data: Bytes) {
-		if data.len() != 0 {
+		if !data.is_empty() {
 			self.send_queue.push_back(Cursor::new(data));
 		}
 		if !self.interest.is_writable() {
@@ -132,20 +134,19 @@ impl Connection {
 	}
 
 	/// Register this connection with the IO event loop.
-	pub fn register<Host: Handler>(&mut self, event_loop: &mut EventLoop<Host>) -> io::Result<()> {
-		trace!(target: "net", "connection register; token={:?}", self.token);
-		self.interest.insert(EventSet::readable());
-		event_loop.register(&self.socket, self.token, self.interest, PollOpt::edge() | PollOpt::oneshot()).or_else(|e| {
-			error!("Failed to register {:?}, {:?}", self.token, e);
+	pub fn register_socket<Host: Handler>(&self, reg: Token, event_loop: &mut EventLoop<Host>) -> io::Result<()> {
+		trace!(target: "net", "connection register; token={:?}", reg);
+		event_loop.register(&self.socket, reg, self.interest, PollOpt::edge() | PollOpt::oneshot()).or_else(|e| {
+			error!("Failed to register {:?}, {:?}", reg, e);
 			Err(e)
 		})
 	}
 
 	/// Update connection registration. Should be called at the end of the IO handler.
-	pub fn reregister<Host: Handler>(&mut self, event_loop: &mut EventLoop<Host>) -> io::Result<()> {
-		trace!(target: "net", "connection reregister; token={:?}", self.token);
-		event_loop.reregister( &self.socket, self.token, self.interest, PollOpt::edge() | PollOpt::oneshot()).or_else(|e| {
-			error!("Failed to reregister {:?}, {:?}", self.token, e);
+	pub fn update_socket<Host: Handler>(&self, reg: Token, event_loop: &mut EventLoop<Host>) -> io::Result<()> {
+		trace!(target: "net", "connection reregister; token={:?}", reg);
+		event_loop.reregister( &self.socket, reg, self.interest, PollOpt::edge() | PollOpt::oneshot()).or_else(|e| {
+			error!("Failed to reregister {:?}, {:?}", reg, e);
 			Err(e)
 		})
 	}
@@ -182,8 +183,6 @@ pub struct EncryptedConnection {
 	ingress_mac: Keccak,
 	/// Read state
 	read_state: EncryptedConnectionState,
-	/// Disconnect timeout
-	idle_timeout: Option<Timeout>,
 	/// Protocol id for the last received packet
 	protocol_id: u16,
 	/// Payload expected to be received for the last header.
@@ -192,7 +191,7 @@ pub struct EncryptedConnection {
 
 impl EncryptedConnection {
 	/// Create an encrypted connection out of the handshake. Consumes a handshake object.
-	pub fn new(handshake: Handshake) -> Result<EncryptedConnection, UtilError> {
+	pub fn new(mut handshake: Handshake) -> Result<EncryptedConnection, UtilError> {
 		let shared = try!(crypto::ecdh::agree(handshake.ecdhe.secret(), &handshake.remote_public));
 		let mut nonce_material = H512::new();
 		if handshake.originated {
@@ -227,6 +226,7 @@ impl EncryptedConnection {
 		ingress_mac.update(&mac_material);
 		ingress_mac.update(if handshake.originated { &handshake.ack_cipher } else { &handshake.auth_cipher });
 
+		handshake.connection.expect(ENCRYPTED_HEADER_LEN);
 		Ok(EncryptedConnection {
 			connection: handshake.connection,
 			encoder: encoder,
@@ -235,7 +235,6 @@ impl EncryptedConnection {
 			egress_mac: egress_mac,
 			ingress_mac: ingress_mac,
 			read_state: EncryptedConnectionState::Header,
-			idle_timeout: None,
 			protocol_id: 0,
 			payload_len: 0
 		})
@@ -337,16 +336,14 @@ impl EncryptedConnection {
 	}
 
 	/// Readable IO handler. Tracker receive status and returns decoded packet if avaialable.
-	pub fn readable<Host:Handler>(&mut self, event_loop: &mut EventLoop<Host>) -> Result<Option<Packet>, UtilError> {
-		self.idle_timeout.map(|t| event_loop.clear_timeout(t));
+	pub fn readable<Message>(&mut self, io: &IoContext<Message>) -> Result<Option<Packet>, UtilError> where Message: Send + Clone{
+		io.clear_timer(self.connection.token).unwrap();
 		match self.read_state {
 			EncryptedConnectionState::Header => {
-				match try!(self.connection.readable()) {
-					Some(data)  => {
-						try!(self.read_header(&data));
-					},
-					None => {}
-				};
+				if let Some(data) = try!(self.connection.readable()) {
+					try!(self.read_header(&data));
+					try!(io.register_timer(self.connection.token, RECIEVE_PAYLOAD_TIMEOUT));
+				}
 				Ok(None)
 			},
 			EncryptedConnectionState::Payload => {
@@ -363,24 +360,15 @@ impl EncryptedConnection {
 	}
 
 	/// Writable IO handler. Processes send queeue.
-	pub fn writable<Host:Handler>(&mut self, event_loop: &mut EventLoop<Host>) -> Result<(), UtilError> {
-		self.idle_timeout.map(|t| event_loop.clear_timeout(t));
+	pub fn writable<Message>(&mut self, io: &IoContext<Message>) -> Result<(), UtilError> where Message: Send + Clone {
+		io.clear_timer(self.connection.token).unwrap();
 		try!(self.connection.writable());
 		Ok(())
 	}
 
-	/// Register this connection with the event handler.
-	pub fn register<Host:Handler<Timeout=Token>>(&mut self, event_loop: &mut EventLoop<Host>) -> Result<(), UtilError> {
-		self.connection.expect(ENCRYPTED_HEADER_LEN);
-		self.idle_timeout.map(|t| event_loop.clear_timeout(t));
-		self.idle_timeout = event_loop.timeout_ms(self.connection.token, 1800).ok();
-		try!(self.connection.reregister(event_loop));
-		Ok(())
-	}
-
 	/// Update connection registration. This should be called at the end of the event loop.
-	pub fn reregister<Host:Handler>(&mut self, event_loop: &mut EventLoop<Host>) -> Result<(), UtilError> {
-		try!(self.connection.reregister(event_loop));
+	pub fn update_socket<Host:Handler>(&self, reg: Token, event_loop: &mut EventLoop<Host>) -> Result<(), UtilError> {
+		try!(self.connection.update_socket(reg, event_loop));
 		Ok(())
 	}
 }
diff --git a/util/src/network/discovery.rs b/util/src/network/discovery.rs
index d2a4f21a2..36fc500ee 100644
--- a/util/src/network/discovery.rs
+++ b/util/src/network/discovery.rs
@@ -62,7 +62,7 @@ impl Discovery {
 			discovery_round: 0,
 			discovery_id: NodeId::new(),
 			discovery_nodes: HashSet::new(),
-			node_buckets: (0..NODE_BINS).map(|x| NodeBucket::new(x)).collect(),
+			node_buckets: (0..NODE_BINS).map(NodeBucket::new).collect(),
 		}
 	}
 
@@ -122,7 +122,8 @@ impl Discovery {
 		ret
 	}
 
-	fn nearest_node_entries<'b>(source: &NodeId, target: &NodeId, buckets: &'b Vec<NodeBucket>) -> Vec<&'b NodeId>
+	#[allow(cyclomatic_complexity)]
+	fn nearest_node_entries<'b>(source: &NodeId, target: &NodeId, buckets: &'b [NodeBucket]) -> Vec<&'b NodeId>
 	{
 		// send ALPHA FindNode packets to nodes we know, closest to target
 		const LAST_BIN: u32 = NODE_BINS - 1;
@@ -136,21 +137,21 @@ impl Discovery {
 		if head > 1 && tail != LAST_BIN {
 			while head != tail && head < NODE_BINS && count < BUCKET_SIZE
 			{
-				for n in buckets[head as usize].nodes.iter()
+				for n in &buckets[head as usize].nodes
 				{
 						if count < BUCKET_SIZE {
 							count += 1;
-							found.entry(Discovery::distance(target, &n)).or_insert(Vec::new()).push(n);
+							found.entry(Discovery::distance(target, &n)).or_insert_with(Vec::new).push(n);
 						}
 						else {
 							break;
 						}
 				}
 				if count < BUCKET_SIZE && tail != 0 {
-					for n in buckets[tail as usize].nodes.iter() {
+					for n in &buckets[tail as usize].nodes {
 						if count < BUCKET_SIZE {
 							count += 1;
-							found.entry(Discovery::distance(target, &n)).or_insert(Vec::new()).push(n);
+							found.entry(Discovery::distance(target, &n)).or_insert_with(Vec::new).push(n);
 						}
 						else {
 							break;
@@ -166,10 +167,10 @@ impl Discovery {
 		}
 		else if head < 2 {
 			while head < NODE_BINS && count < BUCKET_SIZE {
-				for n in buckets[head as usize].nodes.iter() {
+				for n in &buckets[head as usize].nodes {
 						if count < BUCKET_SIZE {
 							count += 1;
-							found.entry(Discovery::distance(target, &n)).or_insert(Vec::new()).push(n);
+							found.entry(Discovery::distance(target, &n)).or_insert_with(Vec::new).push(n);
 						}
 						else {
 							break;
@@ -180,10 +181,10 @@ impl Discovery {
 		}
 		else {
 			while tail > 0 && count < BUCKET_SIZE {
-				for n in buckets[tail as usize].nodes.iter() {
+				for n in &buckets[tail as usize].nodes {
 						if count < BUCKET_SIZE {
 							count += 1;
-							found.entry(Discovery::distance(target, &n)).or_insert(Vec::new()).push(n);
+							found.entry(Discovery::distance(target, &n)).or_insert_with(Vec::new).push(n);
 						}
 						else {
 							break;
diff --git a/util/src/network/error.rs b/util/src/network/error.rs
index d255cb043..b9dfdc892 100644
--- a/util/src/network/error.rs
+++ b/util/src/network/error.rs
@@ -19,11 +19,17 @@ pub enum DisconnectReason
 }
 
 #[derive(Debug)]
+/// Network error.
 pub enum NetworkError {
+	/// Authentication error.
 	Auth,
+	/// Unrecognised protocol.
 	BadProtocol,
+	/// Peer not found.
 	PeerNotFound,
+	/// Peer is diconnected.
 	Disconnect(DisconnectReason),
+	/// Socket IO error.
 	Io(IoError),
 }
 
diff --git a/util/src/network/handshake.rs b/util/src/network/handshake.rs
index ca95808b4..ddeab17b7 100644
--- a/util/src/network/handshake.rs
+++ b/util/src/network/handshake.rs
@@ -10,6 +10,7 @@ use network::host::{HostInfo};
 use network::node::NodeId;
 use error::*;
 use network::error::NetworkError;
+use io::{IoContext, StreamToken};
 
 #[derive(PartialEq, Eq, Debug)]
 enum HandshakeState {
@@ -33,8 +34,6 @@ pub struct Handshake {
 	state: HandshakeState,
 	/// Outgoing or incoming connection
 	pub originated: bool,
-	/// Disconnect timeout
-	idle_timeout: Option<Timeout>,
 	/// ECDH ephemeral
 	pub ecdhe: KeyPair,
 	/// Connection nonce
@@ -51,16 +50,16 @@ pub struct Handshake {
 
 const AUTH_PACKET_SIZE: usize = 307;
 const ACK_PACKET_SIZE: usize = 210;
+const HANDSHAKE_TIMEOUT: u64 = 30000;
 
 impl Handshake {
 	/// Create a new handshake object
-	pub fn new(token: Token, id: &NodeId, socket: TcpStream, nonce: &H256) -> Result<Handshake, UtilError> {
+	pub fn new(token: StreamToken, id: &NodeId, socket: TcpStream, nonce: &H256) -> Result<Handshake, UtilError> {
 		Ok(Handshake {
 			id: id.clone(),
 			connection: Connection::new(token, socket),
 			originated: false,
 			state: HandshakeState::New,
-			idle_timeout: None,
 			ecdhe: try!(KeyPair::create()),
 			nonce: nonce.clone(),
 			remote_public: Public::new(),
@@ -71,8 +70,9 @@ impl Handshake {
 	}
 
 	/// Start a handhsake
-	pub fn start(&mut self, host: &HostInfo, originated: bool) -> Result<(), UtilError> {
+	pub fn start<Message>(&mut self, io: &IoContext<Message>, host: &HostInfo, originated: bool) -> Result<(), UtilError> where Message: Send + Clone{
 		self.originated = originated;
+		io.register_timer(self.connection.token, HANDSHAKE_TIMEOUT).ok();
 		if originated {
 			try!(self.write_auth(host));
 		}
@@ -89,50 +89,48 @@ impl Handshake {
 	}
 
 	/// Readable IO handler. Drives the state change.
-	pub fn readable<Host:Handler>(&mut self, event_loop: &mut EventLoop<Host>, host: &HostInfo) -> Result<(), UtilError> {
-		self.idle_timeout.map(|t| event_loop.clear_timeout(t));
+	pub fn readable<Message>(&mut self, io: &IoContext<Message>, host: &HostInfo) -> Result<(), UtilError> where Message: Send + Clone {
+		io.clear_timer(self.connection.token).unwrap();
 		match self.state {
 			HandshakeState::ReadingAuth => {
-				match try!(self.connection.readable()) {
-					Some(data)  => {
-						try!(self.read_auth(host, &data));
-						try!(self.write_ack());
-					},
-					None => {}
+				if let Some(data) = try!(self.connection.readable()) {
+					try!(self.read_auth(host, &data));
+					try!(self.write_ack());
 				};
 			},
 			HandshakeState::ReadingAck => {
-				match try!(self.connection.readable()) {
-					Some(data)  => {
-						try!(self.read_ack(host, &data));
-						self.state = HandshakeState::StartSession;
-					},
-					None => {}
+				if let Some(data) = try!(self.connection.readable()) {
+					try!(self.read_ack(host, &data));
+					self.state = HandshakeState::StartSession;
 				};
 			},
+			HandshakeState::StartSession => {},
 			_ => { panic!("Unexpected state"); }
 		}
 		if self.state != HandshakeState::StartSession {
-			try!(self.connection.reregister(event_loop));
+			try!(io.update_registration(self.connection.token));
 		}
 		Ok(())
 	}
 
 	/// Writabe IO handler.
-	pub fn writable<Host:Handler>(&mut self, event_loop: &mut EventLoop<Host>, _host: &HostInfo) -> Result<(), UtilError> {
-		self.idle_timeout.map(|t| event_loop.clear_timeout(t));
+	pub fn writable<Message>(&mut self, io: &IoContext<Message>, _host: &HostInfo) -> Result<(), UtilError> where Message: Send + Clone {
+		io.clear_timer(self.connection.token).unwrap();
 		try!(self.connection.writable());
 		if self.state != HandshakeState::StartSession {
-			try!(self.connection.reregister(event_loop));
+			io.update_registration(self.connection.token).unwrap();
 		}
 		Ok(())
 	}
 
-	/// Register the IO handler with the event loop
-	pub fn register<Host:Handler<Timeout=Token>>(&mut self, event_loop: &mut EventLoop<Host>) -> Result<(), UtilError> {
-		self.idle_timeout.map(|t| event_loop.clear_timeout(t));
-		self.idle_timeout = event_loop.timeout_ms(self.connection.token, 1800).ok();
-		try!(self.connection.register(event_loop));
+	/// Register the socket with the event loop
+	pub fn register_socket<Host:Handler<Timeout=Token>>(&self, reg: Token, event_loop: &mut EventLoop<Host>) -> Result<(), UtilError> {
+		try!(self.connection.register_socket(reg, event_loop));
+		Ok(())
+	}
+
+	pub fn update_socket<Host:Handler<Timeout=Token>>(&self, reg: Token, event_loop: &mut EventLoop<Host>) -> Result<(), UtilError> {
+		try!(self.connection.update_socket(reg, event_loop));
 		Ok(())
 	}
 
diff --git a/util/src/network/host.rs b/util/src/network/host.rs
index 67a9c56db..06e7f5a4e 100644
--- a/util/src/network/host.rs
+++ b/util/src/network/host.rs
@@ -1,8 +1,9 @@
-use std::mem;
 use std::net::{SocketAddr};
 use std::collections::{HashMap};
 use std::hash::{Hasher};
 use std::str::{FromStr};
+use std::sync::*;
+use std::ops::*;
 use mio::*;
 use mio::tcp::*;
 use mio::udp::*;
@@ -64,19 +65,25 @@ pub type PacketId = u8;
 pub type ProtocolId = &'static str;
 
 /// Messages used to communitate with the event loop from other threads.
-pub enum NetworkIoMessage<Message> where Message: Send {
+#[derive(Clone)]
+pub enum NetworkIoMessage<Message> where Message: Send + Sync + Clone {
 	/// Register a new protocol handler.
 	AddHandler {
-		handler: Option<Box<NetworkProtocolHandler<Message>+Send>>,
+		/// Handler shared instance.
+		handler: Arc<NetworkProtocolHandler<Message> + Sync>,
+		/// Protocol Id.
 		protocol: ProtocolId,
+		/// Supported protocol versions.
 		versions: Vec<u8>,
 	},
-	/// Send data over the network.
-	Send {
-		peer: PeerId,
-		packet_id: PacketId,
+	/// Register a new protocol timer
+	AddTimer {
+		/// Protocol Id.
 		protocol: ProtocolId,
-		data: Vec<u8>,
+		/// Timer token.
+		token: TimerToken,
+		/// Timer delay in milliseconds.
+		delay: u64,
 	},
 	/// User message
 	User(Message),
@@ -104,46 +111,45 @@ impl Encodable for CapabilityInfo {
 }
 
 /// IO access point. This is passed to all IO handlers and provides an interface to the IO subsystem.
-pub struct NetworkContext<'s, 'io, Message> where Message: Send + 'static, 'io: 's {
-	io: &'s mut IoContext<'io, NetworkIoMessage<Message>>,
+pub struct NetworkContext<'s, Message> where Message: Send + Sync + Clone + 'static, 's {
+	io: &'s IoContext<NetworkIoMessage<Message>>,
 	protocol: ProtocolId,
-	connections: &'s mut Slab<ConnectionEntry>,
-	timers: &'s mut HashMap<TimerToken, ProtocolId>,
+	connections: Arc<RwLock<Slab<SharedConnectionEntry>>>,
 	session: Option<StreamToken>,
 }
 
-impl<'s, 'io, Message> NetworkContext<'s, 'io, Message> where Message: Send + 'static, {
+impl<'s, Message> NetworkContext<'s, Message> where Message: Send + Sync + Clone + 'static, {
 	/// Create a new network IO access point. Takes references to all the data that can be updated within the IO handler.
-	fn new(io: &'s mut IoContext<'io, NetworkIoMessage<Message>>, 
+	fn new(io: &'s IoContext<NetworkIoMessage<Message>>, 
 		protocol: ProtocolId, 
-		session: Option<StreamToken>, connections: &'s mut Slab<ConnectionEntry>, 
-		timers: &'s mut HashMap<TimerToken, ProtocolId>) -> NetworkContext<'s, 'io, Message> {
+		session: Option<StreamToken>, connections: Arc<RwLock<Slab<SharedConnectionEntry>>>) -> NetworkContext<'s, Message> {
 		NetworkContext {
 			io: io,
 			protocol: protocol,
 			session: session,
 			connections: connections,
-			timers: timers,
 		}
 	}
 
 	/// Send a packet over the network to another peer.
-	pub fn send(&mut self, peer: PeerId, packet_id: PacketId, data: Vec<u8>) -> Result<(), UtilError> {
-		match self.connections.get_mut(peer) {
-			Some(&mut ConnectionEntry::Session(ref mut s)) => {
-				s.send_packet(self.protocol, packet_id as u8, &data).unwrap_or_else(|e| {
-					warn!(target: "net", "Send error: {:?}", e);
-				}); //TODO: don't copy vector data
-			},
-			_ => {
-				warn!(target: "net", "Send: Peer does not exist");
+	pub fn send(&self, peer: PeerId, packet_id: PacketId, data: Vec<u8>) -> Result<(), UtilError> {
+		if let Some(connection) = self.connections.read().unwrap().get(peer).cloned() {
+			match *connection.lock().unwrap().deref_mut() {
+				ConnectionEntry::Session(ref mut s) => {
+					s.send_packet(self.protocol, packet_id as u8, &data).unwrap_or_else(|e| {
+						warn!(target: "net", "Send error: {:?}", e);
+					}); //TODO: don't copy vector data
+				},
+				_ => warn!(target: "net", "Send: Peer is not connected yet")
 			}
+		} else  {
+			warn!(target: "net", "Send: Peer does not exist")
 		}
 		Ok(())
 	}
 
 	/// Respond to a current network message. Panics if no there is no packet in the context.
-	pub fn respond(&mut self, packet_id: PacketId, data: Vec<u8>) -> Result<(), UtilError> {
+	pub fn respond(&self, packet_id: PacketId, data: Vec<u8>) -> Result<(), UtilError> {
 		match self.session {
 			Some(session) => self.send(session, packet_id, data),
 			None => {
@@ -153,31 +159,28 @@ impl<'s, 'io, Message> NetworkContext<'s, 'io, Message> where Message: Send + 's
 	}
 
 	/// Disable current protocol capability for given peer. If no capabilities left peer gets disconnected.
-	pub fn disable_peer(&mut self, _peer: PeerId) {
+	pub fn disable_peer(&self, _peer: PeerId) {
 		//TODO: remove capability, disconnect if no capabilities left
 	}
 
-	/// Register a new IO timer. Returns a new timer token. 'NetworkProtocolHandler::timeout' will be called with the token.
-	pub fn register_timer(&mut self, ms: u64) -> Result<TimerToken, UtilError>{
-		match self.io.register_timer(ms) {
-			Ok(token) => {
-				self.timers.insert(token, self.protocol);
-				Ok(token)
-			},
-			e => e,
-		}
+	/// Register a new IO timer. 'IoHandler::timeout' will be called with the token.
+	pub fn register_timer(&self, token: TimerToken, ms: u64) -> Result<(), UtilError> {
+		self.io.message(NetworkIoMessage::AddTimer {
+			token: token,
+			delay: ms,
+			protocol: self.protocol,
+		});
+		Ok(())
 	}
 
 	/// Returns peer identification string
 	pub fn peer_info(&self, peer: PeerId) -> String {
-		match self.connections.get(peer) {
-			Some(&ConnectionEntry::Session(ref s)) => {
-				s.info.client_version.clone()
-			},
-			_ => {
-				"unknown".to_string()
+		if let Some(connection) = self.connections.read().unwrap().get(peer).cloned() {
+			if let ConnectionEntry::Session(ref s) = *connection.lock().unwrap().deref() {
+				return s.info.client_version.clone()
 			}
 		}
+		"unknown".to_owned()
 	}
 }
 
@@ -213,7 +216,7 @@ impl HostInfo {
 	/// Increments and returns connection nonce.
 	pub fn next_nonce(&mut self) -> H256 {
 		self.nonce = self.nonce.sha3();
-		return self.nonce.clone();
+		self.nonce.clone()
 	}
 }
 
@@ -222,66 +225,92 @@ enum ConnectionEntry {
 	Session(Session)
 }
 
-/// Root IO handler. Manages protocol handlers, IO timers and network connections.
-pub struct Host<Message> where Message: Send {
-	pub info: HostInfo,
-	udp_socket: UdpSocket,
-	listener: TcpListener,
-	connections: Slab<ConnectionEntry>,
-	timers: HashMap<TimerToken, ProtocolId>,
-	nodes: HashMap<NodeId, Node>,
-	handlers: HashMap<ProtocolId, Box<NetworkProtocolHandler<Message>>>,
+type SharedConnectionEntry = Arc<Mutex<ConnectionEntry>>;
+
+#[derive(Copy, Clone)]
+struct ProtocolTimer {
+	pub protocol: ProtocolId,
+	pub token: TimerToken, // Handler level token
 }
 
-impl<Message> Host<Message> where Message: Send {
+/// Root IO handler. Manages protocol handlers, IO timers and network connections.
+pub struct Host<Message> where Message: Send + Sync + Clone {
+	pub info: RwLock<HostInfo>,
+	udp_socket: Mutex<UdpSocket>,
+	tcp_listener: Mutex<TcpListener>,
+	connections: Arc<RwLock<Slab<SharedConnectionEntry>>>,
+	nodes: RwLock<HashMap<NodeId, Node>>,
+	handlers: RwLock<HashMap<ProtocolId, Arc<NetworkProtocolHandler<Message>>>>,
+	timers: RwLock<HashMap<TimerToken, ProtocolTimer>>,
+	timer_counter: RwLock<usize>,
+}
+
+impl<Message> Host<Message> where Message: Send + Sync + Clone {
 	pub fn new() -> Host<Message> {
 		let config = NetworkConfiguration::new();
 		let addr = config.listen_address;
 		// Setup the server socket
-		let listener = TcpListener::bind(&addr).unwrap();
+		let tcp_listener = TcpListener::bind(&addr).unwrap();
 		let udp_socket = UdpSocket::bound(&addr).unwrap();
-		Host::<Message> {
-			info: HostInfo {
+		let host = Host::<Message> {
+			info: RwLock::new(HostInfo {
 				keys: KeyPair::create().unwrap(),
 				config: config,
 				nonce: H256::random(),
 				protocol_version: 4,
-				client_version: "parity".to_string(),
+				client_version: "parity".to_owned(),
 				listen_port: 0,
 				capabilities: Vec::new(),
-			},
-			udp_socket: udp_socket,
-			listener: listener,
-			connections: Slab::new_starting_at(FIRST_CONNECTION, MAX_CONNECTIONS),
-			timers: HashMap::new(),
-			nodes: HashMap::new(),
-			handlers: HashMap::new(),
-		}
+			}),
+			udp_socket: Mutex::new(udp_socket),
+			tcp_listener: Mutex::new(tcp_listener),
+			connections: Arc::new(RwLock::new(Slab::new_starting_at(FIRST_CONNECTION, MAX_CONNECTIONS))),
+			nodes: RwLock::new(HashMap::new()),
+			handlers: RwLock::new(HashMap::new()),
+			timers: RwLock::new(HashMap::new()),
+			timer_counter: RwLock::new(LAST_CONNECTION + 1),
+		};
+		let port = host.info.read().unwrap().config.listen_address.port();
+		host.info.write().unwrap().deref_mut().listen_port = port;
+
+		/*
+		match ::ifaces::Interface::get_all().unwrap().into_iter().filter(|x| x.kind == ::ifaces::Kind::Packet && x.addr.is_some()).next() {
+		Some(iface) => config.public_address = iface.addr.unwrap(),
+		None => warn!("No public network interface"),
+		*/
+		host
 	}
 
 	pub fn add_node(&mut self, id: &str) {
 		match Node::from_str(id) {
 			Err(e) => { warn!("Could not add node: {:?}", e); },
 			Ok(n) => {
-				self.nodes.insert(n.id.clone(), n);
+				self.nodes.write().unwrap().insert(n.id.clone(), n);
 			}
 		}
 	}
 
-	fn maintain_network(&mut self, io: &mut IoContext<NetworkIoMessage<Message>>) {
+	pub fn client_version(&self) -> String {
+		self.info.read().unwrap().client_version.clone()
+	}
+
+	pub fn client_id(&self) -> NodeId {
+		self.info.read().unwrap().id().clone()
+	}
+
+	fn maintain_network(&self, io: &IoContext<NetworkIoMessage<Message>>) {
 		self.connect_peers(io);
-		io.event_loop.timeout_ms(Token(IDLE), MAINTENANCE_TIMEOUT).unwrap();
 	}
 
 	fn have_session(&self, id: &NodeId) -> bool {
-		self.connections.iter().any(|e| match e { &ConnectionEntry::Session(ref s) => s.info.id.eq(&id), _ => false  })
+		self.connections.read().unwrap().iter().any(|e| match *e.lock().unwrap().deref() { ConnectionEntry::Session(ref s) => s.info.id.eq(&id), _ => false  })
 	}
 
 	fn connecting_to(&self, id: &NodeId) -> bool {
-		self.connections.iter().any(|e| match e { &ConnectionEntry::Handshake(ref h) => h.id.eq(&id), _ => false  })
+		self.connections.read().unwrap().iter().any(|e| match *e.lock().unwrap().deref() { ConnectionEntry::Handshake(ref h) => h.id.eq(&id), _ => false  })
 	}
 
-	fn connect_peers(&mut self, io: &mut IoContext<NetworkIoMessage<Message>>) {
+	fn connect_peers(&self, io: &IoContext<NetworkIoMessage<Message>>) {
 		struct NodeInfo {
 			id: NodeId,
 			peer_type: PeerType
@@ -292,18 +321,19 @@ impl<Message> Host<Message> where Message: Send {
 		let mut req_conn = 0;
 		//TODO: use nodes from discovery here
 		//for n in self.node_buckets.iter().flat_map(|n| &n.nodes).map(|id| NodeInfo { id: id.clone(), peer_type: self.nodes.get(id).unwrap().peer_type}) {
-		for n in self.nodes.values().map(|n| NodeInfo { id: n.id.clone(), peer_type: n.peer_type }) {
+		let pin = self.info.read().unwrap().deref().config.pin;
+		for n in self.nodes.read().unwrap().values().map(|n| NodeInfo { id: n.id.clone(), peer_type: n.peer_type }) {
 			let connected = self.have_session(&n.id) || self.connecting_to(&n.id);
 			let required = n.peer_type == PeerType::Required;
 			if connected && required {
 				req_conn += 1;
 			}
-			else if !connected && (!self.info.config.pin || required) {
+			else if !connected && (!pin || required) {
 				to_connect.push(n);
 			}
 		}
 
-		for n in to_connect.iter() {
+		for n in &to_connect {
 			if n.peer_type == PeerType::Required {
 				if req_conn < IDEAL_PEERS {
 					self.connect_peer(&n.id, io);
@@ -312,13 +342,12 @@ impl<Message> Host<Message> where Message: Send {
 			}
 		}
 
-		if !self.info.config.pin
-		{
+		if !pin {
 			let pending_count = 0; //TODO:
 			let peer_count = 0;
 			let mut open_slots = IDEAL_PEERS - peer_count  - pending_count + req_conn;
 			if open_slots > 0 {
-				for n in to_connect.iter() {
+				for n in &to_connect {
 					if n.peer_type == PeerType::Optional && open_slots > 0 {
 						open_slots -= 1;
 						self.connect_peer(&n.id, io);
@@ -328,23 +357,27 @@ impl<Message> Host<Message> where Message: Send {
 		}
 	}
 
-	fn connect_peer(&mut self, id: &NodeId, io: &mut IoContext<NetworkIoMessage<Message>>) {
+	#[allow(single_match)]
+	#[allow(block_in_if_condition_stmt)]
+	fn connect_peer(&self, id: &NodeId, io: &IoContext<NetworkIoMessage<Message>>) {
 		if self.have_session(id)
 		{
 			warn!("Aborted connect. Node already connected.");
 			return;
 		}
-		if self.connecting_to(id)
-		{
+		if self.connecting_to(id) {
 			warn!("Aborted connect. Node already connecting.");
 			return;
 		}
 
 		let socket = {
-			let node = self.nodes.get_mut(id).unwrap();
-			node.last_attempted = Some(::time::now());
-
-			match TcpStream::connect(&node.endpoint.address) {
+			let address = {
+				let mut nodes = self.nodes.write().unwrap();
+				let node = nodes.get_mut(id).unwrap();
+				node.last_attempted = Some(::time::now());
+				node.endpoint.address
+			};
+			match TcpStream::connect(&address) {
 				Ok(socket) => socket,
 				Err(_) => {
 					warn!("Cannot connect to node");
@@ -353,216 +386,182 @@ impl<Message> Host<Message> where Message: Send {
 			}
 		};
 
-		let nonce = self.info.next_nonce();
-		match self.connections.insert_with(|token| ConnectionEntry::Handshake(Handshake::new(Token(token), id, socket, &nonce).expect("Can't create handshake"))) {
-			Some(token) => {
-				match self.connections.get_mut(token) {
-					Some(&mut ConnectionEntry::Handshake(ref mut h)) => {
-						h.start(&self.info, true)
-							.and_then(|_| h.register(io.event_loop))
-							.unwrap_or_else (|e| {
-								debug!(target: "net", "Handshake create error: {:?}", e);
-							});
-					},
-					_ => {}
-				}
-			},
-			None => { warn!("Max connections reached") }
+		let nonce = self.info.write().unwrap().next_nonce();
+		if self.connections.write().unwrap().insert_with(|token| {
+			let mut handshake = Handshake::new(token, id, socket, &nonce).expect("Can't create handshake");
+			handshake.start(io, &self.info.read().unwrap(), true).and_then(|_| io.register_stream(token)).unwrap_or_else (|e| {
+				debug!(target: "net", "Handshake create error: {:?}", e);
+			});
+			Arc::new(Mutex::new(ConnectionEntry::Handshake(handshake)))
+		}).is_none() {
+			warn!("Max connections reached");
 		}
 	}
 
-
-	fn accept(&mut self, _io: &mut IoContext<NetworkIoMessage<Message>>) {
+	fn accept(&self, _io: &IoContext<NetworkIoMessage<Message>>) {
 		trace!(target: "net", "accept");
 	}
 
-	fn connection_writable<'s>(&'s mut self, token: StreamToken, io: &mut IoContext<'s, NetworkIoMessage<Message>>) {
-		let mut kill = false;
+	#[allow(single_match)]
+	fn connection_writable(&self, token: StreamToken, io: &IoContext<NetworkIoMessage<Message>>) {
 		let mut create_session = false;
-		match self.connections.get_mut(token) {
-			Some(&mut ConnectionEntry::Handshake(ref mut h)) => {
-				h.writable(io.event_loop, &self.info).unwrap_or_else(|e| {
-					debug!(target: "net", "Handshake write error: {:?}", e);
-					kill = true;
-				});
-				create_session = h.done();
-			},
-			Some(&mut ConnectionEntry::Session(ref mut s)) => {
-				s.writable(io.event_loop, &self.info).unwrap_or_else(|e| {
-					debug!(target: "net", "Session write error: {:?}", e);
-					kill = true;
-				});
+		let mut kill = false;
+		if let Some(connection) = self.connections.read().unwrap().get(token).cloned() {
+			match *connection.lock().unwrap().deref_mut() {
+				ConnectionEntry::Handshake(ref mut h) => {
+					match h.writable(io, &self.info.read().unwrap()) {
+						Err(e) => {
+							debug!(target: "net", "Handshake write error: {:?}", e);
+							kill = true;
+						},
+						Ok(_) => ()
+					}
+					if h.done() {
+						create_session = true;
+					}
+				},
+				ConnectionEntry::Session(ref mut s) => {
+					match s.writable(io, &self.info.read().unwrap()) {
+						Err(e) => {
+							debug!(target: "net", "Session write error: {:?}", e);
+							kill = true;
+						},
+						Ok(_) => ()
+					}
+					io.update_registration(token).unwrap_or_else(|e| debug!(target: "net", "Session registration error: {:?}", e));
+				}
 			}
-			_ => {
-				warn!(target: "net", "Received event for unknown connection");
-			}
-		}
+		} 
 		if kill {
-			self.kill_connection(token, io);
+			self.kill_connection(token, io); //TODO: mark connection as dead an check in kill_connection
 			return;
 		} else if create_session {
 			self.start_session(token, io);
-		}
-		match self.connections.get_mut(token) {
-			Some(&mut ConnectionEntry::Session(ref mut s)) => {
-				s.reregister(io.event_loop).unwrap_or_else(|e| debug!(target: "net", "Session registration error: {:?}", e));
-			},
-			_ => (),
+			io.update_registration(token).unwrap_or_else(|e| debug!(target: "net", "Session registration error: {:?}", e));
 		}
 	}
 
-	fn connection_closed<'s>(&'s mut self, token: TimerToken, io: &mut IoContext<'s, NetworkIoMessage<Message>>) {
+	fn connection_closed(&self, token: TimerToken, io: &IoContext<NetworkIoMessage<Message>>) {
 		self.kill_connection(token, io);
 	}
 
-	fn connection_readable<'s>(&'s mut self, token: StreamToken, io: &mut IoContext<'s, NetworkIoMessage<Message>>) {
-		let mut kill = false;
-		let mut create_session = false;
+	fn connection_readable(&self, token: StreamToken, io: &IoContext<NetworkIoMessage<Message>>) {
 		let mut ready_data: Vec<ProtocolId> = Vec::new();
 		let mut packet_data: Option<(ProtocolId, PacketId, Vec<u8>)> = None;
-		match self.connections.get_mut(token) {
-			Some(&mut ConnectionEntry::Handshake(ref mut h)) => {
-				h.readable(io.event_loop, &self.info).unwrap_or_else(|e| {
-					debug!(target: "net", "Handshake read error: {:?}", e);
-					kill = true;
-				});
-				create_session = h.done();
-			},
-			Some(&mut ConnectionEntry::Session(ref mut s)) => {
-				let sd = { s.readable(io.event_loop, &self.info).unwrap_or_else(|e| {
-					debug!(target: "net", "Session read error: {:?}", e);
-					kill = true;
-					SessionData::None
-				}) };
-				match sd {
-					SessionData::Ready => {
-						for (p, _) in self.handlers.iter_mut() {
-							if s.have_capability(p)  {
-								ready_data.push(p);
+		let mut create_session = false;
+		let mut kill = false;
+		if let Some(connection) = self.connections.read().unwrap().get(token).cloned() {
+			match *connection.lock().unwrap().deref_mut() {
+				ConnectionEntry::Handshake(ref mut h) => {
+					if let Err(e) = h.readable(io, &self.info.read().unwrap()) {
+						debug!(target: "net", "Handshake read error: {:?}", e);
+						kill = true;
+					}
+					if h.done() {
+						create_session = true;
+					}
+				},
+				ConnectionEntry::Session(ref mut s) => {
+					match s.readable(io, &self.info.read().unwrap()) {
+						Err(e) => {
+							debug!(target: "net", "Handshake read error: {:?}", e);
+							kill = true;
+						},
+						Ok(SessionData::Ready) => {
+							for (p, _) in self.handlers.read().unwrap().iter() {
+								if s.have_capability(p)  {
+									ready_data.push(p);
+								}
 							}
-						}
-					},
-					SessionData::Packet {
-						data,
-						protocol,
-						packet_id,
-					} => {
-						match self.handlers.get_mut(protocol) {
-							None => { warn!(target: "net", "No handler found for protocol: {:?}", protocol) },
-							Some(_) => packet_data = Some((protocol, packet_id, data)),
-						}
-					},
-					SessionData::None => {},
-				}
-			}
-			_ => {
-				warn!(target: "net", "Received event for unknown connection");
-			}
-		}
-		if kill {
-			self.kill_connection(token, io);
-			return;
-		}
-		if create_session {
-			self.start_session(token, io);
-		}
-		for p in ready_data {
-			let mut h = self.handlers.get_mut(p).unwrap();
-			h.connected(&mut NetworkContext::new(io, p, Some(token), &mut self.connections, &mut self.timers), &token);
-		}
-		if let Some((p, packet_id, data)) = packet_data {
-			let mut h = self.handlers.get_mut(p).unwrap();
-			h.read(&mut NetworkContext::new(io, p, Some(token), &mut self.connections, &mut self.timers), &token, packet_id, &data[1..]);
-		}
-
-		match self.connections.get_mut(token) {
-			Some(&mut ConnectionEntry::Session(ref mut s)) => {
-				s.reregister(io.event_loop).unwrap_or_else(|e| debug!(target: "net", "Session registration error: {:?}", e));
-			},
-			_ => (),
-		}
-	}
-
-	fn start_session(&mut self, token: StreamToken, io: &mut IoContext<NetworkIoMessage<Message>>) {
-		let info = &self.info;
-		// TODO: use slab::replace_with (currently broken)
-		/*
-		match self.connections.remove(token) {
-			Some(ConnectionEntry::Handshake(h)) => {
-				match Session::new(h, io.event_loop, info) {
-					Ok(session) => {
-						assert!(token == self.connections.insert(ConnectionEntry::Session(session)).ok().unwrap());
-					},
-					Err(e) => {
-						debug!(target: "net", "Session construction error: {:?}", e);
+						},
+						Ok(SessionData::Packet {
+							data,
+							protocol,
+							packet_id,
+						}) => {
+							match self.handlers.read().unwrap().get(protocol) {
+								None => { warn!(target: "net", "No handler found for protocol: {:?}", protocol) },
+								Some(_) => packet_data = Some((protocol, packet_id, data)),
+							}
+						},
+						Ok(SessionData::None) => {},
 					}
 				}
-			},
-			_ => panic!("Error updating slab with session")
-		}*/
-		self.connections.replace_with(token, |c| {
-			match c {
-				ConnectionEntry::Handshake(h) => Session::new(h, io.event_loop, info)
-					.map(|s| Some(ConnectionEntry::Session(s)))
-					.unwrap_or_else(|e| {
-						debug!(target: "net", "Session construction error: {:?}", e);
-						None
-					}),
-					_ => { panic!("No handshake to create a session from"); }
 			}
-		}).expect("Error updating slab with session");
+		} 
+		if kill {
+			self.kill_connection(token, io); //TODO: mark connection as dead an check in kill_connection
+			return;
+		} else if create_session {
+			self.start_session(token, io);
+			io.update_registration(token).unwrap_or_else(|e| debug!(target: "net", "Session registration error: {:?}", e));
+		}
+		for p in ready_data {
+			let h = self.handlers.read().unwrap().get(p).unwrap().clone();
+			h.connected(&NetworkContext::new(io, p, Some(token), self.connections.clone()), &token);
+		}
+		if let Some((p, packet_id, data)) = packet_data {
+			let h = self.handlers.read().unwrap().get(p).unwrap().clone();
+			h.read(&NetworkContext::new(io, p, Some(token), self.connections.clone()), &token, packet_id, &data[1..]);
+		}
+		io.update_registration(token).unwrap_or_else(|e| debug!(target: "net", "Token registration error: {:?}", e));
 	}
 
-	fn connection_timeout<'s>(&'s mut self, token: StreamToken, io: &mut IoContext<'s, NetworkIoMessage<Message>>) {
+	fn start_session(&self, token: StreamToken, io: &IoContext<NetworkIoMessage<Message>>) {
+		self.connections.write().unwrap().replace_with(token, |c| {
+			match Arc::try_unwrap(c).ok().unwrap().into_inner().unwrap() {
+				ConnectionEntry::Handshake(h) => {
+					let session = Session::new(h, io, &self.info.read().unwrap()).expect("Session creation error");
+					io.update_registration(token).expect("Error updating session registration");
+					Some(Arc::new(Mutex::new(ConnectionEntry::Session(session))))
+				},
+				_ => { None } // handshake expired
+			}
+		}).ok();
+	}
+
+	fn connection_timeout(&self, token: StreamToken, io: &IoContext<NetworkIoMessage<Message>>) {
 		self.kill_connection(token, io)
 	}
 
-	fn kill_connection<'s>(&'s mut self, token: StreamToken, io: &mut IoContext<'s, NetworkIoMessage<Message>>) {
+	fn kill_connection(&self, token: StreamToken, io: &IoContext<NetworkIoMessage<Message>>) {
 		let mut to_disconnect: Vec<ProtocolId> = Vec::new();
-		let mut remove = true;
-		match self.connections.get_mut(token) {
-			Some(&mut ConnectionEntry::Handshake(_)) => (), // just abandon handshake
-			Some(&mut ConnectionEntry::Session(ref mut s)) if s.is_ready() => {
-				for (p, _) in self.handlers.iter_mut() {
-					if s.have_capability(p)  {
-						to_disconnect.push(p);
-					}
+		{
+			let mut connections = self.connections.write().unwrap();
+			if let Some(connection) = connections.get(token).cloned() {
+				match *connection.lock().unwrap().deref_mut() {
+					ConnectionEntry::Handshake(_) => {
+						connections.remove(token);
+					},
+					ConnectionEntry::Session(ref mut s) if s.is_ready() => {
+						for (p, _) in self.handlers.read().unwrap().iter() {
+							if s.have_capability(p)  {
+								to_disconnect.push(p);
+							}
+						}
+						connections.remove(token);
+					},
+					_ => {},
 				}
-			},
-			_ => {
-				remove = false;
-			},
+			}
 		}
 		for p in to_disconnect {
-			let mut h = self.handlers.get_mut(p).unwrap();
-			h.disconnected(&mut NetworkContext::new(io, p, Some(token), &mut self.connections, &mut self.timers), &token);
-		}
-		if remove {
-			self.connections.remove(token);
+			let h = self.handlers.read().unwrap().get(p).unwrap().clone();
+			h.disconnected(&NetworkContext::new(io, p, Some(token), self.connections.clone()), &token);
 		}
 	}
 }
 
-impl<Message> IoHandler<NetworkIoMessage<Message>> for Host<Message> where Message: Send + 'static {
+impl<Message> IoHandler<NetworkIoMessage<Message>> for Host<Message> where Message: Send + Sync + Clone + 'static {
 	/// Initialize networking
-	fn initialize(&mut self, io: &mut IoContext<NetworkIoMessage<Message>>) {
-		/*
-		match ::ifaces::Interface::get_all().unwrap().into_iter().filter(|x| x.kind == ::ifaces::Kind::Packet && x.addr.is_some()).next() {
-		Some(iface) => config.public_address = iface.addr.unwrap(),
-		None => warn!("No public network interface"),
-		*/
-
-		// Start listening for incoming connections
-		io.event_loop.register(&self.listener, Token(TCP_ACCEPT), EventSet::readable(), PollOpt::edge()).unwrap();
-		io.event_loop.timeout_ms(Token(IDLE), MAINTENANCE_TIMEOUT).unwrap();
-		// open the udp socket
-		io.event_loop.register(&self.udp_socket, Token(NODETABLE_RECEIVE), EventSet::readable(), PollOpt::edge()).unwrap();
-		io.event_loop.timeout_ms(Token(NODETABLE_MAINTAIN), 7200).unwrap();
-		let port = self.info.config.listen_address.port();
-		self.info.listen_port = port;
+	fn initialize(&self, io: &IoContext<NetworkIoMessage<Message>>) {
+		io.register_stream(TCP_ACCEPT).expect("Error registering TCP listener");
+		io.register_stream(NODETABLE_RECEIVE).expect("Error registering UDP listener");
+		io.register_timer(IDLE, MAINTENANCE_TIMEOUT).expect("Error registering Network idle timer");
+		//io.register_timer(NODETABLE_MAINTAIN, 7200);
 	}
 
-	fn stream_hup<'s>(&'s mut self, io: &mut IoContext<'s, NetworkIoMessage<Message>>, stream: StreamToken) {
+	fn stream_hup(&self, io: &IoContext<NetworkIoMessage<Message>>, stream: StreamToken) {
 		trace!(target: "net", "Hup: {}", stream);
 		match stream {
 			FIRST_CONNECTION ... LAST_CONNECTION => self.connection_closed(stream, io),
@@ -570,7 +569,7 @@ impl<Message> IoHandler<NetworkIoMessage<Message>> for Host<Message> where Messa
 		};
 	}
 
-	fn stream_readable<'s>(&'s mut self, io: &mut IoContext<'s, NetworkIoMessage<Message>>, stream: StreamToken) {
+	fn stream_readable(&self, io: &IoContext<NetworkIoMessage<Message>>, stream: StreamToken) {
 		match stream {
 			FIRST_CONNECTION ... LAST_CONNECTION => self.connection_readable(stream, io),
 			NODETABLE_RECEIVE => {},
@@ -579,65 +578,97 @@ impl<Message> IoHandler<NetworkIoMessage<Message>> for Host<Message> where Messa
 		}
 	}
 
-	fn stream_writable<'s>(&'s mut self, io: &mut IoContext<'s, NetworkIoMessage<Message>>, stream: StreamToken) {
+	fn stream_writable(&self, io: &IoContext<NetworkIoMessage<Message>>, stream: StreamToken) {
 		match stream {
 			FIRST_CONNECTION ... LAST_CONNECTION => self.connection_writable(stream, io),
+			NODETABLE_RECEIVE => {},
 			_ => panic!("Received unknown writable token"),
 		}
 	}
 
-	fn timeout<'s>(&'s mut self, io: &mut IoContext<'s, NetworkIoMessage<Message>>, token: TimerToken) {
+	fn timeout(&self, io: &IoContext<NetworkIoMessage<Message>>, token: TimerToken) {
 		match token {
 			IDLE => self.maintain_network(io),
 			FIRST_CONNECTION ... LAST_CONNECTION => self.connection_timeout(token, io),
 			NODETABLE_DISCOVERY => {},
 			NODETABLE_MAINTAIN => {},
-			_ => match self.timers.get_mut(&token).map(|p| *p) {
-					Some(protocol) => match self.handlers.get_mut(protocol) {
-							None => { warn!(target: "net", "No handler found for protocol: {:?}", protocol) },
-							Some(h) => { h.timeout(&mut NetworkContext::new(io, protocol, Some(token), &mut self.connections, &mut self.timers), token); }
-					},
-					None => {} // time not registerd through us
+			_ => match self.timers.read().unwrap().get(&token).cloned() {
+				Some(timer) => match self.handlers.read().unwrap().get(timer.protocol).cloned() {
+						None => { warn!(target: "net", "No handler found for protocol: {:?}", timer.protocol) },
+						Some(h) => { h.timeout(&NetworkContext::new(io, timer.protocol, None, self.connections.clone()), timer.token); }
+				},
+				None => { warn!("Unknown timer token: {}", token); } // timer is not registerd through us
 			}
 		}
 	}
 
-	fn message<'s>(&'s mut self, io: &mut IoContext<'s, NetworkIoMessage<Message>>, message: &'s mut NetworkIoMessage<Message>) {
-		match message {
-			&mut NetworkIoMessage::AddHandler {
-				ref mut handler,
+	fn message(&self, io: &IoContext<NetworkIoMessage<Message>>, message: &NetworkIoMessage<Message>) {
+		match *message {
+			NetworkIoMessage::AddHandler {
+				ref handler,
 				ref protocol,
 				ref versions
 			} => {
-				let mut h = mem::replace(handler, None).unwrap();
-				h.initialize(&mut NetworkContext::new(io, protocol, None, &mut self.connections, &mut self.timers));
-				self.handlers.insert(protocol, h);
+				let h = handler.clone();
+				h.initialize(&NetworkContext::new(io, protocol, None, self.connections.clone()));
+				self.handlers.write().unwrap().insert(protocol, h);
+				let mut info = self.info.write().unwrap();
 				for v in versions {
-					self.info.capabilities.push(CapabilityInfo { protocol: protocol, version: *v, packet_count:0 });
+					info.capabilities.push(CapabilityInfo { protocol: protocol, version: *v, packet_count:0 });
 				}
 			},
-			&mut NetworkIoMessage::Send {
-				ref peer,
-				ref packet_id,
+			NetworkIoMessage::AddTimer {
 				ref protocol,
-				ref data,
+				ref delay,
+				ref token,
 			} => {
-				match self.connections.get_mut(*peer as usize) {
-					Some(&mut ConnectionEntry::Session(ref mut s)) => {
-						s.send_packet(protocol, *packet_id as u8, &data).unwrap_or_else(|e| {
-							warn!(target: "net", "Send error: {:?}", e);
-						}); //TODO: don't copy vector data
-					},
-					_ => {
-						warn!(target: "net", "Send: Peer does not exist");
-					}
-				}
+				let handler_token = {
+					let mut timer_counter = self.timer_counter.write().unwrap();
+					let counter = timer_counter.deref_mut();
+					let handler_token = *counter;
+					*counter += 1;
+					handler_token
+				};
+				self.timers.write().unwrap().insert(handler_token, ProtocolTimer { protocol: protocol, token: *token });
+				io.register_timer(handler_token, *delay).expect("Error registering timer");
 			},
-			&mut NetworkIoMessage::User(ref message) => {
-				for (p, h) in self.handlers.iter_mut() {
-					h.message(&mut NetworkContext::new(io, p, None, &mut self.connections, &mut self.timers), &message);
+			NetworkIoMessage::User(ref message) => {
+				for (p, h) in self.handlers.read().unwrap().iter() {
+					h.message(&NetworkContext::new(io, p, None, self.connections.clone()), &message);
 				}
 			}
 		}
 	}
+
+	fn register_stream(&self, stream: StreamToken, reg: Token, event_loop: &mut EventLoop<IoManager<NetworkIoMessage<Message>>>) {
+		match stream {
+			FIRST_CONNECTION ... LAST_CONNECTION => {
+				if let Some(connection) = self.connections.read().unwrap().get(stream).cloned() {
+					match *connection.lock().unwrap().deref() {
+						ConnectionEntry::Handshake(ref h) => h.register_socket(reg, event_loop).expect("Error registering socket"),
+						ConnectionEntry::Session(_) => warn!("Unexpected session stream registration")
+					}
+				} else {} // expired
+			}
+			NODETABLE_RECEIVE => event_loop.register(self.udp_socket.lock().unwrap().deref(), Token(NODETABLE_RECEIVE), EventSet::all(), PollOpt::edge()).expect("Error registering stream"),
+			TCP_ACCEPT => event_loop.register(self.tcp_listener.lock().unwrap().deref(), Token(TCP_ACCEPT), EventSet::all(), PollOpt::edge()).expect("Error registering stream"),
+			_ => warn!("Unexpected stream registration")
+		}
+	}
+
+	fn update_stream(&self, stream: StreamToken, reg: Token, event_loop: &mut EventLoop<IoManager<NetworkIoMessage<Message>>>) {
+		match stream {
+			FIRST_CONNECTION ... LAST_CONNECTION => {
+				if let Some(connection) = self.connections.read().unwrap().get(stream).cloned() {
+					match *connection.lock().unwrap().deref() {
+						ConnectionEntry::Handshake(ref h) => h.update_socket(reg, event_loop).expect("Error updating socket"),
+						ConnectionEntry::Session(ref s) => s.update_socket(reg, event_loop).expect("Error updating socket"),
+					}
+				} else {} // expired
+			}
+			NODETABLE_RECEIVE => event_loop.reregister(self.udp_socket.lock().unwrap().deref(), Token(NODETABLE_RECEIVE), EventSet::all(), PollOpt::edge()).expect("Error reregistering stream"),
+			TCP_ACCEPT => event_loop.reregister(self.tcp_listener.lock().unwrap().deref(), Token(TCP_ACCEPT), EventSet::all(), PollOpt::edge()).expect("Error reregistering stream"),
+			_ => warn!("Unexpected stream update")
+		}
+	}
 }
diff --git a/util/src/network/mod.rs b/util/src/network/mod.rs
index 2c9e71585..0c734442d 100644
--- a/util/src/network/mod.rs
+++ b/util/src/network/mod.rs
@@ -8,39 +8,40 @@
 ///
 /// struct MyHandler;
 ///
+/// #[derive(Clone)]
 /// struct MyMessage {
 /// 	data: u32
 /// }
 ///
 /// impl NetworkProtocolHandler<MyMessage> for MyHandler {
-///		fn initialize(&mut self, io: &mut NetworkContext<MyMessage>) {
-///			io.register_timer(1000);
+///		fn initialize(&self, io: &NetworkContext<MyMessage>) {
+///			io.register_timer(0, 1000);
 ///		}
 ///
-///		fn read(&mut self, io: &mut NetworkContext<MyMessage>, peer: &PeerId, packet_id: u8, data: &[u8]) {
+///		fn read(&self, io: &NetworkContext<MyMessage>, peer: &PeerId, packet_id: u8, data: &[u8]) {
 ///			println!("Received {} ({} bytes) from {}", packet_id, data.len(), peer);
 ///		}
 ///
-///		fn connected(&mut self, io: &mut NetworkContext<MyMessage>, peer: &PeerId) {
+///		fn connected(&self, io: &NetworkContext<MyMessage>, peer: &PeerId) {
 ///			println!("Connected {}", peer);
 ///		}
 ///
-///		fn disconnected(&mut self, io: &mut NetworkContext<MyMessage>, peer: &PeerId) {
+///		fn disconnected(&self, io: &NetworkContext<MyMessage>, peer: &PeerId) {
 ///			println!("Disconnected {}", peer);
 ///		}
 ///
-///		fn timeout(&mut self, io: &mut NetworkContext<MyMessage>, timer: TimerToken) {
+///		fn timeout(&self, io: &NetworkContext<MyMessage>, timer: TimerToken) {
 ///			println!("Timeout {}", timer);
 ///		}
 ///
-///		fn message(&mut self, io: &mut NetworkContext<MyMessage>, message: &MyMessage) {
+///		fn message(&self, io: &NetworkContext<MyMessage>, message: &MyMessage) {
 ///			println!("Message {}", message.data);
 ///		}
 /// }
 ///
 /// fn main () {
 /// 	let mut service = NetworkService::<MyMessage>::start().expect("Error creating network service");
-/// 	service.register_protocol(Box::new(MyHandler), "myproto", &[1u8]);
+/// 	service.register_protocol(Arc::new(MyHandler), "myproto", &[1u8]);
 ///
 /// 	// Wait for quit condition
 /// 	// ...
@@ -57,36 +58,78 @@ mod error;
 mod node;
 
 /// TODO [arkpar] Please document me
-pub type PeerId = host::PeerId;
+pub use network::host::PeerId;
 /// TODO [arkpar] Please document me
-pub type PacketId = host::PacketId;
+pub use network::host::PacketId;
 /// TODO [arkpar] Please document me
-pub type NetworkContext<'s,'io,  Message> = host::NetworkContext<'s, 'io, Message>;
+pub use network::host::NetworkContext;
 /// TODO [arkpar] Please document me
-pub type NetworkService<Message> = service::NetworkService<Message>;
+pub use network::service::NetworkService;
+/// TODO [arkpar] Please document me
+pub use network::host::NetworkIoMessage;
 /// TODO [arkpar] Please document me
-pub type NetworkIoMessage<Message> = host::NetworkIoMessage<Message>;
 pub use network::host::NetworkIoMessage::User as UserMessage;
 /// TODO [arkpar] Please document me
-pub type NetworkError = error::NetworkError;
+pub use network::error::NetworkError;
 
-use io::*;
+use io::TimerToken;
 
 /// Network IO protocol handler. This needs to be implemented for each new subprotocol.
 /// All the handler function are called from within IO event loop.
 /// `Message` is the type for message data.
-pub trait NetworkProtocolHandler<Message>: Send where Message: Send {
+pub trait NetworkProtocolHandler<Message>: Sync + Send where Message: Send + Sync + Clone {
 	/// Initialize the handler
-	fn initialize(&mut self, _io: &mut NetworkContext<Message>) {}
+	fn initialize(&self, _io: &NetworkContext<Message>) {}
 	/// Called when new network packet received.
-	fn read(&mut self, io: &mut NetworkContext<Message>, peer: &PeerId, packet_id: u8, data: &[u8]);
+	fn read(&self, io: &NetworkContext<Message>, peer: &PeerId, packet_id: u8, data: &[u8]);
 	/// Called when new peer is connected. Only called when peer supports the same protocol.
-	fn connected(&mut self, io: &mut NetworkContext<Message>, peer: &PeerId);
+	fn connected(&self, io: &NetworkContext<Message>, peer: &PeerId);
 	/// Called when a previously connected peer disconnects.
-	fn disconnected(&mut self, io: &mut NetworkContext<Message>, peer: &PeerId);
+	fn disconnected(&self, io: &NetworkContext<Message>, peer: &PeerId);
 	/// Timer function called after a timeout created with `NetworkContext::timeout`.
-	fn timeout(&mut self, _io: &mut NetworkContext<Message>, _timer: TimerToken) {}
+	fn timeout(&self, _io: &NetworkContext<Message>, _timer: TimerToken) {}
 	/// Called when a broadcasted message is received. The message can only be sent from a different IO handler.
-	fn message(&mut self, _io: &mut NetworkContext<Message>, _message: &Message) {}
+	fn message(&self, _io: &NetworkContext<Message>, _message: &Message) {}
 }
 
+
+#[test]
+fn test_net_service() {
+
+	use std::sync::Arc;
+	struct MyHandler;
+
+	#[derive(Clone)]
+	struct MyMessage {
+		data: u32
+	}
+
+	impl NetworkProtocolHandler<MyMessage> for MyHandler {
+		fn initialize(&self, io: &NetworkContext<MyMessage>) {
+			io.register_timer(0, 1000).unwrap();
+		}
+
+		fn read(&self, _io: &NetworkContext<MyMessage>, peer: &PeerId, packet_id: u8, data: &[u8]) {
+			println!("Received {} ({} bytes) from {}", packet_id, data.len(), peer);
+		}
+
+		fn connected(&self, _io: &NetworkContext<MyMessage>, peer: &PeerId) {
+			println!("Connected {}", peer);
+		}
+
+		fn disconnected(&self, _io: &NetworkContext<MyMessage>, peer: &PeerId) {
+			println!("Disconnected {}", peer);
+		}
+
+		fn timeout(&self, _io: &NetworkContext<MyMessage>, timer: TimerToken) {
+			println!("Timeout {}", timer);
+		}
+
+		fn message(&self, _io: &NetworkContext<MyMessage>, message: &MyMessage) {
+			println!("Message {}", message.data);
+		}
+	}
+
+	let mut service = NetworkService::<MyMessage>::start().expect("Error creating network service");
+	service.register_protocol(Arc::new(MyHandler), "myproto", &[1u8]).unwrap();
+}
diff --git a/util/src/network/node.rs b/util/src/network/node.rs
index 5c08e0a66..fd27e58e2 100644
--- a/util/src/network/node.rs
+++ b/util/src/network/node.rs
@@ -20,14 +20,16 @@ pub struct NodeEndpoint {
 	pub udp_port: u16
 }
 
-impl NodeEndpoint {
+impl FromStr for NodeEndpoint {
+	type Err = UtilError;
+
 	/// Create endpoint from string. Performs name resolution if given a host name.
 	fn from_str(s: &str) -> Result<NodeEndpoint, UtilError> {
 		let address = s.to_socket_addrs().map(|mut i| i.next());
 		match address {
 			Ok(Some(a)) => Ok(NodeEndpoint {
 				address: a,
-				address_str: s.to_string(),
+				address_str: s.to_owned(),
 				udp_port: a.port()
 			}),
 			Ok(_) => Err(UtilError::AddressResolve(None)),
diff --git a/util/src/network/service.rs b/util/src/network/service.rs
index c5083e981..811730d4b 100644
--- a/util/src/network/service.rs
+++ b/util/src/network/service.rs
@@ -1,24 +1,26 @@
+use std::sync::*;
 use error::*;
 use network::{NetworkProtocolHandler};
 use network::error::{NetworkError};
-use network::host::{Host, NetworkIoMessage, PeerId, PacketId, ProtocolId};
+use network::host::{Host, NetworkIoMessage, ProtocolId};
 use io::*;
 
 /// IO Service with networking
 /// `Message` defines a notification data type.
-pub struct NetworkService<Message> where Message: Send + 'static {
+pub struct NetworkService<Message> where Message: Send + Sync + Clone + 'static {
 	io_service: IoService<NetworkIoMessage<Message>>,
 	host_info: String,
 }
 
-impl<Message> NetworkService<Message> where Message: Send + 'static {
+impl<Message> NetworkService<Message> where Message: Send + Sync + Clone + 'static {
 	/// Starts IO event loop
-	pub fn start(init_nodes: &Vec<String>) -> Result<NetworkService<Message>, UtilError> {
+	pub fn start(init_nodes: &[String]) -> Result<NetworkService<Message>, UtilError> {
 		let mut io_service = try!(IoService::<NetworkIoMessage<Message>>::start());
-		let mut host = Box::new(Host::new());
+		let mut host = Host::new();
 		for n in init_nodes { host.add_node(&n); }
-		let host_info = host.info.client_version.clone();
-		info!("NetworkService::start(): id={:?}", host.info.id());
+		let host = Arc::new(host);
+		let host_info = host.client_version();
+		info!("NetworkService::start(): id={:?}", host.client_id());
 		try!(io_service.register_handler(host));
 		Ok(NetworkService {
 			io_service: io_service,
@@ -26,21 +28,10 @@ impl<Message> NetworkService<Message> where Message: Send + 'static {
 		})
 	}
 
-	/// Send a message over the network. Normaly `HostIo::send` should be used. This can be used from non-io threads.
-	pub fn send(&mut self, peer: &PeerId, packet_id: PacketId, protocol: ProtocolId, data: &[u8]) -> Result<(), NetworkError> {
-		try!(self.io_service.send_message(NetworkIoMessage::Send {
-			peer: *peer,
-			packet_id: packet_id,
-			protocol: protocol,
-			data: data.to_vec()
-		}));
-		Ok(())
-	}
-
 	/// Regiter a new protocol handler with the event loop.
-	pub fn register_protocol(&mut self, handler: Box<NetworkProtocolHandler<Message>+Send>, protocol: ProtocolId, versions: &[u8]) -> Result<(), NetworkError> {
+	pub fn register_protocol(&mut self, handler: Arc<NetworkProtocolHandler<Message>+Send + Sync>, protocol: ProtocolId, versions: &[u8]) -> Result<(), NetworkError> {
 		try!(self.io_service.send_message(NetworkIoMessage::AddHandler {
-			handler: Some(handler),
+			handler: handler,
 			protocol: protocol,
 			versions: versions.to_vec(),
 		}));
diff --git a/util/src/network/session.rs b/util/src/network/session.rs
index 828e4b062..8f580f476 100644
--- a/util/src/network/session.rs
+++ b/util/src/network/session.rs
@@ -4,6 +4,7 @@ use rlp::*;
 use network::connection::{EncryptedConnection, Packet};
 use network::handshake::Handshake;
 use error::*;
+use io::{IoContext};
 use network::error::{NetworkError, DisconnectReason};
 use network::host::*;
 use network::node::NodeId;
@@ -84,7 +85,7 @@ const PACKET_LAST: u8 = 0x7f;
 
 impl Session {
 	/// Create a new session out of comepleted handshake. Consumes handshake object.
-	pub fn new<Host:Handler<Timeout=Token>>(h: Handshake, event_loop: &mut EventLoop<Host>, host: &HostInfo) -> Result<Session, UtilError> {
+	pub fn new<Message>(h: Handshake, _io: &IoContext<Message>, host: &HostInfo) -> Result<Session, UtilError> where Message: Send + Sync + Clone {
 		let id = h.id.clone();
 		let connection = try!(EncryptedConnection::new(h));
 		let mut session = Session {
@@ -99,7 +100,6 @@ impl Session {
 		};
 		try!(session.write_hello(host));
 		try!(session.write_ping());
-		try!(session.connection.register(event_loop));
 		Ok(session)
 	}
 
@@ -109,16 +109,16 @@ impl Session {
 	}
 
 	/// Readable IO handler. Returns packet data if available.
-	pub fn readable<Host:Handler>(&mut self, event_loop: &mut EventLoop<Host>, host: &HostInfo) -> Result<SessionData, UtilError> {
-		match try!(self.connection.readable(event_loop)) {
+	pub fn readable<Message>(&mut self, io: &IoContext<Message>, host: &HostInfo) -> Result<SessionData, UtilError>  where Message: Send + Sync + Clone {
+		match try!(self.connection.readable(io)) {
 			Some(data) => Ok(try!(self.read_packet(data, host))),
 			None => Ok(SessionData::None)
 		}
 	}
 
 	/// Writable IO handler. Sends pending packets.
-	pub fn writable<Host:Handler>(&mut self, event_loop: &mut EventLoop<Host>, _host: &HostInfo) -> Result<(), UtilError> {
-		self.connection.writable(event_loop)
+	pub fn writable<Message>(&mut self, io: &IoContext<Message>, _host: &HostInfo) -> Result<(), UtilError> where Message: Send + Sync + Clone {
+		self.connection.writable(io)
 	}
 
 	/// Checks if peer supports given capability
@@ -127,8 +127,8 @@ impl Session {
 	}
 
 	/// Update registration with the event loop. Should be called at the end of the IO handler.
-	pub fn reregister<Host:Handler>(&mut self, event_loop: &mut EventLoop<Host>) -> Result<(), UtilError> {
-		self.connection.reregister(event_loop)
+	pub fn update_socket<Host:Handler>(&self, reg:Token, event_loop: &mut EventLoop<Host>) -> Result<(), UtilError> {
+		self.connection.update_socket(reg, event_loop)
 	}
 
 	/// Send a protocol packet to peer.
@@ -182,7 +182,7 @@ impl Session {
 				// map to protocol
 				let protocol = self.info.capabilities[i].protocol;
 				let pid = packet_id - self.info.capabilities[i].id_offset;
-				return Ok(SessionData::Packet { data: packet.data, protocol: protocol, packet_id: pid } )
+				Ok(SessionData::Packet { data: packet.data, protocol: protocol, packet_id: pid } )
 			},
 			_ => {
 				debug!(target: "net", "Unkown packet: {:?}", packet_id);
@@ -212,7 +212,7 @@ impl Session {
 		// Intersect with host capabilities
 		// Leave only highset mutually supported capability version
 		let mut caps: Vec<SessionCapabilityInfo> = Vec::new();
-		for hc in host.capabilities.iter() {
+		for hc in &host.capabilities {
 			if peer_caps.iter().any(|c| c.protocol == hc.protocol && c.version == hc.version) {
 				caps.push(SessionCapabilityInfo {
 					protocol: hc.protocol,
diff --git a/util/src/overlaydb.rs b/util/src/overlaydb.rs
index e8492091f..d2f56a520 100644
--- a/util/src/overlaydb.rs
+++ b/util/src/overlaydb.rs
@@ -169,7 +169,7 @@ impl HashDB for OverlayDB {
 		match k {
 			Some(&(ref d, rc)) if rc > 0 => Some(d),
 			_ => {
-				let memrc = k.map(|&(_, rc)| rc).unwrap_or(0);
+				let memrc = k.map_or(0, |&(_, rc)| rc);
 				match self.payload(key) {
 					Some(x) => {
 						let (d, rc) = x;
@@ -194,16 +194,11 @@ impl HashDB for OverlayDB {
 		match k {
 			Some(&(_, rc)) if rc > 0 => true,
 			_ => {
-				let memrc = k.map(|&(_, rc)| rc).unwrap_or(0);
+				let memrc = k.map_or(0, |&(_, rc)| rc);
 				match self.payload(key) {
 					Some(x) => {
 						let (_, rc) = x;
-						if rc as i32 + memrc > 0 {
-							true
-						}
-						else {
-							false
-						}
+						rc as i32 + memrc > 0
 					}
 					// Replace above match arm with this once https://github.com/rust-lang/rust/issues/15287 is done.
 					//Some((d, rc)) if rc + memrc > 0 => true,
diff --git a/util/src/rlp/rlpstream.rs b/util/src/rlp/rlpstream.rs
index 724974e08..ac22736fc 100644
--- a/util/src/rlp/rlpstream.rs
+++ b/util/src/rlp/rlpstream.rs
@@ -41,7 +41,7 @@ impl Stream for RlpStream {
 		stream
 	}
 
-	fn append<'a, E>(&'a mut self, object: &E) -> &'a mut RlpStream where E: Encodable {
+	fn append<E>(&mut self, object: &E) -> &mut RlpStream where E: Encodable {
 		// encode given value and add it at the end of the stream
 		object.encode(&mut self.encoder);
 
@@ -52,7 +52,7 @@ impl Stream for RlpStream {
 		self
 	}
 
-	fn append_list<'a>(&'a mut self, len: usize) -> &'a mut RlpStream {
+	fn append_list(&mut self, len: usize) -> &mut RlpStream {
 		match len {
 			0 => {
 				// we may finish, if the appended list len is equal 0
@@ -69,7 +69,7 @@ impl Stream for RlpStream {
 		self
 	}
 
-	fn append_empty_data<'a>(&'a mut self) -> &'a mut RlpStream {
+	fn append_empty_data(&mut self) -> &mut RlpStream {
 		// self push raw item
 		self.encoder.bytes.push(0x80);
 
diff --git a/util/src/rlp/rlptraits.rs b/util/src/rlp/rlptraits.rs
index 6fbc2125c..d6ef16932 100644
--- a/util/src/rlp/rlptraits.rs
+++ b/util/src/rlp/rlptraits.rs
@@ -9,7 +9,7 @@ pub trait Decoder: Sized {
 	/// TODO [arkpar] Please document me
 	fn as_list(&self) -> Result<Vec<Self>, DecoderError>;
 	/// TODO [Gav Wood] Please document me
-	fn as_rlp<'a>(&'a self) -> &'a UntrustedRlp<'a>;
+	fn as_rlp(&self) -> &UntrustedRlp;
 	/// TODO [debris] Please document me
 	fn as_raw(&self) -> &[u8];
 }
@@ -255,7 +255,7 @@ pub trait Stream: Sized {
 	/// 	assert_eq!(out, vec![0xca, 0xc8, 0x83, b'c', b'a', b't', 0x83, b'd', b'o', b'g', 0x80]);
 	/// }
 	/// ```
-	fn append_list<'a>(&'a mut self, len: usize) -> &'a mut Self;
+	fn append_list(&mut self, len: usize) -> &mut Self;
 
 	/// Apends null to the end of stream, chainable.
 	///
@@ -270,7 +270,7 @@ pub trait Stream: Sized {
 	/// 	assert_eq!(out, vec![0xc2, 0x80, 0x80]);
 	/// }
 	/// ```
-	fn append_empty_data<'a>(&'a mut self) -> &'a mut Self;
+	fn append_empty_data(&mut self) -> &mut Self;
 
 	/// Appends raw (pre-serialised) RLP data. Use with caution. Chainable.
 	fn append_raw<'a>(&'a mut self, bytes: &[u8], item_count: usize) -> &'a mut Self;
diff --git a/util/src/rlp/tests.rs b/util/src/rlp/tests.rs
index 7c2099124..f33cec177 100644
--- a/util/src/rlp/tests.rs
+++ b/util/src/rlp/tests.rs
@@ -15,25 +15,25 @@ fn rlp_at() {
 		assert!(rlp.is_list());
 		//let animals = <Vec<String> as rlp::Decodable>::decode_untrusted(&rlp).unwrap();
 		let animals: Vec<String> = rlp.as_val().unwrap();
-		assert_eq!(animals, vec!["cat".to_string(), "dog".to_string()]);
+		assert_eq!(animals, vec!["cat".to_owned(), "dog".to_owned()]);
 
 		let cat = rlp.at(0).unwrap();
 		assert!(cat.is_data());
 		assert_eq!(cat.as_raw(), &[0x83, b'c', b'a', b't']);
-		//assert_eq!(String::decode_untrusted(&cat).unwrap(), "cat".to_string());
-		assert_eq!(cat.as_val::<String>().unwrap(), "cat".to_string());
+		//assert_eq!(String::decode_untrusted(&cat).unwrap(), "cat".to_owned());
+		assert_eq!(cat.as_val::<String>().unwrap(), "cat".to_owned());
 
 		let dog = rlp.at(1).unwrap();
 		assert!(dog.is_data());
 		assert_eq!(dog.as_raw(), &[0x83, b'd', b'o', b'g']);
-		//assert_eq!(String::decode_untrusted(&dog).unwrap(), "dog".to_string());
-		assert_eq!(dog.as_val::<String>().unwrap(), "dog".to_string());
+		//assert_eq!(String::decode_untrusted(&dog).unwrap(), "dog".to_owned());
+		assert_eq!(dog.as_val::<String>().unwrap(), "dog".to_owned());
 
 		let cat_again = rlp.at(0).unwrap();
 		assert!(cat_again.is_data());
 		assert_eq!(cat_again.as_raw(), &[0x83, b'c', b'a', b't']);
-		//assert_eq!(String::decode_untrusted(&cat_again).unwrap(), "cat".to_string());
-		assert_eq!(cat_again.as_val::<String>().unwrap(), "cat".to_string());
+		//assert_eq!(String::decode_untrusted(&cat_again).unwrap(), "cat".to_owned());
+		assert_eq!(cat_again.as_val::<String>().unwrap(), "cat".to_owned());
 	}
 }
 
@@ -268,13 +268,13 @@ fn decode_untrusted_u256() {
 
 #[test]
 fn decode_untrusted_str() {
-	let tests = vec![DTestPair("cat".to_string(), vec![0x83, b'c', b'a', b't']),
-					 DTestPair("dog".to_string(), vec![0x83, b'd', b'o', b'g']),
-					 DTestPair("Marek".to_string(),
+	let tests = vec![DTestPair("cat".to_owned(), vec![0x83, b'c', b'a', b't']),
+					 DTestPair("dog".to_owned(), vec![0x83, b'd', b'o', b'g']),
+					 DTestPair("Marek".to_owned(),
 							   vec![0x85, b'M', b'a', b'r', b'e', b'k']),
-					 DTestPair("".to_string(), vec![0x80]),
+					 DTestPair("".to_owned(), vec![0x80]),
 					 DTestPair("Lorem ipsum dolor sit amet, consectetur adipisicing elit"
-								   .to_string(),
+								   .to_owned(),
 							   vec![0xb8, 0x38, b'L', b'o', b'r', b'e', b'm', b' ', b'i',
 									b'p', b's', b'u', b'm', b' ', b'd', b'o', b'l', b'o',
 									b'r', b' ', b's', b'i', b't', b' ', b'a', b'm', b'e',
@@ -311,14 +311,14 @@ fn decode_untrusted_vector_u64() {
 
 #[test]
 fn decode_untrusted_vector_str() {
-	let tests = vec![DTestPair(vec!["cat".to_string(), "dog".to_string()],
+	let tests = vec![DTestPair(vec!["cat".to_owned(), "dog".to_owned()],
 							   vec![0xc8, 0x83, b'c', b'a', b't', 0x83, b'd', b'o', b'g'])];
 	run_decode_tests(tests);
 }
 
 #[test]
 fn decode_untrusted_vector_of_vectors_str() {
-	let tests = vec![DTestPair(vec![vec!["cat".to_string()]],
+	let tests = vec![DTestPair(vec![vec!["cat".to_owned()]],
 							   vec![0xc5, 0xc4, 0x83, b'c', b'a', b't'])];
 	run_decode_tests(tests);
 }
diff --git a/util/src/rlp/untrusted_rlp.rs b/util/src/rlp/untrusted_rlp.rs
index 3f11fa070..768d058c1 100644
--- a/util/src/rlp/untrusted_rlp.rs
+++ b/util/src/rlp/untrusted_rlp.rs
@@ -288,7 +288,7 @@ impl<'a> BasicDecoder<'a> {
 
 	/// Return first item info
 	fn payload_info(bytes: &[u8]) -> Result<PayloadInfo, DecoderError> {
-		let item = match bytes.first().map(|&x| x) {
+		let item = match bytes.first().cloned() {
 			None => return Err(DecoderError::RlpIsTooShort),
 			Some(0...0x7f) => PayloadInfo::new(0, 1),
 			Some(l @ 0x80...0xb7) => PayloadInfo::new(1, l as usize - 0x80),
@@ -324,7 +324,7 @@ impl<'a> Decoder for BasicDecoder<'a> {
 
 		let bytes = self.rlp.as_raw();
 
-		match bytes.first().map(|&x| x) {
+		match bytes.first().cloned() {
 			// rlp is too short
 			None => Err(DecoderError::RlpIsTooShort),
 			// single byt value
@@ -355,12 +355,12 @@ impl<'a> Decoder for BasicDecoder<'a> {
 
 	fn as_list(&self) -> Result<Vec<Self>, DecoderError> {
 		let v: Vec<BasicDecoder<'a>> = self.rlp.iter()
-			.map(| i | BasicDecoder::new(i))
+			.map(BasicDecoder::new)
 			.collect();
 		Ok(v)
 	}
 
-	fn as_rlp<'s>(&'s self) -> &'s UntrustedRlp<'s> {
+	fn as_rlp(&self) -> &UntrustedRlp {
 		&self.rlp
 	}
 }
@@ -405,6 +405,7 @@ impl<T> Decodable for Option<T> where T: Decodable {
 macro_rules! impl_array_decodable {
 	($index_type:ty, $len:expr ) => (
 		impl<T> Decodable for [T; $len] where T: Decodable {
+			#[allow(len_zero)]
 			fn decode<D>(decoder: &D) -> Result<Self, DecoderError>  where D: Decoder {
 				let decoders = try!(decoder.as_list());
 
diff --git a/util/src/squeeze.rs b/util/src/squeeze.rs
index 10f446395..3fb4a81f9 100644
--- a/util/src/squeeze.rs
+++ b/util/src/squeeze.rs
@@ -42,7 +42,7 @@ pub trait Squeeze {
 
 impl<K, T> Squeeze for HashMap<K, T> where K: Eq + Hash + Clone + HeapSizeOf, T: HeapSizeOf {
 	fn squeeze(&mut self, size: usize) {
-		if self.len() == 0 {
+		if self.is_empty() {
 			return
 		}
 		
@@ -50,7 +50,7 @@ impl<K, T> Squeeze for HashMap<K, T> where K: Eq + Hash + Clone + HeapSizeOf, T:
 		let all_entries = size_of_entry * self.len();
 		let mut shrinked_size = all_entries;
 
-		while self.len() > 0 && shrinked_size > size {
+		while !self.is_empty() && shrinked_size > size {
 			// could be optimized
 			let key = self.keys().next().unwrap().clone();
 			self.remove(&key);
diff --git a/util/src/trie/triedb.rs b/util/src/trie/triedb.rs
index b0fcfcd16..7179c395e 100644
--- a/util/src/trie/triedb.rs
+++ b/util/src/trie/triedb.rs
@@ -38,6 +38,7 @@ pub struct TrieDB<'db> {
 	pub hash_count: usize,
 }
 
+#[allow(wrong_self_convention)]
 impl<'db> TrieDB<'db> {
 	/// Create a new trie with the backing database `db` and `root`
 	/// Panics, if `root` does not exist
@@ -103,7 +104,7 @@ impl<'db> TrieDB<'db> {
 
 		match node {
 			Node::Extension(_, payload) => handle_payload(payload),
-			Node::Branch(payloads, _) => for payload in payloads.iter() { handle_payload(payload) },
+			Node::Branch(payloads, _) => for payload in &payloads { handle_payload(payload) },
 			_ => {},
 		}
 	}
@@ -141,12 +142,9 @@ impl<'db> TrieDB<'db> {
 			},
 			Node::Branch(ref nodes, ref value) => {
 				try!(writeln!(f, ""));
-				match value {
-					&Some(v) => {
-						try!(self.fmt_indent(f, deepness + 1));
-						try!(writeln!(f, "=: {:?}", v.pretty()))
-					},
-					&None => {}
+				if let Some(v) = *value {
+					try!(self.fmt_indent(f, deepness + 1));
+					try!(writeln!(f, "=: {:?}", v.pretty()))
 				}
 				for i in 0..16 {
 					match self.get_node(nodes[i]) {
diff --git a/util/src/trie/triedbmut.rs b/util/src/trie/triedbmut.rs
index 3f62b2fdb..48749bf0d 100644
--- a/util/src/trie/triedbmut.rs
+++ b/util/src/trie/triedbmut.rs
@@ -50,6 +50,7 @@ enum MaybeChanged<'a> {
 	Changed(Bytes),
 }
 
+#[allow(wrong_self_convention)]
 impl<'db> TrieDBMut<'db> {
 	/// Create a new trie with the backing database `db` and empty `root`
 	/// Initialise to the state entailed by the genesis block.
@@ -145,7 +146,7 @@ impl<'db> TrieDBMut<'db> {
 
 		match node {
 			Node::Extension(_, payload) => handle_payload(payload),
-			Node::Branch(payloads, _) => for payload in payloads.iter() { handle_payload(payload) },
+			Node::Branch(payloads, _) => for payload in &payloads { handle_payload(payload) },
 			_ => {},
 		}
 	}
@@ -178,12 +179,9 @@ impl<'db> TrieDBMut<'db> {
 			},
 			Node::Branch(ref nodes, ref value) => {
 				try!(writeln!(f, ""));
-				match value {
-					&Some(v) => {
-						try!(self.fmt_indent(f, deepness + 1));
-						try!(writeln!(f, "=: {:?}", v.pretty()))
-					},
-					&None => {}
+				if let Some(v) = *value {
+					try!(self.fmt_indent(f, deepness + 1));
+					try!(writeln!(f, "=: {:?}", v.pretty()))
 				}
 				for i in 0..16 {
 					match self.get_node(nodes[i]) {
@@ -331,6 +329,7 @@ impl<'db> TrieDBMut<'db> {
 		}
 	}
 
+	#[allow(cyclomatic_complexity)]
 	/// Determine the RLP of the node, assuming we're inserting `partial` into the
 	/// node currently of data `old`. This will *not* delete any hash of `old` from the database;
 	/// it will just return the new RLP that includes the new node.
@@ -694,7 +693,7 @@ mod tests {
 		}
 	}
 
-	fn populate_trie<'db>(db: &'db mut HashDB, root: &'db mut H256, v: &Vec<(Vec<u8>, Vec<u8>)>) -> TrieDBMut<'db> {
+	fn populate_trie<'db>(db: &'db mut HashDB, root: &'db mut H256, v: &[(Vec<u8>, Vec<u8>)]) -> TrieDBMut<'db> {
 		let mut t = TrieDBMut::new(db, root);
 		for i in 0..v.len() {
 			let key: &[u8]= &v[i].0;
@@ -704,8 +703,8 @@ mod tests {
 		t
 	}
 
-	fn unpopulate_trie<'a, 'db>(t: &mut TrieDBMut<'db>, v: &Vec<(Vec<u8>, Vec<u8>)>) {
-		for i in v.iter() {
+	fn unpopulate_trie<'db>(t: &mut TrieDBMut<'db>, v: &[(Vec<u8>, Vec<u8>)]) {
+		for i in v {
 			let key: &[u8]= &i.0;
 			t.remove(&key);
 		}
@@ -761,7 +760,7 @@ mod tests {
 				println!("TRIE MISMATCH");
 				println!("");
 				println!("{:?} vs {:?}", memtrie.root(), real);
-				for i in x.iter() {
+				for i in &x {
 					println!("{:?} -> {:?}", i.0.pretty(), i.1.pretty());
 				}
 				println!("{:?}", memtrie);
@@ -774,7 +773,7 @@ mod tests {
 				println!("");
 				println!("remaining: {:?}", memtrie.db_items_remaining());
 				println!("{:?} vs {:?}", memtrie.root(), real);
-				for i in x.iter() {
+				for i in &x {
 					println!("{:?} -> {:?}", i.0.pretty(), i.1.pretty());
 				}
 				println!("{:?}", memtrie);
@@ -1051,12 +1050,12 @@ mod tests {
 				println!("TRIE MISMATCH");
 				println!("");
 				println!("ORIGINAL... {:?}", memtrie.root());
-				for i in x.iter() {
+				for i in &x {
 					println!("{:?} -> {:?}", i.0.pretty(), i.1.pretty());
 				}
 				println!("{:?}", memtrie);
 				println!("SORTED... {:?}", memtrie_sorted.root());
-				for i in y.iter() {
+				for i in &y {
 					println!("{:?} -> {:?}", i.0.pretty(), i.1.pretty());
 				}
 				println!("{:?}", memtrie_sorted);
diff --git a/util/src/uint.rs b/util/src/uint.rs
index 5721c5614..ab136d7c6 100644
--- a/util/src/uint.rs
+++ b/util/src/uint.rs
@@ -200,7 +200,7 @@ macro_rules! construct_uint {
 			#[inline]
 			fn byte(&self, index: usize) -> u8 {
 				let &$name(ref arr) = self;
-				(arr[index / 8] >> ((index % 8)) * 8) as u8
+				(arr[index / 8] >> (((index % 8)) * 8)) as u8
 			}
 
 			fn to_bytes(&self, bytes: &mut[u8]) {
@@ -446,16 +446,16 @@ macro_rules! construct_uint {
 
 		impl FromJson for $name {
 			fn from_json(json: &Json) -> Self {
-				match json {
-					&Json::String(ref s) => {
+				match *json {
+					Json::String(ref s) => {
 						if s.len() >= 2 && &s[0..2] == "0x" {
-							FromStr::from_str(&s[2..]).unwrap_or(Default::default())
+							FromStr::from_str(&s[2..]).unwrap_or_else(|_| Default::default())
 						} else {
-							Uint::from_dec_str(s).unwrap_or(Default::default())
+							Uint::from_dec_str(s).unwrap_or_else(|_| Default::default())
 						}
 					},
-					&Json::U64(u) => From::from(u),
-					&Json::I64(i) => From::from(i as u64),
+					Json::U64(u) => From::from(u),
+					Json::I64(i) => From::from(i as u64),
 					_ => Uint::zero(),
 				}
 			}
@@ -488,7 +488,7 @@ macro_rules! construct_uint {
 				for i in 0..bytes.len() {
 					let rev = bytes.len() - 1 - i;
 					let pos = rev / 8;
-					ret[pos] += (bytes[i] as u64) << (rev % 8) * 8;
+					ret[pos] += (bytes[i] as u64) << ((rev % 8) * 8);
 				}
 				$name(ret)
 			}
@@ -500,7 +500,7 @@ macro_rules! construct_uint {
 			fn from_str(value: &str) -> Result<$name, Self::Err> {
 				let bytes: Vec<u8> = match value.len() % 2 == 0 {
 					true => try!(value.from_hex()),
-					false => try!(("0".to_string() + value).from_hex())
+					false => try!(("0".to_owned() + value).from_hex())
 				};
 
 				let bytes_ref: &[u8] = &bytes;
@@ -1061,6 +1061,7 @@ mod tests {
 	}
 
 	#[test]
+	#[allow(eq_op)]
 	pub fn uint256_comp_test() {
 		let small = U256([10u64, 0, 0, 0]);
 		let big = U256([0x8C8C3EE70C644118u64, 0x0209E7378231E632, 0, 0]);