Merge remote-tracking branch 'parity/master' into bft

2016-11-16 10:29:54 +00:00
parent 1c958695c3 df1fbf50d8
commit 8ac989cbeb
74 changed files with 9310 additions and 7902 deletions
--- a/ethcore/res/authority_round.json
+++ b/ethcore/res/authority_round.json
@@ -0,0 +1,42 @@
+{
+	"name": "TestAuthorityRound",
+	"engine": {
+		"AuthorityRound": {
+			"params": {
+				"gasLimitBoundDivisor": "0x0400",
+				"stepDuration": "1",
+				"authorities" : [
+					"0x7d577a597b2742b498cb5cf0c26cdcd726d39e6e",
+					"0x82a978b3f5962a5b0957d9ee9eef472ee55b42f1"
+				]
+			}
+		}
+	},
+	"params": {
+		"accountStartNonce": "0x0",
+		"maximumExtraDataSize": "0x20",
+		"minGasLimit": "0x1388",
+		"networkID" : "0x69"
+	},
+	"genesis": {
+		"seal": {
+			"generic": {
+				"fields": 1,
+				"rlp": "0x11bbe8db4e347b4e8c937c1c8370e4b5ed33adb3db69cbdb7a38e1e50b1b82fa"
+			}
+		},
+		"difficulty": "0x20000",
+		"author": "0x0000000000000000000000000000000000000000",
+		"timestamp": "0x00",
+		"parentHash": "0x0000000000000000000000000000000000000000000000000000000000000000",
+		"extraData": "0x",
+		"gasLimit": "0x2fefd8"
+	},
+	"accounts": {
+		"0000000000000000000000000000000000000001": { "balance": "1", "nonce": "1048576", "builtin": { "name": "ecrecover", "pricing": { "linear": { "base": 3000, "word": 0 } } } },
+		"0000000000000000000000000000000000000002": { "balance": "1", "nonce": "1048576", "builtin": { "name": "sha256", "pricing": { "linear": { "base": 60, "word": 12 } } } },
+		"0000000000000000000000000000000000000003": { "balance": "1", "nonce": "1048576", "builtin": { "name": "ripemd160", "pricing": { "linear": { "base": 600, "word": 120 } } } },
+		"0000000000000000000000000000000000000004": { "balance": "1", "nonce": "1048576", "builtin": { "name": "identity", "pricing": { "linear": { "base": 15, "word": 3 } } } },
+		"9cce34f7ab185c7aba1b7c8140d620b4bda941d6": { "balance": "1606938044258990275541962092341162602522202993782792835301376", "nonce": "1048576" }
+	}
+}
--- a/ethcore/res/basic_authority.json
+++ b/ethcore/res/basic_authority.json
@@ -1,5 +1,5 @@
 {
-	"name": "TestAuthority",
+	"name": "TestBasicAuthority",
 	"engine": {
 		"BasicAuthority": {
 			"params": {
--- a/ethcore/res/ethereum/frontier.json
+++ b/ethcore/res/ethereum/frontier.json
@@ -131,10 +131,11 @@
 					"0x807640a13483f8ac783c557fcdf27be11ea4ac7a"
 				],
 				"eip150Transition": "0x259518",
-				"eip155Transition": "0x7fffffffffffffff",
-				"eip160Transition": "0x7fffffffffffffff",
-				"eip161abcTransition": "0x7fffffffffffffff",
-				"eip161dTransition": "0x7fffffffffffffff"
+				"eip155Transition": 2675000,
+				"eip160Transition": 2675000,
+				"eip161abcTransition": 2675000,
+				"eip161dTransition": 2675000,
+				"maxCodeSize": 24576
 			}
 		}
 	},
--- a/ethcore/res/ethereum/morden.json
+++ b/ethcore/res/ethereum/morden.json
@@ -11,10 +11,10 @@
 				"registrar": "0x52dff57a8a1532e6afb3dc07e2af58bb9eb05b3d",
 				"homesteadTransition": "0x789b0",
 				"eip150Transition": "0x1b34d8",
-				"eip155Transition": "0x7fffffffffffffff",
-				"eip160Transition": "0x7fffffffffffffff",
-				"eip161abcTransition": "0x7fffffffffffffff",
-				"eip161dTransition": "0x7fffffffffffffff"
+				"eip155Transition": 1885000,
+				"eip160Transition": 1885000,
+				"eip161abcTransition": 1885000,
+				"eip161dTransition": 1885000
 			}
 		}
 	},
--- a/ethcore/src/client/client.rs
+++ b/ethcore/src/client/client.rs
@@ -556,6 +556,7 @@ impl Client {

 	/// Import transactions from the IO queue
 	pub fn import_queued_transactions(&self, transactions: &[Bytes]) -> usize {
+		trace!(target: "external_tx", "Importing queued");
 		let _timer = PerfTimer::new("import_queued_transactions");
 		self.queue_transactions.fetch_sub(transactions.len(), AtomicOrdering::SeqCst);
 		let txs = transactions.iter().filter_map(|bytes| UntrustedRlp::new(bytes).as_val().ok()).collect();
@@ -563,6 +564,11 @@ impl Client {
 		results.len()
 	}

+	/// Used by PoA to try sealing on period change.
+	pub fn update_sealing(&self) {
+		self.miner.update_sealing(self)
+	}
+
 	/// Attempt to get a copy of a specific block's final state.
 	///
 	/// This will not fail if given BlockID::Latest.
@@ -1195,7 +1201,9 @@ impl BlockChainClient for Client {
 	}

 	fn queue_transactions(&self, transactions: Vec<Bytes>) {
-		if self.queue_transactions.load(AtomicOrdering::Relaxed) > MAX_TX_QUEUE_SIZE {
+		let queue_size = self.queue_transactions.load(AtomicOrdering::Relaxed);
+		trace!(target: "external_tx", "Queue size: {}", queue_size);
+		if queue_size > MAX_TX_QUEUE_SIZE {
 			debug!("Ignoring {} transactions: queue is full", transactions.len());
 		} else {
 			let len = transactions.len();
--- a/ethcore/src/client/test_client.rs
+++ b/ethcore/src/client/test_client.rs
@@ -119,6 +119,16 @@ impl TestBlockChainClient {
 	/// Creates new test client with specified extra data for each block
 	pub fn new_with_extra_data(extra_data: Bytes) -> Self {
 		let spec = Spec::new_test();
+		TestBlockChainClient::new_with_spec_and_extra(spec, extra_data)
+	}
+
+	/// Create test client with custom spec.
+	pub fn new_with_spec(spec: Spec) -> Self {
+		TestBlockChainClient::new_with_spec_and_extra(spec, Bytes::new())
+	}
+
+	/// Create test client with custom spec and extra data.
+	pub fn new_with_spec_and_extra(spec: Spec, extra_data: Bytes) -> Self {
 		let mut client = TestBlockChainClient {
 			blocks: RwLock::new(HashMap::new()),
 			numbers: RwLock::new(HashMap::new()),
@@ -315,7 +325,7 @@ pub fn get_temp_state_db() -> GuardedTempResult<StateDB> {

 impl MiningBlockChainClient for TestBlockChainClient {
 	fn latest_schedule(&self) -> Schedule {
-		Schedule::new_post_eip150(true, true, true)
+		Schedule::new_post_eip150(24576, true, true, true)
 	}

 	fn prepare_open_block(&self, author: Address, gas_range_target: (U256, U256), extra_data: Bytes) -> OpenBlock {
--- a/ethcore/src/engines/authority_round.rs
+++ b/ethcore/src/engines/authority_round.rs
@@ -0,0 +1,429 @@
+// Copyright 2015, 2016 Ethcore (UK) Ltd.
+// This file is part of Parity.
+
+// Parity is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Parity is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Parity.  If not, see <http://www.gnu.org/licenses/>.
+
+//! A blockchain engine that supports a non-instant BFT proof-of-authority.
+
+use std::sync::atomic::{AtomicUsize, AtomicBool, Ordering as AtomicOrdering};
+use std::sync::Weak;
+use std::time::{UNIX_EPOCH, Duration};
+use util::*;
+use ethkey::{verify_address, Signature};
+use rlp::{UntrustedRlp, View, encode};
+use account_provider::AccountProvider;
+use block::*;
+use spec::CommonParams;
+use engines::Engine;
+use header::Header;
+use error::{Error, BlockError};
+use evm::Schedule;
+use ethjson;
+use io::{IoContext, IoHandler, TimerToken, IoService, IoChannel};
+use service::ClientIoMessage;
+use transaction::SignedTransaction;
+use env_info::EnvInfo;
+use builtin::Builtin;
+
+/// `AuthorityRound` params.
+#[derive(Debug, PartialEq)]
+pub struct AuthorityRoundParams {
+	/// Gas limit divisor.
+	pub gas_limit_bound_divisor: U256,
+	/// Time to wait before next block or authority switching.
+	pub step_duration: Duration,
+	/// Valid authorities.
+	pub authorities: Vec<Address>,
+	/// Number of authorities.
+	pub authority_n: usize,
+}
+
+impl From<ethjson::spec::AuthorityRoundParams> for AuthorityRoundParams {
+	fn from(p: ethjson::spec::AuthorityRoundParams) -> Self {
+		AuthorityRoundParams {
+			gas_limit_bound_divisor: p.gas_limit_bound_divisor.into(),
+			step_duration: Duration::from_secs(p.step_duration.into()),
+			authority_n: p.authorities.len(),
+			authorities: p.authorities.into_iter().map(Into::into).collect::<Vec<_>>(),
+		}
+	}
+}
+
+/// Engine using `AuthorityRound` proof-of-work consensus algorithm, suitable for Ethereum
+/// mainnet chains in the Olympic, Frontier and Homestead eras.
+pub struct AuthorityRound {
+	params: CommonParams,
+	our_params: AuthorityRoundParams,
+	builtins: BTreeMap<Address, Builtin>,
+	transition_service: IoService<BlockArrived>,
+	message_channel: Mutex<Option<IoChannel<ClientIoMessage>>>,
+	step: AtomicUsize,
+	proposed: AtomicBool,
+}
+
+fn header_step(header: &Header) -> Result<usize, ::rlp::DecoderError> {
+	UntrustedRlp::new(&header.seal()[0]).as_val()
+}
+
+fn header_signature(header: &Header) -> Result<Signature, ::rlp::DecoderError> {
+	UntrustedRlp::new(&header.seal()[1]).as_val::<H520>().map(Into::into)
+}
+
+trait AsMillis {
+	fn as_millis(&self) -> u64;
+}
+
+impl AsMillis for Duration {
+	fn as_millis(&self) -> u64 {
+		self.as_secs()*1_000 + (self.subsec_nanos()/1_000_000) as u64
+	}
+}
+
+impl AuthorityRound {
+	/// Create a new instance of AuthorityRound engine.
+	pub fn new(params: CommonParams, our_params: AuthorityRoundParams, builtins: BTreeMap<Address, Builtin>) -> Result<Arc<Self>, Error> {
+		let initial_step = (unix_now().as_secs() / our_params.step_duration.as_secs()) as usize;
+		let engine = Arc::new(
+			AuthorityRound {
+				params: params,
+				our_params: our_params,
+				builtins: builtins,
+				transition_service: try!(IoService::<BlockArrived>::start()),
+				message_channel: Mutex::new(None),
+				step: AtomicUsize::new(initial_step),
+				proposed: AtomicBool::new(false)
+			});
+		let handler = TransitionHandler { engine: Arc::downgrade(&engine) };
+		try!(engine.transition_service.register_handler(Arc::new(handler)));
+		Ok(engine)
+	}
+
+	fn step(&self) -> usize {
+		self.step.load(AtomicOrdering::SeqCst)
+	}
+
+	fn remaining_step_duration(&self) -> Duration {
+		let now = unix_now();
+		let step_end = self.our_params.step_duration * (self.step() as u32 + 1);
+		if step_end > now {
+			step_end - now
+		} else {
+			Duration::from_secs(0)
+		}
+	}
+
+	fn step_proposer(&self, step: usize) -> &Address {
+		let ref p = self.our_params;
+		p.authorities.get(step % p.authority_n).expect("There are authority_n authorities; taking number modulo authority_n gives number in authority_n range; qed")
+	}
+
+	fn is_step_proposer(&self, step: usize, address: &Address) -> bool {
+		self.step_proposer(step) == address
+	}
+}
+
+fn unix_now() -> Duration {
+	UNIX_EPOCH.elapsed().expect("Valid time has to be set in your system.")
+}
+
+struct TransitionHandler {
+	engine: Weak<AuthorityRound>,
+}
+
+#[derive(Clone)]
+struct BlockArrived;
+
+const ENGINE_TIMEOUT_TOKEN: TimerToken = 23;
+
+impl IoHandler<BlockArrived> for TransitionHandler {
+	fn initialize(&self, io: &IoContext<BlockArrived>) {
+		if let Some(engine) = self.engine.upgrade() {
+			io.register_timer_once(ENGINE_TIMEOUT_TOKEN, engine.remaining_step_duration().as_millis())
+				.unwrap_or_else(|e| warn!(target: "poa", "Failed to start consensus step timer: {}.", e))
+		}
+	}
+
+	fn timeout(&self, io: &IoContext<BlockArrived>, timer: TimerToken) {
+		if timer == ENGINE_TIMEOUT_TOKEN {
+			if let Some(engine) = self.engine.upgrade() {
+				engine.step.fetch_add(1, AtomicOrdering::SeqCst);
+				engine.proposed.store(false, AtomicOrdering::SeqCst);
+				if let Some(ref channel) = *engine.message_channel.lock() {
+					match channel.send(ClientIoMessage::UpdateSealing) {
+						Ok(_) => trace!(target: "poa", "timeout: UpdateSealing message sent for step {}.", engine.step.load(AtomicOrdering::Relaxed)),
+						Err(err) => trace!(target: "poa", "timeout: Could not send a sealing message {} for step {}.", err, engine.step.load(AtomicOrdering::Relaxed)),
+					}
+				}
+				io.register_timer_once(ENGINE_TIMEOUT_TOKEN, engine.remaining_step_duration().as_millis())
+					.unwrap_or_else(|e| warn!(target: "poa", "Failed to restart consensus step timer: {}.", e))
+			}
+		}
+	}
+}
+
+impl Engine for AuthorityRound {
+	fn name(&self) -> &str { "AuthorityRound" }
+	fn version(&self) -> SemanticVersion { SemanticVersion::new(1, 0, 0) }
+	/// Two fields - consensus step and the corresponding proposer signature.
+	fn seal_fields(&self) -> usize { 2 }
+
+	fn params(&self) -> &CommonParams { &self.params }
+	fn builtins(&self) -> &BTreeMap<Address, Builtin> { &self.builtins }
+
+	/// Additional engine-specific information for the user/developer concerning `header`.
+	fn extra_info(&self, header: &Header) -> BTreeMap<String, String> {
+		map![
+			"step".into() => header_step(header).as_ref().map(ToString::to_string).unwrap_or("".into()),
+			"signature".into() => header_signature(header).as_ref().map(ToString::to_string).unwrap_or("".into())
+		]
+	}
+
+	fn schedule(&self, _env_info: &EnvInfo) -> Schedule {
+		Schedule::new_post_eip150(usize::max_value(), true, true, true)
+	}
+
+	fn populate_from_parent(&self, header: &mut Header, parent: &Header, gas_floor_target: U256, _gas_ceil_target: U256) {
+		header.set_difficulty(parent.difficulty().clone());
+		header.set_gas_limit({
+			let gas_limit = parent.gas_limit().clone();
+			let bound_divisor = self.our_params.gas_limit_bound_divisor;
+			if gas_limit < gas_floor_target {
+				min(gas_floor_target, gas_limit + gas_limit / bound_divisor - 1.into())
+			} else {
+				max(gas_floor_target, gas_limit - gas_limit / bound_divisor + 1.into())
+			}
+		});
+	}
+
+	/// 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 ExecutedBlock) {}
+
+	fn is_sealer(&self, author: &Address) -> Option<bool> {
+		let ref p = self.our_params;
+		Some(p.authorities.contains(author))
+	}
+
+	/// Attempt to seal the block internally.
+	///
+	/// This operation is synchronous and may (quite reasonably) not be available, in which `false` will
+	/// be returned.
+	fn generate_seal(&self, block: &ExecutedBlock, accounts: Option<&AccountProvider>) -> Option<Vec<Bytes>> {
+		if self.proposed.load(AtomicOrdering::SeqCst) { return None; }
+		let header = block.header();
+		let step = self.step();
+		if self.is_step_proposer(step, header.author()) {
+			if let Some(ap) = accounts {
+				// Account should be permanently unlocked, otherwise sealing will fail.
+				if let Ok(signature) = ap.sign(*header.author(), None, header.bare_hash()) {
+					trace!(target: "poa", "generate_seal: Issuing a block for step {}.", step);
+					self.proposed.store(true, AtomicOrdering::SeqCst);
+					return Some(vec![encode(&step).to_vec(), encode(&(&*signature as &[u8])).to_vec()]);
+				} else {
+					warn!(target: "poa", "generate_seal: FAIL: Accounts secret key unavailable.");
+				}
+			} else {
+				warn!(target: "poa", "generate_seal: FAIL: Accounts not provided.");
+			}
+		}
+		None
+	}
+
+	/// Check the number of seal fields.
+	fn verify_block_basic(&self, header: &Header, _block: Option<&[u8]>) -> Result<(), Error> {
+		if header.seal().len() != self.seal_fields() {
+			trace!(target: "poa", "verify_block_basic: wrong number of seal fields");
+			Err(From::from(BlockError::InvalidSealArity(
+				Mismatch { expected: self.seal_fields(), found: header.seal().len() }
+			)))
+		} else {
+			Ok(())
+		}
+	}
+
+	/// Check if the signature belongs to the correct proposer.
+	fn verify_block_unordered(&self, header: &Header, _block: Option<&[u8]>) -> Result<(), Error> {
+        let header_step = try!(header_step(header));
+        // Give one step slack if step is lagging, double vote is still not possible.
+		if header_step <= self.step() + 1 {
+			let proposer_signature = try!(header_signature(header));
+			let ok_sig = try!(verify_address(self.step_proposer(header_step), &proposer_signature, &header.bare_hash()));
+			if ok_sig {
+				Ok(())
+			} else {
+				trace!(target: "poa", "verify_block_unordered: invalid seal signature");
+				try!(Err(BlockError::InvalidSeal))
+			}
+		} else {
+			trace!(target: "poa", "verify_block_unordered: block from the future");
+			try!(Err(BlockError::InvalidSeal))
+		}
+	}
+
+	fn verify_block_family(&self, header: &Header, parent: &Header, _block: Option<&[u8]>) -> Result<(), Error> {
+		// Don't calculate difficulty for genesis blocks.
+		if header.number() == 0 {
+			return Err(From::from(BlockError::RidiculousNumber(OutOfBounds { min: Some(1), max: None, found: header.number() })));
+		}
+
+		let step = try!(header_step(header));
+		// Check if parent is from a previous step.
+		if step == try!(header_step(parent)) { 
+			trace!(target: "poa", "Multiple blocks proposed for step {}.", step);
+			try!(Err(BlockError::DoubleVote(header.author().clone())));
+		}
+
+		// Check difficulty is correct given the two timestamps.
+		if header.difficulty() != parent.difficulty() {
+			return Err(From::from(BlockError::InvalidDifficulty(Mismatch { expected: *parent.difficulty(), found: *header.difficulty() })))
+		}
+		let gas_limit_divisor = self.our_params.gas_limit_bound_divisor;
+		let min_gas = parent.gas_limit().clone() - parent.gas_limit().clone() / gas_limit_divisor;
+		let max_gas = parent.gas_limit().clone() + parent.gas_limit().clone() / gas_limit_divisor;
+		if header.gas_limit() <= &min_gas || header.gas_limit() >= &max_gas {
+			return Err(From::from(BlockError::InvalidGasLimit(OutOfBounds { min: Some(min_gas), max: Some(max_gas), found: header.gas_limit().clone() })));
+		}
+		Ok(())
+	}
+
+	fn verify_transaction_basic(&self, t: &SignedTransaction, _header: &Header) -> Result<(), Error> {
+		try!(t.check_low_s());
+		Ok(())
+	}
+
+	fn verify_transaction(&self, t: &SignedTransaction, _header: &Header) -> Result<(), Error> {
+		t.sender().map(|_|()) // Perform EC recovery and cache sender
+	}
+
+	fn register_message_channel(&self, message_channel: IoChannel<ClientIoMessage>) {
+		let mut guard = self.message_channel.lock();
+		*guard = Some(message_channel);
+	}
+}
+
+#[cfg(test)]
+mod tests {
+	use util::*;
+	use env_info::EnvInfo;
+	use header::Header;
+	use error::{Error, BlockError};
+	use rlp::encode;
+	use block::*;
+	use tests::helpers::*;
+	use account_provider::AccountProvider;
+	use spec::Spec;
+	use std::time::UNIX_EPOCH;
+
+	#[test]
+	fn has_valid_metadata() {
+		let engine = Spec::new_test_round().engine;
+		assert!(!engine.name().is_empty());
+		assert!(engine.version().major >= 1);
+	}
+
+	#[test]
+	fn can_return_schedule() {
+		let engine = Spec::new_test_round().engine;
+		let schedule = engine.schedule(&EnvInfo {
+			number: 10000000,
+			author: 0.into(),
+			timestamp: 0,
+			difficulty: 0.into(),
+			last_hashes: Arc::new(vec![]),
+			gas_used: 0.into(),
+			gas_limit: 0.into(),
+		});
+
+		assert!(schedule.stack_limit > 0);
+	}
+
+	#[test]
+	fn verification_fails_on_short_seal() {
+		let engine = Spec::new_test_round().engine;
+		let header: Header = Header::default();
+
+		let verify_result = engine.verify_block_basic(&header, None);
+
+		match verify_result {
+			Err(Error::Block(BlockError::InvalidSealArity(_))) => {},
+			Err(_) => { panic!("should be block seal-arity mismatch error (got {:?})", verify_result); },
+			_ => { panic!("Should be error, got Ok"); },
+		}
+	}
+
+	#[test]
+	fn can_do_signature_verification_fail() {
+		let engine = Spec::new_test_round().engine;
+		let mut header: Header = Header::default();
+		header.set_seal(vec![encode(&H520::default()).to_vec()]);
+
+		let verify_result = engine.verify_block_unordered(&header, None);
+		assert!(verify_result.is_err());
+	}
+
+	#[test]
+	fn generates_seal_and_does_not_double_propose() {
+		let tap = AccountProvider::transient_provider();
+		let addr1 = tap.insert_account("1".sha3(), "1").unwrap();
+		tap.unlock_account_permanently(addr1, "1".into()).unwrap();
+		let addr2 = tap.insert_account("2".sha3(), "2").unwrap();
+		tap.unlock_account_permanently(addr2, "2".into()).unwrap();
+
+		let spec = Spec::new_test_round();
+		let engine = &*spec.engine;
+		let genesis_header = spec.genesis_header();
+		let mut db1 = get_temp_state_db().take();
+		spec.ensure_db_good(&mut db1).unwrap();
+		let mut db2 = get_temp_state_db().take();
+		spec.ensure_db_good(&mut db2).unwrap();
+		let last_hashes = Arc::new(vec![genesis_header.hash()]);
+		let b1 = OpenBlock::new(engine, Default::default(), false, db1, &genesis_header, last_hashes.clone(), addr1, (3141562.into(), 31415620.into()), vec![]).unwrap();
+		let b1 = b1.close_and_lock();
+		let b2 = OpenBlock::new(engine, Default::default(), false, db2, &genesis_header, last_hashes, addr2, (3141562.into(), 31415620.into()), vec![]).unwrap();
+		let b2 = b2.close_and_lock();
+
+		if let Some(seal) = engine.generate_seal(b1.block(), Some(&tap)) {
+			assert!(b1.clone().try_seal(engine, seal).is_ok());
+			// Second proposal is forbidden.
+			assert!(engine.generate_seal(b1.block(), Some(&tap)).is_none());
+		}
+
+		if let Some(seal) = engine.generate_seal(b2.block(), Some(&tap)) {
+			assert!(b2.clone().try_seal(engine, seal).is_ok());
+			// Second proposal is forbidden.
+			assert!(engine.generate_seal(b2.block(), Some(&tap)).is_none());
+		}
+	}
+
+	#[test]
+	fn proposer_switching() {
+		let mut header: Header = Header::default();
+		let tap = AccountProvider::transient_provider();
+		let addr = tap.insert_account("0".sha3(), "0").unwrap();
+
+		header.set_author(addr);
+
+		let engine = Spec::new_test_round().engine;
+
+		let signature = tap.sign(addr, Some("0".into()), header.bare_hash()).unwrap();
+		let mut step = UNIX_EPOCH.elapsed().unwrap().as_secs();
+		header.set_seal(vec![encode(&step).to_vec(), encode(&(&*signature as &[u8])).to_vec()]);
+		let first_ok = engine.verify_block_seal(&header).is_ok();
+		step = step + 1;
+		header.set_seal(vec![encode(&step).to_vec(), encode(&(&*signature as &[u8])).to_vec()]);
+		let second_ok = engine.verify_block_seal(&header).is_ok();
+
+		assert!(first_ok ^ second_ok);
+	}
+}
--- a/ethcore/src/engines/basic_authority.rs
+++ b/ethcore/src/engines/basic_authority.rs
@@ -181,13 +181,6 @@ impl Engine for BasicAuthority {
 	}
 }

-impl Header {
-	/// Get the none field of the header.
-	pub fn signature(&self) -> H520 {
-		::rlp::decode(&self.seal()[0])
-	}
-}
-
 #[cfg(test)]
 mod tests {
 	use util::*;
@@ -201,7 +194,7 @@ mod tests {

 	/// Create a new test chain spec with `BasicAuthority` consensus engine.
 	fn new_test_authority() -> Spec {
-		let bytes: &[u8] = include_bytes!("../../res/test_authority.json");
+		let bytes: &[u8] = include_bytes!("../../res/basic_authority.json");
 		Spec::load(bytes).expect("invalid chain spec")
 	}

--- a/ethcore/src/engines/instant_seal.rs
+++ b/ethcore/src/engines/instant_seal.rs
@@ -55,7 +55,7 @@ impl Engine for InstantSeal {
 	}

 	fn schedule(&self, _env_info: &EnvInfo) -> Schedule {
-		Schedule::new_post_eip150(false, false, false)
+		Schedule::new_post_eip150(usize::max_value(), false, false, false)
 	}

 	fn is_sealer(&self, _author: &Address) -> Option<bool> { Some(true) }
--- a/ethcore/src/engines/mod.rs
+++ b/ethcore/src/engines/mod.rs
@@ -19,13 +19,16 @@
 mod null_engine;
 mod instant_seal;
 mod basic_authority;
+mod authority_round;
 mod tendermint;
 mod signed_vote;
 mod propose_collect;

+
 pub use self::null_engine::NullEngine;
 pub use self::instant_seal::InstantSeal;
 pub use self::basic_authority::BasicAuthority;
+pub use self::authority_round::AuthorityRound;
 pub use self::tendermint::Tendermint;
 pub use self::signed_vote::SignedVote;
 pub use self::propose_collect::ProposeCollect;
@@ -39,6 +42,8 @@ use env_info::EnvInfo;
 use error::Error;
 use spec::CommonParams;
 use evm::Schedule;
+use io::IoChannel;
+use service::ClientIoMessage;
 use header::Header;
 use transaction::SignedTransaction;
 use ethereum::ethash;
@@ -171,6 +176,9 @@ pub trait Engine : Sync + Send {
 		self.builtins().get(a).expect("attempted to execute nonexistent builtin").execute(input, output);
 	}

+	/// Add a channel for communication with Client which can be used for sealing.
+	fn register_message_channel(&self, _message_channel: IoChannel<ClientIoMessage>) {}
+
 	/// Check if new block should be chosen as the one  in chain.
 	fn is_new_best_block(&self, best_total_difficulty: U256, _best_header: HeaderView, parent_details: &BlockDetails, new_header: &HeaderView) -> bool {
 		ethash::is_new_best_block(best_total_difficulty, parent_details, new_header)
--- a/ethcore/src/engines/tendermint/message.rs
+++ b/ethcore/src/engines/tendermint/message.rs
@@ -23,19 +23,19 @@ use rlp::{View, DecoderError, Decodable, Decoder, Encodable, RlpStream, Stream};
 #[derive(Debug, PartialEq, Eq)]
 pub struct ConsensusMessage {
 	pub signature: H520,
-	height: Height,
-	round: Round,
+	pub height: Height,
+	pub round: Round,
 	pub step: Step,
-	block_hash: Option<BlockHash>
+	pub block_hash: Option<BlockHash>
 }

 impl ConsensusMessage {
-	fn is_round(&self, height: Height, round: Round) -> bool {
+	pub fn is_round(&self, height: Height, round: Round) -> bool {
 		self.height == height && self.round == round
 	}

-	fn is_step(&self, height: Height, round: Round, step: Step) -> bool {
-		self.height == height && self.round == round && self.step == step
+	pub fn is_step(&self, height: Height, round: Round, step: &Step) -> bool {
+		self.height == height && self.round == round && &self.step == step
 	}

 	pub fn is_aligned(&self, height: Height, round: Round, block_hash: Option<H256>) -> bool {
--- a/ethcore/src/engines/tendermint/mod.rs
+++ b/ethcore/src/engines/tendermint/mod.rs
@@ -73,12 +73,12 @@ pub struct Tendermint {
 	round: AtomicUsize,
 	/// Consensus step.
 	step: RwLock<Step>,
-	/// Current step timeout in ms.
-	timeout: AtomicMs,
 	/// Used to swith proposer.
 	proposer_nonce: AtomicUsize,
 	/// Vote accumulator.
-	votes: VoteCollector
+	votes: VoteCollector,
+	/// Channel for updating the sealing.
+	message_channel: Mutex<Option<IoChannel<ClientIoMessage>>>
 }

 impl Tendermint {
@@ -87,7 +87,6 @@ impl Tendermint {
 		let engine = Arc::new(
 			Tendermint {
 				params: params,
-				timeout: AtomicUsize::new(our_params.timeouts.propose),
 				our_params: our_params,
 				builtins: builtins,
 				timeout_service: try!(IoService::<NextStep>::start()),
@@ -96,7 +95,8 @@ impl Tendermint {
 				round: AtomicUsize::new(0),
 				step: RwLock::new(Step::Propose),
 				proposer_nonce: AtomicUsize::new(0),
-				votes: VoteCollector::new()
+				votes: VoteCollector::new(),
+				message_channel: Mutex::new(None)
 			});
 		let handler = TimerHandler { engine: Arc::downgrade(&engine) };
 		try!(engine.timeout_service.register_handler(Arc::new(handler)));
@@ -116,95 +116,21 @@ impl Tendermint {
 		self.our_params.authorities.contains(address)
 	}

-	fn new_vote(&self, proposal: BlockHash) -> ProposeCollect {
-		ProposeCollect::new(proposal,
-							self.our_params.authorities.iter().cloned().collect(),
-							self.threshold())
-	}
-
-	fn to_step(&self, step: Step) {
-		let mut guard = self.step.try_write().unwrap();
-		*guard = step;
-	}
-
-	fn to_propose(&self) {
-		trace!(target: "poa", "step: entering propose");
-		println!("step: entering propose");
-		self.proposer_nonce.fetch_add(1, AtomicOrdering::Relaxed);
-		self.to_step(Step::Propose);
-	}
-
-	fn propose_message(&self, message: UntrustedRlp) -> Result<Bytes, Error> {
-		// Check if message is for correct step.
-		match *self.step.try_read().unwrap() {
-			Step::Propose => (),
-			_ => try!(Err(EngineError::WrongStep)),
-		}
-		let proposal = try!(message.as_val());
-		self.to_prevote(proposal);
-		Ok(message.as_raw().to_vec())
-	}
-
-	fn to_prevote(&self, proposal: BlockHash) {
-		trace!(target: "poa", "step: entering prevote");
-		println!("step: entering prevote");
-		// Proceed to the prevote step.
-		self.to_step(Step::Prevote(self.new_vote(proposal)));
-	}
-
-	fn prevote_message(&self, sender: Address, message: UntrustedRlp) -> Result<Bytes, Error> {
-		// Check if message is for correct step.
-		let hash = match *self.step.try_write().unwrap() {
-			Step::Prevote => {
-				// Vote if message is about the right block.
-				if vote.hash == try!(message.as_val()) {
-					vote.vote(sender);
-					// Move to next step is prevote is won.
-					if vote.is_won() {
-						// If won assign a hash used for precommit.
-						vote.hash.clone()
-					} else {
-						// Just propoagate the message if not won yet.
-						return Ok(message.as_raw().to_vec());
-					}
-				} else {
-					try!(Err(EngineError::WrongVote))
-				}
-			},
-			_ => try!(Err(EngineError::WrongStep)),
-		};
-		self.to_precommit(hash);
-		Ok(message.as_raw().to_vec())
-	}
-
-	fn to_precommit(&self, proposal: BlockHash) {
-		trace!(target: "poa", "step: entering precommit");
-		println!("step: entering precommit");
-		self.to_step(Step::Precommit(self.new_vote(proposal), Vec::new()));
-	}
-
-	/// Move to commit step, when valid block is known and being distributed.
-	pub fn to_commit(&self, block_hash: H256, seal: Vec<Bytes>) {
-		trace!(target: "poa", "step: entering commit");
-		println!("step: entering commit");
-		self.to_step(Step::Commit(block_hash, seal));
-	}
-
 	fn threshold(&self) -> usize {
 		self.our_params.authority_n * 2/3
 	}

-	fn next_timeout(&self) -> u64 {
-		self.timeout.load(AtomicOrdering::Relaxed) as u64
-	}
-
 	/// Round proposer switching.
 	fn is_proposer(&self, address: &Address) -> bool {
 		self.is_nonce_proposer(self.proposer_nonce.load(AtomicOrdering::SeqCst), address)
 	}

 	fn is_current(&self, message: &ConsensusMessage) -> bool {
-		message.is_step(self.height.load(AtomicOrdering::SeqCst), self.round.load(AtomicOrdering::SeqCst), self.step.load(AtomicOrdering::SeqCst)) 
+		message.is_step(self.height.load(AtomicOrdering::SeqCst), self.round.load(AtomicOrdering::SeqCst), &self.step.read()) 
+	}
+
+	fn has_enough_any_votes(&self) -> bool {
+		self.votes.count_step_votes(self.height.load(AtomicOrdering::SeqCst), self.round.load(AtomicOrdering::SeqCst), &self.step.read()) > self.threshold()	
 	}
 }

@@ -213,12 +139,12 @@ fn block_hash(header: &Header) -> H256 {
 	header.rlp(Seal::WithSome(1)).sha3()
 }

-fn proposer_signature(header: &Header) -> H520 {
-	try!(UntrustedRlp::new(header.seal()[1].as_slice()).as_val())
+fn proposer_signature(header: &Header) -> Result<H520, ::rlp::DecoderError> {
+	UntrustedRlp::new(header.seal()[1].as_slice()).as_val()
 }

-fn consensus_round(header: &Header) -> Round {
-	try!(UntrustedRlp::new(header.seal()[0].as_slice()).as_val())
+fn consensus_round(header: &Header) -> Result<Round, ::rlp::DecoderError> {
+	UntrustedRlp::new(header.seal()[0].as_slice()).as_val()
 }

 impl Engine for Tendermint {
@@ -233,10 +159,10 @@ impl Engine for Tendermint {
 	/// Additional engine-specific information for the user/developer concerning `header`.
 	fn extra_info(&self, header: &Header) -> BTreeMap<String, String> {
 		map![
-			"signature".into() => proposer_signature(header).to_string(),
+			"signature".into() => proposer_signature(header).as_ref().map(ToString::to_string).unwrap_or("".into()),
 			"height".into() => header.number().to_string(),
-			"round".into() => consensus_round(header).to_string(),
-			"block_hash".into() => block_hash(header).to_string().unwrap_or("".into())
+			"round".into() => consensus_round(header).as_ref().map(ToString::to_string).unwrap_or("".into()),
+			"block_hash".into() => block_hash(header).to_string()
 		]
 	}

@@ -326,10 +252,10 @@ impl Engine for Tendermint {
 		}

 		// Check if the message affects the current step.
-		if self.is_current(message) {
-				match self.step.load(AtomicOrdering::SeqCst) {
+		if self.is_current(&message) {
+				match *self.step.read() {
 					Step::Prevote => {
-						let votes = aligned_signatures(message);
+						let votes = self.votes.aligned_signatures(&message);
 						if votes.len() > self.threshold() {
 						}
 					},
@@ -352,14 +278,15 @@ impl Engine for Tendermint {

 	/// Also transitions to Prevote if verifying Proposal.
 	fn verify_block_unordered(&self, header: &Header, _block: Option<&[u8]>) -> Result<(), Error> {
-		let proposer = public_to_address(&try!(recover(&proposal_signature(header).into(), &block_hash(header))));
+		let signature = try!(proposer_signature(header));
+		let proposer = public_to_address(&try!(recover(&signature.into(), &block_hash(header))));
 		if !self.is_proposer(&proposer) {
 			try!(Err(BlockError::InvalidSeal))
 		}
 		let proposal = ConsensusMessage {
-			signature: proposal_signature,
+			signature: signature,
 			height: header.number() as Height,
-			round: consensus_round(header),
+			round: try!(consensus_round(header)),
 			step: Step::Propose,
 			block_hash: Some(block_hash(header))
 		};
@@ -368,7 +295,7 @@ impl Engine for Tendermint {
 		for rlp in votes_rlp.iter() {
 			let sig: H520 = try!(rlp.as_val());
 			let address = public_to_address(&try!(recover(&sig.into(), &block_hash(header))));
-			if !self.our_params.authorities.contains(a) {
+			if !self.our_params.authorities.contains(&address) {
 				try!(Err(BlockError::InvalidSeal))
 			}
 		}
@@ -408,6 +335,11 @@ impl Engine for Tendermint {
 		let best_signatures = best_header.seal().get(2).expect("Tendermint seal should have three elements.").len();
 		new_signatures > best_signatures
 	}
+
+	fn register_message_channel(&self, message_channel: IoChannel<ClientIoMessage>) {
+		let mut guard = self.message_channel.lock();
+		*guard = Some(message_channel);
+	}
 }

 #[cfg(test)]
--- a/ethcore/src/engines/tendermint/params.rs
+++ b/ethcore/src/engines/tendermint/params.rs
@@ -19,6 +19,7 @@
 use ethjson;
 use super::timeout::TendermintTimeouts;
 use util::{Address, U256};
+use time::Duration;

 /// `Tendermint` params.
 #[derive(Debug, Clone)]
@@ -41,25 +42,30 @@ impl Default for TendermintParams {
 			gas_limit_bound_divisor: 0x0400.into(),
 			authorities: authorities,
 			authority_n: val_n,
-			timeouts:  DefaultTimeouts::default()
+			timeouts: TendermintTimeouts::default()
 		}
 	}
 }

+fn to_duration(ms: ethjson::uint::Uint) -> Duration {
+	let ms: usize = ms.into();
+	Duration::milliseconds(ms as i64)
+}
+
 impl From<ethjson::spec::TendermintParams> for TendermintParams {
 	fn from(p: ethjson::spec::TendermintParams) -> Self {
 		let val: Vec<_> = p.authorities.into_iter().map(Into::into).collect();
 		let val_n = val.len();
+		let dt = TendermintTimeouts::default();
 		TendermintParams {
 			gas_limit_bound_divisor: p.gas_limit_bound_divisor.into(),
 			authorities: val,
 			authority_n: val_n,
-			let dt = TendermintTimeouts::default();
 			timeouts: TendermintTimeouts {
-				propose: p.timeout_propose.unwrap_or(dt.propose),
-				prevote: p.timeout_prevote.unwrap_or(dt.prevote),
-				precommit: p.timeout_precommit.unwrap_or(dt.precommit),
-				commit: p.timeout_commit.unwrap_or(dt.commit)
+				propose: p.timeout_propose.map_or(dt.propose, to_duration),
+				prevote: p.timeout_prevote.map_or(dt.prevote, to_duration),
+				precommit: p.timeout_precommit.map_or(dt.precommit, to_duration),
+				commit: p.timeout_commit.map_or(dt.commit, to_duration)
 			}
 		}
 	}
--- a/ethcore/src/engines/tendermint/timeout.rs
+++ b/ethcore/src/engines/tendermint/timeout.rs
@@ -30,14 +30,14 @@ pub struct TimerHandler {
 /// Base timeout of each step in ms.
 #[derive(Debug, Clone)]
 pub struct TendermintTimeouts {
-	propose: Duration,
-	prevote: Duartion,
-	precommit: Duration,
-	commit: Duration
+	pub propose: Duration,
+	pub prevote: Duration,
+	pub precommit: Duration,
+	pub commit: Duration
 }

 impl TendermintTimeouts {
-	pub fn for_step(step: Step) -> Duration {
+	pub fn for_step(&self, step: Step) -> Duration {
 		match step {
 			Step::Propose => self.propose,
 			Step::Prevote => self.prevote,
@@ -49,7 +49,7 @@ impl TendermintTimeouts {

 impl Default for TendermintTimeouts {
 	fn default() -> Self {
-		DefaultTimeouts {
+		TendermintTimeouts {
 			propose: Duration::milliseconds(1000),
 			prevote: Duration::milliseconds(1000),
 			precommit: Duration::milliseconds(1000),
@@ -64,38 +64,55 @@ pub struct NextStep;
 /// Timer token representing the consensus step timeouts.
 pub const ENGINE_TIMEOUT_TOKEN: TimerToken = 23;

+fn set_timeout(io: &IoContext<NextStep>, timeout: Duration) {
+	io.register_timer_once(ENGINE_TIMEOUT_TOKEN, timeout.num_milliseconds() as u64)
+		.unwrap_or_else(|e| warn!(target: "poa", "Failed to set consensus step timeout: {}.", e))
+}
+
+fn update_sealing(io_channel: Mutex<Option<IoChannel<ClientIoMessage>>>) {
+	if let Some(ref channel) = *io_channel.lock() {
+		match channel.send(ClientIoMessage::UpdateSealing) {
+			Ok(_) => trace!(target: "poa", "timeout: UpdateSealing message sent for round {}.", engine.round.load(AtomicOrdering::SeqCst)),
+			Err(err) => trace!(target: "poa", "timeout: Could not send a sealing message {} for round {}.", err, engine.round.load(AtomicOrdering::SeqCst)),
+		}
+	}
+}
+
 impl IoHandler<NextStep> for TimerHandler {
 	fn initialize(&self, io: &IoContext<NextStep>) {
 		if let Some(engine) = self.engine.upgrade() {
-			io.register_timer_once(ENGINE_TIMEOUT_TOKEN, engine.remaining_step_duration().as_millis())
-				.unwrap_or_else(|e| warn!(target: "poa", "Failed to start consensus step timer: {}.", e))
+			set_timeout(io, engine.our_params.timeouts.propose)
 		}
 	}

 	fn timeout(&self, io: &IoContext<NextStep>, timer: TimerToken) {
 		if timer == ENGINE_TIMEOUT_TOKEN {
 			if let Some(engine) = self.engine.upgrade() {
-				engine.step.fetch_add(1, AtomicOrdering::SeqCst);
-				engine.proposed.store(false, AtomicOrdering::SeqCst);
-				let next_step = match *engine.step.try_read().unwrap() {
-					Step::Propose => Step::Prevote,
-					Step::Prevote => Step::Precommit,
-					Step::Precommit => Step::Propose,
-					Step::Commit => {
-						engine.round.fetch_add(1, AtomicOrdering::Relaxed);
-						Step::Propose
+				let next_step = match *engine.step.read() {
+					Step::Propose => {
+						set_timeout(io, engine.our_params.timeouts.prevote);
+						Some(Step::Prevote)
 					},
+					Step::Prevote if engine.has_enough_any_votes() => {
+						set_timeout(io, engine.our_params.timeouts.precommit);
+						Some(Step::Precommit)
+					},
+					Step::Precommit if engine.has_enough_any_votes() => {
+						set_timeout(io, engine.our_params.timeouts.propose);
+						engine.round.fetch_add(1, AtomicOrdering::SeqCst);
+						Some(Step::Propose)
+					},
+					Step::Commit => {
+						set_timeout(io, engine.our_params.timeouts.propose);
+						engine.round.store(0, AtomicOrdering::SeqCst);
+						engine.height.fetch_add(1, AtomicOrdering::SeqCst);
+						Some(Step::Propose)
+					},
+					_ => None,
 				};

-
-				io.register_timer_once(ENGINE_TIMEOUT_TOKEN, engine.next_timeout().as_millis())
-					.unwrap_or_else(|e| warn!(target: "poa", "Failed to restart consensus step timer: {}.", e))
-
-				if let Some(ref channel) = *engine.message_channel.lock() {
-					match channel.send(ClientIoMessage::UpdateSealing) {
-						Ok(_) => trace!(target: "poa", "timeout: UpdateSealing message sent for step {}.", engine.step.),
-						Err(err) => trace!(target: "poa", "timeout: Could not send a sealing message {} for step {}.", err, engine.step.load(AtomicOrdering::Relaxed)),
-					}
+				if let Some(step) = next_step {
+					*engine.step.write() = step
 				}

 			}
--- a/ethcore/src/engines/tendermint/vote_collector.rs
+++ b/ethcore/src/engines/tendermint/vote_collector.rs
@@ -33,9 +33,7 @@ impl VoteCollector {
 	}

 	pub fn vote(&self, message: ConsensusMessage, voter: Address) {
-		if let Some(mut guard) = self.votes.write() {
-			*guard.insert(message, voter);
-		}
+		self.votes.write().insert(message, voter);
 	}

 	pub fn seal_signatures(&self, height: Height, round: Round, block_hash: Option<H256>) -> Vec<H520> {
@@ -52,13 +50,11 @@ impl VoteCollector {
 		self.seal_signatures(message.height, message.round, message.block_hash)
 	}

-	pub fn count_signatures(&self, height: Height, round: Round) -> usize {
+	pub fn count_step_votes(&self, height: Height, round: Round, step: &Step) -> usize {
 		self.votes
 			.read()
 			.keys()
-			// Get only Propose and Precommits.
-			.filter(|m| m.is_round(height, round) && m.step != Step::Prevote)
-			.map(|m| m.signature)
-			.collect()	
+			.filter(|m| m.is_step(height, round, step))
+			.count()	
 	}
 }
--- a/ethcore/src/error.rs
+++ b/ethcore/src/error.rs
@@ -168,6 +168,8 @@ pub enum BlockError {
 	UnknownParent(H256),
 	/// Uncle parent given is unknown.
 	UnknownUncleParent(H256),
+	/// The same author issued different votes at the same step.
+	DoubleVote(H160),
 }

 impl fmt::Display for BlockError {
@@ -201,6 +203,7 @@ impl fmt::Display for BlockError {
 			RidiculousNumber(ref oob) => format!("Implausible block number. {}", oob),
 			UnknownParent(ref hash) => format!("Unknown parent: {}", hash),
 			UnknownUncleParent(ref hash) => format!("Unknown uncle parent: {}", hash),
+			DoubleVote(ref address) => format!("Author {} issued too many blocks.", address),
 		};

 		f.write_fmt(format_args!("Block error ({})", msg))
--- a/ethcore/src/ethereum/ethash.rs
+++ b/ethcore/src/ethereum/ethash.rs
@@ -75,7 +75,9 @@ pub struct EthashParams {
 	/// Number of first block where ECIP-1010 begins.
 	pub ecip1010_pause_transition: u64,
 	/// Number of first block where ECIP-1010 ends.
-	pub ecip1010_continue_transition: u64
+	pub ecip1010_continue_transition: u64,
+	/// Maximum amount of code that can be deploying into a contract.
+	pub max_code_size: u64,
 }

 impl From<ethjson::spec::EthashParams> for EthashParams {
@@ -89,19 +91,20 @@ impl From<ethjson::spec::EthashParams> for EthashParams {
 			block_reward: p.block_reward.into(),
 			registrar: p.registrar.map_or_else(Address::new, Into::into),
 			homestead_transition: p.homestead_transition.map_or(0, Into::into),
-			dao_hardfork_transition: p.dao_hardfork_transition.map_or(0x7fffffffffffffff, Into::into),
+			dao_hardfork_transition: p.dao_hardfork_transition.map_or(u64::max_value(), Into::into),
 			dao_hardfork_beneficiary: p.dao_hardfork_beneficiary.map_or_else(Address::new, Into::into),
 			dao_hardfork_accounts: p.dao_hardfork_accounts.unwrap_or_else(Vec::new).into_iter().map(Into::into).collect(),
-			difficulty_hardfork_transition: p.difficulty_hardfork_transition.map_or(0x7fffffffffffffff, Into::into),
+			difficulty_hardfork_transition: p.difficulty_hardfork_transition.map_or(u64::max_value(), Into::into),
 			difficulty_hardfork_bound_divisor: p.difficulty_hardfork_bound_divisor.map_or(p.difficulty_bound_divisor.into(), Into::into),
-			bomb_defuse_transition: p.bomb_defuse_transition.map_or(0x7fffffffffffffff, Into::into),
+			bomb_defuse_transition: p.bomb_defuse_transition.map_or(u64::max_value(), Into::into),
 			eip150_transition: p.eip150_transition.map_or(0, Into::into),
 			eip155_transition: p.eip155_transition.map_or(0, Into::into),
 			eip160_transition: p.eip160_transition.map_or(0, Into::into),
 			eip161abc_transition: p.eip161abc_transition.map_or(0, Into::into),
-			eip161d_transition: p.eip161d_transition.map_or(0x7fffffffffffffff, Into::into),
-			ecip1010_pause_transition: p.ecip1010_pause_transition.map_or(0x7fffffffffffffff, Into::into),
-			ecip1010_continue_transition: p.ecip1010_continue_transition.map_or(0x7fffffffffffffff, Into::into),
+			eip161d_transition: p.eip161d_transition.map_or(u64::max_value(), Into::into),
+			ecip1010_pause_transition: p.ecip1010_pause_transition.map_or(u64::max_value(), Into::into),
+			ecip1010_continue_transition: p.ecip1010_continue_transition.map_or(u64::max_value(), Into::into),
+			max_code_size: p.max_code_size.map_or(u64::max_value(), Into::into),
 		}
 	}
 }
@@ -154,6 +157,7 @@ impl Engine for Ethash {
 			Schedule::new_homestead()
 		} else {
 			Schedule::new_post_eip150(
+				self.ethash_params.max_code_size as usize,
 				env_info.number >= self.ethash_params.eip160_transition,
 				env_info.number >= self.ethash_params.eip161abc_transition,
 				env_info.number >= self.ethash_params.eip161d_transition
--- a/ethcore/src/evm/schedule.rs
+++ b/ethcore/src/evm/schedule.rs
@@ -70,6 +70,8 @@ pub struct Schedule {
 	pub quad_coeff_div: usize,
 	/// Cost for contract length when executing `CREATE`
 	pub create_data_gas: usize,
+	/// Maximum code size when creating a contract.
+	pub create_data_limit: usize,
 	/// Transaction cost
 	pub tx_gas: usize,
 	/// `CREATE` transaction cost
@@ -111,7 +113,7 @@ impl Schedule {
 	}

 	/// Schedule for the post-EIP-150-era of the Ethereum main net.
-	pub fn new_post_eip150(fix_exp: bool, no_empty: bool, kill_empty: bool) -> Schedule {
+	pub fn new_post_eip150(max_code_size: usize, fix_exp: bool, no_empty: bool, kill_empty: bool) -> Schedule {
 		Schedule {
 			exceptional_failed_code_deposit: true,
 			have_delegate_call: true,
@@ -139,6 +141,7 @@ impl Schedule {
 			memory_gas: 3,
 			quad_coeff_div: 512,
 			create_data_gas: 200,
+			create_data_limit: max_code_size,
 			tx_gas: 21000,
 			tx_create_gas: 53000,
 			tx_data_zero_gas: 4,
@@ -183,6 +186,7 @@ impl Schedule {
 			memory_gas: 3,
 			quad_coeff_div: 512,
 			create_data_gas: 200,
+			create_data_limit: usize::max_value(),
 			tx_gas: 21000,
 			tx_create_gas: tcg,
 			tx_data_zero_gas: 4,
--- a/ethcore/src/externalities.rs
+++ b/ethcore/src/externalities.rs
@@ -242,7 +242,7 @@ impl<'a, T, V> Ext for Externalities<'a, T, V> where T: 'a + Tracer, V: 'a + VMT
 			},
 			OutputPolicy::InitContract(ref mut copy) => {
 				let return_cost = U256::from(data.len()) * U256::from(self.schedule.create_data_gas);
-				if return_cost > *gas {
+				if return_cost > *gas || data.len() > self.schedule.create_data_limit {
 					return match self.schedule.exceptional_failed_code_deposit {
 						true => Err(evm::Error::OutOfGas),
 						false => Ok(*gas)
--- a/ethcore/src/miner/miner.rs
+++ b/ethcore/src/miner/miner.rs
@@ -212,7 +212,8 @@ pub struct Miner {
 	sealing_block_last_request: Mutex<u64>,
 	// for sealing...
 	options: MinerOptions,
-	seals_internally: bool,
+	/// Does the node perform internal (without work) sealing.
+	pub seals_internally: bool,

 	gas_range_target: RwLock<(U256, U256)>,
 	author: RwLock<Address>,
@@ -267,6 +268,11 @@ impl Miner {
 		}
 	}

+	/// Creates new instance of miner with accounts and with given spec.
+	pub fn with_spec_and_accounts(spec: &Spec, accounts: Option<Arc<AccountProvider>>) -> Miner {
+		Miner::new_raw(Default::default(), GasPricer::new_fixed(20_000_000_000u64.into()), spec, accounts)
+	}
+
 	/// Creates new instance of miner without accounts, but with given spec.
 	pub fn with_spec(spec: &Spec) -> Miner {
 		Miner::new_raw(Default::default(), GasPricer::new_fixed(20_000_000_000u64.into()), spec, None)
@@ -429,6 +435,7 @@ impl Miner {
 			let last_request = *self.sealing_block_last_request.lock();
 			let should_disable_sealing = !self.forced_sealing()
 				&& !has_local_transactions
+				&& !self.seals_internally
 				&& best_block > last_request
 				&& best_block - last_request > SEALING_TIMEOUT_IN_BLOCKS;

@@ -472,9 +479,10 @@ impl Miner {

 	/// Uses Engine to seal the block internally and then imports it to chain.
 	fn seal_and_import_block_internally(&self, chain: &MiningBlockChainClient, block: ClosedBlock) -> bool {
-		if !block.transactions().is_empty() {
+		if !block.transactions().is_empty() || self.forced_sealing() {
 			if let Ok(sealed) = self.seal_block_internally(block) {
 				if chain.import_block(sealed.rlp_bytes()).is_ok() {
+					trace!(target: "miner", "import_block_internally: imported internally sealed block");
 					return true
 				}
 			}
@@ -773,7 +781,7 @@ impl MinerService for Miner {
 		chain: &MiningBlockChainClient,
 		transactions: Vec<SignedTransaction>
 	) -> Vec<Result<TransactionImportResult, Error>> {
-
+		trace!(target: "external_tx", "Importing external transactions");
 		let results = {
 			let mut transaction_queue = self.transaction_queue.lock();
 			self.add_transactions_to_queue(
--- a/ethcore/src/service.rs
+++ b/ethcore/src/service.rs
@@ -48,6 +48,8 @@ pub enum ClientIoMessage {
 	FeedBlockChunk(H256, Bytes),
 	/// Take a snapshot for the block with given number.
 	TakeSnapshot(u64),
+	/// Trigger sealing update (useful for internal sealing).
+	UpdateSealing,
 }

 /// Client service setup. Creates and registers client and network services with the IO subsystem.
@@ -111,6 +113,8 @@ impl ClientService {
 		});
 		try!(io_service.register_handler(client_io));

+		spec.engine.register_message_channel(io_service.channel());
+
 		let stop_guard = ::devtools::StopGuard::new();
 		run_ipc(ipc_path, client.clone(), snapshot.clone(), stop_guard.share());

@@ -213,8 +217,11 @@ impl IoHandler<ClientIoMessage> for ClientIoHandler {
 				if let Err(e) = res {
 					debug!(target: "snapshot", "Failed to initialize periodic snapshot thread: {:?}", e);
 				}
-
-			}
+			},
+			ClientIoMessage::UpdateSealing => {
+				trace!(target: "authorityround", "message: UpdateSealing");
+				self.client.update_sealing()
+			},
 			_ => {} // ignore other messages
 		}
 	}
--- a/ethcore/src/spec/spec.rs
+++ b/ethcore/src/spec/spec.rs
@@ -18,7 +18,7 @@

 use util::*;
 use builtin::Builtin;
-use engines::{Engine, NullEngine, InstantSeal, BasicAuthority, Tendermint};
+use engines::{Engine, NullEngine, InstantSeal, BasicAuthority, AuthorityRound, Tendermint};
 use pod_state::*;
 use account_db::*;
 use header::{BlockNumber, Header};
@@ -150,6 +150,7 @@ impl Spec {
 			ethjson::spec::Engine::InstantSeal => Arc::new(InstantSeal::new(params, builtins)),
 			ethjson::spec::Engine::Ethash(ethash) => Arc::new(ethereum::Ethash::new(params, From::from(ethash.params), builtins)),
 			ethjson::spec::Engine::BasicAuthority(basic_authority) => Arc::new(BasicAuthority::new(params, From::from(basic_authority.params), builtins)),
+			ethjson::spec::Engine::AuthorityRound(authority_round) => AuthorityRound::new(params, From::from(authority_round.params), builtins).expect("Failed to start AuthorityRound consensus engine."),
 			ethjson::spec::Engine::Tendermint(tendermint) => Tendermint::new(params, From::from(tendermint.params), builtins).expect("Failed to start the Tendermint consensus engine."),
 		}
 	}
@@ -282,6 +283,10 @@ impl Spec {
 	/// Create a new Spec with InstantSeal consensus which does internal sealing (not requiring work).
 	pub fn new_instant() -> Spec { load_bundled!("instant_seal") }

+	/// Create a new Spec with AuthorityRound consensus which does internal sealing (not requiring work).
+	/// Accounts with secrets "1".sha3() and "2".sha3() are the authorities.
+	pub fn new_test_round() -> Self { load_bundled!("authority_round") }
+
 	/// Create a new Spec with Tendermint consensus which does internal sealing (not requiring work).
 	/// Account "0".sha3() and "1".sha3() are a authorities.
 	pub fn new_test_tendermint() -> Self { load_bundled!("tendermint") }
--- a/ethcore/src/tests/helpers.rs
+++ b/ethcore/src/tests/helpers.rs
@@ -433,18 +433,19 @@ pub fn get_default_ethash_params() -> EthashParams{
 		block_reward: U256::from(0),
 		registrar: "0000000000000000000000000000000000000001".into(),
 		homestead_transition: 1150000,
-		dao_hardfork_transition: 0x7fffffffffffffff,
+		dao_hardfork_transition: u64::max_value(),
 		dao_hardfork_beneficiary: "0000000000000000000000000000000000000001".into(),
 		dao_hardfork_accounts: vec![],
-		difficulty_hardfork_transition: 0x7fffffffffffffff,
+		difficulty_hardfork_transition: u64::max_value(),
 		difficulty_hardfork_bound_divisor: U256::from(0),
-		bomb_defuse_transition: 0x7fffffffffffffff,
-		eip150_transition: 0x7fffffffffffffff,
-		eip155_transition: 0x7fffffffffffffff,
-		eip160_transition: 0x7fffffffffffffff,
-		eip161abc_transition: 0x7fffffffffffffff,
-		eip161d_transition: 0x7fffffffffffffff,
-		ecip1010_pause_transition: 0x7fffffffffffffff,
-		ecip1010_continue_transition: 0x7fffffffffffffff
+		bomb_defuse_transition: u64::max_value(),
+		eip150_transition: u64::max_value(),
+		eip155_transition: u64::max_value(),
+		eip160_transition: u64::max_value(),
+		eip161abc_transition: u64::max_value(),
+		eip161d_transition: u64::max_value(),
+		ecip1010_pause_transition: u64::max_value(),
+		ecip1010_continue_transition: u64::max_value(),
+		max_code_size: u64::max_value(),
 	}
 }