[beta] Backports (#8558)

* Fetching logs by hash in blockchain database (#8463)

* Fetch logs by hash in blockchain database

* Fix tests

* Add unit test for branch block logs fetching

* Add docs that blocks must already be sorted

* Handle branch block cases properly

* typo: empty -> is_empty

* Remove return_empty_if_none by using a closure

* Use BTreeSet to avoid sorting again

* Move is_canon to BlockChain

* typo: pass value by reference

* Use loop and wrap inside blocks to simplify the code

Borrowed from https://github.com/paritytech/parity/pull/8463#discussion_r183453326

* typo: missed a comment

* Pass on storage keys tracing to handle the case when it is not modified (#8491)

* Pass on storage keys even if it is not modified

* typo: account and storage query

`to_pod_diff` builds both `touched_addresses` merge and storage keys merge.

* Fix tests

* Use state query directly because of suicided accounts

* Fix a RefCell borrow issue

* Add tests for unmodified storage trace

* Address grumbles

* typo: remove unwanted empty line

* ensure_cached compiles with the original signature

* Update wasmi and pwasm-utils (#8493)

* Update wasmi to 0.2

New wasmi supports 32bit platforms and no longer requires a special feature to build for such platforms.

* Update pwasm-utils to 0.1.5

* Show imported messages for light client (#8517)

* Enable WebAssembly and Byzantium for Ellaism (#8520)

* Enable WebAssembly and Byzantium for Ellaism

* Fix indentation

* Remove empty lines

* Don't panic in import_block if invalid rlp (#8522)

* Don't panic in import_block if invalid rlp

* Remove redundant type annotation

* Replace RLP header view usage with safe decoding

Using the view will panic with invalid RLP. Here we use Rlp decoding directly which will return a `Result<_, DecoderError>`. While this path currently should not have any invalid RLP - it makes it safer if ever called with invalid RLP from other code paths.

* Node table sorting according to last contact data (#8541)

* network-devp2p: sort nodes in node table using last contact data

* network-devp2p: rename node contact types in node table json output

* network-devp2p: fix node table tests

* network-devp2p: note node failure when failed to establish connection

* network-devp2p: handle UselessPeer error

* network-devp2p: note failure when marking node as useless

Cargo.lock

@@ -1770,6 +1770,11 @@ dependencies = [
  "tiny-keccak 1.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "nan-preserving-float"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "net2"
 version = "0.2.31"
@@ -2586,7 +2591,7 @@ dependencies = [
 
 [[package]]
 name = "pwasm-utils"
-version = "0.1.3"
+version = "0.1.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "byteorder 1.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -3625,18 +3630,19 @@ dependencies = [
  "libc 0.2.36 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
  "parity-wasm 0.27.5 (registry+https://github.com/rust-lang/crates.io-index)",
- "pwasm-utils 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "pwasm-utils 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "vm 0.1.0",
- "wasmi 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "wasmi 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "wasmi"
-version = "0.1.3"
+version = "0.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "byteorder 1.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "memory_units 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "nan-preserving-float 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "parity-wasm 0.27.5 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -3888,6 +3894,7 @@ dependencies = [
 "checksum msdos_time 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)" = "aad9dfe950c057b1bfe9c1f2aa51583a8468ef2a5baba2ebbe06d775efeb7729"
 "checksum multibase 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)" = "b9c35dac080fd6e16a99924c8dfdef0af89d797dd851adab25feaffacf7850d6"
 "checksum multihash 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)" = "7d49add5f49eb08bfc4d01ff286b84a48f53d45314f165c2d6efe477222d24f3"
+"checksum nan-preserving-float 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "34d4f00fcc2f4c9efa8cc971db0da9e28290e28e97af47585e48691ef10ff31f"
 "checksum net2 0.2.31 (registry+https://github.com/rust-lang/crates.io-index)" = "3a80f842784ef6c9a958b68b7516bc7e35883c614004dd94959a4dca1b716c09"
 "checksum nodrop 0.1.12 (registry+https://github.com/rust-lang/crates.io-index)" = "9a2228dca57108069a5262f2ed8bd2e82496d2e074a06d1ccc7ce1687b6ae0a2"
 "checksum ntp 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)" = "143149743832c6543b60a8ef2a26cd9122dfecec2b767158e852a7beecf6d7a0"
@@ -3928,7 +3935,7 @@ dependencies = [
 "checksum proc-macro2 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)" = "388d7ea47318c5ccdeb9ba6312cee7d3f65dd2804be8580a170fce410d50b786"
 "checksum protobuf 1.5.1 (registry+https://github.com/rust-lang/crates.io-index)" = "40e2484e639dcae0985fc483ad76ce7ad78ee5aa092751d7d538f0b20d76486b"
 "checksum pulldown-cmark 0.0.3 (registry+https://github.com/rust-lang/crates.io-index)" = "8361e81576d2e02643b04950e487ec172b687180da65c731c03cf336784e6c07"
-"checksum pwasm-utils 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)" = "54d440c3b56eee028aa5d4f18cbed8c6e0c9ae23563b93f344beb7e73854ea02"
+"checksum pwasm-utils 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)" = "d51e9954a77aab7b4b606dc315a49cbed187924f163b6750cdf6d5677dbf0839"
 "checksum quasi 0.32.0 (registry+https://github.com/rust-lang/crates.io-index)" = "18c45c4854d6d1cf5d531db97c75880feb91c958b0720f4ec1057135fec358b3"
 "checksum quasi_codegen 0.32.0 (registry+https://github.com/rust-lang/crates.io-index)" = "51b9e25fa23c044c1803f43ca59c98dac608976dd04ce799411edd58ece776d4"
 "checksum quasi_macros 0.32.0 (registry+https://github.com/rust-lang/crates.io-index)" = "29cec87bc2816766d7e4168302d505dd06b0a825aed41b00633d296e922e02dd"
@@ -4033,7 +4040,7 @@ dependencies = [
 "checksum vergen 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "8c3365f36c57e5df714a34be40902b27a992eeddb9996eca52d0584611cf885d"
 "checksum version_check 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)" = "6b772017e347561807c1aa192438c5fd74242a670a6cffacc40f2defd1dc069d"
 "checksum void 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)" = "6a02e4885ed3bc0f2de90ea6dd45ebcbb66dacffe03547fadbb0eeae2770887d"
-"checksum wasmi 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)" = "d19da510b59247935ad5f598357b3cc739912666d75d3d28318026478d95bbdb"
+"checksum wasmi 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "46df76793c28cd8f590d5667f540a81c1c245440a17b03560e381226e27cf348"
 "checksum webpki 0.17.0 (registry+https://github.com/rust-lang/crates.io-index)" = "9e1622384bcb5458c6a3e3fa572f53ea8fef1cc85e535a2983dea87e9154fac2"
 "checksum webpki-roots 0.13.0 (registry+https://github.com/rust-lang/crates.io-index)" = "155d4060e5befdf3a6076bd28c22513473d9900b763c9e4521acc6f78a75415c"
 "checksum winapi 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)" = "167dc9d6949a9b857f3451275e911c3f44255842c1f7a76f33c55103a909087a"

ethcore/light/src/client/service.rs

@@ -30,7 +30,7 @@ use kvdb::KeyValueDB;
 use cache::Cache;
 use parking_lot::Mutex;
 
-use super::{ChainDataFetcher, Client, Config as ClientConfig};
+use super::{ChainDataFetcher, LightChainNotify, Client, Config as ClientConfig};
 
 /// Errors on service initialization.
 #[derive(Debug)]
@@ -86,6 +86,11 @@ impl<T: ChainDataFetcher> Service<T> {
 		})
 	}
 
+	/// Set the actor to be notified on certain chain events
+	pub fn add_notify(&self, notify: Arc<LightChainNotify>) {
+		self.client.add_listener(Arc::downgrade(&notify));
+	}
+
 	/// Register an I/O handler on the service.
 	pub fn register_handler(&self, handler: Arc<IoHandler<ClientIoMessage> + Send>) -> Result<(), IoError> {
 		self.io_service.register_handler(handler)

ethcore/res/ethereum/ellaism.json

@@ -13,9 +13,9 @@
         "eip150Transition": "0x0",
         "eip160Transition": "0x0",
         "ecip1017EraRounds": 10000000,
-
         "eip161abcTransition": "0x7fffffffffffffff",
-        "eip161dTransition": "0x7fffffffffffffff"
+        "eip161dTransition": "0x7fffffffffffffff",
+        "eip100bTransition": 2000000
       }
     }
   },
@@ -29,7 +29,12 @@
     "chainID": "0x40",
     "eip155Transition": "0x0",
     "eip98Transition": "0x7fffffffffffff",
-    "eip86Transition": "0x7fffffffffffff"
+    "eip86Transition": "0x7fffffffffffff",
+    "wasmActivationTransition": 2000000,
+    "eip140Transition": 2000000,
+    "eip211Transition": 2000000,
+    "eip214Transition": 2000000,
+    "eip658Transition": 2000000
   },
   "genesis": {
     "seal": {
@@ -60,6 +65,10 @@
     "0000000000000000000000000000000000000001": { "builtin": { "name": "ecrecover", "pricing": { "linear": { "base": 3000, "word": 0 } } } },
     "0000000000000000000000000000000000000002": { "builtin": { "name": "sha256", "pricing": { "linear": { "base": 60, "word": 12 } } } },
     "0000000000000000000000000000000000000003": { "builtin": { "name": "ripemd160", "pricing": { "linear": { "base": 600, "word": 120 } } } },
-    "0000000000000000000000000000000000000004": { "builtin": { "name": "identity", "pricing": { "linear": { "base": 15, "word": 3 } } } }
+    "0000000000000000000000000000000000000004": { "builtin": { "name": "identity", "pricing": { "linear": { "base": 15, "word": 3 } } } },
+    "0000000000000000000000000000000000000005": { "builtin": { "name": "modexp", "activate_at": 2000000, "pricing": { "modexp": { "divisor": 20 } } } },
+    "0000000000000000000000000000000000000006": { "builtin": { "name": "alt_bn128_add", "activate_at": 2000000, "pricing": { "linear": { "base": 500, "word": 0 } } } },
+    "0000000000000000000000000000000000000007": { "builtin": { "name": "alt_bn128_mul", "activate_at": 2000000, "pricing": { "linear": { "base": 40000, "word": 0 } } } },
+    "0000000000000000000000000000000000000008": { "builtin": { "name": "alt_bn128_pairing", "activate_at": 2000000, "pricing": { "alt_bn128_pairing": { "base": 100000, "pair": 80000 } } } }
   }
 }

ethcore/src/blockchain/blockchain.rs

@@ -57,6 +57,12 @@ pub trait BlockProvider {
 	/// (though not necessarily a part of the canon chain).
 	fn is_known(&self, hash: &H256) -> bool;
 
+	/// Returns true if the given block is known and in the canon chain.
+	fn is_canon(&self, hash: &H256) -> bool {
+		let is_canon = || Some(hash == &self.block_hash(self.block_number(hash)?)?);
+		is_canon().unwrap_or(false)
+	}
+
 	/// Get the first block of the best part of the chain.
 	/// Return `None` if there is no gap and the first block is the genesis.
 	/// Any queries of blocks which precede this one are not guaranteed to
@@ -148,7 +154,7 @@ pub trait BlockProvider {
 	fn blocks_with_bloom(&self, bloom: &Bloom, from_block: BlockNumber, to_block: BlockNumber) -> Vec<BlockNumber>;
 
 	/// Returns logs matching given filter.
-	fn logs<F>(&self, blocks: Vec<BlockNumber>, matches: F, limit: Option<usize>) -> Vec<LocalizedLogEntry>
+	fn logs<F>(&self, blocks: Vec<H256>, matches: F, limit: Option<usize>) -> Vec<LocalizedLogEntry>
 		where F: Fn(&LogEntry) -> bool + Send + Sync, Self: Sized;
 }
 
@@ -332,16 +338,18 @@ impl BlockProvider for BlockChain {
 			.collect()
 	}
 
-	fn logs<F>(&self, mut blocks: Vec<BlockNumber>, matches: F, limit: Option<usize>) -> Vec<LocalizedLogEntry>
+	/// Returns logs matching given filter. The order of logs returned will be the same as the order of the blocks
+	/// provided. And it's the callers responsibility to sort blocks provided in advance.
+	fn logs<F>(&self, mut blocks: Vec<H256>, matches: F, limit: Option<usize>) -> Vec<LocalizedLogEntry>
 		where F: Fn(&LogEntry) -> bool + Send + Sync, Self: Sized {
 		// sort in reverse order
-		blocks.sort_by(|a, b| b.cmp(a));
+		blocks.reverse();
 
 		let mut logs = blocks
 			.chunks(128)
 			.flat_map(move |blocks_chunk| {
 				blocks_chunk.into_par_iter()
-					.filter_map(|number| self.block_hash(*number).map(|hash| (*number, hash)))
+					.filter_map(|hash| self.block_number(&hash).map(|r| (r, hash)))
 					.filter_map(|(number, hash)| self.block_receipts(&hash).map(|r| (number, hash, r.receipts)))
 					.filter_map(|(number, hash, receipts)| self.block_body(&hash).map(|ref b| (number, hash, receipts, b.transaction_hashes())))
 					.flat_map(|(number, hash, mut receipts, mut hashes)| {
@@ -368,7 +376,7 @@ impl BlockProvider for BlockChain {
 									.enumerate()
 									.map(move |(i, log)| LocalizedLogEntry {
 										entry: log,
-										block_hash: hash,
+										block_hash: *hash,
 										block_number: number,
 										transaction_hash: tx_hash,
 										// iterating in reverse order
@@ -1933,17 +1941,33 @@ mod tests {
 			value: 103.into(),
 			data: "601080600c6000396000f3006000355415600957005b60203560003555".from_hex().unwrap(),
 		}.sign(&secret(), None);
+		let t4 = Transaction {
+			nonce: 0.into(),
+			gas_price: 0.into(),
+			gas: 100_000.into(),
+			action: Action::Create,
+			value: 104.into(),
+			data: "601080600c6000396000f3006000355415600957005b60203560003555".from_hex().unwrap(),
+		}.sign(&secret(), None);
 		let tx_hash1 = t1.hash();
 		let tx_hash2 = t2.hash();
 		let tx_hash3 = t3.hash();
+		let tx_hash4 = t4.hash();
 
 		let genesis = BlockBuilder::genesis();
 		let b1 = genesis.add_block_with_transactions(vec![t1, t2]);
 		let b2 = b1.add_block_with_transactions(iter::once(t3));
+		let b3 = genesis.add_block_with(|| BlockOptions {
+			transactions: vec![t4.clone()],
+			difficulty: U256::from(9),
+			..Default::default()
+		}); // Branch block
 		let b1_hash = b1.last().hash();
 		let b1_number = b1.last().number();
 		let b2_hash = b2.last().hash();
 		let b2_number = b2.last().number();
+		let b3_hash = b3.last().hash();
+		let b3_number = b3.last().number();
 
 		let db = new_db();
 		let bc = new_chain(&genesis.last().encoded(), db.clone());
@@ -1974,10 +1998,21 @@ mod tests {
 				],
 			}
 		]);
+		insert_block(&db, &bc, &b3.last().encoded(), vec![
+			Receipt {
+				outcome: TransactionOutcome::StateRoot(H256::default()),
+				gas_used: 10_000.into(),
+				log_bloom: Default::default(),
+				logs: vec![
+					LogEntry { address: Default::default(), topics: vec![], data: vec![5], },
+				],
+			}
+		]);
 
 		// when
-		let logs1 = bc.logs(vec![1, 2], |_| true, None);
+		let logs1 = bc.logs(vec![b1_hash, b2_hash], |_| true, None);
-		let logs2 = bc.logs(vec![1, 2], |_| true, Some(1));
+		let logs2 = bc.logs(vec![b1_hash, b2_hash], |_| true, Some(1));
+		let logs3 = bc.logs(vec![b3_hash], |_| true, None);
 
 		// then
 		assert_eq!(logs1, vec![
@@ -2029,6 +2064,17 @@ mod tests {
 				log_index: 0,
 			}
 		]);
+		assert_eq!(logs3, vec![
+			LocalizedLogEntry {
+				entry: LogEntry { address: Default::default(), topics: vec![], data: vec![5] },
+				block_hash: b3_hash,
+				block_number: b3_number,
+				transaction_hash: tx_hash4,
+				transaction_index: 0,
+				transaction_log_index: 0,
+				log_index: 0,
+			}
+		]);
 	}
 
 	#[test]

ethcore/src/client/client.rs

@@ -14,7 +14,7 @@
 // You should have received a copy of the GNU General Public License
 // along with Parity.  If not, see <http://www.gnu.org/licenses/>.
 
-use std::collections::{HashSet, HashMap, BTreeMap, VecDeque};
+use std::collections::{HashSet, HashMap, BTreeMap, BTreeSet, VecDeque};
 use std::str::FromStr;
 use std::sync::{Arc, Weak};
 use std::sync::atomic::{AtomicUsize, AtomicBool, Ordering as AtomicOrdering};
@@ -452,9 +452,7 @@ impl Importer {
 	///
 	/// The block is guaranteed to be the next best blocks in the
 	/// first block sequence. Does no sealing or transaction validation.
-	fn import_old_block(&self, block_bytes: Bytes, receipts_bytes: Bytes, db: &KeyValueDB, chain: &BlockChain) -> Result<H256, ::error::Error> {
+	fn import_old_block(&self, header: &Header, block_bytes: Bytes, receipts_bytes: Bytes, db: &KeyValueDB, chain: &BlockChain) -> Result<H256, ::error::Error> {
-		let block = view!(BlockView, &block_bytes);
-		let header = block.header();
 		let receipts = ::rlp::decode_list(&receipts_bytes);
 		let hash = header.hash();
 		let _import_lock = self.import_lock.lock();
@@ -1413,7 +1411,7 @@ impl ImportBlock for Client {
 		use verification::queue::kind::blocks::Unverified;
 
 		// create unverified block here so the `keccak` calculation can be cached.
-		let unverified = Unverified::new(bytes);
+		let unverified = Unverified::from_rlp(bytes)?;
 
 		{
 			if self.chain.read().is_known(&unverified.hash()) {
@@ -1428,19 +1426,19 @@ impl ImportBlock for Client {
 	}
 
 	fn import_block_with_receipts(&self, block_bytes: Bytes, receipts_bytes: Bytes) -> Result<H256, BlockImportError> {
+		let header: Header = ::rlp::Rlp::new(&block_bytes).val_at(0)?;
 		{
 			// check block order
-			let header = view!(BlockView, &block_bytes).header_view();
 			if self.chain.read().is_known(&header.hash()) {
 				bail!(BlockImportErrorKind::Import(ImportErrorKind::AlreadyInChain));
 			}
-			let status = self.block_status(BlockId::Hash(header.parent_hash()));
+			let status = self.block_status(BlockId::Hash(*header.parent_hash()));
 			if status == BlockStatus::Unknown || status == BlockStatus::Pending {
-				bail!(BlockImportErrorKind::Block(BlockError::UnknownParent(header.parent_hash())));
+				bail!(BlockImportErrorKind::Block(BlockError::UnknownParent(*header.parent_hash())));
 			}
 		}
 
-		self.importer.import_old_block(block_bytes, receipts_bytes, &**self.db.read(), &*self.chain.read()).map_err(Into::into)
+		self.importer.import_old_block(&header, block_bytes, receipts_bytes, &**self.db.read(), &*self.chain.read()).map_err(Into::into)
 	}
 }
 
@@ -1853,23 +1851,82 @@ impl BlockChainClient for Client {
 	}
 
 	fn logs(&self, filter: Filter) -> Vec<LocalizedLogEntry> {
-		let (from, to) = match (self.block_number_ref(&filter.from_block), self.block_number_ref(&filter.to_block)) {
+		// Wrap the logic inside a closure so that we can take advantage of question mark syntax.
-			(Some(from), Some(to)) => (from, to),
+		let fetch_logs = || {
-			_ => return Vec::new(),
+			let chain = self.chain.read();
+
+			// First, check whether `filter.from_block` and `filter.to_block` is on the canon chain. If so, we can use the
+			// optimized version.
+			let is_canon = |id| {
+				match id {
+					// If it is referred by number, then it is always on the canon chain.
+					&BlockId::Earliest | &BlockId::Latest | &BlockId::Number(_) => true,
+					// If it is referred by hash, we see whether a hash -> number -> hash conversion gives us the same
+					// result.
+					&BlockId::Hash(ref hash) => chain.is_canon(hash),
+				}
 			};
 
-		let chain = self.chain.read();
+			let blocks = if is_canon(&filter.from_block) && is_canon(&filter.to_block) {
-		let blocks = filter.bloom_possibilities().iter()
+				// If we are on the canon chain, use bloom filter to fetch required hashes.
-			.map(move |bloom| {
+				let from = self.block_number_ref(&filter.from_block)?;
+				let to = self.block_number_ref(&filter.to_block)?;
+
+				filter.bloom_possibilities().iter()
+					.map(|bloom| {
 						chain.blocks_with_bloom(bloom, from, to)
 					})
 					.flat_map(|m| m)
 					// remove duplicate elements
-			.collect::<HashSet<u64>>()
+					.collect::<BTreeSet<u64>>()
 					.into_iter()
-			.collect::<Vec<u64>>();
+					.filter_map(|n| chain.block_hash(n))
+					.collect::<Vec<H256>>()
 
-		self.chain.read().logs(blocks, |entry| filter.matches(entry), filter.limit)
+			} else {
+				// Otherwise, we use a slower version that finds a link between from_block and to_block.
+				let from_hash = Self::block_hash(&chain, filter.from_block)?;
+				let from_number = chain.block_number(&from_hash)?;
+				let to_hash = Self::block_hash(&chain, filter.from_block)?;
+
+				let blooms = filter.bloom_possibilities();
+				let bloom_match = |header: &encoded::Header| {
+					blooms.iter().any(|bloom| header.log_bloom().contains_bloom(bloom))
+				};
+
+				let (blocks, last_hash) = {
+					let mut blocks = Vec::new();
+					let mut current_hash = to_hash;
+
+					loop {
+						let header = chain.block_header_data(&current_hash)?;
+						if bloom_match(&header) {
+							blocks.push(current_hash);
+						}
+
+						// Stop if `from` block is reached.
+						if header.number() <= from_number {
+							break;
+						}
+						current_hash = header.parent_hash();
+					}
+
+					blocks.reverse();
+					(blocks, current_hash)
+				};
+
+				// Check if we've actually reached the expected `from` block.
+				if last_hash != from_hash || blocks.is_empty() {
+					return None;
+				}
+
+				blocks
+			};
+
+			Some(self.chain.read().logs(blocks, |entry| filter.matches(entry), filter.limit))
+		};
+
+		fetch_logs().unwrap_or_default()
 	}
 
 	fn filter_traces(&self, filter: TraceFilter) -> Option<Vec<LocalizedTrace>> {

ethcore/src/error.rs

@@ -190,6 +190,7 @@ error_chain! {
 
 	foreign_links {
 		Block(BlockError) #[doc = "Block error"];
+		Decoder(::rlp::DecoderError) #[doc = "Rlp decoding error"];
 	}
 
 	errors {
@@ -206,6 +207,7 @@ impl From<Error> for BlockImportError {
 		match e {
 			Error(ErrorKind::Block(block_error), _) => BlockImportErrorKind::Block(block_error).into(),
 			Error(ErrorKind::Import(import_error), _) => BlockImportErrorKind::Import(import_error.into()).into(),
+			Error(ErrorKind::Util(util_error::ErrorKind::Decoder(decoder_err)), _) => BlockImportErrorKind::Decoder(decoder_err).into(),
 			_ => BlockImportErrorKind::Other(format!("other block import error: {:?}", e)).into(),
 		}
 	}

ethcore/src/state/mod.rs

@@ -21,7 +21,7 @@
 
 use std::cell::{RefCell, RefMut};
 use std::collections::hash_map::Entry;
-use std::collections::{HashMap, BTreeMap, HashSet};
+use std::collections::{HashMap, BTreeMap, BTreeSet, HashSet};
 use std::fmt;
 use std::sync::Arc;
 use hash::{KECCAK_NULL_RLP, KECCAK_EMPTY};
@@ -862,40 +862,65 @@ impl<B: Backend> State<B> {
 		}))
 	}
 
-	// Return a list of all touched addresses in cache.
+	/// Populate a PodAccount map from this state, with another state as the account and storage query.
-	fn touched_addresses(&self) -> Vec<Address> {
+	pub fn to_pod_diff<X: Backend>(&mut self, query: &State<X>) -> trie::Result<PodState> {
 		assert!(self.checkpoints.borrow().is_empty());
-		self.cache.borrow().iter().map(|(add, _)| *add).collect()
+
+		// Merge PodAccount::to_pod for cache of self and `query`.
+		let all_addresses = self.cache.borrow().keys().cloned()
+			.chain(query.cache.borrow().keys().cloned())
+			.collect::<BTreeSet<_>>();
+
+		Ok(PodState::from(all_addresses.into_iter().fold(Ok(BTreeMap::new()), |m: trie::Result<_>, address| {
+			let mut m = m?;
+
+			let account = self.ensure_cached(&address, RequireCache::Code, true, |acc| {
+				acc.map(|acc| {
+					// Merge all modified storage keys.
+					let all_keys = {
+						let self_keys = acc.storage_changes().keys().cloned()
+							.collect::<BTreeSet<_>>();
+
+						if let Some(ref query_storage) = query.cache.borrow().get(&address)
+							.and_then(|opt| {
+								Some(opt.account.as_ref()?.storage_changes().keys().cloned()
+									 .collect::<BTreeSet<_>>())
+							})
+						{
+							self_keys.union(&query_storage).cloned().collect::<Vec<_>>()
+						} else {
+							self_keys.into_iter().collect::<Vec<_>>()
+						}
+					};
+
+					// Storage must be fetched after ensure_cached to avoid borrow problem.
+					(*acc.balance(), *acc.nonce(), all_keys, acc.code().map(|x| x.to_vec()))
+				})
+			})?;
+
+			if let Some((balance, nonce, storage_keys, code)) = account {
+				let storage = storage_keys.into_iter().fold(Ok(BTreeMap::new()), |s: trie::Result<_>, key| {
+					let mut s = s?;
+
+					s.insert(key, self.storage_at(&address, &key)?);
+					Ok(s)
+				})?;
+
+				m.insert(address, PodAccount {
+					balance, nonce, storage, code
+				});
 			}
 
-	fn query_pod(&mut self, query: &PodState, touched_addresses: &[Address]) -> trie::Result<()> {
+			Ok(m)
-		let pod = query.get();
+		})?))
-
-		for address in touched_addresses {
-			if !self.ensure_cached(address, RequireCache::Code, true, |a| a.is_some())? {
-				continue
-			}
-
-			if let Some(pod_account) = pod.get(address) {
-				// needs to be split into two parts for the refcell code here
-				// to work.
-				for key in pod_account.storage.keys() {
-					self.storage_at(address, key)?;
-				}
-			}
-		}
-
-		Ok(())
 	}
 
 	/// Returns a `StateDiff` describing the difference from `orig` to `self`.
 	/// Consumes self.
-	pub fn diff_from<X: Backend>(&self, orig: State<X>) -> trie::Result<StateDiff> {
+	pub fn diff_from<X: Backend>(&self, mut orig: State<X>) -> trie::Result<StateDiff> {
-		let addresses_post = self.touched_addresses();
 		let pod_state_post = self.to_pod();
-		let mut state_pre = orig;
+		let pod_state_pre = orig.to_pod_diff(self)?;
-		state_pre.query_pod(&pod_state_post, &addresses_post)?;
+		Ok(pod_state::diff_pod(&pod_state_pre, &pod_state_post))
-		Ok(pod_state::diff_pod(&state_pre.to_pod(), &pod_state_post))
 	}
 
 	// load required account data from the databases.
@@ -2243,9 +2268,6 @@ mod tests {
 		let original = state.clone();
 		state.kill_account(&a);
 
-		assert_eq!(original.touched_addresses(), vec![]);
-		assert_eq!(state.touched_addresses(), vec![a]);
-
 		let diff = state.diff_from(original).unwrap();
 		let diff_map = diff.get();
 		assert_eq!(diff_map.len(), 1);
@@ -2258,4 +2280,42 @@ mod tests {
 					   storage: Default::default()
 				   }), None).as_ref());
 	}
+
+	#[test]
+	fn should_trace_diff_unmodified_storage() {
+		use pod_account;
+
+		let a = 10.into();
+		let db = get_temp_state_db();
+
+		let (root, db) = {
+			let mut state = State::new(db, U256::from(0), Default::default());
+			state.set_storage(&a, H256::from(&U256::from(1u64)), H256::from(&U256::from(20u64))).unwrap();
+			state.commit().unwrap();
+			state.drop()
+		};
+
+		let mut state = State::from_existing(db, root, U256::from(0u8), Default::default()).unwrap();
+		let original = state.clone();
+		state.set_storage(&a, H256::from(&U256::from(1u64)), H256::from(&U256::from(100u64))).unwrap();
+
+		let diff = state.diff_from(original).unwrap();
+		let diff_map = diff.get();
+		assert_eq!(diff_map.len(), 1);
+		assert!(diff_map.get(&a).is_some());
+		assert_eq!(diff_map.get(&a),
+				   pod_account::diff_pod(Some(&PodAccount {
+					   balance: U256::zero(),
+					   nonce: U256::zero(),
+					   code: Some(Default::default()),
+					   storage: vec![(H256::from(&U256::from(1u64)), H256::from(&U256::from(20u64)))]
+						   .into_iter().collect(),
+				   }), Some(&PodAccount {
+					   balance: U256::zero(),
+					   nonce: U256::zero(),
+					   code: Some(Default::default()),
+					   storage: vec![(H256::from(&U256::from(1u64)), H256::from(&U256::from(100u64)))]
+						   .into_iter().collect(),
+				   })).as_ref());
+	}
 }

ethcore/src/tests/client.rs

@@ -36,6 +36,7 @@ use views::BlockView;
 use ethkey::KeyPair;
 use transaction::{PendingTransaction, Transaction, Action, Condition};
 use miner::MinerService;
+use rlp::{RlpStream, EMPTY_LIST_RLP};
 use tempdir::TempDir;
 
 #[test]
@@ -111,6 +112,25 @@ fn imports_good_block() {
 	assert!(!block.into_inner().is_empty());
 }
 
+#[test]
+fn fails_to_import_block_with_invalid_rlp() {
+	use error::{BlockImportError, BlockImportErrorKind};
+
+	let client = generate_dummy_client(6);
+	let mut rlp = RlpStream::new_list(3);
+	rlp.append_raw(&EMPTY_LIST_RLP, 1); // empty header
+	rlp.append_raw(&EMPTY_LIST_RLP, 1);
+	rlp.append_raw(&EMPTY_LIST_RLP, 1);
+	let invalid_header_block = rlp.out();
+
+	match client.import_block(invalid_header_block) {
+		Err(BlockImportError(BlockImportErrorKind::Decoder(_), _)) => (), // all good
+		Err(_) => panic!("Should fail with a decoder error"),
+		Ok(_) => panic!("Should not import block with invalid header"),
+	}
+}
+
+
 #[test]
 fn query_none_block() {
 	let tempdir = TempDir::new("").unwrap();

ethcore/src/verification/queue/kind.rs

@@ -119,14 +119,13 @@ pub mod blocks {
 
 	impl Unverified {
 		/// Create an `Unverified` from raw bytes.
-		pub fn new(bytes: Bytes) -> Self {
+		pub fn from_rlp(bytes: Bytes) -> Result<Self, ::rlp::DecoderError> {
-			use views::BlockView;
 
-			let header = view!(BlockView, &bytes).header();
+			let header = ::rlp::Rlp::new(&bytes).val_at(0)?; 
-			Unverified {
+			Ok(Unverified {
 				header: header,
 				bytes: bytes,
-			}
+			})
 		}
 	}
 

ethcore/src/verification/queue/mod.rs

@@ -734,6 +734,7 @@ mod tests {
 	use test_helpers::{get_good_dummy_block_seq, get_good_dummy_block};
 	use error::*;
 	use views::BlockView;
+	use bytes::Bytes;
 
 	// create a test block queue.
 	// auto_scaling enables verifier adjustment.
@@ -746,6 +747,10 @@ mod tests {
 		BlockQueue::new(config, engine, IoChannel::disconnected(), true)
 	}
 
+	fn new_unverified(bytes: Bytes) -> Unverified {
+		Unverified::from_rlp(bytes).expect("Should be valid rlp")
+	}
+
 	#[test]
 	fn can_be_created() {
 		// TODO better test
@@ -757,7 +762,7 @@ mod tests {
 	#[test]
 	fn can_import_blocks() {
 		let queue = get_test_queue(false);
-		if let Err(e) = queue.import(Unverified::new(get_good_dummy_block())) {
+		if let Err(e) = queue.import(new_unverified(get_good_dummy_block())) {
 			panic!("error importing block that is valid by definition({:?})", e);
 		}
 	}
@@ -765,11 +770,11 @@ mod tests {
 	#[test]
 	fn returns_error_for_duplicates() {
 		let queue = get_test_queue(false);
-		if let Err(e) = queue.import(Unverified::new(get_good_dummy_block())) {
+		if let Err(e) = queue.import(new_unverified(get_good_dummy_block())) {
 			panic!("error importing block that is valid by definition({:?})", e);
 		}
 
-		let duplicate_import = queue.import(Unverified::new(get_good_dummy_block()));
+		let duplicate_import = queue.import(new_unverified(get_good_dummy_block()));
 		match duplicate_import {
 			Err(e) => {
 				match e {
@@ -786,7 +791,7 @@ mod tests {
 		let queue = get_test_queue(false);
 		let block = get_good_dummy_block();
 		let hash = view!(BlockView, &block).header().hash().clone();
-		if let Err(e) = queue.import(Unverified::new(block)) {
+		if let Err(e) = queue.import(new_unverified(block)) {
 			panic!("error importing block that is valid by definition({:?})", e);
 		}
 		queue.flush();
@@ -802,14 +807,14 @@ mod tests {
 		let queue = get_test_queue(false);
 		let block = get_good_dummy_block();
 		let hash = view!(BlockView, &block).header().hash().clone();
-		if let Err(e) = queue.import(Unverified::new(block)) {
+		if let Err(e) = queue.import(new_unverified(block)) {
 			panic!("error importing block that is valid by definition({:?})", e);
 		}
 		queue.flush();
 		queue.drain(10);
 		queue.mark_as_good(&[ hash ]);
 
-		if let Err(e) = queue.import(Unverified::new(get_good_dummy_block())) {
+		if let Err(e) = queue.import(new_unverified(get_good_dummy_block())) {
 			panic!("error importing block that has already been drained ({:?})", e);
 		}
 	}
@@ -817,7 +822,7 @@ mod tests {
 	#[test]
 	fn returns_empty_once_finished() {
 		let queue = get_test_queue(false);
-		queue.import(Unverified::new(get_good_dummy_block()))
+		queue.import(new_unverified(get_good_dummy_block()))
 			.expect("error importing block that is valid by definition");
 		queue.flush();
 		queue.drain(1);
@@ -835,7 +840,7 @@ mod tests {
 		assert!(!queue.queue_info().is_full());
 		let mut blocks = get_good_dummy_block_seq(50);
 		for b in blocks.drain(..) {
-			queue.import(Unverified::new(b)).unwrap();
+			queue.import(new_unverified(b)).unwrap();
 		}
 		assert!(queue.queue_info().is_full());
 	}
@@ -863,7 +868,7 @@ mod tests {
 		*queue.state.0.lock() = State::Work(0);
 
 		for block in get_good_dummy_block_seq(5000) {
-			queue.import(Unverified::new(block)).expect("Block good by definition; qed");
+			queue.import(new_unverified(block)).expect("Block good by definition; qed");
 		}
 
 		// almost all unverified == bump verifier count.

ethcore/src/verification/verification.rs

@@ -476,7 +476,7 @@ mod tests {
 			unimplemented!()
 		}
 
-		fn logs<F>(&self, _blocks: Vec<BlockNumber>, _matches: F, _limit: Option<usize>) -> Vec<LocalizedLogEntry>
+		fn logs<F>(&self, _blocks: Vec<H256>, _matches: F, _limit: Option<usize>) -> Vec<LocalizedLogEntry>
 			where F: Fn(&LogEntry) -> bool, Self: Sized {
 			unimplemented!()
 		}

ethcore/wasm/Cargo.toml

@@ -12,4 +12,4 @@ libc = "0.2"
 pwasm-utils = "0.1"
 vm = { path = "../vm" }
 ethcore-logger = { path = "../../logger" }
-wasmi = { version = "0.1.3", features = ["opt-in-32bit"] }
+wasmi = { version = "0.2" }

parity/informant.rs

@@ -33,7 +33,7 @@ use ethcore::snapshot::service::Service as SnapshotService;
 use sync::{LightSyncProvider, LightSync, SyncProvider, ManageNetwork};
 use io::{TimerToken, IoContext, IoHandler};
 use light::Cache as LightDataCache;
-use light::client::LightChainClient;
+use light::client::{LightChainClient, LightChainNotify};
 use number_prefix::{binary_prefix, Standalone, Prefixed};
 use parity_rpc::{is_major_importing};
 use parity_rpc::informant::RpcStats;
@@ -395,6 +395,33 @@ impl ChainNotify for Informant<FullNodeInformantData> {
 	}
 }
 
+impl LightChainNotify for Informant<LightNodeInformantData> {
+	fn new_headers(&self, good: &[H256]) {
+		let mut last_import = self.last_import.lock();
+		let client = &self.target.client;
+
+		let importing = self.target.is_major_importing();
+		let ripe = Instant::now() > *last_import + Duration::from_secs(1) && !importing;
+
+		if ripe {
+			if let Some(header) = good.last().and_then(|h| client.block_header(BlockId::Hash(*h))) {
+				info!(target: "import", "Imported {} {} ({} Mgas){}",
+					  Colour::White.bold().paint(format!("#{}", header.number())),
+					  Colour::White.bold().paint(format!("{}", header.hash())),
+					  Colour::Yellow.bold().paint(format!("{:.2}", header.gas_used().low_u64() as f32  / 1000000f32)),
+					  if good.len() > 1 {
+						  format!(" + another {} header(s)",
+								  Colour::Red.bold().paint(format!("{}", good.len() - 1)))
+					  } else {
+						  String::new()
+					  }
+				);
+				*last_import = Instant::now();
+			}
+		}
+	}
+}
+
 const INFO_TIMER: TimerToken = 0;
 
 impl<T: InformantData> IoHandler<ClientIoMessage> for Informant<T> {

parity/run.rs

@@ -412,7 +412,7 @@ fn execute_light_impl(cmd: RunCmd, logger: Arc<RotatingLogger>) -> Result<Runnin
 		Some(rpc_stats),
 		cmd.logger_config.color,
 	));
-
+	service.add_notify(informant.clone());
 	service.register_handler(informant.clone()).map_err(|_| "Unable to register informant handler".to_owned())?;
 
 	Ok(RunningClient::Light {

util/network-devp2p/src/host.rs

@@ -105,10 +105,13 @@ pub struct NetworkContext<'s> {
 
 impl<'s> NetworkContext<'s> {
 	/// 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 IoContext<NetworkIoMessage>,
+	fn new(
+		io: &'s IoContext<NetworkIoMessage>,
 		protocol: ProtocolId,
-		session: Option<SharedSession>, sessions: Arc<RwLock<Slab<SharedSession>>>,
+		session: Option<SharedSession>,
-		reserved_peers: &'s HashSet<NodeId>) -> NetworkContext<'s> {
+		sessions: Arc<RwLock<Slab<SharedSession>>>,
+		reserved_peers: &'s HashSet<NodeId>,
+	) -> NetworkContext<'s> {
 		let id = session.as_ref().map(|s| s.lock().token());
 		NetworkContext {
 			io: io,
@@ -585,10 +588,8 @@ impl Host {
 			let address = {
 				let mut nodes = self.nodes.write();
 				if let Some(node) = nodes.get_mut(id) {
-					node.attempts += 1;
 					node.endpoint.address
-				}
+				} else {
-				else {
 					debug!(target: "network", "Connection to expired node aborted");
 					return;
 				}
@@ -600,6 +601,7 @@ impl Host {
 				},
 				Err(e) => {
 					debug!(target: "network", "{}: Can't connect to address {:?}: {:?}", id, address, e);
+					self.nodes.write().note_failure(&id);
 					return;
 				}
 			}
@@ -685,10 +687,12 @@ impl Host {
 						Err(e) => {
 							let s = session.lock();
 							trace!(target: "network", "Session read error: {}:{:?} ({:?}) {:?}", token, s.id(), s.remote_addr(), e);
-							if let ErrorKind::Disconnect(DisconnectReason::IncompatibleProtocol) = *e.kind() {
+							if let ErrorKind::Disconnect(DisconnectReason::UselessPeer) = *e.kind() {
 								if let Some(id) = s.id() {
 									if !self.reserved_nodes.read().contains(id) {
-										self.nodes.write().mark_as_useless(id);
+										let mut nodes = self.nodes.write();
+										nodes.note_failure(&id);
+										nodes.mark_as_useless(id);
 									}
 								}
 							}
@@ -754,6 +758,10 @@ impl Host {
 									}
 								}
 							}
+
+							// Note connection success
+							self.nodes.write().note_success(&id);
+
 							for (p, _) in self.handlers.read().iter() {
 								if s.have_capability(*p) {
 									ready_data.push(*p);
@@ -1024,7 +1032,9 @@ impl IoHandler<NetworkIoMessage> for Host {
 				if let Some(session) = session {
 					session.lock().disconnect(io, DisconnectReason::DisconnectRequested);
 					if let Some(id) = session.lock().id() {
-						self.nodes.write().mark_as_useless(id)
+						let mut nodes = self.nodes.write();
+						nodes.note_failure(&id);
+						nodes.mark_as_useless(id);
 					}
 				}
 				trace!(target: "network", "Disabling peer {}", peer);

util/network-devp2p/src/node_table.rs

@@ -21,6 +21,8 @@ use std::net::{SocketAddr, ToSocketAddrs, SocketAddrV4, SocketAddrV6, Ipv4Addr,
 use std::path::PathBuf;
 use std::str::FromStr;
 use std::{fs, mem, slice};
+use std::time::{self, Duration, SystemTime};
+use rand::{self, Rng};
 use ethereum_types::H512;
 use rlp::{Rlp, RlpStream, DecoderError};
 use network::{Error, ErrorKind, AllowIP, IpFilter};
@@ -128,40 +130,64 @@ impl FromStr for NodeEndpoint {
 	}
 }
 
-#[derive(PartialEq, Eq, Copy, Clone)]
+#[derive(Debug, PartialEq, Eq, Copy, Clone)]
 pub enum PeerType {
 	_Required,
 	Optional
 }
 
+/// A type for representing an interaction (contact) with a node at a given time
+/// that was either a success or a failure.
+#[derive(Clone, Copy, Debug)]
+pub enum NodeContact {
+	Success(SystemTime),
+	Failure(SystemTime),
+}
+
+impl NodeContact {
+	fn success() -> NodeContact {
+		NodeContact::Success(SystemTime::now())
+	}
+
+	fn failure() -> NodeContact {
+		NodeContact::Failure(SystemTime::now())
+	}
+
+	fn time(&self) -> SystemTime {
+		match *self {
+			NodeContact::Success(t) | NodeContact::Failure(t) => t
+		}
+	}
+
+	/// Filters and old contact, returning `None` if it happened longer than a
+	/// week ago.
+	fn recent(&self) -> Option<&NodeContact> {
+		let t = self.time();
+		if let Ok(d) = t.elapsed() {
+			if d < Duration::from_secs(60 * 60 * 24 * 7) {
+				return Some(self);
+			}
+		}
+
+		None
+	}
+}
+
+#[derive(Debug)]
 pub struct Node {
 	pub id: NodeId,
 	pub endpoint: NodeEndpoint,
 	pub peer_type: PeerType,
-	pub attempts: u32,
+	pub last_contact: Option<NodeContact>,
-	pub failures: u32,
 }
 
-const DEFAULT_FAILURE_PERCENTAGE: usize = 50;
-
 impl Node {
 	pub fn new(id: NodeId, endpoint: NodeEndpoint) -> Node {
 		Node {
 			id: id,
 			endpoint: endpoint,
 			peer_type: PeerType::Optional,
-			attempts: 0,
+			last_contact: None,
-			failures: 0,
-		}
-	}
-
-	/// Returns the node's failure percentage (0..100) in buckets of 5%. If there are 0 connection attempts for this
-	/// node the default failure percentage is returned (50%).
-	pub fn failure_percentage(&self) -> usize {
-		if self.attempts == 0 {
-			DEFAULT_FAILURE_PERCENTAGE
-		} else {
-			(self.failures * 100 / self.attempts / 5 * 5) as usize
 		}
 	}
 }
@@ -191,8 +217,7 @@ impl FromStr for Node {
 			id: id,
 			endpoint: endpoint,
 			peer_type: PeerType::Optional,
-			attempts: 0,
+			last_contact: None,
-			failures: 0,
 		})
 	}
 }
@@ -231,28 +256,61 @@ impl NodeTable {
 
 	/// Add a node to table
 	pub fn add_node(&mut self, mut node: Node) {
-		// preserve attempts and failure counter
+		// preserve node last_contact
-		let (attempts, failures) =
+		node.last_contact = self.nodes.get(&node.id).and_then(|n| n.last_contact);
-			self.nodes.get(&node.id).map_or((0, 0), |n| (n.attempts, n.failures));
-
-		node.attempts = attempts;
-		node.failures = failures;
-
 		self.nodes.insert(node.id.clone(), node);
 	}
 
+	/// Returns a list of ordered nodes according to their most recent contact
+	/// and filtering useless nodes. The algorithm for creating the sorted nodes
+	/// is:
+	/// - Contacts that aren't recent (older than 1 week) are discarded
+	/// - (1) Nodes with a successful contact are ordered (most recent success first)
+	/// - (2) Nodes with unknown contact (older than 1 week or new nodes) are randomly shuffled
+	/// - (3) Nodes with a failed contact are ordered (oldest failure first)
+	/// - The final result is the concatenation of (1), (2) and (3)
 	fn ordered_entries(&self) -> Vec<&Node> {
-		let mut refs: Vec<&Node> = self.nodes.values()
+		let mut success = Vec::new();
-			.filter(|n| !self.useless_nodes.contains(&n.id))
+		let mut failures = Vec::new();
-			.collect();
+		let mut unknown = Vec::new();
 
-		refs.sort_by(|a, b| {
+		let nodes = self.nodes.values()
-			a.failure_percentage().cmp(&b.failure_percentage())
+			.filter(|n| !self.useless_nodes.contains(&n.id));
-				.then_with(|| a.failures.cmp(&b.failures))
+
-				.then_with(|| b.attempts.cmp(&a.attempts)) // we use reverse ordering for number of attempts
+		for node in nodes {
+			// discard contact points older that aren't recent
+			match node.last_contact.as_ref().and_then(|c| c.recent()) {
+				Some(&NodeContact::Success(_)) => {
+					success.push(node);
+				},
+				Some(&NodeContact::Failure(_)) => {
+					failures.push(node);
+				},
+				None => {
+					unknown.push(node);
+				},
+			}
+		}
+
+		success.sort_by(|a, b| {
+			let a = a.last_contact.expect("vector only contains values with defined last_contact; qed");
+			let b = b.last_contact.expect("vector only contains values with defined last_contact; qed");
+			// inverse ordering, most recent successes come first
+			b.time().cmp(&a.time())
 		});
 
-		refs
+		failures.sort_by(|a, b| {
+			let a = a.last_contact.expect("vector only contains values with defined last_contact; qed");
+			let b = b.last_contact.expect("vector only contains values with defined last_contact; qed");
+			// normal ordering, most distant failures come first
+			a.time().cmp(&b.time())
+		});
+
+		rand::thread_rng().shuffle(&mut unknown);
+
+		success.append(&mut unknown);
+		success.append(&mut failures);
+		success
 	}
 
 	/// Returns node ids sorted by failure percentage, for nodes with the same failure percentage the absolute number of
@@ -296,10 +354,17 @@ impl NodeTable {
 		}
 	}
 
-	/// Increase failure counte for a node
+	/// Set last contact as failure for a node
 	pub fn note_failure(&mut self, id: &NodeId) {
 		if let Some(node) = self.nodes.get_mut(id) {
-			node.failures += 1;
+			node.last_contact = Some(NodeContact::failure());
+		}
+	}
+
+	/// Set last contact as success for a node
+	pub fn note_success(&mut self, id: &NodeId) {
+		if let Some(node) = self.nodes.get_mut(id) {
+			node.last_contact = Some(NodeContact::success());
 		}
 	}
 
@@ -396,19 +461,38 @@ mod json {
 		pub nodes: Vec<Node>,
 	}
 
+	#[derive(Serialize, Deserialize)]
+	pub enum NodeContact {
+		#[serde(rename = "success")]
+		Success(u64),
+		#[serde(rename = "failure")]
+		Failure(u64),
+	}
+
+	impl NodeContact {
+		pub fn into_node_contact(self) -> super::NodeContact {
+			match self {
+				NodeContact::Success(s) => super::NodeContact::Success(
+					time::UNIX_EPOCH + Duration::from_secs(s)
+				),
+				NodeContact::Failure(s) => super::NodeContact::Failure(
+					time::UNIX_EPOCH + Duration::from_secs(s)
+				),
+			}
+		}
+	}
+
 	#[derive(Serialize, Deserialize)]
 	pub struct Node {
 		pub url: String,
-		pub attempts: u32,
+		pub last_contact: Option<NodeContact>,
-		pub failures: u32,
 	}
 
 	impl Node {
 		pub fn into_node(self) -> Option<super::Node> {
 			match super::Node::from_str(&self.url) {
 				Ok(mut node) => {
-					node.attempts = self.attempts;
+					node.last_contact = self.last_contact.map(|c| c.into_node_contact());
-					node.failures = self.failures;
 					Some(node)
 				},
 				_ => None,
@@ -418,10 +502,18 @@ mod json {
 
 	impl<'a> From<&'a super::Node> for Node {
 		fn from(node: &'a super::Node) -> Self {
+			let last_contact = node.last_contact.and_then(|c| {
+				match c {
+					super::NodeContact::Success(t) =>
+						t.duration_since(time::UNIX_EPOCH).ok().map(|d| NodeContact::Success(d.as_secs())),
+					super::NodeContact::Failure(t) =>
+						t.duration_since(time::UNIX_EPOCH).ok().map(|d| NodeContact::Failure(d.as_secs())),
+				}
+			});
+
 			Node {
 				url: format!("{}", node),
-				attempts: node.attempts,
+				last_contact
-				failures: node.failures,
 			}
 		}
 	}
@@ -464,42 +556,54 @@ mod tests {
 	}
 
 	#[test]
-	fn table_failure_percentage_order() {
+	fn table_last_contact_order() {
 		let node1 = Node::from_str("enode://a979fb575495b8d6db44f750317d0f4622bf4c2aa3365d6af7c284339968eef29b69ad0dce72a4d8db5ebb4968de0e3bec910127f134779fbcb0cb6d3331163c@22.99.55.44:7770").unwrap();
 		let node2 = Node::from_str("enode://b979fb575495b8d6db44f750317d0f4622bf4c2aa3365d6af7c284339968eef29b69ad0dce72a4d8db5ebb4968de0e3bec910127f134779fbcb0cb6d3331163c@22.99.55.44:7770").unwrap();
 		let node3 = Node::from_str("enode://c979fb575495b8d6db44f750317d0f4622bf4c2aa3365d6af7c284339968eef29b69ad0dce72a4d8db5ebb4968de0e3bec910127f134779fbcb0cb6d3331163c@22.99.55.44:7770").unwrap();
 		let node4 = Node::from_str("enode://d979fb575495b8d6db44f750317d0f4622bf4c2aa3365d6af7c284339968eef29b69ad0dce72a4d8db5ebb4968de0e3bec910127f134779fbcb0cb6d3331163c@22.99.55.44:7770").unwrap();
+		let node5 = Node::from_str("enode://e979fb575495b8d6db44f750317d0f4622bf4c2aa3365d6af7c284339968eef29b69ad0dce72a4d8db5ebb4968de0e3bec910127f134779fbcb0cb6d3331163c@22.99.55.44:7770").unwrap();
+		let node6 = Node::from_str("enode://f979fb575495b8d6db44f750317d0f4622bf4c2aa3365d6af7c284339968eef29b69ad0dce72a4d8db5ebb4968de0e3bec910127f134779fbcb0cb6d3331163c@22.99.55.44:7770").unwrap();
 		let id1 = H512::from_str("a979fb575495b8d6db44f750317d0f4622bf4c2aa3365d6af7c284339968eef29b69ad0dce72a4d8db5ebb4968de0e3bec910127f134779fbcb0cb6d3331163c").unwrap();
 		let id2 = H512::from_str("b979fb575495b8d6db44f750317d0f4622bf4c2aa3365d6af7c284339968eef29b69ad0dce72a4d8db5ebb4968de0e3bec910127f134779fbcb0cb6d3331163c").unwrap();
 		let id3 = H512::from_str("c979fb575495b8d6db44f750317d0f4622bf4c2aa3365d6af7c284339968eef29b69ad0dce72a4d8db5ebb4968de0e3bec910127f134779fbcb0cb6d3331163c").unwrap();
 		let id4 = H512::from_str("d979fb575495b8d6db44f750317d0f4622bf4c2aa3365d6af7c284339968eef29b69ad0dce72a4d8db5ebb4968de0e3bec910127f134779fbcb0cb6d3331163c").unwrap();
+		let id5 = H512::from_str("e979fb575495b8d6db44f750317d0f4622bf4c2aa3365d6af7c284339968eef29b69ad0dce72a4d8db5ebb4968de0e3bec910127f134779fbcb0cb6d3331163c").unwrap();
+		let id6 = H512::from_str("f979fb575495b8d6db44f750317d0f4622bf4c2aa3365d6af7c284339968eef29b69ad0dce72a4d8db5ebb4968de0e3bec910127f134779fbcb0cb6d3331163c").unwrap();
 		let mut table = NodeTable::new(None);
 
 		table.add_node(node1);
 		table.add_node(node2);
 		table.add_node(node3);
 		table.add_node(node4);
+		table.add_node(node5);
+		table.add_node(node6);
 
-		// node 1 - failure percentage 100%
+		// failures - nodes 1 & 2
-		table.get_mut(&id1).unwrap().attempts = 2;
 		table.note_failure(&id1);
-		table.note_failure(&id1);
-
-		// node2 - failure percentage 33%
-		table.get_mut(&id2).unwrap().attempts = 3;
 		table.note_failure(&id2);
 
-		// node3 - failure percentage 0%
+		// success - nodes 3 & 4
-		table.get_mut(&id3).unwrap().attempts = 1;
+		table.note_success(&id3);
+		table.note_success(&id4);
 
-		// node4 - failure percentage 50% (default when no attempts)
+		// success - node 5 (old contact)
+		table.get_mut(&id5).unwrap().last_contact = Some(NodeContact::Success(time::UNIX_EPOCH));
+
+		// unknown - node 6
 
 		let r = table.nodes(IpFilter::default());
 
-		assert_eq!(r[0][..], id3[..]);
+		assert_eq!(r[0][..], id4[..]); // most recent success
-		assert_eq!(r[1][..], id2[..]);
+		assert_eq!(r[1][..], id3[..]);
-		assert_eq!(r[2][..], id4[..]);
+
-		assert_eq!(r[3][..], id1[..]);
+		// unknown (old contacts and new nodes), randomly shuffled
+		assert!(
+			r[2][..] == id5[..] && r[3][..] == id6[..] ||
+			r[2][..] == id6[..] && r[3][..] == id5[..]
+		);
+
+		assert_eq!(r[4][..], id1[..]); // oldest failure
+		assert_eq!(r[5][..], id2[..]);
 	}
 
 	#[test]
@@ -507,23 +611,27 @@ mod tests {
 		let tempdir = TempDir::new("").unwrap();
 		let node1 = Node::from_str("enode://a979fb575495b8d6db44f750317d0f4622bf4c2aa3365d6af7c284339968eef29b69ad0dce72a4d8db5ebb4968de0e3bec910127f134779fbcb0cb6d3331163c@22.99.55.44:7770").unwrap();
 		let node2 = Node::from_str("enode://b979fb575495b8d6db44f750317d0f4622bf4c2aa3365d6af7c284339968eef29b69ad0dce72a4d8db5ebb4968de0e3bec910127f134779fbcb0cb6d3331163c@22.99.55.44:7770").unwrap();
+		let node3 = Node::from_str("enode://c979fb575495b8d6db44f750317d0f4622bf4c2aa3365d6af7c284339968eef29b69ad0dce72a4d8db5ebb4968de0e3bec910127f134779fbcb0cb6d3331163c@22.99.55.44:7770").unwrap();
 		let id1 = H512::from_str("a979fb575495b8d6db44f750317d0f4622bf4c2aa3365d6af7c284339968eef29b69ad0dce72a4d8db5ebb4968de0e3bec910127f134779fbcb0cb6d3331163c").unwrap();
 		let id2 = H512::from_str("b979fb575495b8d6db44f750317d0f4622bf4c2aa3365d6af7c284339968eef29b69ad0dce72a4d8db5ebb4968de0e3bec910127f134779fbcb0cb6d3331163c").unwrap();
+		let id3 = H512::from_str("c979fb575495b8d6db44f750317d0f4622bf4c2aa3365d6af7c284339968eef29b69ad0dce72a4d8db5ebb4968de0e3bec910127f134779fbcb0cb6d3331163c").unwrap();
+
 		{
 			let mut table = NodeTable::new(Some(tempdir.path().to_str().unwrap().to_owned()));
 			table.add_node(node1);
 			table.add_node(node2);
+			table.add_node(node3);
 
-			table.get_mut(&id1).unwrap().attempts = 1;
+			table.note_success(&id2);
-			table.get_mut(&id2).unwrap().attempts = 1;
+			table.note_failure(&id3);
-			table.note_failure(&id2);
 		}
 
 		{
 			let table = NodeTable::new(Some(tempdir.path().to_str().unwrap().to_owned()));
 			let r = table.nodes(IpFilter::default());
-			assert_eq!(r[0][..], id1[..]);
+			assert_eq!(r[0][..], id2[..]); // latest success
-			assert_eq!(r[1][..], id2[..]);
+			assert_eq!(r[1][..], id1[..]); // unknown
+			assert_eq!(r[2][..], id3[..]); // oldest failure
 		}
 	}