Squashed commit of Rust-ifying the repo:

commit e31c1965a2e6b9a21ce68be63b81915b2b090f1d Author: Hernando Castano <castano.ha@gmail.com> Date: Sun Feb 2 21:15:42 2020 -0500 Get Ethereum bridge module compiling commit a497fc1640e68682f61b39414ffb15206c6120e2 Author: Hernando Castano <castano.ha@gmail.com> Date: Thu Jan 30 12:15:43 2020 -0500 Make the toml file look a bit better commit 898fb7b06cfac7cf866e1a28fed9a4f02bd246a7 Author: Hernando Castano <castano.ha@gmail.com> Date: Thu Jan 30 12:06:27 2020 -0500 Get substrate bridge module compiling commit 81e1547e6bec9f590cad9ffba0ee5dfa82cda1c1 Author: Hernando Castano <castano.ha@gmail.com> Date: Thu Jan 30 11:40:29 2020 -0500 Create workspace and move more files around
2026-05-31 07:31:02 +00:00 · 2020-02-02 21:29:06 -05:00
parent c06777a42a
commit fbaa803034
25 changed files with 142 additions and 6355 deletions
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+// Copyright 2019 Parity Technologies (UK) Ltd.
+// This file is part of Parity-Bridge.
+
+// Parity-Bridge 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-Bridge 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-Bridge.  If not, see <http://www.gnu.org/licenses/>.
+
+use sp_std::prelude::*;
+use primitives::{Address, H256, Header, LogEntry, Receipt, U256};
+use crate::Storage;
+use crate::error::Error;
+
+/// The hash of InitiateChange event of the validators set contract.
+const CHANGE_EVENT_HASH: &'static [u8; 32] = &[0x55, 0x25, 0x2f, 0xa6, 0xee, 0xe4, 0x74, 0x1b,
+	0x4e, 0x24, 0xa7, 0x4a, 0x70, 0xe9, 0xc1, 0x1f, 0xd2, 0xc2, 0x28, 0x1d, 0xf8, 0xd6, 0xea,
+	0x13, 0x12, 0x6f, 0xf8, 0x45, 0xf7, 0x82, 0x5c, 0x89];
+
+/// Where source of validators addresses come from. This covers the chain lifetime.
+pub enum ValidatorsConfiguration {
+	/// There's a single source for the whole chain lifetime.
+	Single(ValidatorsSource),
+	/// Validators source changes at given blocks. The blocks are ordered
+	/// by the block number.
+	Multi(Vec<(u64, ValidatorsSource)>),
+}
+
+/// Where validators addresses come from.
+///
+/// This source is valid within some blocks range. The blocks range could
+/// cover multiple epochs - i.e. the validators that are authoring blocks
+/// within this range could change, but the source itself can not.
+#[cfg_attr(test, derive(Debug, PartialEq))]
+pub enum ValidatorsSource {
+	/// The validators addresses are hardcoded and never change.
+	List(Vec<Address>),
+	/// The validators addresses are determined by the validators set contract
+	/// deployed at given address. The contract must implement the `ValidatorSet`
+	/// interface. Additionally, the initial validators set must be provided.
+	Contract(Address, Vec<Address>),
+}
+
+/// Validators manager.
+pub struct Validators<'a> {
+	config: &'a ValidatorsConfiguration,
+}
+
+impl<'a> Validators<'a> {
+	/// Creates new validators manager using given configuration.
+	pub fn new(config: &'a ValidatorsConfiguration) -> Self {
+		Self { config }
+	}
+
+	/// Returns true if header (probabilistically) signals validators change and
+	/// the caller needs to provide transactions receipts to import the header.
+	pub fn maybe_signals_validators_change(&self, header: &Header) -> bool {
+		let (_, _, source) = self.source_at(header.number);
+
+		// if we are taking validators set from the fixed list, there's always
+		// single epoch
+		// => we never require transactions receipts
+		let contract_address = match source {
+			ValidatorsSource::List(_) => return false,
+			ValidatorsSource::Contract(contract_address, _) => contract_address,
+		};
+
+		// else we need to check logs bloom and if it has required bits set, it means
+		// that the contract has (probably) emitted epoch change event
+		let expected_bloom = LogEntry {
+			address: *contract_address,
+			topics: vec![
+				CHANGE_EVENT_HASH.into(),
+				header.parent_hash,
+			],
+			data: Vec::new(), // irrelevant for bloom.
+		}.bloom();
+
+		header.log_bloom.contains(&expected_bloom)
+	}
+
+	/// Extracts validators change signal from the header.
+	///
+	/// Returns tuple where first element is the change scheduled by this header
+	/// (i.e. this change is only applied starting from the block that has finalized
+	/// current block). The second element is the immediately applied change.
+	pub fn extract_validators_change(
+		&self,
+		header: &Header,
+		receipts: Option<Vec<Receipt>>,
+	) -> Result<(Option<Vec<Address>>, Option<Vec<Address>>), Error> {
+		// let's first check if new source is starting from this header
+		let (source_index, _, source) = self.source_at(header.number);
+		let (next_starts_at, next_source) = self.source_at_next_header(source_index, header.number);
+		if next_starts_at == header.number {
+			match *next_source {
+				ValidatorsSource::List(ref new_list) => return Ok((None, Some(new_list.clone()))),
+				ValidatorsSource::Contract(_, ref new_list) => return Ok((Some(new_list.clone()), None)),
+			}
+		}
+
+		// else deal with previous source
+		//
+		// if we are taking validators set from the fixed list, there's always
+		// single epoch
+		// => we never require transactions receipts
+		let contract_address = match source {
+			ValidatorsSource::List(_) => return Ok((None, None)),
+			ValidatorsSource::Contract(contract_address, _) => contract_address,
+		};
+
+		// else we need to check logs bloom and if it has required bits set, it means
+		// that the contract has (probably) emitted epoch change event
+		let expected_bloom = LogEntry {
+			address: *contract_address,
+			topics: vec![
+				CHANGE_EVENT_HASH.into(),
+				header.parent_hash,
+			],
+			data: Vec::new(), // irrelevant for bloom.
+		}.bloom();
+
+		if !header.log_bloom.contains(&expected_bloom) {
+			return Ok((None, None));
+		}
+
+		let receipts = receipts.ok_or(Error::MissingTransactionsReceipts)?;
+		if !header.check_transactions_receipts(&receipts) {
+			return Err(Error::TransactionsReceiptsMismatch);
+		}
+
+		// iterate in reverse because only the _last_ change in a given
+		// block actually has any effect
+		Ok((receipts.iter()
+			.rev()
+			.filter(|r| r.log_bloom.contains(&expected_bloom))
+			.flat_map(|r| r.logs.iter())
+			.filter(|l| l.address == *contract_address &&
+				l.topics.len() == 2 &&
+				l.topics[0].as_fixed_bytes() == CHANGE_EVENT_HASH &&
+				l.topics[1] == header.parent_hash
+			)
+			.filter_map(|l| {
+				let data_len = l.data.len();
+				if data_len < 64 {
+					return None;
+				}
+
+				let new_validators_len_u256 = U256::from_big_endian(&l.data[32..64]);
+				let new_validators_len = new_validators_len_u256.low_u64();
+				if new_validators_len_u256 != new_validators_len.into() {
+					return None;
+				}
+
+				if (data_len - 64) as u64 != new_validators_len.saturating_mul(32) {
+					return None;
+				}
+
+				Some(l.data[64..]
+					.chunks(32)
+					.map(|chunk| {
+						let mut new_validator = Address::default();
+						new_validator.as_mut().copy_from_slice(&chunk[12..32]);
+						new_validator
+					})
+					.collect())
+			})
+			.next(), None))
+	}
+
+	/// Finalize changes when blocks are finalized.
+	pub fn finalize_validators_change<S: Storage>(
+		&self,
+		storage: &mut S,
+		finalized_blocks: &[(u64, H256)],
+	) -> Option<Vec<Address>> {
+		for (_, finalized_hash) in finalized_blocks.iter().rev() {
+			if let Some(changes) = storage.scheduled_change(finalized_hash) {
+				return Some(changes);
+			}
+		}
+		None
+	}
+
+	/// Returns source of validators that should author the header.
+	fn source_at<'b>(&'b self, header_number: u64) -> (usize, u64, &'b ValidatorsSource) {
+		match self.config {
+			ValidatorsConfiguration::Single(ref source) => (0, 0, source),
+			ValidatorsConfiguration::Multi(ref sources) => sources.iter().rev()
+				.enumerate()
+				.find(|(_, &(begin, _))| begin < header_number)
+				.map(|(i, (begin, source))| (sources.len() - 1 - i, *begin, source))
+				.expect("there's always entry for the initial block;\
+					we do not touch any headers with number < initial block number; qed"),
+		}
+	}
+
+	/// Returns source of validators that should author the next header.
+	fn source_at_next_header<'b>(
+		&'b self,
+		header_source_index: usize,
+		header_number: u64,
+	) -> (u64, &'b ValidatorsSource) {
+		match self.config {
+			ValidatorsConfiguration::Single(ref source) => (0, source),
+			ValidatorsConfiguration::Multi(ref sources) => {
+				let next_source_index = header_source_index + 1;
+				if next_source_index < sources.len() {
+					let next_source = &sources[next_source_index];
+					if next_source.0 < header_number + 1 {
+						return (next_source.0, &next_source.1);
+					}
+				}
+
+				let source = &sources[header_source_index];
+				(source.0, &source.1)
+			},
+		}
+	}
+}
+
+impl ValidatorsSource {
+	/// Returns initial validators set.
+	pub fn initial_epoch_validators(&self) -> Vec<Address> {
+		match self {
+			ValidatorsSource::List(ref list) => list.clone(),
+			ValidatorsSource::Contract(_, ref list) => list.clone(),
+		}
+	}
+}
+
+/// Get validator that should author the block at given step.
+pub fn step_validator(header_validators: &[Address], header_step: u64) -> Address {
+	header_validators[(header_step % header_validators.len() as u64) as usize]
+}
+
+#[cfg(test)]
+pub(crate) mod tests {
+	use primitives::TransactionOutcome;
+	use crate::kovan_validators_config;
+	use super::*;
+
+	pub(crate) fn validators_change_recept(parent_hash: H256) -> Receipt {
+		Receipt {
+			gas_used: 0.into(),
+			log_bloom: (&[0xff; 256]).into(),
+			outcome: TransactionOutcome::Unknown,
+			logs: vec![
+				LogEntry {
+					address: [3; 20].into(),
+					topics: vec![
+						CHANGE_EVENT_HASH.into(),
+						parent_hash,
+					],
+					data: vec![
+						0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+							0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+						0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+							0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1,
+						7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
+							7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
+					],
+				},
+			],
+		}
+	}
+
+	#[test]
+	fn source_at_works() {
+		let config = ValidatorsConfiguration::Multi(vec![
+			(0, ValidatorsSource::List(vec![[1; 20].into()])),
+			(100, ValidatorsSource::List(vec![[2; 20].into()])),
+			(200, ValidatorsSource::Contract([3; 20].into(), vec![[3; 20].into()])),
+		]);
+		let validators = Validators::new(&config);
+
+		assert_eq!(
+			validators.source_at(99),
+			(0, 0, &ValidatorsSource::List(vec![[1; 20].into()])),
+		);
+		assert_eq!(
+			validators.source_at_next_header(0, 99),
+			(0, &ValidatorsSource::List(vec![[1; 20].into()])),
+		);
+
+		assert_eq!(
+			validators.source_at(100),
+			(0, 0, &ValidatorsSource::List(vec![[1; 20].into()])),
+		);
+		assert_eq!(
+			validators.source_at_next_header(0, 100),
+			(100, &ValidatorsSource::List(vec![[2; 20].into()])),
+		);
+
+		assert_eq!(
+			validators.source_at(200),
+			(1, 100, &ValidatorsSource::List(vec![[2; 20].into()])),
+		);
+		assert_eq!(
+			validators.source_at_next_header(1, 200),
+			(200, &ValidatorsSource::Contract([3; 20].into(), vec![[3; 20].into()])),
+		);
+	}
+
+	#[test]
+	fn maybe_signals_validators_change_works() {
+		// when contract is active, but bloom has no required bits set
+		let config = kovan_validators_config();
+		let validators = Validators::new(&config);
+		let mut header = Header::default();
+		header.number = u64::max_value();
+		assert!(!validators.maybe_signals_validators_change(&header));
+
+		// when contract is active and bloom has required bits set
+		header.log_bloom = (&[0xff; 256]).into();
+		assert!(validators.maybe_signals_validators_change(&header));
+
+		// when list is active and bloom has required bits set
+		let config = ValidatorsConfiguration::Single(ValidatorsSource::List(vec![[42; 20].into()]));
+		let validators = Validators::new(&config);
+		assert!(!validators.maybe_signals_validators_change(&header));
+	}
+
+	#[test]
+	fn extract_validators_change_works() {
+		let config = ValidatorsConfiguration::Multi(vec![
+			(0, ValidatorsSource::List(vec![[1; 20].into()])),
+			(100, ValidatorsSource::List(vec![[2; 20].into()])),
+			(200, ValidatorsSource::Contract([3; 20].into(), vec![[3; 20].into()])),
+		]);
+		let validators = Validators::new(&config);
+		let mut header = Header::default();
+
+		// when we're at the block that switches to list source
+		header.number = 100;
+		assert_eq!(
+			validators.extract_validators_change(&header, None),
+			Ok((None, Some(vec![[2; 20].into()]))),
+		);
+
+		// when we're inside list range
+		header.number = 150;
+		assert_eq!(
+			validators.extract_validators_change(&header, None),
+			Ok((None, None)),
+		);
+
+		// when we're at the block that switches to contract source
+		header.number = 200;
+		assert_eq!(
+			validators.extract_validators_change(&header, None),
+			Ok((Some(vec![[3; 20].into()]), None)),
+		);
+
+		// when we're inside contract range and logs bloom signals change
+		// but we have no receipts
+		header.number = 250;
+		header.log_bloom = (&[0xff; 256]).into();
+		assert_eq!(
+			validators.extract_validators_change(&header, None),
+			Err(Error::MissingTransactionsReceipts),
+		);
+
+		// when we're inside contract range and logs bloom signals change
+		// but there's no change in receipts
+		header.receipts_root = "56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421".parse().unwrap();
+		assert_eq!(
+			validators.extract_validators_change(&header, Some(Vec::new())),
+			Ok((None, None)),
+		);
+
+		// when we're inside contract range and logs bloom signals change
+		// and there's change in receipts
+		let receipts = vec![validators_change_recept(Default::default())];
+		header.receipts_root = "81ce88dc524403b796222046bf3daf543978329b87ffd50228f1d3987031dc45".parse().unwrap();
+		assert_eq!(
+			validators.extract_validators_change(&header, Some(receipts)),
+			Ok((Some(vec![[7; 20].into()]), None)),
+		);
+
+		// when incorrect receipts root passed
+		assert_eq!(
+			validators.extract_validators_change(&header, Some(Vec::new())),
+			Err(Error::TransactionsReceiptsMismatch),
+		);
+	}
+}