fix: Complete snowbridge pezpallet rebrand and critical bug fixes

- snowbridge-pezpallet-* → pezsnowbridge-pezpallet-* (201 refs)
- pallet/ directories → pezpallet/ (4 locations)
- Fixed pezpallet.rs self-include recursion bug
- Fixed sc-chain-spec hardcoded crate name in derive macro
- Reverted .pezpallet_by_name() to .pallet_by_name() (subxt API)
- Added BizinikiwiConfig type alias for zombienet tests
- Deleted obsolete session state files

Verified: pezsnowbridge-pezpallet-*, pezpallet-staking,
pezpallet-staking-async, pezframe-benchmarking-cli all pass cargo check

pezbridges/relays/equivocation/src/block_checker.rs

@@ -0,0 +1,476 @@
+// Copyright (C) Parity Technologies (UK) Ltd.
+// This file is part of Parity Bridges Common.
+
+// Parity Bridges Common 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 Bridges Common 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 Bridges Common.  If not, see <http://www.gnu.org/licenses/>.
+
+use crate::{
+	handle_client_error, reporter::EquivocationsReporter, EquivocationDetectionPipeline,
+	EquivocationReportingContext, HeaderFinalityInfo, SourceClient, TargetClient,
+};
+
+use bp_header_pez_chain::{FinalityProof, FindEquivocations as FindEquivocationsT};
+use pez_finality_relay::FinalityProofsBuf;
+use futures::future::{BoxFuture, FutureExt};
+use num_traits::Saturating;
+
+/// First step in the block checking state machine.
+///
+/// Getting the finality info associated to the source headers synced with the target chain
+/// at the specified block.
+#[cfg_attr(test, derive(Debug, PartialEq))]
+pub struct ReadSyncedHeaders<P: EquivocationDetectionPipeline> {
+	pub target_block_num: P::TargetNumber,
+}
+
+impl<P: EquivocationDetectionPipeline> ReadSyncedHeaders<P> {
+	pub async fn next<TC: TargetClient<P>>(
+		self,
+		target_client: &mut TC,
+	) -> Result<ReadContext<P>, Self> {
+		match target_client.synced_headers_finality_info(self.target_block_num).await {
+			Ok(synced_headers) =>
+				Ok(ReadContext { target_block_num: self.target_block_num, synced_headers }),
+			Err(e) => {
+				tracing::error!(
+					target: "bridge",
+					error=?e,
+					source=%P::SOURCE_NAME,
+					target=%P::TARGET_NAME,
+					block=%self.target_block_num,
+					"Could not get headers synced at block"
+				);
+
+				// Reconnect target client in case of a connection error.
+				handle_client_error(target_client, e).await;
+
+				Err(self)
+			},
+		}
+	}
+}
+
+/// Second step in the block checking state machine.
+///
+/// Reading the equivocation reporting context from the target chain.
+#[cfg_attr(test, derive(Debug))]
+pub struct ReadContext<P: EquivocationDetectionPipeline> {
+	target_block_num: P::TargetNumber,
+	synced_headers: Vec<HeaderFinalityInfo<P>>,
+}
+
+impl<P: EquivocationDetectionPipeline> ReadContext<P> {
+	pub async fn next<TC: TargetClient<P>>(
+		self,
+		target_client: &mut TC,
+	) -> Result<Option<FindEquivocations<P>>, Self> {
+		match EquivocationReportingContext::try_read_from_target::<TC>(
+			target_client,
+			self.target_block_num.saturating_sub(1.into()),
+		)
+		.await
+		{
+			Ok(Some(context)) => Ok(Some(FindEquivocations {
+				target_block_num: self.target_block_num,
+				synced_headers: self.synced_headers,
+				context,
+			})),
+			Ok(None) => Ok(None),
+			Err(e) => {
+				tracing::error!(
+					target: "bridge",
+					error=?e,
+					source=%P::SOURCE_NAME,
+					target=%P::TARGET_NAME,
+					block=%self.target_block_num.saturating_sub(1.into()),
+					"Could not read `EquivocationReportingContext` at block",
+				);
+
+				// Reconnect target client in case of a connection error.
+				handle_client_error(target_client, e).await;
+
+				Err(self)
+			},
+		}
+	}
+}
+
+/// Third step in the block checking state machine.
+///
+/// Searching for equivocations in the source headers synced with the target chain.
+#[cfg_attr(test, derive(Debug))]
+pub struct FindEquivocations<P: EquivocationDetectionPipeline> {
+	target_block_num: P::TargetNumber,
+	synced_headers: Vec<HeaderFinalityInfo<P>>,
+	context: EquivocationReportingContext<P>,
+}
+
+impl<P: EquivocationDetectionPipeline> FindEquivocations<P> {
+	pub fn next(
+		mut self,
+		finality_proofs_buf: &mut FinalityProofsBuf<P>,
+	) -> Vec<ReportEquivocations<P>> {
+		let mut result = vec![];
+		for synced_header in self.synced_headers {
+			match P::EquivocationsFinder::find_equivocations(
+				&self.context.synced_verification_context,
+				&synced_header.finality_proof,
+				finality_proofs_buf.buf().as_slice(),
+			) {
+				Ok(equivocations) =>
+					if !equivocations.is_empty() {
+						result.push(ReportEquivocations {
+							source_block_hash: self.context.synced_header_hash,
+							equivocations,
+						})
+					},
+				Err(e) => {
+					tracing::error!(
+						target: "bridge",
+						error=?e,
+						source_header=?synced_header.finality_proof.target_header_hash(),
+						block=%self.target_block_num,
+						"Could not search for equivocations in the finality proof \
+						for source header synced at target block"
+					);
+				},
+			};
+
+			finality_proofs_buf.prune(synced_header.finality_proof.target_header_number(), None);
+			self.context.update(synced_header);
+		}
+
+		result
+	}
+}
+
+/// Fourth step in the block checking state machine.
+///
+/// Reporting the detected equivocations (if any).
+#[cfg_attr(test, derive(Debug))]
+pub struct ReportEquivocations<P: EquivocationDetectionPipeline> {
+	source_block_hash: P::Hash,
+	equivocations: Vec<P::EquivocationProof>,
+}
+
+impl<P: EquivocationDetectionPipeline> ReportEquivocations<P> {
+	pub async fn next<SC: SourceClient<P>>(
+		mut self,
+		source_client: &mut SC,
+		reporter: &mut EquivocationsReporter<'_, P, SC>,
+	) -> Result<(), Self> {
+		let mut unprocessed_equivocations = vec![];
+		for equivocation in self.equivocations {
+			match reporter
+				.submit_report(source_client, self.source_block_hash, equivocation.clone())
+				.await
+			{
+				Ok(_) => {},
+				Err(e) => {
+					tracing::error!(
+						target: "bridge",
+						error=?e,
+						source=%P::SOURCE_NAME,
+						?equivocation,
+						"Could not submit equivocation report"
+					);
+
+					// Mark the equivocation as unprocessed
+					unprocessed_equivocations.push(equivocation);
+					// Reconnect source client in case of a connection error.
+					handle_client_error(source_client, e).await;
+				},
+			}
+		}
+
+		self.equivocations = unprocessed_equivocations;
+		if !self.equivocations.is_empty() {
+			return Err(self);
+		}
+
+		Ok(())
+	}
+}
+
+/// Block checking state machine.
+#[cfg_attr(test, derive(Debug))]
+pub enum BlockChecker<P: EquivocationDetectionPipeline> {
+	ReadSyncedHeaders(ReadSyncedHeaders<P>),
+	ReadContext(ReadContext<P>),
+	ReportEquivocations(Vec<ReportEquivocations<P>>),
+}
+
+impl<P: EquivocationDetectionPipeline> BlockChecker<P> {
+	pub fn new(target_block_num: P::TargetNumber) -> Self {
+		Self::ReadSyncedHeaders(ReadSyncedHeaders { target_block_num })
+	}
+
+	pub fn run<'a, SC: SourceClient<P>, TC: TargetClient<P>>(
+		self,
+		source_client: &'a mut SC,
+		target_client: &'a mut TC,
+		finality_proofs_buf: &'a mut FinalityProofsBuf<P>,
+		reporter: &'a mut EquivocationsReporter<P, SC>,
+	) -> BoxFuture<'a, Result<(), Self>> {
+		async move {
+			match self {
+				Self::ReadSyncedHeaders(state) => {
+					let read_context =
+						state.next(target_client).await.map_err(Self::ReadSyncedHeaders)?;
+					Self::ReadContext(read_context)
+						.run(source_client, target_client, finality_proofs_buf, reporter)
+						.await
+				},
+				Self::ReadContext(state) => {
+					let maybe_find_equivocations =
+						state.next(target_client).await.map_err(Self::ReadContext)?;
+					let find_equivocations = match maybe_find_equivocations {
+						Some(find_equivocations) => find_equivocations,
+						None => return Ok(()),
+					};
+					Self::ReportEquivocations(find_equivocations.next(finality_proofs_buf))
+						.run(source_client, target_client, finality_proofs_buf, reporter)
+						.await
+				},
+				Self::ReportEquivocations(state) => {
+					let mut failures = vec![];
+					for report_equivocations in state {
+						if let Err(failure) =
+							report_equivocations.next(source_client, reporter).await
+						{
+							failures.push(failure);
+						}
+					}
+
+					if !failures.is_empty() {
+						return Err(Self::ReportEquivocations(failures));
+					}
+
+					Ok(())
+				},
+			}
+		}
+		.boxed()
+	}
+}
+
+#[cfg(test)]
+mod tests {
+	use super::*;
+	use crate::mock::*;
+	use std::collections::HashMap;
+
+	impl PartialEq for ReadContext<TestEquivocationDetectionPipeline> {
+		fn eq(&self, other: &Self) -> bool {
+			self.target_block_num == other.target_block_num &&
+				self.synced_headers == other.synced_headers
+		}
+	}
+
+	impl PartialEq for FindEquivocations<TestEquivocationDetectionPipeline> {
+		fn eq(&self, other: &Self) -> bool {
+			self.target_block_num == other.target_block_num &&
+				self.synced_headers == other.synced_headers &&
+				self.context == other.context
+		}
+	}
+
+	impl PartialEq for ReportEquivocations<TestEquivocationDetectionPipeline> {
+		fn eq(&self, other: &Self) -> bool {
+			self.source_block_hash == other.source_block_hash &&
+				self.equivocations == other.equivocations
+		}
+	}
+
+	impl PartialEq for BlockChecker<TestEquivocationDetectionPipeline> {
+		fn eq(&self, _other: &Self) -> bool {
+			matches!(self, _other)
+		}
+	}
+
+	#[async_std::test]
+	async fn block_checker_works() {
+		let mut source_client = TestSourceClient { ..Default::default() };
+		let mut target_client = TestTargetClient {
+			best_synced_header_hash: HashMap::from([(9, Ok(Some(5)))]),
+			finality_verification_context: HashMap::from([(
+				9,
+				Ok(TestFinalityVerificationContext { check_equivocations: true }),
+			)]),
+			synced_headers_finality_info: HashMap::from([(
+				10,
+				Ok(vec![
+					new_header_finality_info(6, None),
+					new_header_finality_info(7, Some(false)),
+					new_header_finality_info(8, None),
+					new_header_finality_info(9, Some(true)),
+					new_header_finality_info(10, None),
+					new_header_finality_info(11, None),
+					new_header_finality_info(12, None),
+				]),
+			)]),
+			..Default::default()
+		};
+		let mut reporter =
+			EquivocationsReporter::<TestEquivocationDetectionPipeline, TestSourceClient>::new();
+
+		let block_checker = BlockChecker::new(10);
+		assert!(block_checker
+			.run(
+				&mut source_client,
+				&mut target_client,
+				&mut FinalityProofsBuf::new(vec![
+					TestFinalityProof(6, vec!["6-1"]),
+					TestFinalityProof(7, vec![]),
+					TestFinalityProof(8, vec!["8-1"]),
+					TestFinalityProof(9, vec!["9-1"]),
+					TestFinalityProof(10, vec![]),
+					TestFinalityProof(11, vec!["11-1", "11-2"]),
+					TestFinalityProof(12, vec!["12-1"])
+				]),
+				&mut reporter
+			)
+			.await
+			.is_ok());
+		assert_eq!(
+			*source_client.reported_equivocations.lock().unwrap(),
+			HashMap::from([(5, vec!["6-1"]), (9, vec!["11-1", "11-2", "12-1"])])
+		);
+	}
+
+	#[async_std::test]
+	async fn block_checker_works_with_empty_context() {
+		let mut target_client = TestTargetClient {
+			best_synced_header_hash: HashMap::from([(9, Ok(None))]),
+			finality_verification_context: HashMap::from([(
+				9,
+				Ok(TestFinalityVerificationContext { check_equivocations: true }),
+			)]),
+			synced_headers_finality_info: HashMap::from([(
+				10,
+				Ok(vec![new_header_finality_info(6, None)]),
+			)]),
+			..Default::default()
+		};
+		let mut source_client = TestSourceClient { ..Default::default() };
+		let mut reporter =
+			EquivocationsReporter::<TestEquivocationDetectionPipeline, TestSourceClient>::new();
+
+		let block_checker = BlockChecker::new(10);
+		assert!(block_checker
+			.run(
+				&mut source_client,
+				&mut target_client,
+				&mut FinalityProofsBuf::new(vec![TestFinalityProof(6, vec!["6-1"])]),
+				&mut reporter
+			)
+			.await
+			.is_ok());
+		assert_eq!(*source_client.reported_equivocations.lock().unwrap(), HashMap::default());
+	}
+
+	#[async_std::test]
+	async fn read_synced_headers_handles_errors() {
+		let mut target_client = TestTargetClient {
+			synced_headers_finality_info: HashMap::from([
+				(10, Err(TestClientError::NonConnection)),
+				(11, Err(TestClientError::Connection)),
+			]),
+			..Default::default()
+		};
+		let mut source_client = TestSourceClient { ..Default::default() };
+		let mut reporter =
+			EquivocationsReporter::<TestEquivocationDetectionPipeline, TestSourceClient>::new();
+
+		// NonConnection error
+		let block_checker = BlockChecker::new(10);
+		assert_eq!(
+			block_checker
+				.run(
+					&mut source_client,
+					&mut target_client,
+					&mut FinalityProofsBuf::new(vec![]),
+					&mut reporter
+				)
+				.await,
+			Err(BlockChecker::ReadSyncedHeaders(ReadSyncedHeaders { target_block_num: 10 }))
+		);
+		assert_eq!(target_client.num_reconnects, 0);
+
+		// Connection error
+		let block_checker = BlockChecker::new(11);
+		assert_eq!(
+			block_checker
+				.run(
+					&mut source_client,
+					&mut target_client,
+					&mut FinalityProofsBuf::new(vec![]),
+					&mut reporter
+				)
+				.await,
+			Err(BlockChecker::ReadSyncedHeaders(ReadSyncedHeaders { target_block_num: 11 }))
+		);
+		assert_eq!(target_client.num_reconnects, 1);
+	}
+
+	#[async_std::test]
+	async fn read_context_handles_errors() {
+		let mut target_client = TestTargetClient {
+			synced_headers_finality_info: HashMap::from([(10, Ok(vec![])), (11, Ok(vec![]))]),
+			best_synced_header_hash: HashMap::from([
+				(9, Err(TestClientError::NonConnection)),
+				(10, Err(TestClientError::Connection)),
+			]),
+			..Default::default()
+		};
+		let mut source_client = TestSourceClient { ..Default::default() };
+		let mut reporter =
+			EquivocationsReporter::<TestEquivocationDetectionPipeline, TestSourceClient>::new();
+
+		// NonConnection error
+		let block_checker = BlockChecker::new(10);
+		assert_eq!(
+			block_checker
+				.run(
+					&mut source_client,
+					&mut target_client,
+					&mut FinalityProofsBuf::new(vec![]),
+					&mut reporter
+				)
+				.await,
+			Err(BlockChecker::ReadContext(ReadContext {
+				target_block_num: 10,
+				synced_headers: vec![]
+			}))
+		);
+		assert_eq!(target_client.num_reconnects, 0);
+
+		// Connection error
+		let block_checker = BlockChecker::new(11);
+		assert_eq!(
+			block_checker
+				.run(
+					&mut source_client,
+					&mut target_client,
+					&mut FinalityProofsBuf::new(vec![]),
+					&mut reporter
+				)
+				.await,
+			Err(BlockChecker::ReadContext(ReadContext {
+				target_block_num: 11,
+				synced_headers: vec![]
+			}))
+		);
+		assert_eq!(target_client.num_reconnects, 1);
+	}
+}

pezbridges/relays/equivocation/src/equivocation_loop.rs

@@ -0,0 +1,310 @@
+// Copyright 2019-2023 Parity Technologies (UK) Ltd.
+// This file is part of Parity Bridges Common.
+
+// Parity Bridges Common 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 Bridges Common 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 Bridges Common.  If not, see <http://www.gnu.org/licenses/>.
+
+use crate::{
+	handle_client_error, reporter::EquivocationsReporter, EquivocationDetectionPipeline,
+	SourceClient, TargetClient,
+};
+
+use crate::block_checker::BlockChecker;
+use pez_finality_relay::{FinalityProofsBuf, FinalityProofsStream};
+use futures::{select_biased, FutureExt};
+use num_traits::Saturating;
+use relay_utils::{metrics::MetricsParams, FailedClient};
+use std::{future::Future, time::Duration};
+
+/// Equivocations detection loop state.
+struct EquivocationDetectionLoop<
+	P: EquivocationDetectionPipeline,
+	SC: SourceClient<P>,
+	TC: TargetClient<P>,
+> {
+	source_client: SC,
+	target_client: TC,
+
+	from_block_num: Option<P::TargetNumber>,
+	until_block_num: Option<P::TargetNumber>,
+
+	reporter: EquivocationsReporter<'static, P, SC>,
+
+	finality_proofs_stream: FinalityProofsStream<P, SC>,
+	finality_proofs_buf: FinalityProofsBuf<P>,
+}
+
+impl<P: EquivocationDetectionPipeline, SC: SourceClient<P>, TC: TargetClient<P>>
+	EquivocationDetectionLoop<P, SC, TC>
+{
+	async fn ensure_finality_proofs_stream(&mut self) {
+		match self.finality_proofs_stream.ensure_stream(&self.source_client).await {
+			Ok(_) => {},
+			Err(e) => {
+				tracing::error!(
+					target: "bridge",
+					error=?e,
+					source=%P::SOURCE_NAME,
+					"Could not connect to `FinalityProofsStream`"
+				);
+
+				// Reconnect to the source client if needed
+				handle_client_error(&mut self.source_client, e).await;
+			},
+		}
+	}
+
+	async fn best_finalized_target_block_number(&mut self) -> Option<P::TargetNumber> {
+		match self.target_client.best_finalized_header_number().await {
+			Ok(block_num) => Some(block_num),
+			Err(e) => {
+				tracing::error!(
+					target: "bridge",
+					error=?e,
+					target=%P::TARGET_NAME,
+					"Could not read best finalized header number"
+				);
+
+				// Reconnect target client and move on
+				handle_client_error(&mut self.target_client, e).await;
+
+				None
+			},
+		}
+	}
+
+	async fn do_run(&mut self, tick: Duration, exit_signal: impl Future<Output = ()>) {
+		let exit_signal = exit_signal.fuse();
+		futures::pin_mut!(exit_signal);
+
+		loop {
+			// Make sure that we are connected to the source finality proofs stream.
+			self.ensure_finality_proofs_stream().await;
+			// Check the status of the pending equivocation reports
+			self.reporter.process_pending_reports().await;
+
+			// Update blocks range.
+			if let Some(block_number) = self.best_finalized_target_block_number().await {
+				self.from_block_num.get_or_insert(block_number);
+				self.until_block_num = Some(block_number);
+			}
+			let (from, until) = match (self.from_block_num, self.until_block_num) {
+				(Some(from), Some(until)) => (from, until),
+				_ => continue,
+			};
+
+			// Check the available blocks
+			let mut current_block_number = from;
+			while current_block_number <= until {
+				self.finality_proofs_buf.fill(&mut self.finality_proofs_stream);
+				let block_checker = BlockChecker::new(current_block_number);
+				let _ = block_checker
+					.run(
+						&mut self.source_client,
+						&mut self.target_client,
+						&mut self.finality_proofs_buf,
+						&mut self.reporter,
+					)
+					.await;
+				current_block_number = current_block_number.saturating_add(1.into());
+			}
+			self.from_block_num = Some(current_block_number);
+
+			select_biased! {
+				_ = exit_signal => return,
+				_ = async_std::task::sleep(tick).fuse() => {},
+			}
+		}
+	}
+
+	pub async fn run(
+		source_client: SC,
+		target_client: TC,
+		tick: Duration,
+		exit_signal: impl Future<Output = ()>,
+	) -> Result<(), FailedClient> {
+		let mut equivocation_detection_loop = Self {
+			source_client,
+			target_client,
+			from_block_num: None,
+			until_block_num: None,
+			reporter: EquivocationsReporter::<P, SC>::new(),
+			finality_proofs_stream: FinalityProofsStream::new(),
+			finality_proofs_buf: FinalityProofsBuf::new(vec![]),
+		};
+
+		equivocation_detection_loop.do_run(tick, exit_signal).await;
+		Ok(())
+	}
+}
+
+/// Spawn the equivocations detection loop.
+pub async fn run<P: EquivocationDetectionPipeline>(
+	source_client: impl SourceClient<P>,
+	target_client: impl TargetClient<P>,
+	tick: Duration,
+	metrics_params: MetricsParams,
+	exit_signal: impl Future<Output = ()> + 'static + Send,
+) -> Result<(), relay_utils::Error> {
+	let exit_signal = exit_signal.shared();
+	relay_utils::relay_loop(source_client, target_client)
+		.with_metrics(metrics_params)
+		.expose()
+		.await?
+		.run(
+			format!("{}_to_{}_EquivocationDetection", P::SOURCE_NAME, P::TARGET_NAME),
+			move |source_client, target_client, _metrics| {
+				EquivocationDetectionLoop::run(
+					source_client,
+					target_client,
+					tick,
+					exit_signal.clone(),
+				)
+			},
+		)
+		.await
+}
+
+#[cfg(test)]
+mod tests {
+	use super::*;
+	use crate::mock::*;
+	use futures::{channel::mpsc::UnboundedSender, StreamExt};
+	use std::{
+		collections::{HashMap, VecDeque},
+		sync::{Arc, Mutex},
+	};
+
+	fn best_finalized_header_number(
+		best_finalized_headers: &Mutex<VecDeque<Result<TestTargetNumber, TestClientError>>>,
+		exit_sender: &UnboundedSender<()>,
+	) -> Result<TestTargetNumber, TestClientError> {
+		let mut best_finalized_headers = best_finalized_headers.lock().unwrap();
+		let result = best_finalized_headers.pop_front().unwrap();
+		if best_finalized_headers.is_empty() {
+			exit_sender.unbounded_send(()).unwrap();
+		}
+		result
+	}
+
+	#[async_std::test]
+	async fn multiple_blocks_are_checked_correctly() {
+		let best_finalized_headers = Arc::new(Mutex::new(VecDeque::from([Ok(10), Ok(12), Ok(13)])));
+		let (exit_sender, exit_receiver) = futures::channel::mpsc::unbounded();
+
+		let source_client = TestSourceClient {
+			finality_proofs: Arc::new(Mutex::new(vec![
+				TestFinalityProof(2, vec!["2-1"]),
+				TestFinalityProof(3, vec!["3-1", "3-2"]),
+				TestFinalityProof(4, vec!["4-1"]),
+				TestFinalityProof(5, vec!["5-1"]),
+				TestFinalityProof(6, vec!["6-1", "6-2"]),
+				TestFinalityProof(7, vec!["7-1", "7-2"]),
+			])),
+			..Default::default()
+		};
+		let reported_equivocations = source_client.reported_equivocations.clone();
+		let target_client = TestTargetClient {
+			best_finalized_header_number: Arc::new(move || {
+				best_finalized_header_number(&best_finalized_headers, &exit_sender)
+			}),
+			best_synced_header_hash: HashMap::from([
+				(9, Ok(Some(1))),
+				(10, Ok(Some(3))),
+				(11, Ok(Some(5))),
+				(12, Ok(Some(6))),
+			]),
+			finality_verification_context: HashMap::from([
+				(9, Ok(TestFinalityVerificationContext { check_equivocations: true })),
+				(10, Ok(TestFinalityVerificationContext { check_equivocations: true })),
+				(11, Ok(TestFinalityVerificationContext { check_equivocations: false })),
+				(12, Ok(TestFinalityVerificationContext { check_equivocations: true })),
+			]),
+			synced_headers_finality_info: HashMap::from([
+				(
+					10,
+					Ok(vec![new_header_finality_info(2, None), new_header_finality_info(3, None)]),
+				),
+				(
+					11,
+					Ok(vec![
+						new_header_finality_info(4, None),
+						new_header_finality_info(5, Some(false)),
+					]),
+				),
+				(12, Ok(vec![new_header_finality_info(6, None)])),
+				(13, Ok(vec![new_header_finality_info(7, None)])),
+			]),
+			..Default::default()
+		};
+
+		assert!(run::<TestEquivocationDetectionPipeline>(
+			source_client,
+			target_client,
+			Duration::from_secs(0),
+			MetricsParams { address: None, registry: Default::default() },
+			exit_receiver.into_future().map(|(_, _)| ()),
+		)
+		.await
+		.is_ok());
+		assert_eq!(
+			*reported_equivocations.lock().unwrap(),
+			HashMap::from([
+				(1, vec!["2-1", "3-1", "3-2"]),
+				(3, vec!["4-1", "5-1"]),
+				(6, vec!["7-1", "7-2"])
+			])
+		);
+	}
+
+	#[async_std::test]
+	async fn blocks_following_error_are_checked_correctly() {
+		let best_finalized_headers = Mutex::new(VecDeque::from([Ok(10), Ok(11)]));
+		let (exit_sender, exit_receiver) = futures::channel::mpsc::unbounded();
+
+		let source_client = TestSourceClient {
+			finality_proofs: Arc::new(Mutex::new(vec![
+				TestFinalityProof(2, vec!["2-1"]),
+				TestFinalityProof(3, vec!["3-1"]),
+			])),
+			..Default::default()
+		};
+		let reported_equivocations = source_client.reported_equivocations.clone();
+		let target_client = TestTargetClient {
+			best_finalized_header_number: Arc::new(move || {
+				best_finalized_header_number(&best_finalized_headers, &exit_sender)
+			}),
+			best_synced_header_hash: HashMap::from([(9, Ok(Some(1))), (10, Ok(Some(2)))]),
+			finality_verification_context: HashMap::from([
+				(9, Ok(TestFinalityVerificationContext { check_equivocations: true })),
+				(10, Ok(TestFinalityVerificationContext { check_equivocations: true })),
+			]),
+			synced_headers_finality_info: HashMap::from([
+				(10, Err(TestClientError::NonConnection)),
+				(11, Ok(vec![new_header_finality_info(3, None)])),
+			]),
+			..Default::default()
+		};
+
+		assert!(run::<TestEquivocationDetectionPipeline>(
+			source_client,
+			target_client,
+			Duration::from_secs(0),
+			MetricsParams { address: None, registry: Default::default() },
+			exit_receiver.into_future().map(|(_, _)| ()),
+		)
+		.await
+		.is_ok());
+		assert_eq!(*reported_equivocations.lock().unwrap(), HashMap::from([(2, vec!["3-1"]),]));
+	}
+}

pezbridges/relays/equivocation/src/lib.rs

@@ -0,0 +1,137 @@
+// Copyright 2019-2023 Parity Technologies (UK) Ltd.
+// This file is part of Parity Bridges Common.
+
+// Parity Bridges Common 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 Bridges Common 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 Bridges Common.  If not, see <http://www.gnu.org/licenses/>.
+
+mod block_checker;
+mod equivocation_loop;
+mod mock;
+mod reporter;
+
+use async_trait::async_trait;
+use bp_header_pez_chain::{FinalityProof, FindEquivocations};
+use pez_finality_relay::{FinalityPipeline, SourceClientBase};
+use relay_utils::{relay_loop::Client as RelayClient, MaybeConnectionError, TransactionTracker};
+use std::{fmt::Debug, time::Duration};
+
+pub use equivocation_loop::run;
+
+#[cfg(not(test))]
+const RECONNECT_DELAY: Duration = relay_utils::relay_loop::RECONNECT_DELAY;
+#[cfg(test)]
+const RECONNECT_DELAY: Duration = mock::TEST_RECONNECT_DELAY;
+
+pub trait EquivocationDetectionPipeline: FinalityPipeline {
+	/// Block number of the target chain.
+	type TargetNumber: relay_utils::BlockNumberBase;
+	/// The context needed for validating finality proofs.
+	type FinalityVerificationContext: Debug + Send;
+	/// The type of the equivocation proof.
+	type EquivocationProof: Clone + Debug + Send + Sync;
+	/// The equivocations finder.
+	type EquivocationsFinder: FindEquivocations<
+		Self::FinalityProof,
+		Self::FinalityVerificationContext,
+		Self::EquivocationProof,
+	>;
+}
+
+type HeaderFinalityInfo<P> = bp_header_pez_chain::HeaderFinalityInfo<
+	<P as FinalityPipeline>::FinalityProof,
+	<P as EquivocationDetectionPipeline>::FinalityVerificationContext,
+>;
+
+/// Source client used in equivocation detection loop.
+#[async_trait]
+pub trait SourceClient<P: EquivocationDetectionPipeline>: SourceClientBase<P> {
+	/// Transaction tracker to track submitted transactions.
+	type TransactionTracker: TransactionTracker;
+
+	/// Report equivocation.
+	async fn report_equivocation(
+		&self,
+		at: P::Hash,
+		equivocation: P::EquivocationProof,
+	) -> Result<Self::TransactionTracker, Self::Error>;
+}
+
+/// Target client used in equivocation detection loop.
+#[async_trait]
+pub trait TargetClient<P: EquivocationDetectionPipeline>: RelayClient {
+	/// Get the best finalized header number.
+	async fn best_finalized_header_number(&self) -> Result<P::TargetNumber, Self::Error>;
+
+	/// Get the hash of the best source header known by the target at the provided block number.
+	async fn best_synced_header_hash(
+		&self,
+		at: P::TargetNumber,
+	) -> Result<Option<P::Hash>, Self::Error>;
+
+	/// Get the data stored by the target at the specified block for validating source finality
+	/// proofs.
+	async fn finality_verification_context(
+		&self,
+		at: P::TargetNumber,
+	) -> Result<P::FinalityVerificationContext, Self::Error>;
+
+	/// Get the finality info associated to the source headers synced with the target chain at the
+	/// specified block.
+	async fn synced_headers_finality_info(
+		&self,
+		at: P::TargetNumber,
+	) -> Result<Vec<HeaderFinalityInfo<P>>, Self::Error>;
+}
+
+/// The context needed for finding equivocations inside finality proofs and reporting them.
+#[derive(Debug, PartialEq)]
+struct EquivocationReportingContext<P: EquivocationDetectionPipeline> {
+	pub synced_header_hash: P::Hash,
+	pub synced_verification_context: P::FinalityVerificationContext,
+}
+
+impl<P: EquivocationDetectionPipeline> EquivocationReportingContext<P> {
+	/// Try to get the `EquivocationReportingContext` used by the target chain
+	/// at the provided block.
+	pub async fn try_read_from_target<TC: TargetClient<P>>(
+		target_client: &TC,
+		at: P::TargetNumber,
+	) -> Result<Option<Self>, TC::Error> {
+		let maybe_best_synced_header_hash = target_client.best_synced_header_hash(at).await?;
+		Ok(match maybe_best_synced_header_hash {
+			Some(best_synced_header_hash) => Some(EquivocationReportingContext {
+				synced_header_hash: best_synced_header_hash,
+				synced_verification_context: target_client
+					.finality_verification_context(at)
+					.await?,
+			}),
+			None => None,
+		})
+	}
+
+	/// Update with the new context introduced by the `HeaderFinalityInfo<P>` if any.
+	pub fn update(&mut self, info: HeaderFinalityInfo<P>) {
+		if let Some(new_verification_context) = info.new_verification_context {
+			self.synced_header_hash = info.finality_proof.target_header_hash();
+			self.synced_verification_context = new_verification_context;
+		}
+	}
+}
+
+async fn handle_client_error<C: RelayClient>(client: &mut C, e: C::Error) {
+	if e.is_connection_error() {
+		client.reconnect_until_success(RECONNECT_DELAY).await;
+	} else {
+		async_std::task::sleep(RECONNECT_DELAY).await;
+	}
+}

pezbridges/relays/equivocation/src/mock.rs

@@ -0,0 +1,285 @@
+// Copyright (C) Parity Technologies (UK) Ltd.
+// This file is part of Parity Bridges Common.
+
+// Parity Bridges Common 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 Bridges Common 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 Bridges Common.  If not, see <http://www.gnu.org/licenses/>.
+
+#![cfg(test)]
+
+use crate::{EquivocationDetectionPipeline, HeaderFinalityInfo, SourceClient, TargetClient};
+use async_trait::async_trait;
+use bp_header_pez_chain::{FinalityProof, FindEquivocations};
+use pez_finality_relay::{FinalityPipeline, SourceClientBase};
+use futures::{Stream, StreamExt};
+use relay_utils::{
+	relay_loop::Client as RelayClient, HeaderId, MaybeConnectionError, TrackedTransactionStatus,
+	TransactionTracker,
+};
+use std::{
+	collections::HashMap,
+	pin::Pin,
+	sync::{Arc, Mutex},
+	time::Duration,
+};
+
+pub type TestSourceHashAndNumber = u64;
+pub type TestTargetNumber = u64;
+pub type TestEquivocationProof = &'static str;
+
+pub const TEST_RECONNECT_DELAY: Duration = Duration::from_secs(0);
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct TestFinalityProof(pub TestSourceHashAndNumber, pub Vec<TestEquivocationProof>);
+
+impl FinalityProof<TestSourceHashAndNumber, TestSourceHashAndNumber> for TestFinalityProof {
+	fn target_header_hash(&self) -> TestSourceHashAndNumber {
+		self.0
+	}
+
+	fn target_header_number(&self) -> TestSourceHashAndNumber {
+		self.0
+	}
+}
+
+#[derive(Debug, Clone, PartialEq)]
+pub struct TestEquivocationDetectionPipeline;
+
+impl FinalityPipeline for TestEquivocationDetectionPipeline {
+	const SOURCE_NAME: &'static str = "TestSource";
+	const TARGET_NAME: &'static str = "TestTarget";
+
+	type Hash = TestSourceHashAndNumber;
+	type Number = TestSourceHashAndNumber;
+	type FinalityProof = TestFinalityProof;
+}
+
+#[derive(Clone, Debug, PartialEq)]
+pub struct TestFinalityVerificationContext {
+	pub check_equivocations: bool,
+}
+
+pub struct TestEquivocationsFinder;
+
+impl FindEquivocations<TestFinalityProof, TestFinalityVerificationContext, TestEquivocationProof>
+	for TestEquivocationsFinder
+{
+	type Error = ();
+
+	fn find_equivocations(
+		verification_context: &TestFinalityVerificationContext,
+		synced_proof: &TestFinalityProof,
+		source_proofs: &[TestFinalityProof],
+	) -> Result<Vec<TestEquivocationProof>, Self::Error> {
+		if verification_context.check_equivocations {
+			// Get the equivocations from the source proofs, in order to make sure
+			// that they are correctly provided.
+			if let Some(proof) = source_proofs.iter().find(|proof| proof.0 == synced_proof.0) {
+				return Ok(proof.1.clone());
+			}
+		}
+
+		Ok(vec![])
+	}
+}
+
+impl EquivocationDetectionPipeline for TestEquivocationDetectionPipeline {
+	type TargetNumber = TestTargetNumber;
+	type FinalityVerificationContext = TestFinalityVerificationContext;
+	type EquivocationProof = TestEquivocationProof;
+	type EquivocationsFinder = TestEquivocationsFinder;
+}
+
+#[derive(Debug, Clone)]
+pub enum TestClientError {
+	Connection,
+	NonConnection,
+}
+
+impl MaybeConnectionError for TestClientError {
+	fn is_connection_error(&self) -> bool {
+		match self {
+			TestClientError::Connection => true,
+			TestClientError::NonConnection => false,
+		}
+	}
+}
+
+#[derive(Clone)]
+pub struct TestSourceClient {
+	pub num_reconnects: u32,
+	pub finality_proofs: Arc<Mutex<Vec<TestFinalityProof>>>,
+	pub reported_equivocations:
+		Arc<Mutex<HashMap<TestSourceHashAndNumber, Vec<TestEquivocationProof>>>>,
+}
+
+impl Default for TestSourceClient {
+	fn default() -> Self {
+		Self {
+			num_reconnects: 0,
+			finality_proofs: Arc::new(Mutex::new(vec![])),
+			reported_equivocations: Arc::new(Mutex::new(Default::default())),
+		}
+	}
+}
+
+#[async_trait]
+impl RelayClient for TestSourceClient {
+	type Error = TestClientError;
+
+	async fn reconnect(&mut self) -> Result<(), Self::Error> {
+		self.num_reconnects += 1;
+
+		Ok(())
+	}
+}
+
+#[async_trait]
+impl SourceClientBase<TestEquivocationDetectionPipeline> for TestSourceClient {
+	type FinalityProofsStream = Pin<Box<dyn Stream<Item = TestFinalityProof> + 'static + Send>>;
+
+	async fn finality_proofs(&self) -> Result<Self::FinalityProofsStream, Self::Error> {
+		let finality_proofs = std::mem::take(&mut *self.finality_proofs.lock().unwrap());
+		Ok(futures::stream::iter(finality_proofs).boxed())
+	}
+}
+
+#[derive(Clone, Debug)]
+pub struct TestTransactionTracker(
+	pub TrackedTransactionStatus<HeaderId<TestSourceHashAndNumber, TestSourceHashAndNumber>>,
+);
+
+impl Default for TestTransactionTracker {
+	fn default() -> TestTransactionTracker {
+		TestTransactionTracker(TrackedTransactionStatus::Finalized(Default::default()))
+	}
+}
+
+#[async_trait]
+impl TransactionTracker for TestTransactionTracker {
+	type HeaderId = HeaderId<TestSourceHashAndNumber, TestSourceHashAndNumber>;
+
+	async fn wait(
+		self,
+	) -> TrackedTransactionStatus<HeaderId<TestSourceHashAndNumber, TestSourceHashAndNumber>> {
+		self.0
+	}
+}
+
+#[async_trait]
+impl SourceClient<TestEquivocationDetectionPipeline> for TestSourceClient {
+	type TransactionTracker = TestTransactionTracker;
+
+	async fn report_equivocation(
+		&self,
+		at: TestSourceHashAndNumber,
+		equivocation: TestEquivocationProof,
+	) -> Result<Self::TransactionTracker, Self::Error> {
+		self.reported_equivocations
+			.lock()
+			.unwrap()
+			.entry(at)
+			.or_default()
+			.push(equivocation);
+
+		Ok(TestTransactionTracker::default())
+	}
+}
+
+#[derive(Clone)]
+pub struct TestTargetClient {
+	pub num_reconnects: u32,
+	pub best_finalized_header_number:
+		Arc<dyn Fn() -> Result<TestTargetNumber, TestClientError> + Send + Sync>,
+	pub best_synced_header_hash:
+		HashMap<TestTargetNumber, Result<Option<TestSourceHashAndNumber>, TestClientError>>,
+	pub finality_verification_context:
+		HashMap<TestTargetNumber, Result<TestFinalityVerificationContext, TestClientError>>,
+	pub synced_headers_finality_info: HashMap<
+		TestTargetNumber,
+		Result<Vec<HeaderFinalityInfo<TestEquivocationDetectionPipeline>>, TestClientError>,
+	>,
+}
+
+impl Default for TestTargetClient {
+	fn default() -> Self {
+		Self {
+			num_reconnects: 0,
+			best_finalized_header_number: Arc::new(|| Ok(0)),
+			best_synced_header_hash: Default::default(),
+			finality_verification_context: Default::default(),
+			synced_headers_finality_info: Default::default(),
+		}
+	}
+}
+
+#[async_trait]
+impl RelayClient for TestTargetClient {
+	type Error = TestClientError;
+
+	async fn reconnect(&mut self) -> Result<(), Self::Error> {
+		self.num_reconnects += 1;
+
+		Ok(())
+	}
+}
+
+#[async_trait]
+impl TargetClient<TestEquivocationDetectionPipeline> for TestTargetClient {
+	async fn best_finalized_header_number(&self) -> Result<TestTargetNumber, Self::Error> {
+		(self.best_finalized_header_number)()
+	}
+
+	async fn best_synced_header_hash(
+		&self,
+		at: TestTargetNumber,
+	) -> Result<Option<TestSourceHashAndNumber>, Self::Error> {
+		self.best_synced_header_hash
+			.get(&at)
+			.unwrap_or(&Err(TestClientError::NonConnection))
+			.clone()
+	}
+
+	async fn finality_verification_context(
+		&self,
+		at: TestTargetNumber,
+	) -> Result<TestFinalityVerificationContext, Self::Error> {
+		self.finality_verification_context
+			.get(&at)
+			.unwrap_or(&Err(TestClientError::NonConnection))
+			.clone()
+	}
+
+	async fn synced_headers_finality_info(
+		&self,
+		at: TestTargetNumber,
+	) -> Result<Vec<HeaderFinalityInfo<TestEquivocationDetectionPipeline>>, Self::Error> {
+		self.synced_headers_finality_info
+			.get(&at)
+			.unwrap_or(&Err(TestClientError::NonConnection))
+			.clone()
+	}
+}
+
+pub fn new_header_finality_info(
+	source_hdr: TestSourceHashAndNumber,
+	check_following_equivocations: Option<bool>,
+) -> HeaderFinalityInfo<TestEquivocationDetectionPipeline> {
+	HeaderFinalityInfo::<TestEquivocationDetectionPipeline> {
+		finality_proof: TestFinalityProof(source_hdr, vec![]),
+		new_verification_context: check_following_equivocations.map(
+			|check_following_equivocations| TestFinalityVerificationContext {
+				check_equivocations: check_following_equivocations,
+			},
+		),
+	}
+}

pezbridges/relays/equivocation/src/reporter.rs

@@ -0,0 +1,129 @@
+// Copyright 2019-2023 Parity Technologies (UK) Ltd.
+// This file is part of Parity Bridges Common.
+
+// Parity Bridges Common 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 Bridges Common 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 Bridges Common.  If not, see <http://www.gnu.org/licenses/>.
+
+//! Helper struct used for submitting finality reports and tracking their status.
+
+use crate::{EquivocationDetectionPipeline, SourceClient};
+
+use futures::FutureExt;
+use relay_utils::{TrackedTransactionFuture, TrackedTransactionStatus, TransactionTracker};
+use std::{
+	future::poll_fn,
+	task::{Context, Poll},
+};
+
+pub struct EquivocationsReporter<'a, P: EquivocationDetectionPipeline, SC: SourceClient<P>> {
+	pending_reports: Vec<TrackedTransactionFuture<'a, SC::TransactionTracker>>,
+}
+
+impl<'a, P: EquivocationDetectionPipeline, SC: SourceClient<P>> EquivocationsReporter<'a, P, SC> {
+	pub fn new() -> Self {
+		Self { pending_reports: vec![] }
+	}
+
+	/// Submit a `report_equivocation()` transaction to the source chain.
+	///
+	/// We store the transaction tracker for future monitoring.
+	pub async fn submit_report(
+		&mut self,
+		source_client: &SC,
+		at: P::Hash,
+		equivocation: P::EquivocationProof,
+	) -> Result<(), SC::Error> {
+		let pending_report = source_client.report_equivocation(at, equivocation).await?;
+		self.pending_reports.push(pending_report.wait());
+
+		Ok(())
+	}
+
+	fn do_process_pending_reports(&mut self, cx: &mut Context<'_>) -> Poll<()> {
+		self.pending_reports.retain_mut(|pending_report| {
+			match pending_report.poll_unpin(cx) {
+				Poll::Ready(tx_status) => {
+					match tx_status {
+						TrackedTransactionStatus::Lost => {
+							tracing::error!(target: "bridge", "Equivocation report tx was lost");
+						},
+						TrackedTransactionStatus::Finalized(id) => {
+							tracing::error!(target: "bridge", ?id, "Equivocation report tx was finalized in source block");
+						},
+					}
+
+					// The future was processed. Drop it.
+					false
+				},
+				Poll::Pending => {
+					// The future is still pending. Retain it.
+					true
+				},
+			}
+		});
+
+		Poll::Ready(())
+	}
+
+	/// Iterate through all the pending `report_equivocation()` transactions
+	/// and log the ones that finished.
+	pub async fn process_pending_reports(&mut self) {
+		poll_fn(|cx| self.do_process_pending_reports(cx)).await
+	}
+}
+
+#[cfg(test)]
+mod tests {
+	use super::*;
+	use crate::mock::*;
+	use relay_utils::HeaderId;
+	use std::sync::Mutex;
+
+	#[async_std::test]
+	async fn process_pending_reports_works() {
+		let polled_reports = Mutex::new(vec![]);
+		let finished_reports = Mutex::new(vec![]);
+
+		let mut reporter =
+			EquivocationsReporter::<TestEquivocationDetectionPipeline, TestSourceClient> {
+				pending_reports: vec![
+					Box::pin(async {
+						polled_reports.lock().unwrap().push(1);
+						finished_reports.lock().unwrap().push(1);
+						TrackedTransactionStatus::Finalized(HeaderId(1, 1))
+					}),
+					Box::pin(async {
+						polled_reports.lock().unwrap().push(2);
+						finished_reports.lock().unwrap().push(2);
+						TrackedTransactionStatus::Finalized(HeaderId(2, 2))
+					}),
+					Box::pin(async {
+						polled_reports.lock().unwrap().push(3);
+						std::future::pending::<()>().await;
+						finished_reports.lock().unwrap().push(3);
+						TrackedTransactionStatus::Finalized(HeaderId(3, 3))
+					}),
+					Box::pin(async {
+						polled_reports.lock().unwrap().push(4);
+						finished_reports.lock().unwrap().push(4);
+						TrackedTransactionStatus::Finalized(HeaderId(4, 4))
+					}),
+				],
+			};
+
+		reporter.process_pending_reports().await;
+		assert_eq!(*polled_reports.lock().unwrap(), vec![1, 2, 3, 4]);
+		assert_eq!(*finished_reports.lock().unwrap(), vec![1, 2, 4]);
+		assert_eq!(reporter.pending_reports.len(), 1);
+	}
+}