Dispute spam protection (#4134)

* Mostly notes.

* Better error messages.

* Introduce Fatal/NonFatal + drop back channel participation

- Fatal/NonFatal - in order to make it easier to use utility functions.
- We drop the back channel in dispute participation as it won't be
needed any more.

* Better error messages.

* Utility function for receiving `CandidateEvent`s.

* Ordering module typechecks.

* cargo fmt

* Prepare spam slots module.

* Implement SpamSlots mechanism.

* Implement queues.

* cargo fmt

* Participation.

* Participation taking shape.

* Finish participation.

* cargo fmt

* Cleanup.

* WIP: Cleanup + Integration.

* Make `RollingSessionWindow` initialized by default.

* Make approval voting typecheck.

* Get rid of lazy_static & fix approval voting tests

* Move `SessionWindowSize` to node primitives.

* Implement dispute coordinator initialization.

* cargo fmt

* Make queues return error instead of boolean.

* Initialized: WIP

* Introduce chain api for getting finalized block.

* Fix ordering to only prune candidates on finalized events.

* Pruning of old sessions in spam slots.

* New import logic.

* Make everything typecheck.

* Fix warnings.

* Get rid of obsolete dispute-participation.

* Fixes.

* Add back accidentelly deleted Cargo.lock

* Deliver disputes in an ordered fashion.

* Add module docs for errors

* Use type synonym.

* hidden docs.

* Fix overseer tests.

* Ordering provider taking `CandidateReceipt`.

... To be kicked on one next commit.

* Fix ordering to use relay_parent

as included block is not unique per candidate.

* Add comment in ordering.rs.

* Take care of duplicate entries in queues.

* Better spam slots.

* Review remarks + docs.

* Fix db tests.

* Participation tests.

* Also scrape votes on first leaf for good measure.

* Make tests typecheck.

* Spelling.

* Only participate in actual disputes, not on every import.

* Don't account backing votes to spam slots.

* Fix more tests.

* Don't participate if we don't have keys.

* Fix tests, typos and warnings.

* Fix merge error.

* Spelling fixes.

* Add missing docs.

* Queue tests.

* More tests.

* Add metrics + don't short circuit import.

* Basic test for ordering provider.

* Import fix.

* Remove dead link.

* One more dead link.

Co-authored-by: Lldenaurois <Ljdenaurois@gmail.com>

polkadot/node/overseer/src/tests.rs

@@ -888,17 +888,6 @@ fn test_dispute_coordinator_msg() -> DisputeCoordinatorMessage {
 	DisputeCoordinatorMessage::RecentDisputes(sender)
 }
 
-fn test_dispute_participation_msg() -> DisputeParticipationMessage {
-	let (sender, _) = oneshot::channel();
-	DisputeParticipationMessage::Participate {
-		candidate_hash: Default::default(),
-		candidate_receipt: Default::default(),
-		session: 0,
-		n_validators: 0,
-		report_availability: sender,
-	}
-}
-
 fn test_dispute_distribution_msg() -> DisputeDistributionMessage {
 	let dummy_dispute_message = UncheckedDisputeMessage {
 		candidate_receipt: Default::default(),
@@ -930,7 +919,7 @@ fn test_chain_selection_msg() -> ChainSelectionMessage {
 // Checks that `stop`, `broadcast_signal` and `broadcast_message` are implemented correctly.
 #[test]
 fn overseer_all_subsystems_receive_signals_and_messages() {
-	const NUM_SUBSYSTEMS: usize = 21;
+	const NUM_SUBSYSTEMS: usize = 20;
 	// -3 for BitfieldSigning, GossipSupport and AvailabilityDistribution
 	const NUM_SUBSYSTEMS_MESSAGED: usize = NUM_SUBSYSTEMS - 3;
 
@@ -1009,9 +998,6 @@ fn overseer_all_subsystems_receive_signals_and_messages() {
 		handle
 			.send_msg_anon(AllMessages::DisputeCoordinator(test_dispute_coordinator_msg()))
 			.await;
-		handle
-			.send_msg_anon(AllMessages::DisputeParticipation(test_dispute_participation_msg()))
-			.await;
 		handle
 			.send_msg_anon(AllMessages::DisputeDistribution(test_dispute_distribution_msg()))
 			.await;
@@ -1069,7 +1055,6 @@ fn context_holds_onto_message_until_enough_signals_received() {
 	let (approval_voting_bounded_tx, _) = metered::channel(CHANNEL_CAPACITY);
 	let (gossip_support_bounded_tx, _) = metered::channel(CHANNEL_CAPACITY);
 	let (dispute_coordinator_bounded_tx, _) = metered::channel(CHANNEL_CAPACITY);
-	let (dispute_participation_bounded_tx, _) = metered::channel(CHANNEL_CAPACITY);
 	let (dispute_distribution_bounded_tx, _) = metered::channel(CHANNEL_CAPACITY);
 	let (chain_selection_bounded_tx, _) = metered::channel(CHANNEL_CAPACITY);
 
@@ -1091,7 +1076,6 @@ fn context_holds_onto_message_until_enough_signals_received() {
 	let (approval_voting_unbounded_tx, _) = metered::unbounded();
 	let (gossip_support_unbounded_tx, _) = metered::unbounded();
 	let (dispute_coordinator_unbounded_tx, _) = metered::unbounded();
-	let (dispute_participation_unbounded_tx, _) = metered::unbounded();
 	let (dispute_distribution_unbounded_tx, _) = metered::unbounded();
 	let (chain_selection_unbounded_tx, _) = metered::unbounded();
 
@@ -1114,7 +1098,6 @@ fn context_holds_onto_message_until_enough_signals_received() {
 		approval_voting: approval_voting_bounded_tx.clone(),
 		gossip_support: gossip_support_bounded_tx.clone(),
 		dispute_coordinator: dispute_coordinator_bounded_tx.clone(),
-		dispute_participation: dispute_participation_bounded_tx.clone(),
 		dispute_distribution: dispute_distribution_bounded_tx.clone(),
 		chain_selection: chain_selection_bounded_tx.clone(),
 
@@ -1136,7 +1119,6 @@ fn context_holds_onto_message_until_enough_signals_received() {
 		approval_voting_unbounded: approval_voting_unbounded_tx.clone(),
 		gossip_support_unbounded: gossip_support_unbounded_tx.clone(),
 		dispute_coordinator_unbounded: dispute_coordinator_unbounded_tx.clone(),
-		dispute_participation_unbounded: dispute_participation_unbounded_tx.clone(),
 		dispute_distribution_unbounded: dispute_distribution_unbounded_tx.clone(),
 		chain_selection_unbounded: chain_selection_unbounded_tx.clone(),
 	};