Blockchain service provides IsCanonical getter

beacon-chain/blockchain/chain_info.go

@@ -21,6 +21,7 @@ type ChainInfoFetcher interface {
 	HeadFetcher
 	FinalizationFetcher
 	GenesisFetcher
+	CanonicalFetcher
 }
 
 // TimeFetcher retrieves the Eth2 data that's related to time.
@@ -51,6 +52,11 @@ type ForkFetcher interface {
 	CurrentFork() *pb.Fork
 }
 
+// CanonicalFetcher retrieves the current chain's canonical information.
+type CanonicalFetcher interface {
+	IsCanonical(ctx context.Context, blockRoot [32]byte) (bool, error)
+}
+
 // FinalizationFetcher defines a common interface for methods in blockchain service which
 // directly retrieves finalization and justification related data.
 type FinalizationFetcher interface {
@@ -222,3 +228,17 @@ func (s *Service) Participation(epoch uint64) *precompute.Balance {
 
 	return s.epochParticipation[epoch]
 }
+
+// IsCanonical returns true if the input block root is part of the canonical chain.
+func (s *Service) IsCanonical(ctx context.Context, blockRoot [32]byte) (bool, error) {
+	// If the block has been finalized, the block will always be part of the canonical chain.
+	if s.beaconDB.IsFinalizedBlock(ctx, blockRoot) {
+		return true, nil
+	}
+
+	// If the block has not been finalized, the block must be recent. Check recent canonical roots
+	// mapping which uses proto array fork choice.
+	s.recentCanonicalBlocksLock.RLock()
+	defer s.recentCanonicalBlocksLock.RUnlock()
+	return s.recentCanonicalBlocks[blockRoot], nil
+}

beacon-chain/blockchain/head.go

@@ -8,6 +8,7 @@ import (
 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/feed"
 	statefeed "github.com/prysmaticlabs/prysm/beacon-chain/core/feed/state"
+	"github.com/prysmaticlabs/prysm/beacon-chain/forkchoice/protoarray"
 	"github.com/prysmaticlabs/prysm/beacon-chain/state"
 	stateTrie "github.com/prysmaticlabs/prysm/beacon-chain/state"
 	"github.com/prysmaticlabs/prysm/shared/bytesutil"
@@ -46,6 +47,10 @@ func (s *Service) updateHead(ctx context.Context, balances []uint64) error {
 		return err
 	}
 
+	if err := s.updateRecentCanonicalBlocks(ctx, headRoot); err != nil {
+		return err
+	}
+
 	// Save head to the local service cache.
 	return s.saveHead(ctx, headRoot)
 }
@@ -254,3 +259,28 @@ func (s *Service) hasHeadState() bool {
 
 	return s.head != nil && s.head.state != nil
 }
+
+// This updates recent canonical block mapping. It uses input head root and retrieves
+// all the canonical block roots that are ancestor of the input head block root.
+func (s *Service) updateRecentCanonicalBlocks(ctx context.Context, headRoot [32]byte) error {
+	s.recentCanonicalBlocksLock.Lock()
+	defer s.recentCanonicalBlocksLock.Unlock()
+
+	s.recentCanonicalBlocks = make(map[[32]byte]bool)
+	s.recentCanonicalBlocks[headRoot] = true
+	nodes := s.forkChoiceStore.Nodes()
+	node := s.forkChoiceStore.Node(headRoot)
+	if node == nil {
+		return nil
+	}
+
+	for node.Parent != protoarray.NonExistentNode {
+		if ctx.Err() != nil {
+			return ctx.Err()
+		}
+		node = nodes[node.Parent]
+		s.recentCanonicalBlocks[node.Root] = true
+	}
+
+	return nil
+}

beacon-chain/blockchain/head_test.go

@@ -139,3 +139,62 @@ func TestSaveHead_Different_Reorg(t *testing.T) {
 	}
 	testutil.AssertLogsContain(t, hook, "Chain reorg occurred")
 }
+
+func TestUpdateRecentCanonicalBlocks_CanUpdateWithoutParent(t *testing.T) {
+	db := testDB.SetupDB(t)
+	service := setupBeaconChain(t, db)
+
+	r := [32]byte{'a'}
+	if err := service.updateRecentCanonicalBlocks(context.Background(), r); err != nil {
+		t.Fatal(err)
+	}
+	canonical, err := service.IsCanonical(context.Background(), r)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !canonical {
+		t.Error("Block should be canonical")
+	}
+}
+
+func TestUpdateRecentCanonicalBlocks_CanUpdateWithParent(t *testing.T) {
+	db := testDB.SetupDB(t)
+	service := setupBeaconChain(t, db)
+	oldHead := [32]byte{'a'}
+	if err := service.forkChoiceStore.ProcessBlock(context.Background(), 1, oldHead, [32]byte{'g'}, [32]byte{}, 0, 0); err != nil {
+		t.Fatal(err)
+	}
+	currentHead := [32]byte{'b'}
+	if err := service.forkChoiceStore.ProcessBlock(context.Background(), 3, currentHead, oldHead, [32]byte{}, 0, 0); err != nil {
+		t.Fatal(err)
+	}
+	forkedRoot := [32]byte{'c'}
+	if err := service.forkChoiceStore.ProcessBlock(context.Background(), 2, forkedRoot, oldHead, [32]byte{}, 0, 0); err != nil {
+		t.Fatal(err)
+	}
+
+	if err := service.updateRecentCanonicalBlocks(context.Background(), currentHead); err != nil {
+		t.Fatal(err)
+	}
+	canonical, err := service.IsCanonical(context.Background(), currentHead)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !canonical {
+		t.Error("Block should be canonical")
+	}
+	canonical, err = service.IsCanonical(context.Background(), oldHead)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !canonical {
+		t.Error("Block should be canonical")
+	}
+	canonical, err = service.IsCanonical(context.Background(), forkedRoot)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if canonical {
+		t.Error("Block should not be canonical")
+	}
+}

beacon-chain/blockchain/service.go

@@ -43,40 +43,42 @@ import (
 // Service represents a service that handles the internal
 // logic of managing the full PoS beacon chain.
 type Service struct {
-	ctx                    context.Context
-	cancel                 context.CancelFunc
-	beaconDB               db.HeadAccessDatabase
-	depositCache           *depositcache.DepositCache
-	chainStartFetcher      powchain.ChainStartFetcher
-	attPool                attestations.Pool
-	slashingPool           *slashings.Pool
-	exitPool               *voluntaryexits.Pool
-	genesisTime            time.Time
-	p2p                    p2p.Broadcaster
-	maxRoutines            int64
-	head                   *head
-	headLock               sync.RWMutex
-	stateNotifier          statefeed.Notifier
-	genesisRoot            [32]byte
-	epochParticipation     map[uint64]*precompute.Balance
-	epochParticipationLock sync.RWMutex
-	forkChoiceStore        f.ForkChoicer
-	justifiedCheckpt       *ethpb.Checkpoint
-	prevJustifiedCheckpt   *ethpb.Checkpoint
-	bestJustifiedCheckpt   *ethpb.Checkpoint
-	finalizedCheckpt       *ethpb.Checkpoint
-	prevFinalizedCheckpt   *ethpb.Checkpoint
-	nextEpochBoundarySlot  uint64
-	voteLock               sync.RWMutex
-	initSyncState          map[[32]byte]*stateTrie.BeaconState
-	boundaryRoots          [][32]byte
-	initSyncStateLock      sync.RWMutex
-	checkpointState        *cache.CheckpointStateCache
-	checkpointStateLock    sync.Mutex
-	stateGen               *stategen.State
-	opsService             *attestations.Service
-	initSyncBlocks         map[[32]byte]*ethpb.SignedBeaconBlock
-	initSyncBlocksLock     sync.RWMutex
+	ctx                       context.Context
+	cancel                    context.CancelFunc
+	beaconDB                  db.HeadAccessDatabase
+	depositCache              *depositcache.DepositCache
+	chainStartFetcher         powchain.ChainStartFetcher
+	attPool                   attestations.Pool
+	slashingPool              *slashings.Pool
+	exitPool                  *voluntaryexits.Pool
+	genesisTime               time.Time
+	p2p                       p2p.Broadcaster
+	maxRoutines               int64
+	head                      *head
+	headLock                  sync.RWMutex
+	stateNotifier             statefeed.Notifier
+	genesisRoot               [32]byte
+	epochParticipation        map[uint64]*precompute.Balance
+	epochParticipationLock    sync.RWMutex
+	forkChoiceStore           f.ForkChoicer
+	justifiedCheckpt          *ethpb.Checkpoint
+	prevJustifiedCheckpt      *ethpb.Checkpoint
+	bestJustifiedCheckpt      *ethpb.Checkpoint
+	finalizedCheckpt          *ethpb.Checkpoint
+	prevFinalizedCheckpt      *ethpb.Checkpoint
+	nextEpochBoundarySlot     uint64
+	voteLock                  sync.RWMutex
+	initSyncState             map[[32]byte]*stateTrie.BeaconState
+	boundaryRoots             [][32]byte
+	initSyncStateLock         sync.RWMutex
+	checkpointState           *cache.CheckpointStateCache
+	checkpointStateLock       sync.Mutex
+	stateGen                  *stategen.State
+	opsService                *attestations.Service
+	initSyncBlocks            map[[32]byte]*ethpb.SignedBeaconBlock
+	initSyncBlocksLock        sync.RWMutex
+	recentCanonicalBlocks     map[[32]byte]bool
+	recentCanonicalBlocksLock sync.RWMutex
 }
 
 // Config options for the service.
@@ -101,25 +103,26 @@ type Config struct {
 func NewService(ctx context.Context, cfg *Config) (*Service, error) {
 	ctx, cancel := context.WithCancel(ctx)
 	return &Service{
-		ctx:                ctx,
-		cancel:             cancel,
-		beaconDB:           cfg.BeaconDB,
-		depositCache:       cfg.DepositCache,
-		chainStartFetcher:  cfg.ChainStartFetcher,
-		attPool:            cfg.AttPool,
-		exitPool:           cfg.ExitPool,
-		slashingPool:       cfg.SlashingPool,
-		p2p:                cfg.P2p,
-		maxRoutines:        cfg.MaxRoutines,
-		stateNotifier:      cfg.StateNotifier,
-		epochParticipation: make(map[uint64]*precompute.Balance),
-		forkChoiceStore:    cfg.ForkChoiceStore,
-		initSyncState:      make(map[[32]byte]*stateTrie.BeaconState),
-		boundaryRoots:      [][32]byte{},
-		checkpointState:    cache.NewCheckpointStateCache(),
-		opsService:         cfg.OpsService,
-		stateGen:           cfg.StateGen,
-		initSyncBlocks:     make(map[[32]byte]*ethpb.SignedBeaconBlock),
+		ctx:                   ctx,
+		cancel:                cancel,
+		beaconDB:              cfg.BeaconDB,
+		depositCache:          cfg.DepositCache,
+		chainStartFetcher:     cfg.ChainStartFetcher,
+		attPool:               cfg.AttPool,
+		exitPool:              cfg.ExitPool,
+		slashingPool:          cfg.SlashingPool,
+		p2p:                   cfg.P2p,
+		maxRoutines:           cfg.MaxRoutines,
+		stateNotifier:         cfg.StateNotifier,
+		epochParticipation:    make(map[uint64]*precompute.Balance),
+		forkChoiceStore:       cfg.ForkChoiceStore,
+		initSyncState:         make(map[[32]byte]*stateTrie.BeaconState),
+		boundaryRoots:         [][32]byte{},
+		checkpointState:       cache.NewCheckpointStateCache(),
+		opsService:            cfg.OpsService,
+		stateGen:              cfg.StateGen,
+		initSyncBlocks:        make(map[[32]byte]*ethpb.SignedBeaconBlock),
+		recentCanonicalBlocks: make(map[[32]byte]bool),
 	}, nil
 }
 

beacon-chain/forkchoice/protoarray/ffg_update_test.go

@@ -246,12 +246,12 @@ func setup(justifiedEpoch uint64, finalizedEpoch uint64) *ForkChoice {
 	f.store.nodeIndices[params.BeaconConfig().ZeroHash] = 0
 	f.store.nodes = append(f.store.nodes, &Node{
 		Slot:           0,
-		root:           params.BeaconConfig().ZeroHash,
-		Parent:         nonExistentNode,
+		Root:           params.BeaconConfig().ZeroHash,
+		Parent:         NonExistentNode,
 		justifiedEpoch: justifiedEpoch,
 		finalizedEpoch: finalizedEpoch,
-		bestChild:      nonExistentNode,
-		BestDescendent: nonExistentNode,
+		bestChild:      NonExistentNode,
+		BestDescendent: NonExistentNode,
 		Weight:         0,
 	})
 

beacon-chain/forkchoice/protoarray/helpers.go

@@ -78,11 +78,11 @@ func copyNode(node *Node) *Node {
 	}
 
 	copiedRoot := [32]byte{}
-	copy(copiedRoot[:], node.root[:])
+	copy(copiedRoot[:], node.Root[:])
 
 	return &Node{
 		Slot:           node.Slot,
-		root:           copiedRoot,
+		Root:           copiedRoot,
 		Parent:         node.Parent,
 		justifiedEpoch: node.justifiedEpoch,
 		finalizedEpoch: node.finalizedEpoch,