adding verifiers to ProofService

fraudserv/service.go

@@ -44,10 +44,11 @@ type ProofService struct {
 	storesLk sync.RWMutex
 	stores   map[fraud.ProofType]datastore.Datastore
 
-	pubsub *pubsub.PubSub
-	host   host.Host
-	getter fraud.HeaderFetcher
-	ds     datastore.Datastore
+	pubsub    *pubsub.PubSub
+	host      host.Host
+	getter    fraud.HeaderFetcher
+	verifiers map[fraud.ProofType]fraud.Verifier
+	ds        datastore.Datastore
 
 	syncerEnabled bool
 }
@@ -64,6 +65,7 @@ func NewProofService(
 		pubsub:        p,
 		host:          host,
 		getter:        getter,
+		verifiers:     make(map[fraud.ProofType]fraud.Verifier),
 		topics:        make(map[fraud.ProofType]*pubsub.Topic),
 		stores:        make(map[fraud.ProofType]datastore.Datastore),
 		ds:            ds,
@@ -138,6 +140,14 @@ func (f *ProofService) Broadcast(ctx context.Context, p fraud.Proof) error {
 	return t.Publish(ctx, bin)
 }
 
+func (f *ProofService) AddVerifier(proofType fraud.ProofType, verifier fraud.Verifier) error {
+	if _, ok := f.verifiers[proofType]; ok {
+		return fmt.Errorf("verifier for proof type %s already exist", proofType)
+	}
+	f.verifiers[proofType] = verifier
+	return nil
+}
+
 // processIncoming encompasses the logic for validating fraud proofs.
 func (f *ProofService) processIncoming(
 	ctx context.Context,
@@ -181,6 +191,20 @@ func (f *ProofService) processIncoming(
 			"err", err, "proofType", proof.Type(), "height", proof.Height())
 		return pubsub.ValidationIgnore
 	}
+
+	// execute the verifier for proof type if exists
+	if verifier, ok := f.verifiers[proofType]; ok {
+		status, err := verifier(proof)
+		if err != nil {
+			log.Errorw("failed to run the verifier, err:", err, "proofType", proof.Type())
+			return pubsub.ValidationReject
+		}
+		if !status {
+			log.Errorw("failed to verify fraud proof for proofType", proof.Type())
+			return pubsub.ValidationReject
+		}
+	}
+
 	// validate the fraud proof.
 	// Peer will be added to black list if the validation fails.
 	err = proof.Validate(extHeader)

fraudserv/service_test.go

@@ -15,6 +15,7 @@ import (
 	"github.com/celestiaorg/go-header"
 	"github.com/celestiaorg/go-header/headertest"
 
+	gofraud "github.com/celestiaorg/go-fraud"
 	"github.com/celestiaorg/go-fraud/fraudtest"
 )
 
@@ -26,6 +27,9 @@ func TestService_SubscribeBroadcastValid(t *testing.T) {
 	require.NoError(t, serv.Start(ctx))
 
 	fraud := fraudtest.NewValidProof()
+	serv.AddVerifier(fraud.Type(), func(fraudProof gofraud.Proof) (bool, error) {
+		return true, nil
+	})
 	sub, err := serv.Subscribe(fraud.Type())
 	require.NoError(t, err)
 	defer sub.Cancel()

interface.go

@@ -9,6 +9,9 @@ import (
 // HeaderFetcher aliases a function that is used to fetch an ExtendedHeader from store by height.
 type HeaderFetcher func(context.Context, uint64) (header.Header, error)
 
+// Verifier is a function that is executed as part of processing the incoming fraud proof
+type Verifier func(fraud Proof) (bool, error)
+
 // ProofUnmarshaler aliases a function that parses data to `Proof`.
 type ProofUnmarshaler func([]byte) (Proof, error)