Merge pull request #3170 from oasisprotocol/kostko/feature/consensus-…

…submitevidence-move

go/consensus: Move SubmitEvidence to LightClientBackend

.changelog/3169.feature.md

@@ -0,0 +1,3 @@
+go/consensus: Move SubmitEvidence to LightClientBackend
+
+This allows light clients to submit evidence of Byzantine behavior.

go/consensus/api/api.go

@@ -209,9 +209,6 @@ type ServicesBackend interface {
 	// consensus Halt epoch height is reached.
 	RegisterHaltHook(func(ctx context.Context, blockHeight int64, epoch epochtime.EpochTime))
 
-	// SubmitEvidence submits evidence of misbehavior.
-	SubmitEvidence(ctx context.Context, evidence Evidence) error
-
 	// SubmissionManager returns the transaction submission manager.
 	SubmissionManager() SubmissionManager
 
@@ -245,56 +242,6 @@ type TransactionAuthHandler interface {
 	GetSignerNonce(ctx context.Context, req *GetSignerNonceRequest) (uint64, error)
 }
 
-// EvidenceKind is kind of evindence of a node misbehaving.
-type EvidenceKind int
-
-const (
-	// EvidenceKindConsensus is consensus-layer specific evidence.
-	EvidenceKindConsensus EvidenceKind = 0
-
-	EvidenceKindMax = EvidenceKindConsensus
-)
-
-// String returns a string representation of an EvidenceKind.
-func (k EvidenceKind) String() string {
-	switch k {
-	case EvidenceKindConsensus:
-		return "consensus"
-	default:
-		return "[unknown evidence kind]"
-	}
-}
-
-// Evidence is evidence of a node misbehaving.
-type Evidence interface {
-	// Kind returns the evidence kind.
-	Kind() EvidenceKind
-	// Unwrap returns the unwrapped evidence (if any).
-	Unwrap() interface{}
-}
-
-// ConsensusEvidence is consensus backend-specific evidence.
-type ConsensusEvidence struct {
-	inner interface{}
-}
-
-var _ Evidence = (*ConsensusEvidence)(nil)
-
-// Kind returns the evidence kind.
-func (ce ConsensusEvidence) Kind() EvidenceKind {
-	return EvidenceKindConsensus
-}
-
-// Unwrap returns the unwrapped evidence (if any).
-func (ce ConsensusEvidence) Unwrap() interface{} {
-	return ce.inner
-}
-
-// NewConsensusEvidence creates new consensus backend-specific evidence.
-func NewConsensusEvidence(inner interface{}) ConsensusEvidence {
-	return ConsensusEvidence{inner: inner}
-}
-
 // EstimateGasRequest is a EstimateGas request.
 type EstimateGasRequest struct {
 	Signer      signature.PublicKey      `json:"signer"`

go/consensus/api/base.go

@@ -75,7 +75,7 @@ func (b *BaseBackend) RegisterHaltHook(func(ctx context.Context, blockHeight int
 }
 
 // Implements Backend.
-func (b *BaseBackend) SubmitEvidence(ctx context.Context, evidence Evidence) error {
+func (b *BaseBackend) SubmitEvidence(ctx context.Context, evidence *Evidence) error {
 	panic(ErrUnsupported)
 }
 

go/consensus/api/grpc.go

@@ -59,6 +59,8 @@ var (
 	methodStateSyncIterate = lightServiceName.NewMethod("StateSyncIterate", syncer.IterateRequest{})
 	// methodSubmitTxNoWait is the SubmitTxNoWait method.
 	methodSubmitTxNoWait = lightServiceName.NewMethod("SubmitTxNoWait", transaction.SignedTransaction{})
+	// methodSubmitEvidence is the SubmitEvidence method.
+	methodSubmitEvidence = lightServiceName.NewMethod("SubmitEvidence", &Evidence{})
 
 	// serviceDesc is the gRPC service descriptor.
 	serviceDesc = grpc.ServiceDesc{
@@ -152,6 +154,10 @@ var (
 				MethodName: methodSubmitTxNoWait.ShortName(),
 				Handler:    handlerSubmitTxNoWait,
 			},
+			{
+				MethodName: methodSubmitEvidence.ShortName(),
+				Handler:    handlerSubmitEvidence,
+			},
 		},
 	}
 )
@@ -590,6 +596,29 @@ func handlerSubmitTxNoWait( // nolint: golint
 	return interceptor(ctx, rq, info, handler)
 }
 
+func handlerSubmitEvidence( // nolint: golint
+	srv interface{},
+	ctx context.Context,
+	dec func(interface{}) error,
+	interceptor grpc.UnaryServerInterceptor,
+) (interface{}, error) {
+	rq := new(Evidence)
+	if err := dec(rq); err != nil {
+		return nil, err
+	}
+	if interceptor == nil {
+		return nil, srv.(LightClientBackend).SubmitEvidence(ctx, rq)
+	}
+	info := &grpc.UnaryServerInfo{
+		Server:     srv,
+		FullMethod: methodSubmitEvidence.FullName(),
+	}
+	handler := func(ctx context.Context, req interface{}) (interface{}, error) {
+		return nil, srv.(LightClientBackend).SubmitEvidence(ctx, req.(*Evidence))
+	}
+	return interceptor(ctx, rq, info, handler)
+}
+
 // RegisterService registers a new client backend service with the given gRPC server.
 func RegisterService(server *grpc.Server, service ClientBackend) {
 	server.RegisterService(&serviceDesc, service)
@@ -673,6 +702,11 @@ func (c *consensusLightClient) SubmitTxNoWait(ctx context.Context, tx *transacti
 	return c.conn.Invoke(ctx, methodSubmitTxNoWait.FullName(), tx, nil)
 }
 
+// Implements LightClientBackend.
+func (c *consensusLightClient) SubmitEvidence(ctx context.Context, evidence *Evidence) error {
+	return c.conn.Invoke(ctx, methodSubmitEvidence.FullName(), evidence, nil)
+}
+
 type consensusClient struct {
 	consensusLightClient
 

go/consensus/api/light.go

@@ -26,7 +26,8 @@ type LightClientBackend interface {
 	// to be included in a block. Use SubmitTx if you need to wait for execution.
 	SubmitTxNoWait(ctx context.Context, tx *transaction.SignedTransaction) error
 
-	// TODO: Move SubmitEvidence etc. from Backend.
+	// SubmitEvidence submits evidence of misbehavior.
+	SubmitEvidence(ctx context.Context, evidence *Evidence) error
 }
 
 // SignedHeader is a signed consensus block header.
@@ -54,3 +55,9 @@ type Parameters struct {
 
 	// TODO: Consider also including consensus/genesis.Parameters which are backend-agnostic.
 }
+
+// Evidence is evidence of a node's Byzantine behavior.
+type Evidence struct {
+	// Meta contains the consensus backend specific evidence.
+	Meta []byte `json:"meta"`
+}

go/consensus/tendermint/full/full.go

@@ -23,6 +23,7 @@ import (
 	tmmempool "github.com/tendermint/tendermint/mempool"
 	tmnode "github.com/tendermint/tendermint/node"
 	tmp2p "github.com/tendermint/tendermint/p2p"
+	tmproto "github.com/tendermint/tendermint/proto/tendermint/types"
 	tmproxy "github.com/tendermint/tendermint/proxy"
 	tmcli "github.com/tendermint/tendermint/rpc/client/local"
 	tmrpctypes "github.com/tendermint/tendermint/rpc/core/types"
@@ -537,17 +538,18 @@ func (t *fullService) newSubscriberID() string {
 	return fmt.Sprintf("%s/subscriber-%d", tmSubscriberID, atomic.AddUint64(&t.nextSubscriberID, 1))
 }
 
-func (t *fullService) SubmitEvidence(ctx context.Context, evidence consensusAPI.Evidence) error {
-	if evidence.Kind() != consensusAPI.EvidenceKindConsensus {
-		return fmt.Errorf("tendermint: unsupported evidence kind")
+func (t *fullService) SubmitEvidence(ctx context.Context, evidence *consensusAPI.Evidence) error {
+	var protoEv tmproto.Evidence
+	if err := protoEv.Unmarshal(evidence.Meta); err != nil {
+		return fmt.Errorf("tendermint: malformed evidence while unmarshalling: %w", err)
 	}
 
-	tmEvidence, ok := evidence.Unwrap().(tmtypes.Evidence)
-	if !ok {
-		return fmt.Errorf("tendermint: expected tendermint evidence, got something else")
+	ev, err := tmtypes.EvidenceFromProto(&protoEv)
+	if err != nil {
+		return fmt.Errorf("tendermint: malformed evidence while converting: %w", err)
 	}
 
-	if _, err := t.client.BroadcastEvidence(tmEvidence); err != nil {
+	if _, err := t.client.BroadcastEvidence(ev); err != nil {
 		return fmt.Errorf("tendermint: broadcast evidence failed: %w", err)
 	}
 

go/consensus/tendermint/light/client.go

@@ -112,8 +112,16 @@ func (lp *lightClientProvider) ValidatorSet(height int64) (*tmtypes.ValidatorSet
 
 // Implements tmlightprovider.Provider.
 func (lp *lightClientProvider) ReportEvidence(ev tmtypes.Evidence) error {
-	// TODO: Implement SubmitEvidence.
-	return fmt.Errorf("not yet implemented")
+	proto, err := tmtypes.EvidenceToProto(ev)
+	if err != nil {
+		return fmt.Errorf("failed to convert evidence: %w", err)
+	}
+	meta, err := proto.Marshal()
+	if err != nil {
+		return fmt.Errorf("failed to marshal evidence: %w", err)
+	}
+
+	return lp.client.SubmitEvidence(lp.ctx, &consensus.Evidence{Meta: meta})
 }
 
 // newLightClientProvider creates a new provider for the Tendermint's light client.
@@ -178,6 +186,11 @@ func (lc *lightClient) SubmitTxNoWait(ctx context.Context, tx *transaction.Signe
 	return lc.getPrimary().SubmitTxNoWait(ctx, tx)
 }
 
+// Implements consensus.LightClientBackend.
+func (lc *lightClient) SubmitEvidence(ctx context.Context, evidence *consensus.Evidence) error {
+	return lc.getPrimary().SubmitEvidence(ctx, evidence)
+}
+
 // Implements Client.
 func (lc *lightClient) GetVerifiedSignedHeader(ctx context.Context, height int64) (*tmtypes.SignedHeader, error) {
 	return lc.tmc.VerifyHeaderAtHeight(height, time.Now())

go/consensus/tendermint/tests/evidence.go

@@ -18,7 +18,7 @@ import (
 )
 
 // MakeDoubleSignEvidence creates consensus evidence of double signing.
-func MakeDoubleSignEvidence(t *testing.T, ident *identity.Identity) consensus.Evidence {
+func MakeDoubleSignEvidence(t *testing.T, ident *identity.Identity) *consensus.Evidence {
 	require := require.New(t)
 
 	// Create empty directory for private validator metadata.
@@ -64,7 +64,13 @@ func MakeDoubleSignEvidence(t *testing.T, ident *identity.Identity) consensus.Ev
 		VoteA: makeVote(pv1, genesisTestHelpers.TestChainID, 0, 1, 2, 1, blockID1, now),
 		VoteB: makeVote(pv2, genesisTestHelpers.TestChainID, 0, 1, 2, 1, blockID2, now),
 	}
-	return consensus.NewConsensusEvidence(ev)
+
+	proto, err := tmtypes.EvidenceToProto(ev)
+	require.NoError(err, "EvidenceToProto")
+	meta, err := proto.Marshal()
+	require.NoError(err, "proto.Marshal")
+
+	return &consensus.Evidence{Meta: meta}
 }
 
 // makeVote copied from Tendermint test suite.

go/consensus/tests/tester.go

@@ -130,6 +130,9 @@ func ConsensusImplementationTests(t *testing.T, backend consensus.ClientBackend)
 	err = backend.SubmitTxNoWait(ctx, testSigTx)
 	require.NoError(err, "SubmitTxNoWait")
 
+	err = backend.SubmitEvidence(ctx, &consensus.Evidence{})
+	require.Error(err, "SubmitEvidence should fail with invalid evidence")
+
 	// We should be able to do remote state queries. Of course the state format is backend-specific
 	// so we simply perform some usual storage operations like fetching random keys and iterating
 	// through everything.