refactor: rely on builder api to provide gaslimit

Author: prestwich

common/types.go

@@ -133,15 +133,15 @@ func NewEthNetworkDetails(networkName string) (ret *EthNetworkDetails, err error
 func (e *EthNetworkDetails) String() string {
 	return fmt.Sprintf(
 		`EthNetworkDetails{
-	Name: %s, 
-	GenesisForkVersionHex: %s, 
+	Name: %s,
+	GenesisForkVersionHex: %s,
 	GenesisValidatorsRootHex: %s,
-	BellatrixForkVersionHex: %s, 
-	CapellaForkVersionHex: %s, 
+	BellatrixForkVersionHex: %s,
+	CapellaForkVersionHex: %s,
 	DenebForkVersionHex: %s,
-	DomainBuilder: %x, 
-	DomainBeaconProposerBellatrix: %x, 
-	DomainBeaconProposerCapella: %x, 
+	DomainBuilder: %x,
+	DomainBeaconProposerBellatrix: %x,
+	DomainBeaconProposerCapella: %x,
 	DomainBeaconProposerDeneb: %x
 }`,
 		e.Name,
@@ -1070,3 +1070,8 @@ func (s *SubmitBlockRequestV2Optimistic) SizeSSZ() (size int) {
 
 	return
 }
+
+type BuilderBlockValidationResponseV2 struct {
+	NewGasLimit  uint64        `json:"new_gas_limit,string"`
+	NewBlockHash phase0.Hash32 `json:"new_block_hash"`
+}

database/database.go

@@ -241,7 +241,7 @@ func (s *DatabaseService) SaveBuilderBlockSubmission(payload *common.BuilderSubm
 }
 
 func (s *DatabaseService) GetBlockSubmissionEntry(slot uint64, proposerPubkey, blockHash string) (entry *BuilderBlockSubmissionEntry, err error) {
-	query := `SELECT id, inserted_at, received_at, eligible_at, execution_payload_id, sim_success, sim_error, signature, slot, parent_hash, block_hash, builder_pubkey, proposer_pubkey, proposer_fee_recipient, gas_used, gas_limit, num_tx, value, epoch, block_number, decode_duration, prechecks_duration, simulation_duration, redis_update_duration, total_duration, optimistic_submission 
+	query := `SELECT id, inserted_at, received_at, eligible_at, execution_payload_id, sim_success, sim_error, signature, slot, parent_hash, block_hash, builder_pubkey, proposer_pubkey, proposer_fee_recipient, gas_used, gas_limit, num_tx, value, epoch, block_number, decode_duration, prechecks_duration, simulation_duration, redis_update_duration, total_duration, optimistic_submission
 	FROM ` + vars.TableBuilderBlockSubmission + `
 	WHERE slot=$1 AND proposer_pubkey=$2 AND block_hash=$3
 	ORDER BY builder_pubkey ASC

services/api/blocksim_ratelimiter.go

@@ -28,7 +28,7 @@ var (
 )
 
 type IBlockSimRateLimiter interface {
-	Send(context context.Context, payload *common.BuilderBlockValidationRequest, isHighPrio, fastTrack bool) (error, error)
+	Send(context context.Context, payload *common.BuilderBlockValidationRequest, isHighPrio, fastTrack bool) (*common.BuilderBlockValidationResponseV2, error, error)
 	CurrentCounter() int64
 }
 
@@ -50,7 +50,7 @@ func NewBlockSimulationRateLimiter(blockSimURL string) *BlockSimulationRateLimit
 	}
 }
 
-func (b *BlockSimulationRateLimiter) Send(context context.Context, payload *common.BuilderBlockValidationRequest, isHighPrio, fastTrack bool) (requestErr, validationErr error) {
+func (b *BlockSimulationRateLimiter) Send(context context.Context, payload *common.BuilderBlockValidationRequest, isHighPrio, fastTrack bool) (resp *common.BuilderBlockValidationResponseV2, requestErr, validationErr error) {
 	b.cv.L.Lock()
 	cnt := atomic.AddInt64(&b.counter, 1)
 	if maxConcurrentBlocks > 0 && cnt > maxConcurrentBlocks {
@@ -66,12 +66,12 @@ func (b *BlockSimulationRateLimiter) Send(context context.Context, payload *comm
 	}()
 
 	if err := context.Err(); err != nil {
-		return fmt.Errorf("%w, %w", ErrRequestClosed, err), nil
+		return nil, fmt.Errorf("%w, %w", ErrRequestClosed, err), nil
 	}
 
 	var simReq *jsonrpc.JSONRPCRequest
 	if payload.Capella == nil {
-		return ErrNoCapellaPayload, nil
+		return nil, ErrNoCapellaPayload, nil
 	}
 	// TODO: add deneb support.
 
@@ -87,8 +87,11 @@ func (b *BlockSimulationRateLimiter) Send(context context.Context, payload *comm
 
 	// Create and fire off JSON-RPC request
 	simReq = jsonrpc.NewJSONRPCRequest("1", "flashbots_validateBuilderSubmissionV2", payload)
-	_, requestErr, validationErr = SendJSONRPCRequest(&b.client, *simReq, b.blockSimURL, headers)
-	return requestErr, validationErr
+	rawResp, requestErr, validationErr := SendJSONRPCRequest(&b.client, *simReq, b.blockSimURL, headers)
+
+	json.Unmarshal(rawResp.Result, resp)
+
+	return resp, requestErr, validationErr
 }
 
 // CurrentCounter returns the number of waiting and active requests

services/api/mock_blocksim_ratelimiter.go

@@ -7,11 +7,14 @@ import (
 )
 
 type MockBlockSimulationRateLimiter struct {
+	overrides       common.BuilderBlockValidationResponseV2
 	simulationError error
 }
 
-func (m *MockBlockSimulationRateLimiter) Send(context context.Context, payload *common.BuilderBlockValidationRequest, isHighPrio, fastTrack bool) (error, error) {
-	return nil, m.simulationError
+func (m *MockBlockSimulationRateLimiter) Send(context context.Context, payload *common.BuilderBlockValidationRequest, isHighPrio, fastTrack bool) (
+	*common.BuilderBlockValidationResponseV2, error, error,
+) {
+	return &m.overrides, nil, m.simulationError
 }
 
 func (m *MockBlockSimulationRateLimiter) CurrentCounter() int64 {

services/api/optimistic_test.go

@@ -180,7 +180,7 @@ func TestSimulateBlock(t *testing.T) {
 			backend.relay.blockSimRateLimiter = &MockBlockSimulationRateLimiter{
 				simulationError: tc.simulationError,
 			}
-			_, simErr := backend.relay.simulateBlock(context.Background(), blockSimOptions{
+			_, _, simErr := backend.relay.simulateBlock(context.Background(), blockSimOptions{
 				isHighPrio: true,
 				log:        backend.relay.log,
 				builder: &blockBuilderCacheEntry{

services/api/service.go

@@ -550,9 +550,10 @@ func (api *RelayAPI) startValidatorRegistrationDBProcessor() {
 }
 
 // simulateBlock sends a request for a block simulation to blockSimRateLimiter.
-func (api *RelayAPI) simulateBlock(ctx context.Context, opts blockSimOptions) (requestErr, validationErr error) {
+func (api *RelayAPI) simulateBlock(ctx context.Context, opts blockSimOptions) (overrides *common.BuilderBlockValidationResponseV2, requestErr, validationErr error) {
 	t := time.Now()
-	requestErr, validationErr = api.blockSimRateLimiter.Send(ctx, opts.req, opts.isHighPrio, opts.fastTrack)
+	overrides, requestErr, validationErr = api.blockSimRateLimiter.Send(ctx, opts.req, opts.isHighPrio, opts.fastTrack)
+
 	log := opts.log.WithFields(logrus.Fields{
 		"durationMs": time.Since(t).Milliseconds(),
 		"numWaiting": api.blockSimRateLimiter.CurrentCounter(),
@@ -563,18 +564,18 @@ func (api *RelayAPI) simulateBlock(ctx context.Context, opts blockSimOptions) (r
 			ignoreError := validationErr.Error() == ErrBlockAlreadyKnown || validationErr.Error() == ErrBlockRequiresReorg || strings.Contains(validationErr.Error(), ErrMissingTrieNode)
 			if ignoreError {
 				log.WithError(validationErr).Warn("block validation failed with ignorable error")
-				return nil, nil
+				return nil, nil, nil
 			}
 		}
 		log.WithError(validationErr).Warn("block validation failed")
-		return nil, validationErr
+		return nil, nil, validationErr
 	}
 	if requestErr != nil {
 		log.WithError(requestErr).Warn("block validation failed: request error")
-		return requestErr, nil
+		return nil, requestErr, nil
 	}
 	log.Info("block validation successful")
-	return nil, nil
+	return overrides, nil, nil
 }
 
 func (api *RelayAPI) demoteBuilder(pubkey string, req *common.BuilderSubmitBlockRequest, simError error) {
@@ -620,7 +621,13 @@ func (api *RelayAPI) processOptimisticBlock(opts blockSimOptions, simResultC cha
 		// it for logging, it is not atomic to avoid the performance impact.
 		"optBlocksInFlight": api.optimisticBlocksInFlight,
 	}).Infof("simulating optimistic block with hash: %v", opts.req.BuilderSubmitBlockRequest.BlockHash())
-	reqErr, simErr := api.simulateBlock(ctx, opts)
+	overrides, reqErr, simErr := api.simulateBlock(ctx, opts)
+
+	overrideGasValues(
+		opts.req,
+		overrides,
+	)
+
 	simResultC <- &blockSimResult{reqErr == nil, true, reqErr, simErr}
 	if reqErr != nil || simErr != nil {
 		// Mark builder as non-optimistic.
@@ -1785,13 +1792,6 @@ func (api *RelayAPI) handleSubmitNewBlock(w http.ResponseWriter, req *http.Reque
 		}
 	}
 
-	// Refuse blocks outside the specified gas limit
-	if payload.Capella.ExecutionPayload.GasLimit > RelayActualGasLimit {
-		return
-	}
-	// Overwrite the builder's gasLimit with the relay-set fictitious limit
-	payload.Capella.ExecutionPayload.GasLimit = RelayFictitiousGasLimit
-
 	nextTime = time.Now().UTC()
 	pf.Decode = uint64(nextTime.Sub(prevTime).Microseconds())
 	prevTime = nextTime
@@ -1964,7 +1964,13 @@ func (api *RelayAPI) handleSubmitNewBlock(w http.ResponseWriter, req *http.Reque
 		go api.processOptimisticBlock(opts, simResultC)
 	} else {
 		// Simulate block (synchronously).
-		requestErr, validationErr := api.simulateBlock(context.Background(), opts) // success/error logging happens inside
+		overrides, requestErr, validationErr := api.simulateBlock(context.Background(), opts) // success/error logging happens inside
+
+		overrideGasValues(
+			opts.req,
+			overrides,
+		)
+
 		simResultC <- &blockSimResult{requestErr == nil, false, requestErr, validationErr}
 		validationDurationMs := time.Since(timeBeforeValidation).Milliseconds()
 		log = log.WithFields(logrus.Fields{
@@ -2375,3 +2381,13 @@ func (api *RelayAPI) handleReadyz(w http.ResponseWriter, req *http.Request) {
 		api.RespondMsg(w, http.StatusServiceUnavailable, "not ready")
 	}
 }
+
+func overrideGasValues(
+	req *common.BuilderBlockValidationRequest,
+	overrides *common.BuilderBlockValidationResponseV2,
+) {
+	if overrides != nil {
+		req.Capella.ExecutionPayload.BlockHash = overrides.NewBlockHash
+		req.Capella.ExecutionPayload.GasLimit = overrides.NewGasLimit
+	}
+}