eth/catalyst: pass TargetGasLimit via engine api

beacon/engine/pa_codec.go

@@ -22,6 +22,7 @@ func (p PayloadAttributes) MarshalJSON() ([]byte, error) {
 		Withdrawals           []*types.Withdrawal `json:"withdrawals"`
 		BeaconRoot            *common.Hash        `json:"parentBeaconBlockRoot"`
 		SlotNumber            *hexutil.Uint64     `json:"slotNumber"`
+		TargetGasLimit        *hexutil.Uint64     `json:"targetGasLimit"`
 	}
 	var enc PayloadAttributes
 	enc.Timestamp = hexutil.Uint64(p.Timestamp)
@@ -30,6 +31,7 @@ func (p PayloadAttributes) MarshalJSON() ([]byte, error) {
 	enc.Withdrawals = p.Withdrawals
 	enc.BeaconRoot = p.BeaconRoot
 	enc.SlotNumber = (*hexutil.Uint64)(p.SlotNumber)
+	enc.TargetGasLimit = (*hexutil.Uint64)(p.TargetGasLimit)
 	return json.Marshal(&enc)
 }
 
@@ -42,6 +44,7 @@ func (p *PayloadAttributes) UnmarshalJSON(input []byte) error {
 		Withdrawals           []*types.Withdrawal `json:"withdrawals"`
 		BeaconRoot            *common.Hash        `json:"parentBeaconBlockRoot"`
 		SlotNumber            *hexutil.Uint64     `json:"slotNumber"`
+		TargetGasLimit        *hexutil.Uint64     `json:"targetGasLimit"`
 	}
 	var dec PayloadAttributes
 	if err := json.Unmarshal(input, &dec); err != nil {
@@ -68,5 +71,8 @@ func (p *PayloadAttributes) UnmarshalJSON(input []byte) error {
 	if dec.SlotNumber != nil {
 		p.SlotNumber = (*uint64)(dec.SlotNumber)
 	}
+	if dec.TargetGasLimit != nil {
+		p.TargetGasLimit = (*uint64)(dec.TargetGasLimit)
+	}
 	return nil
 }

beacon/engine/types.go

@@ -74,12 +74,14 @@ type PayloadAttributes struct {
 	Withdrawals           []*types.Withdrawal `json:"withdrawals"`
 	BeaconRoot            *common.Hash        `json:"parentBeaconBlockRoot"`
 	SlotNumber            *uint64             `json:"slotNumber"`
+	TargetGasLimit        *uint64             `json:"targetGasLimit"`
 }
 
 // JSON type overrides for PayloadAttributes.
 type payloadAttributesMarshaling struct {
 	Timestamp      hexutil.Uint64
 	SlotNumber     *hexutil.Uint64
+	TargetGasLimit *hexutil.Uint64
 }
 
 //go:generate go run github.com/fjl/gencodec -type ExecutableData -field-override executableDataMarshaling -out ed_codec.go

eth/catalyst/api.go

@@ -226,6 +226,8 @@ func (api *ConsensusAPI) ForkchoiceUpdatedV4(ctx context.Context, update engine.
 			return engine.STATUS_INVALID, attributesErr("missing beacon root")
 		case params.SlotNumber == nil:
 			return engine.STATUS_INVALID, attributesErr("missing slot number")
+		case params.TargetGasLimit == nil:
+			return engine.STATUS_INVALID, attributesErr("missing target gas limit")
 		case !api.checkFork(params.Timestamp, forks.Amsterdam):
 			return engine.STATUS_INVALID, unsupportedForkErr("fcuV4 must only be called for amsterdam payloads")
 		}
@@ -386,6 +388,7 @@ func (api *ConsensusAPI) forkchoiceUpdated(ctx context.Context, update engine.Fo
 			Withdrawals:  payloadAttributes.Withdrawals,
 			BeaconRoot:   payloadAttributes.BeaconRoot,
 			SlotNum:      payloadAttributes.SlotNumber,
+			TargetGasLimit:    payloadAttributes.TargetGasLimit,
 			Version:      payloadVersion,
 		}
 		id := args.Id()

miner/payload_building.go

@@ -47,6 +47,7 @@ type BuildPayloadArgs struct {
 	Withdrawals    types.Withdrawals     // The provided withdrawals
 	BeaconRoot     *common.Hash          // The provided beaconRoot (Cancun)
 	SlotNum        *uint64               // The provided slotNumber
+	TargetGasLimit *uint64               // The provided target gas limit (Amsterdam)
 	Version        engine.PayloadVersion // Versioning byte for payload id calculation.
 }
 
@@ -254,6 +255,7 @@ func (miner *Miner) buildPayload(ctx context.Context, args *BuildPayloadArgs, wi
 		withdrawals:    args.Withdrawals,
 		beaconRoot:     args.BeaconRoot,
 		slotNum:        args.SlotNum,
+		targetGasLimit: args.TargetGasLimit,
 		noTxs:          true,
 	}
 	empty := miner.generateWork(ctx, emptyParams, witness)
@@ -294,6 +296,7 @@ func (miner *Miner) buildPayload(ctx context.Context, args *BuildPayloadArgs, wi
 			withdrawals:    args.Withdrawals,
 			beaconRoot:     args.BeaconRoot,
 			slotNum:        args.SlotNum,
+			targetGasLimit: args.TargetGasLimit,
 			noTxs:          false,
 		}
 		for {
@@ -351,6 +354,7 @@ func (miner *Miner) BuildTestingPayload(args *BuildPayloadArgs, transactions []*
 		withdrawals:       args.Withdrawals,
 		beaconRoot:        args.BeaconRoot,
 		slotNum:           args.SlotNum,
+		targetGasLimit:    args.TargetGasLimit,
 		noTxs:             empty,
 		forceOverrides:    true,
 		overrideExtraData: extraData,

miner/worker.go

@@ -125,6 +125,7 @@ type generateParams struct {
 	withdrawals    types.Withdrawals // List of withdrawals to include in block (shanghai field)
 	beaconRoot     *common.Hash      // The beacon root (cancun field).
 	slotNum        *uint64           // The slot number (amsterdam field).
+	targetGasLimit *uint64           // The target gas limit requested by the CL (amsterdam field).
 	noTxs          bool              // Flag whether an empty block without any transaction is expected
 
 	forceOverrides    bool // Flag whether we should overwrite extraData and transactions
@@ -267,11 +268,17 @@ func (miner *Miner) prepareWork(ctx context.Context, genParams *generateParams,
 		}
 		timestamp = parent.Time + 1
 	}
+	// Post-Amsterdam use TargetGasLimit provided by CL
+	number := new(big.Int).Add(parent.Number, common.Big1)
+	gasCeil := miner.config.GasCeil
+	if miner.chainConfig.IsAmsterdam(number, timestamp) && genParams.targetGasLimit != nil {
+		gasCeil = *genParams.targetGasLimit
+	}
 	// Construct the sealing block header.
 	header := &types.Header{
 		ParentHash: parent.Hash(),
-		Number:     new(big.Int).Add(parent.Number, common.Big1),
+		Number:     number,
-		GasLimit:   core.CalcGasLimit(parent.GasLimit, miner.config.GasCeil),
+		GasLimit:   core.CalcGasLimit(parent.GasLimit, gasCeil),
 		Time:       timestamp,
 		Coinbase:   genParams.coinbase,
 	}