Merge pull request ethereum#63 from OffchainLabs/intercept-rpc-gas-cap

Intercept RPC Gas Cap

core/state_transition.go

@@ -23,6 +23,7 @@ import (
 
 	"github.com/ethereum/go-ethereum/common"
 	cmath "github.com/ethereum/go-ethereum/common/math"
+	"github.com/ethereum/go-ethereum/core/state"
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/core/vm"
 	"github.com/ethereum/go-ethereum/crypto"
@@ -162,6 +163,7 @@ func IntrinsicGas(data []byte, accessList types.AccessList, isContractCreation b
 
 var ReadyEVMForL2 func(evm *vm.EVM, msg Message)
 var InterceptRPCMessage func(msg types.Message) (types.Message, error)
+var InterceptRPCGasCap func(gascap *uint64, msg types.Message, header *types.Header, statedb *state.StateDB)
 
 // NewStateTransition initialises and returns a new state transition object.
 func NewStateTransition(evm *vm.EVM, msg Message, gp *GasPool) *StateTransition {

eth/tracers/api.go

@@ -840,7 +840,7 @@ func (api *API) TraceCall(ctx context.Context, args ethapi.TransactionArgs, bloc
 		}
 	}
 	// Execute the trace
-	msg, err := args.ToMessage(api.backend.RPCGasCap(), block.BaseFee())
+	msg, err := args.ToMessage(api.backend.RPCGasCap(), block.Header(), statedb)
 	if err != nil {
 		return nil, err
 	}

internal/ethapi/api.go

@@ -912,7 +912,7 @@ func DoCall(ctx context.Context, b Backend, args TransactionArgs, blockNrOrHash
 	defer cancel()
 
 	// Get a new instance of the EVM.
-	msg, err := args.ToMessage(globalGasCap, header.BaseFee)
+	msg, err := args.ToMessage(globalGasCap, header, state)
 	if err != nil {
 		return nil, err
 	}
@@ -1526,7 +1526,7 @@ func AccessList(ctx context.Context, b Backend, blockNrOrHash rpc.BlockNumberOrH
 		statedb := db.Copy()
 		// Set the accesslist to the last al
 		args.AccessList = &accessList
-		msg, err := args.ToMessage(b.RPCGasCap(), header.BaseFee)
+		msg, err := args.ToMessage(b.RPCGasCap(), header, statedb)
 		if err != nil {
 			return nil, 0, nil, err
 		}

internal/ethapi/transaction_args.go

@@ -26,6 +26,8 @@ import (
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/common/hexutil"
 	"github.com/ethereum/go-ethereum/common/math"
+	"github.com/ethereum/go-ethereum/core"
+	"github.com/ethereum/go-ethereum/core/state"
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/log"
 	"github.com/ethereum/go-ethereum/rpc"
@@ -175,7 +177,9 @@ func (args *TransactionArgs) setDefaults(ctx context.Context, b Backend) error {
 // ToMessage converts the transaction arguments to the Message type used by the
 // core evm. This method is used in calls and traces that do not require a real
 // live transaction.
-func (args *TransactionArgs) ToMessage(globalGasCap uint64, baseFee *big.Int) (types.Message, error) {
+func (args *TransactionArgs) ToMessage(globalGasCap uint64, header *types.Header, state *state.StateDB) (types.Message, error) {
+	baseFee := header.BaseFee
+
 	// Reject invalid combinations of pre- and post-1559 fee styles
 	if args.GasPrice != nil && (args.MaxFeePerGas != nil || args.MaxPriorityFeePerGas != nil) {
 		return types.Message{}, errors.New("both gasPrice and (maxFeePerGas or maxPriorityFeePerGas) specified")
@@ -240,6 +244,14 @@ func (args *TransactionArgs) ToMessage(globalGasCap uint64, baseFee *big.Int) (t
 		accessList = *args.AccessList
 	}
 	msg := types.NewMessage(addr, args.To, 0, value, gas, gasPrice, gasFeeCap, gasTipCap, data, accessList, true)
+
+	// Arbitrum: update the gas cap to ignore L1 costs so that it's compute-only
+	if core.InterceptRPCGasCap != nil && state != nil {
+		// ToMessage recurses once to allow ArbOS to intercept the result for all callers
+		// ArbOS uses this to modify globalGasCap so that the cap will ignore this tx's specific L1 data costs
+		core.InterceptRPCGasCap(&globalGasCap, msg, header, state)
+		return args.ToMessage(globalGasCap, header, nil) // we pass a nil to avoid another recursion
+	}
 	return msg, nil
 }