Sequencer Fee Pricing Part 2: Electric Boogaloo: Override EstimateGas to take data price into account (#273)

* fix: add nil check when estimating gas to avoid panic during contract creation

* fix: revert DoEstimateGas changes introduced as a temp fix in #22

* Tweak fudge factor for Geth gas estimation (#292)

* experimenting with gas fudge factor

* fix formatting

* try using 1m gas constant

* Add log statement for the gas estimate

* Add more detail to gas estimate log

* one more log edit

* Try new formula

* Bump base gas

* Even more base gas

* even more

* Just 1m?

* one more time

* Final cleanup

* Minor fix

* Update internal/ethapi/api.go

* don't use cap-1

* Make sure data is not nil

Co-authored-by: Karl Floersch <[email protected]>

* feat(api): make eth_gasPrice always return 1 gwei

* feat: overload estimateGas to return the data+execution fee

* feat: implement static L1 Gas Price oracle

* feat: allow configuring the L1GasPrice via CLI at node startup

* feat: allow configuring the L1GasPrice remotely over a new private RPC namespace

* Sequencer Fee Pricing Part 3, feat: Pull L1Gasprice from the Data Service (#277)

* feat: pull L1GasPrice from the data transport service

* refactor: split out single-iteration of sequencer loop

* test(sync-service): ensure L1GasPrice is set correctly

* chore: gofmt

* fix: parse json response as string and test

* chore: expose L1Gpo in the sync service

* refactor: create helper function for calculating the rollup fee

* docs: add doc for rollup tx size constant

* chore(console_test): add rollup_personal to test

* chore: remove empty line

* chore: adjust review comments

* do not cast gasUsed
* adjust comment on GasPrice method
* add nil check for args.Data
* log gas price changes in the sync service

* chore: re-order imports

* fix: skip txpool max gas check for rollup txs

Security Question: does this introduce a DoS vector?

* chore: debug log

* fix(rollup_fee): normalize charged gas by the charged gas price

* remove intrinsic gas checks

* move intrinsic gas check behind non-ovm codepath

* remove fudging code

* fix wrong gas limit

Co-authored-by: Ben Jones <[email protected]>
Co-authored-by: smartcontracts <[email protected]>
Co-authored-by: Karl Floersch <[email protected]>

Author: 4 people

cmd/geth/consolecmd_test.go

@@ -31,7 +31,7 @@ import (
 )
 
 const (
-	ipcAPIs  = "admin:1.0 debug:1.0 eth:1.0 ethash:1.0 miner:1.0 net:1.0 personal:1.0 rollup:1.0 rpc:1.0 shh:1.0 txpool:1.0 web3:1.0"
+	ipcAPIs  = "admin:1.0 debug:1.0 eth:1.0 ethash:1.0 miner:1.0 net:1.0 personal:1.0 rollup:1.0 rollup_personal:1.0 rpc:1.0 shh:1.0 txpool:1.0 web3:1.0"
 	httpAPIs = "eth:1.0 net:1.0 rpc:1.0 web3:1.0"
 )
 

cmd/geth/main.go

@@ -164,6 +164,7 @@ var (
 		utils.RollupStateDumpPathFlag,
 		utils.RollupDiffDbFlag,
 		utils.RollupMaxCalldataSizeFlag,
+		utils.RollupL1GasPriceFlag,
 	}
 
 	rpcFlags = []cli.Flag{

cmd/geth/usage.go

@@ -78,6 +78,7 @@ var AppHelpFlagGroups = []flagGroup{
 			utils.RollupStateDumpPathFlag,
 			utils.RollupDiffDbFlag,
 			utils.RollupMaxCalldataSizeFlag,
+			utils.RollupL1GasPriceFlag,
 		},
 	},
 	{

cmd/utils/flags.go

@@ -879,6 +879,12 @@ var (
 		Value:  eth.DefaultConfig.Rollup.MaxCallDataSize,
 		EnvVar: "ROLLUP_MAX_CALLDATA_SIZE",
 	}
+	RollupL1GasPriceFlag = BigFlag{
+		Name:   "rollup.l1gasprice",
+		Usage:  "The L1 gas price to use for the sequencer fees",
+		Value:  eth.DefaultConfig.Rollup.L1GasPrice,
+		EnvVar: "ROLLUP_L1_GASPRICE",
+	}
 )
 
 // MakeDataDir retrieves the currently requested data directory, terminating
@@ -1152,6 +1158,9 @@ func setRollup(ctx *cli.Context, cfg *rollup.Config) {
 	if ctx.GlobalIsSet(RollupTimstampRefreshFlag.Name) {
 		cfg.TimestampRefreshThreshold = ctx.GlobalDuration(RollupTimstampRefreshFlag.Name)
 	}
+	if ctx.GlobalIsSet(RollupL1GasPriceFlag.Name) {
+		cfg.L1GasPrice = GlobalBig(ctx, RollupL1GasPriceFlag.Name)
+	}
 }
 
 // setLes configures the les server and ultra light client settings from the command line flags.

core/rollup_fee.go

@@ -0,0 +1,22 @@
+package core
+
+import (
+	"math/big"
+)
+
+/// ROLLUP_BASE_TX_SIZE is the encoded rollup transaction's compressed size excluding
+/// the variable length data.
+/// Ref: https://github.com/ethereum-optimism/contracts/blob/409f190518b90301db20d0d4f53760021bc203a8/contracts/optimistic-ethereum/OVM/precompiles/OVM_SequencerEntrypoint.sol#L47
+const ROLLUP_BASE_TX_SIZE int = 96
+
+/// CalculateFee calculates the fee that must be paid to the Rollup sequencer, taking into
+/// account the cost of publishing data to L1.
+/// Returns: (ROLLUP_BASE_TX_SIZE + len(data)) * dataPrice + executionPrice * gasUsed
+func CalculateRollupFee(data []byte, gasUsed uint64, dataPrice, executionPrice *big.Int) *big.Int {
+	dataLen := int64(ROLLUP_BASE_TX_SIZE + len(data))
+	// get the data fee
+	dataFee := new(big.Int).Mul(dataPrice, big.NewInt(dataLen))
+	executionFee := new(big.Int).Mul(executionPrice, new(big.Int).SetUint64(gasUsed))
+	fee := new(big.Int).Add(dataFee, executionFee)
+	return fee
+}

core/rollup_fee_test.go

@@ -0,0 +1,34 @@
+package core
+
+import (
+	"math/big"
+	"testing"
+)
+
+var feeTests = map[string]struct {
+	dataLen        int
+	gasUsed        uint64
+	dataPrice      int64
+	executionPrice int64
+}{
+	"simple":               {10000, 10, 20, 30},
+	"zero gas used":        {10000, 0, 20, 30},
+	"zero data price":      {10000, 0, 0, 30},
+	"zero execution price": {10000, 0, 0, 0},
+}
+
+func TestCalculateRollupFee(t *testing.T) {
+	for name, tt := range feeTests {
+		t.Run(name, func(t *testing.T) {
+			data := make([]byte, 0, tt.dataLen)
+			fee := CalculateRollupFee(data, tt.gasUsed, big.NewInt(tt.dataPrice), big.NewInt(tt.executionPrice))
+
+			dataFee := uint64((ROLLUP_BASE_TX_SIZE + len(data)) * int(tt.dataPrice))
+			executionFee := uint64(tt.executionPrice) * tt.gasUsed
+			expectedFee := dataFee + executionFee
+			if fee.Cmp(big.NewInt(int64(expectedFee))) != 0 {
+				t.Errorf("rollup fee check failed: expected %d, got %s", expectedFee, fee.String())
+			}
+		})
+	}
+}

core/state_processor.go

@@ -90,7 +90,7 @@ func ApplyTransaction(config *params.ChainConfig, bc ChainContext, author *commo
 		}
 	} else {
 		decompressor := config.StateDump.Accounts["OVM_SequencerEntrypoint"]
-		msg, err = AsOvmMessage(tx, types.MakeSigner(config, header.Number), decompressor.Address)
+		msg, err = AsOvmMessage(tx, types.MakeSigner(config, header.Number), decompressor.Address, header.GasLimit)
 		if err != nil {
 			return nil, err
 		}

core/state_transition_ovm.go

@@ -58,7 +58,7 @@ func toExecutionManagerRun(evm *vm.EVM, msg Message) (Message, error) {
 	return outputmsg, nil
 }
 
-func AsOvmMessage(tx *types.Transaction, signer types.Signer, decompressor common.Address) (Message, error) {
+func AsOvmMessage(tx *types.Transaction, signer types.Signer, decompressor common.Address, gasLimit uint64) (Message, error) {
 	msg, err := tx.AsMessage(signer)
 	if err != nil {
 		// This should only be allowed to pass if the transaction is in the ctc
@@ -85,7 +85,7 @@ func AsOvmMessage(tx *types.Transaction, signer types.Signer, decompressor commo
 		msg.From(),
 		&decompressor,
 		tx.GetMeta().RawTransaction,
-		msg.Gas(),
+		gasLimit,
 	)
 
 	if err != nil {

core/tx_pool.go

@@ -92,8 +92,9 @@ var (
 )
 
 var (
-	evictionInterval    = time.Minute     // Time interval to check for evictable transactions
-	statsReportInterval = 8 * time.Second // Time interval to report transaction pool stats
+	evictionInterval    = time.Minute             // Time interval to check for evictable transactions
+	statsReportInterval = 8 * time.Second         // Time interval to report transaction pool stats
+	gwei                = big.NewInt(params.GWei) // 1 gwei, used as a flag for "rollup" transactions
 )
 
 var (
@@ -537,10 +538,14 @@ func (pool *TxPool) validateTx(tx *types.Transaction, local bool) error {
 	if tx.Value().Sign() < 0 {
 		return ErrNegativeValue
 	}
+
 	// Ensure the transaction doesn't exceed the current block limit gas.
-	if pool.currentMaxGas < tx.Gas() {
+	// We skip this condition check if the transaction's gasPrice is set to 1gwei,
+	// which indicates a "rollup" transaction that's paying for its data.
+	if pool.currentMaxGas < tx.Gas() && tx.GasPrice().Cmp(gwei) != 0 {
 		return ErrGasLimit
 	}
+
 	// Make sure the transaction is signed properly
 	from, err := types.Sender(pool.signer, tx)
 	if err != nil {
@@ -565,14 +570,14 @@ func (pool *TxPool) validateTx(tx *types.Transaction, local bool) error {
 		if pool.currentState.GetBalance(from).Cmp(tx.Cost()) < 0 {
 			return ErrInsufficientFunds
 		}
-	}
-	// Ensure the transaction has more gas than the basic tx fee.
-	intrGas, err := IntrinsicGas(tx.Data(), tx.To() == nil, true, pool.istanbul)
-	if err != nil {
-		return err
-	}
-	if tx.Gas() < intrGas {
-		return ErrIntrinsicGas
+		// Ensure the transaction has more gas than the basic tx fee.
+		intrGas, err := IntrinsicGas(tx.Data(), tx.To() == nil, true, pool.istanbul)
+		if err != nil {
+			return err
+		}
+		if tx.Gas() < intrGas {
+			return ErrIntrinsicGas
+		}
 	}
 	return nil
 }
@@ -585,13 +590,15 @@ func (pool *TxPool) validateTx(tx *types.Transaction, local bool) error {
 // whitelisted, preventing any associated transaction from being dropped out of the pool
 // due to pricing constraints.
 func (pool *TxPool) add(tx *types.Transaction, local bool) (replaced bool, err error) {
+	log.Debug("received tx", "gas", tx.Gas(), "gasprice", tx.GasPrice().Uint64())
 	// If the transaction is already known, discard it
 	hash := tx.Hash()
 	if pool.all.Get(hash) != nil {
 		log.Trace("Discarding already known transaction", "hash", hash)
 		knownTxMeter.Mark(1)
 		return false, fmt.Errorf("known transaction: %x", hash)
 	}
+
 	// If the transaction fails basic validation, discard it
 	if err := pool.validateTx(tx, local); err != nil {
 		log.Trace("Discarding invalid transaction", "hash", hash, "err", err)

eth/api_backend.go

@@ -46,6 +46,7 @@ type EthAPIBackend struct {
 	extRPCEnabled   bool
 	eth             *Ethereum
 	gpo             *gasprice.Oracle
+	l1gpo           *gasprice.L1Oracle
 	verifier        bool
 	gasLimit        uint64
 	UsingOVM        bool
@@ -371,6 +372,14 @@ func (b *EthAPIBackend) SuggestPrice(ctx context.Context) (*big.Int, error) {
 	return b.gpo.SuggestPrice(ctx)
 }
 
+func (b *EthAPIBackend) SuggestDataPrice(ctx context.Context) (*big.Int, error) {
+	return b.l1gpo.SuggestDataPrice(ctx)
+}
+
+func (b *EthAPIBackend) SetL1GasPrice(ctx context.Context, gasPrice *big.Int) {
+	b.l1gpo.SetL1GasPrice(gasPrice)
+}
+
 func (b *EthAPIBackend) ChainDb() ethdb.Database {
 	return b.eth.ChainDb()
 }