l2geth: updated calculate rollup fee (#906)

* l2geth: updated calculate rollup fee

* l2geth: implement the gasprice serialization

* lint: fix

* rollup-test: fix

* l2geth: gaslimit encoding state polling (#927)

* l2geth: rollup gas price oracle state polling

* l2geth: read l2 gasprice from the tip

* l2geth: add config options for L2 gas price

* l2geth: comment to remove code in future

* l2geth: handle 0 and 1 fees

* l2geth: enable 0 and 1 fee tests

* feat: gaslimit encoding end to end (#932)

* core-utils: add fees package

* integration-tests: refactor for new fees

* l2geth: end to end fee spec

* l2geth: use new env var

* deps: regenerate

* lint: fix

* l2geth: fee verification

* tests: update gas prices

* tests: update gas prices

* tests: cleanup

* l2geth: small cleanup

* l2geth: fix max

* feat: fix fee calculations with bigints

* tests: fix

* tests: lint

* core-utils: rename fees to L2GasLimit

* l2geth: fix comment

* l2geth: fix name of env var

* l2geth: delete extra print statement

* l2geth: fix logline

* tests: fix typo

* l2geth: improve readability

* chore: add changeset

* l2geth: fix compiler error

* feat: clean up and fix fees

* lint: fix

* core-utils: refactor api to be more friendly

* lint: fix

* comments: fix

* refactor: clean up style and common language
Co-authored-by: Georgios Konstantopoulos <me@gakonst.com>

.changeset/rich-glasses-brake.md

+---
+'@eth-optimism/integration-tests': patch
+'@eth-optimism/l2geth': patch
+'@eth-optimism/core-utils': patch
+---
+
+End to end fee integration with recoverable L2 gas limit

integration-tests/test/erc20.spec.ts

@@ -63,11 +63,8 @@ describe('Basic ERC20 interactions', async () => {
     const transfer = await ERC20.transfer(other.address, 100)
     const receipt = await transfer.wait()
 
-    // The expected fee paid is the value returned by eth_estimateGas gas multiplied
-    // by 1 gwei, since that's the value eth_gasPrice always returns
-    const expectedFeePaid = (
-      await ERC20.estimateGas.transfer(other.address, 100)
-    ).mul(GWEI)
+    // The expected fee paid is the value returned by eth_estimateGas
+    const expectedFeePaid = await ERC20.estimateGas.transfer(other.address, 100)
 
     // There are two events from the transfer with the first being
     // the ETH fee paid and the second of the value transfered (100)

integration-tests/test/fee-payment.spec.ts

@@ -3,6 +3,7 @@ import chaiAsPromised from 'chai-as-promised'
 chai.use(chaiAsPromised)
 import { BigNumber, utils } from 'ethers'
 import { OptimismEnv } from './shared/env'
+import { L2GasLimit } from '@eth-optimism/core-utils'
 
 describe('Fee Payment Integration Tests', async () => {
   let env: OptimismEnv
@@ -12,14 +13,38 @@ describe('Fee Payment Integration Tests', async () => {
     env = await OptimismEnv.new()
   })
 
+  it('Should return a gasPrice of 1 wei', async () => {
+    const gasPrice = await env.l2Wallet.getGasPrice()
+    expect(gasPrice.eq(1))
+  })
+
+  it('Should estimateGas with recoverable L2 gasLimit', async () => {
+    const gas = await env.ovmEth.estimateGas.transfer(
+      other,
+      utils.parseEther('0.5')
+    )
+    const tx = await env.ovmEth.populateTransaction.transfer(
+      other,
+      utils.parseEther('0.5')
+    )
+    const executionGas = await (env.ovmEth
+      .provider as any).send('eth_estimateExecutionGas', [tx])
+    const decoded = L2GasLimit.decode(gas)
+    expect(BigNumber.from(executionGas)).deep.eq(decoded)
+  })
+
   it('Paying a nonzero but acceptable gasPrice fee', async () => {
     const amount = utils.parseEther('0.5')
-
     const balanceBefore = await env.l2Wallet.getBalance()
-    const tx = await env.ovmEth.transfer(other, amount)
-    await tx.wait()
+    expect(balanceBefore.gt(amount))
+
+    const gas = await env.ovmEth.estimateGas.transfer(other, amount)
+    const tx = await env.ovmEth.transfer(other, amount, { gasPrice: 1 })
+    const receipt = await tx.wait()
+    expect(receipt.status).to.eq(1)
+
     const balanceAfter = await env.l2Wallet.getBalance()
-    // TODO: The fee paid MUST be the receipt.gasUsed, and not the tx.gasLimit
+    // The fee paid MUST be the receipt.gasUsed, and not the tx.gasLimit
     // https://github.com/ethereum-optimism/optimism/blob/0de7a2f9c96a7c4860658822231b2d6da0fefb1d/packages/contracts/contracts/optimistic-ethereum/OVM/accounts/OVM_ECDSAContractAccount.sol#L103
     expect(balanceBefore.sub(balanceAfter)).to.be.deep.eq(
       tx.gasPrice.mul(tx.gasLimit).add(amount)

integration-tests/test/native-eth.spec.ts

@@ -45,13 +45,13 @@ describe('Native ETH Integration Tests', async () => {
       const amount = utils.parseEther('0.5')
       const addr = '0x' + '1234'.repeat(10)
       const gas = await env.ovmEth.estimateGas.transfer(addr, amount)
-      expect(gas).to.be.deep.eq(BigNumber.from(21000))
+      expect(gas).to.be.deep.eq(BigNumber.from(0x23284d28fe6d))
     })
 
     it('Should estimate gas for ETH withdraw', async () => {
       const amount = utils.parseEther('0.5')
       const gas = await env.ovmEth.estimateGas.withdraw(amount)
-      expect(gas).to.be.deep.eq(BigNumber.from(21000))
+      expect(gas).to.be.deep.eq(BigNumber.from(0x207ad91a77b4))
     })
   })
 

integration-tests/test/rpc.spec.ts

-import { injectL2Context } from '@eth-optimism/core-utils'
+import {
+  injectL2Context,
+  L2GasLimit,
+  roundL1GasPrice,
+} from '@eth-optimism/core-utils'
 import { Wallet, BigNumber, Contract } from 'ethers'
 import { ethers } from 'hardhat'
 import chai, { expect } from 'chai'
@@ -19,7 +23,7 @@ describe('Basic RPC tests', () => {
 
   const DEFAULT_TRANSACTION = {
     to: '0x' + '1234'.repeat(10),
-    gasLimit: 4000000,
+    gasLimit: 33600000000001,
     gasPrice: 0,
     data: '0x',
     value: 0,
@@ -95,7 +99,7 @@ describe('Basic RPC tests', () => {
         ...DEFAULT_TRANSACTION,
         chainId: await env.l2Wallet.getChainId(),
         data: '0x',
-        value: ethers.utils.parseEther('5'),
+        value: ethers.utils.parseEther('0.1'),
       }
 
       const balanceBefore = await provider.getBalance(env.l2Wallet.address)
@@ -104,7 +108,7 @@ describe('Basic RPC tests', () => {
       expect(receipt.status).to.deep.equal(1)
 
       expect(await provider.getBalance(env.l2Wallet.address)).to.deep.equal(
-        balanceBefore.sub(ethers.utils.parseEther('5'))
+        balanceBefore.sub(ethers.utils.parseEther('0.1'))
       )
     })
 
@@ -122,6 +126,18 @@ describe('Basic RPC tests', () => {
       )
     })
 
+    it('should reject a transaction with too low of a fee', async () => {
+      const tx = {
+        ...DEFAULT_TRANSACTION,
+        gasLimit: 1,
+        gasPrice: 1,
+      }
+
+      await expect(env.l2Wallet.sendTransaction(tx)).to.be.rejectedWith(
+        'fee too low: 1, use at least tx.gasLimit = 33600000000001 and tx.gasPrice = 1'
+      )
+    })
+
     it('should correctly report OOG for contract creations', async () => {
       const factory = await ethers.getContractFactory('TestOOG')
 
@@ -136,7 +152,7 @@ describe('Basic RPC tests', () => {
       await expect(
         provider.call({
           ...revertingTx,
-          gasLimit: 21_000,
+          gasLimit: 1,
         })
       ).to.be.rejectedWith('out of gas')
     })
@@ -159,7 +175,7 @@ describe('Basic RPC tests', () => {
       await expect(
         provider.call({
           ...revertingDeployTx,
-          gasLimit: 30_000,
+          gasLimit: 1,
         })
       ).to.be.rejectedWith('out of gas')
     })
@@ -182,7 +198,7 @@ describe('Basic RPC tests', () => {
     it('correctly exposes revert data for contract calls', async () => {
       const req: TransactionRequest = {
         ...revertingTx,
-        gasLimit: 8_999_999, // override gas estimation
+        gasLimit: 934111908999999, // override gas estimation
       }
 
       const tx = await wallet.sendTransaction(req)
@@ -205,7 +221,7 @@ describe('Basic RPC tests', () => {
     it('correctly exposes revert data for contract creations', async () => {
       const req: TransactionRequest = {
         ...revertingDeployTx,
-        gasLimit: 8_999_999, // override gas estimation
+        gasLimit: 1051391908999999, // override gas estimation
       }
 
       const tx = await wallet.sendTransaction(req)
@@ -296,7 +312,7 @@ describe('Basic RPC tests', () => {
 
   describe('eth_gasPrice', () => {
     it('gas price should be 1 gwei', async () => {
-      expect(await provider.getGasPrice()).to.be.deep.equal(GWEI)
+      expect(await provider.getGasPrice()).to.be.deep.equal(1)
     })
   })
 
@@ -306,35 +322,41 @@ describe('Basic RPC tests', () => {
         to: DEFAULT_TRANSACTION.to,
         value: 0,
       })
-      expect(estimate).to.be.eq(21000)
+      expect(estimate).to.be.eq(33600000119751)
     })
 
     it('should return a gas estimate that grows with the size of data', async () => {
       const dataLen = [0, 2, 8, 64, 256]
       const l1GasPrice = await env.l1Wallet.provider.getGasPrice()
 
-      // 96 bytes * 16 per non zero byte
-      const onesCost = BigNumber.from(96).mul(16)
-      const expectedCost = dataLen
-        .map((len) => BigNumber.from(len).mul(4))
-        .map((zerosCost) => zerosCost.add(onesCost))
-
       // Repeat this test for a series of possible transaction sizes.
-      for (let i = 0; i < dataLen.length; i++) {
-        const estimate = await l2Provider.estimateGas({
-          ...DEFAULT_TRANSACTION,
-          data: '0x' + '00'.repeat(dataLen[i]),
+      for (const data of dataLen) {
+        const tx = {
+          to: '0x' + '1234'.repeat(10),
+          gasPrice: '0x1',
+          value: '0x0',
+          data: '0x' + '00'.repeat(data),
           from: '0x' + '1234'.repeat(10),
-        })
-
-        // we normalize by gwei here because the RPC does it as well, since the
-        // user provides a 1gwei gas price when submitting txs via the eth_gasPrice
-        // rpc call. The smallest possible value for the expected cost is 21000
-        let expected = expectedCost[i].mul(l1GasPrice).div(GWEI)
-        if (expected.lt(BigNumber.from(21000))) {
-          expected = BigNumber.from(21000)
         }
-        expect(estimate).to.be.deep.eq(expected)
+        const estimate = await l2Provider.estimateGas(tx)
+        const l2Gaslimit = await l2Provider.send('eth_estimateExecutionGas', [
+          tx,
+        ])
+
+        const decoded = L2GasLimit.decode(estimate)
+        expect(decoded).to.deep.eq(BigNumber.from(l2Gaslimit))
+        expect(estimate.toString().endsWith(l2Gaslimit.toString()))
+
+        // The L2GasPrice should be fetched from the L2GasPrice oracle contract,
+        // but it does not yet exist. Use the default value for now
+        const l2GasPrice = BigNumber.from(1)
+        const expected = L2GasLimit.encode({
+          data: tx.data,
+          l1GasPrice: roundL1GasPrice(l1GasPrice),
+          l2GasLimit: BigNumber.from(l2Gaslimit),
+          l2GasPrice,
+        })
+        expect(expected).to.deep.eq(estimate)
       }
     })
 

l2geth/cmd/geth/main.go

@@ -156,7 +156,6 @@ var (
 		utils.Eth1ETHGatewayAddressFlag,
 		utils.Eth1ChainIdFlag,
 		utils.RollupClientHttpFlag,
-		// Enable verifier mode
 		utils.RollupEnableVerifierFlag,
 		utils.RollupAddressManagerOwnerAddressFlag,
 		utils.RollupTimstampRefreshFlag,
@@ -166,6 +165,9 @@ var (
 		utils.RollupMaxCalldataSizeFlag,
 		utils.RollupDataPriceFlag,
 		utils.RollupExecutionPriceFlag,
+		utils.RollupEnableL2GasPollingFlag,
+		utils.RollupGasPriceOracleAddressFlag,
+		utils.RollupEnforceFeesFlag,
 	}
 
 	rpcFlags = []cli.Flag{

l2geth/cmd/geth/usage.go

@@ -80,6 +80,9 @@ var AppHelpFlagGroups = []flagGroup{
 			utils.RollupMaxCalldataSizeFlag,
 			utils.RollupDataPriceFlag,
 			utils.RollupExecutionPriceFlag,
+			utils.RollupEnableL2GasPollingFlag,
+			utils.RollupGasPriceOracleAddressFlag,
+			utils.RollupEnforceFeesFlag,
 		},
 	},
 	{

l2geth/cmd/utils/flags.go

@@ -893,6 +893,22 @@ var (
 		Value:  eth.DefaultConfig.Rollup.ExecutionPrice,
 		EnvVar: "ROLLUP_EXECUTIONPRICE",
 	}
+	RollupGasPriceOracleAddressFlag = cli.StringFlag{
+		Name:   "rollup.gaspriceoracleaddress",
+		Usage:  "Address of the rollup gas price oracle",
+		Value:  "0x0000000000000000000000000000000000000000",
+		EnvVar: "ROLLUP_GAS_PRICE_ORACLE_ADDRESS",
+	}
+	RollupEnableL2GasPollingFlag = cli.BoolFlag{
+		Name:   "rollup.enablel2gaspolling",
+		Usage:  "Poll for the L2 gas price from the L2 state",
+		EnvVar: "ROLLUP_ENABLE_L2_GAS_POLLING",
+	}
+	RollupEnforceFeesFlag = cli.BoolFlag{
+		Name:   "rollup.enforcefeesflag",
+		Usage:  "Disable transactions with 0 gas price",
+		EnvVar: "ROLLUP_ENFORCE_FEES",
+	}
 )
 
 // MakeDataDir retrieves the currently requested data directory, terminating
@@ -1172,6 +1188,16 @@ func setRollup(ctx *cli.Context, cfg *rollup.Config) {
 	if ctx.GlobalIsSet(RollupExecutionPriceFlag.Name) {
 		cfg.ExecutionPrice = GlobalBig(ctx, RollupExecutionPriceFlag.Name)
 	}
+	if ctx.GlobalIsSet(RollupGasPriceOracleAddressFlag.Name) {
+		addr := ctx.GlobalString(RollupGasPriceOracleAddressFlag.Name)
+		cfg.GasPriceOracleAddress = common.HexToAddress(addr)
+	}
+	if ctx.GlobalIsSet(RollupEnableL2GasPollingFlag.Name) {
+		cfg.EnableL2GasPolling = true
+	}
+	if ctx.GlobalIsSet(RollupEnforceFeesFlag.Name) {
+		cfg.EnforceFees = true
+	}
 }
 
 // setLes configures the les server and ultra light client settings from the command line flags.

l2geth/core/rollup_fee.go

 package core
 
 import (
+	"errors"
+	"fmt"
 	"math/big"
 
+	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/params"
 )
 
-// RollupBaseTxSize is the encoded rollup transaction's compressed size excluding
-// the variable length data.
-// Ref: https://github.com/ethereum-optimism/optimism/blob/91a9a3dcddf534ae1c906133b6d8e015a23c463b/packages/contracts/contracts/optimistic-ethereum/OVM/predeploys/OVM_SequencerEntrypoint.sol#L47
-const RollupBaseTxSize uint64 = 96
+// overhead represents the fixed cost of batch submission of a single
+// transaction in gas
+const overhead uint64 = 4200
+
+// hundredMillion is a constant used in the gas encoding formula
+const hundredMillion uint64 = 100_000_000
+
+var bigHundredMillion = new(big.Int).SetUint64(hundredMillion)
+
+// errInvalidGasPrice is the error returned when a user submits an incorrect gas
+// price. The gas price must satisfy a particular equation depending on if it
+// is a L1 gas price or a L2 gas price
+var errInvalidGasPrice = errors.New("rollup fee: invalid gas price")
 
 // CalculateFee calculates the fee that must be paid to the Rollup sequencer, taking into
 // account the cost of publishing data to L1.
-// Returns: (4 * zeroDataBytes + 16 * (nonZeroDataBytes + RollupBaseTxSize)) * dataPrice + executionPrice * gasUsed
-func CalculateRollupFee(data []byte, gasUsed uint64, dataPrice, executionPrice *big.Int) *big.Int {
+// l2_gas_price * l2_gas_limit + l1_gas_price * l1_gas_used
+// where the l2 gas price must satisfy the equation `x % (10**8) = 1`
+// and the l1 gas price must satisfy the equation `x % (10**8) = 0`
+func CalculateRollupFee(data []byte, l1GasPrice, l2GasLimit, l2GasPrice *big.Int) (*big.Int, error) {
+	if err := VerifyL1GasPrice(l1GasPrice); err != nil {
+		return nil, fmt.Errorf("invalid L1 gas price %d: %w", l1GasPrice, err)
+	}
+	if err := VerifyL2GasPrice(l2GasPrice); err != nil {
+		return nil, fmt.Errorf("invalid L2 gas price %d: %w", l2GasPrice, err)
+	}
+	l1GasLimit := calculateL1GasLimit(data, overhead)
+	l1Fee := new(big.Int).Mul(l1GasPrice, l1GasLimit)
+	l2Fee := new(big.Int).Mul(l2GasLimit, l2GasPrice)
+	fee := new(big.Int).Add(l1Fee, l2Fee)
+	return fee, nil
+}
+
+// calculateL1GasLimit computes the L1 gasLimit based on the calldata and
+// constant sized overhead. The overhead can be decreased as the cost of the
+// batch submission goes down via contract optimizations. This will not overflow
+// under standard network conditions.
+func calculateL1GasLimit(data []byte, overhead uint64) *big.Int {
 	zeroes, ones := zeroesAndOnes(data)
-	zeroesCost := new(big.Int).SetUint64(zeroes * params.TxDataZeroGas)
-	onesCost := new(big.Int).SetUint64((RollupBaseTxSize + ones) * params.TxDataNonZeroGasEIP2028)
-	dataCost := new(big.Int).Add(zeroesCost, onesCost)
-
-	// get the data fee
-	dataFee := new(big.Int).Mul(dataPrice, dataCost)
-	executionFee := new(big.Int).Mul(executionPrice, new(big.Int).SetUint64(gasUsed))
-	fee := new(big.Int).Add(dataFee, executionFee)
-	return fee
+	zeroesCost := zeroes * params.TxDataZeroGas
+	onesCost := ones * params.TxDataNonZeroGasEIP2028
+	gasLimit := zeroesCost + onesCost + overhead
+	return new(big.Int).SetUint64(gasLimit)
+}
+
+// ceilModOneHundredMillion rounds the input integer up to the nearest modulus
+// of one hundred million
+func ceilModOneHundredMillion(num *big.Int) *big.Int {
+	if new(big.Int).Mod(num, bigHundredMillion).Cmp(common.Big0) == 0 {
+		return num
+	}
+	sum := new(big.Int).Add(num, bigHundredMillion)
+	mod := new(big.Int).Mod(num, bigHundredMillion)
+	return new(big.Int).Sub(sum, mod)
+}
+
+// VerifyL1GasPrice returns an error if the number is an invalid possible L1 gas
+// price
+func VerifyL1GasPrice(l1GasPrice *big.Int) error {
+	if new(big.Int).Mod(l1GasPrice, bigHundredMillion).Cmp(common.Big0) != 0 {
+		return errInvalidGasPrice
+	}
+	return nil
+}
+
+// VerifyL2GasPrice returns an error if the number is an invalid possible L2 gas
+// price
+func VerifyL2GasPrice(l2GasPrice *big.Int) error {
+	isNonZero := l2GasPrice.Cmp(common.Big0) != 0
+	isNotModHundredMillion := new(big.Int).Mod(l2GasPrice, bigHundredMillion).Cmp(common.Big1) != 0
+	if isNonZero && isNotModHundredMillion {
+		return errInvalidGasPrice
+	}
+	if l2GasPrice.Cmp(common.Big0) == 0 {
+		return errInvalidGasPrice
+	}
+	return nil
+}
+
+// RoundL1GasPrice returns a ceilModOneHundredMillion where 0
+// is the identity function
+func RoundL1GasPrice(gasPrice *big.Int) *big.Int {
+	return ceilModOneHundredMillion(gasPrice)
+}
+
+// RoundL2GasPriceBig implements the algorithm:
+// if gasPrice is 0; return 1
+// if gasPrice is 1; return 10**8 + 1
+// return ceilModOneHundredMillion(gasPrice-1)+1
+func RoundL2GasPrice(gasPrice *big.Int) *big.Int {
+	if gasPrice.Cmp(common.Big0) == 0 {
+		return big.NewInt(1)
+	}
+	if gasPrice.Cmp(common.Big1) == 0 {
+		return new(big.Int).Add(bigHundredMillion, common.Big1)
+	}
+	gp := new(big.Int).Sub(gasPrice, common.Big1)
+	mod := ceilModOneHundredMillion(gp)
+	return new(big.Int).Add(mod, common.Big1)
+}
+
+func DecodeL2GasLimit(gasLimit *big.Int) *big.Int {
+	return new(big.Int).Mod(gasLimit, bigHundredMillion)
 }
 
 func zeroesAndOnes(data []byte) (uint64, uint64) {

l2geth/core/rollup_fee_test.go

 package core
 
 import (
+	"errors"
+	"math"
 	"math/big"
 	"testing"
 )
 
+var roundingL1GasPriceTests = map[string]struct {
+	input  uint64
+	expect uint64
+}{
+	"simple":    {10, pow10(8)},
+	"one-over":  {pow10(8) + 1, 2 * pow10(8)},
+	"exact":     {pow10(8), pow10(8)},
+	"one-under": {pow10(8) - 1, pow10(8)},
+	"small":     {3, pow10(8)},
+	"two":       {2, pow10(8)},
+	"one":       {1, pow10(8)},
+	"zero":      {0, 0},
+}
+
+func TestRoundL1GasPrice(t *testing.T) {
+	for name, tt := range roundingL1GasPriceTests {
+		t.Run(name, func(t *testing.T) {
+			got := RoundL1GasPrice(new(big.Int).SetUint64(tt.input))
+			if got.Uint64() != tt.expect {
+				t.Fatalf("Mismatched rounding to nearest, got %d expected %d", got, tt.expect)
+			}
+		})
+	}
+}
+
+var roundingL2GasPriceTests = map[string]struct {
+	input  uint64
+	expect uint64
+}{
+	"simple":    {10, pow10(8) + 1},
+	"one-over":  {pow10(8) + 2, 2*pow10(8) + 1},
+	"exact":     {pow10(8) + 1, pow10(8) + 1},
+	"one-under": {pow10(8), pow10(8) + 1},
+	"small":     {3, pow10(8) + 1},
+	"two":       {2, pow10(8) + 1},
+	"one":       {1, pow10(8) + 1},
+	"zero":      {0, 1},
+}
+
+func TestRoundL2GasPrice(t *testing.T) {
+	for name, tt := range roundingL2GasPriceTests {
+		t.Run(name, func(t *testing.T) {
+			got := RoundL2GasPrice(new(big.Int).SetUint64(tt.input))
+			if got.Uint64() != tt.expect {
+				t.Fatalf("Mismatched rounding to nearest, got %d expected %d", got, tt.expect)
+			}
+		})
+	}
+}
+
+var l1GasLimitTests = map[string]struct {
+	data     []byte
+	overhead uint64
+	expect   *big.Int
+}{
+	"simple":          {[]byte{}, 0, big.NewInt(0)},
+	"simple-overhead": {[]byte{}, 10, big.NewInt(10)},
+	"zeros":           {[]byte{0x00, 0x00, 0x00, 0x00}, 10, big.NewInt(26)},
+	"ones":            {[]byte{0x01, 0x02, 0x03, 0x04}, 200, big.NewInt(16*4 + 200)},
+}
+
+func TestL1GasLimit(t *testing.T) {
+	for name, tt := range l1GasLimitTests {
+		t.Run(name, func(t *testing.T) {
+			got := calculateL1GasLimit(tt.data, tt.overhead)
+			if got.Cmp(tt.expect) != 0 {
+				t.Fatal("Calculated gas limit does not match")
+			}
+		})
+	}
+}
+
 var feeTests = map[string]struct {
-	dataLen        int
-	gasUsed        uint64
-	dataPrice      int64
-	executionPrice int64
+	dataLen    int
+	l1GasPrice uint64
+	l2GasLimit uint64
+	l2GasPrice uint64
+	err        error
 }{
-	"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},
+	"simple":           {100, 100_000_000, 437118, 100_000_001, nil},
+	"zero-l2-gasprice": {10, 100_000_000, 196205, 0, errInvalidGasPrice},
+	"one-l2-gasprice":  {10, 100_000_000, 196205, 1, nil},
+	"zero-l1-gasprice": {10, 0, 196205, 100_000_001, nil},
+	"one-l1-gasprice":  {10, 1, 23255, 23254, errInvalidGasPrice},
 }
 
 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))
-
-			zeroes, ones := zeroesAndOnes(data)
-			zeroesCost := zeroes * 4
-			onesCost := (96 + ones) * 16
-			dataCost := zeroesCost + onesCost
-			dataFee := int64(dataCost) * tt.dataPrice
-
-			executionFee := uint64(tt.executionPrice) * tt.gasUsed
-			expectedFee := uint64(dataFee) + executionFee
-			if fee.Cmp(big.NewInt(int64(expectedFee))) != 0 {
-				t.Errorf("rollup fee check failed: expected %d, got %s", expectedFee, fee.String())
+			l1GasPrice := new(big.Int).SetUint64(tt.l1GasPrice)
+			l2GasLimit := new(big.Int).SetUint64(tt.l2GasLimit)
+			l2GasPrice := new(big.Int).SetUint64(tt.l2GasPrice)
+
+			fee, err := CalculateRollupFee(data, l1GasPrice, l2GasLimit, l2GasPrice)
+			if !errors.Is(err, tt.err) {
+				t.Fatalf("Cannot calculate fee: %s", err)
+			}
+
+			if err == nil {
+				decodedGasLimit := DecodeL2GasLimit(fee)
+				if l2GasLimit.Cmp(decodedGasLimit) != 0 {
+					t.Errorf("rollup fee check failed: expected %d, got %d", l2GasLimit.Uint64(), decodedGasLimit)
+				}
 			}
 		})
 	}
 }
+
+func pow10(x int) uint64 {
+	return uint64(math.Pow10(x))
+}

l2geth/core/tx_pool.go

@@ -542,7 +542,7 @@ func (pool *TxPool) validateTx(tx *types.Transaction, local bool) error {
 	// Ensure the transaction doesn't exceed the current block limit 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 {
+	if pool.currentMaxGas < tx.L2Gas() && tx.GasPrice().Cmp(gwei) != 0 {
 		return ErrGasLimit
 	}
 

l2geth/core/types/transaction.go

@@ -225,6 +225,7 @@ func (tx *Transaction) UnmarshalJSON(input []byte) error {
 
 func (tx *Transaction) Data() []byte       { return common.CopyBytes(tx.data.Payload) }
 func (tx *Transaction) Gas() uint64        { return tx.data.GasLimit }
+func (tx *Transaction) L2Gas() uint64      { return tx.data.GasLimit % 100_000_000 }
 func (tx *Transaction) GasPrice() *big.Int { return new(big.Int).Set(tx.data.Price) }
 func (tx *Transaction) Value() *big.Int    { return new(big.Int).Set(tx.data.Amount) }
 func (tx *Transaction) Nonce() uint64      { return tx.data.AccountNonce }

l2geth/eth/api_backend.go

@@ -389,20 +389,20 @@ 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.rollupGpo.SuggestDataPrice(ctx)
+func (b *EthAPIBackend) SuggestL1GasPrice(ctx context.Context) (*big.Int, error) {
+	return b.rollupGpo.SuggestL1GasPrice(ctx)
 }
 
-func (b *EthAPIBackend) SuggestExecutionPrice(ctx context.Context) (*big.Int, error) {
-	return b.rollupGpo.SuggestExecutionPrice(ctx)
+func (b *EthAPIBackend) SuggestL2GasPrice(ctx context.Context) (*big.Int, error) {
+	return b.rollupGpo.SuggestL2GasPrice(ctx)
 }
 
-func (b *EthAPIBackend) SetDataPrice(ctx context.Context, gasPrice *big.Int) {
-	b.rollupGpo.SetDataPrice(gasPrice)
+func (b *EthAPIBackend) SetL1GasPrice(ctx context.Context, gasPrice *big.Int) error {
+	return b.rollupGpo.SetL1GasPrice(gasPrice)
 }
 
-func (b *EthAPIBackend) SetExecutionPrice(ctx context.Context, gasPrice *big.Int) {
-	b.rollupGpo.SetExecutionPrice(gasPrice)
+func (b *EthAPIBackend) SetL2GasPrice(ctx context.Context, gasPrice *big.Int) error {
+	return b.rollupGpo.SetL2GasPrice(gasPrice)
 }
 
 func (b *EthAPIBackend) ChainDb() ethdb.Database {

l2geth/eth/gasprice/rollup_gasprice.go

@@ -4,8 +4,12 @@ import (
 	"context"
 	"math/big"
 	"sync"
+
+	"github.com/ethereum/go-ethereum/core"
+	"github.com/ethereum/go-ethereum/log"
 )
 
+// RollupOracle holds the L1 and L2 gas prices for fee calculation
 type RollupOracle struct {
 	dataPrice          *big.Int
 	executionPrice     *big.Int
@@ -13,6 +17,7 @@ type RollupOracle struct {
 	executionPriceLock sync.RWMutex
 }
 
+// NewRollupOracle returns an initialized RollupOracle
 func NewRollupOracle(dataPrice *big.Int, executionPrice *big.Int) *RollupOracle {
 	return &RollupOracle{
 		dataPrice:      dataPrice,
@@ -20,32 +25,42 @@ func NewRollupOracle(dataPrice *big.Int, executionPrice *big.Int) *RollupOracle
 	}
 }
 
-/// SuggestDataPrice returns the gas price which should be charged per byte of published
-/// data by the sequencer.
-func (gpo *RollupOracle) SuggestDataPrice(ctx context.Context) (*big.Int, error) {
+// SuggestL1GasPrice returns the gas price which should be charged per byte of published
+// data by the sequencer.
+func (gpo *RollupOracle) SuggestL1GasPrice(ctx context.Context) (*big.Int, error) {
 	gpo.dataPriceLock.RLock()
-	price := gpo.dataPrice
-	gpo.dataPriceLock.RUnlock()
-	return price, nil
+	defer gpo.dataPriceLock.RUnlock()
+	return gpo.dataPrice, nil
 }
 
-func (gpo *RollupOracle) SetDataPrice(dataPrice *big.Int) {
+// SetL1GasPrice returns the current L1 gas price
+func (gpo *RollupOracle) SetL1GasPrice(dataPrice *big.Int) error {
 	gpo.dataPriceLock.Lock()
+	defer gpo.dataPriceLock.Unlock()
+	if err := core.VerifyL1GasPrice(dataPrice); err != nil {
+		return err
+	}
 	gpo.dataPrice = dataPrice
-	gpo.dataPriceLock.Unlock()
+	log.Info("Set L1 Gas Price", "gasprice", gpo.dataPrice)
+	return nil
 }
 
-/// SuggestExecutionPrice returns the gas price which should be charged per unit of gas
-/// set manually by the sequencer depending on congestion
-func (gpo *RollupOracle) SuggestExecutionPrice(ctx context.Context) (*big.Int, error) {
+// SuggestL2GasPrice returns the gas price which should be charged per unit of gas
+// set manually by the sequencer depending on congestion
+func (gpo *RollupOracle) SuggestL2GasPrice(ctx context.Context) (*big.Int, error) {
 	gpo.executionPriceLock.RLock()
-	price := gpo.executionPrice
-	gpo.executionPriceLock.RUnlock()
-	return price, nil
+	defer gpo.executionPriceLock.RUnlock()
+	return gpo.executionPrice, nil
 }
 
-func (gpo *RollupOracle) SetExecutionPrice(executionPrice *big.Int) {
+// SetL2GasPrice returns the current L2 gas price
+func (gpo *RollupOracle) SetL2GasPrice(executionPrice *big.Int) error {
 	gpo.executionPriceLock.Lock()
+	defer gpo.executionPriceLock.Unlock()
+	if err := core.VerifyL2GasPrice(executionPrice); err != nil {
+		return err
+	}
 	gpo.executionPrice = executionPrice
-	gpo.executionPriceLock.Unlock()
+	log.Info("Set L2 Gas Price", "gasprice", gpo.executionPrice)
+	return nil
 }

l2geth/internal/ethapi/api.go

@@ -50,7 +50,7 @@ import (
 )
 
 const (
-	defaultGasPrice = params.GWei
+	defaultGasPrice = params.Wei
 )
 
 var errOVMUnsupported = errors.New("OVM: Unsupported RPC Method")
@@ -1040,29 +1040,30 @@ func DoEstimateGas(ctx context.Context, b Backend, args CallArgs, blockNrOrHash
 
 	// 2a. fetch the data price, depends on how the sequencer has chosen to update their values based on the
 	// l1 gas prices
-	dataPrice, err := b.SuggestDataPrice(ctx)
+	l1GasPrice, err := b.SuggestL1GasPrice(ctx)
 	if err != nil {
 		return 0, err
 	}
 
 	// 2b. fetch the execution gas price, by the typical mempool dynamics
-	executionPrice, err := b.SuggestExecutionPrice(ctx)
+	l2GasPrice, err := b.SuggestL2GasPrice(ctx)
 	if err != nil {
 		return 0, err
 	}
 
-	// 3. calculate the fee and normalize by the default gas price
 	var data []byte
 	if args.Data == nil {
 		data = []byte{}
 	} else {
 		data = *args.Data
 	}
-	fee := core.CalculateRollupFee(data, uint64(gasUsed), dataPrice, executionPrice).Uint64() / defaultGasPrice
-	if fee < 21000 {
-		fee = 21000
+	// 3. calculate the fee
+	l2GasLimit := new(big.Int).SetUint64(uint64(gasUsed))
+	fee, err := core.CalculateRollupFee(data, l1GasPrice, l2GasLimit, l2GasPrice)
+	if err != nil {
+		return 0, err
 	}
-	return (hexutil.Uint64)(fee), nil
+	return (hexutil.Uint64)(fee.Uint64()), nil
 }
 
 func legacyDoEstimateGas(ctx context.Context, b Backend, args CallArgs, blockNrOrHash rpc.BlockNumberOrHash, gasCap *big.Int) (hexutil.Uint64, error) {
@@ -1140,12 +1141,20 @@ func legacyDoEstimateGas(ctx context.Context, b Backend, args CallArgs, blockNrO
 }
 
 // EstimateGas returns an estimate of the amount of gas needed to execute the
-// given transaction against the current pending block.
+// given transaction against the current pending block. This is modified to
+// encode the fee in wei as gas price is always 1
 func (s *PublicBlockChainAPI) EstimateGas(ctx context.Context, args CallArgs) (hexutil.Uint64, error) {
 	blockNrOrHash := rpc.BlockNumberOrHashWithNumber(rpc.PendingBlockNumber)
 	return DoEstimateGas(ctx, s.b, args, blockNrOrHash, s.b.RPCGasCap())
 }
 
+// EstimateExecutionGas returns an estimate of the amount of gas needed to execute the
+// given transaction against the current pending block.
+func (s *PublicBlockChainAPI) EstimateExecutionGas(ctx context.Context, args CallArgs) (hexutil.Uint64, error) {
+	blockNrOrHash := rpc.BlockNumberOrHashWithNumber(rpc.PendingBlockNumber)
+	return legacyDoEstimateGas(ctx, s.b, args, blockNrOrHash, s.b.RPCGasCap())
+}
+
 // ExecutionResult groups all structured logs emitted by the EVM
 // while replaying a transaction in debug mode as well as transaction
 // execution status, the amount of gas used and the return value
@@ -1996,15 +2005,15 @@ func NewPrivateRollupAPI(b Backend) *PrivateRollupAPI {
 	return &PrivateRollupAPI{b: b}
 }
 
-// SetDataPrice sets the gas price to be used when quoting calldata publishing costs
+// SetL1GasPrice sets the gas price to be used when quoting calldata publishing costs
 // to users
-func (api *PrivateRollupAPI) SetDataPrice(ctx context.Context, gasPrice hexutil.Big) {
-	api.b.SetDataPrice(ctx, (*big.Int)(&gasPrice))
+func (api *PrivateRollupAPI) SetL1GasPrice(ctx context.Context, gasPrice hexutil.Big) error {
+	return api.b.SetL1GasPrice(ctx, (*big.Int)(&gasPrice))
 }
 
-// SetExecutionPrice sets the gas price to be used when executing transactions on
-func (api *PrivateRollupAPI) SetExecutionPrice(ctx context.Context, gasPrice hexutil.Big) {
-	api.b.SetExecutionPrice(ctx, (*big.Int)(&gasPrice))
+// SetL2GasPrice sets the gas price to be used when executing transactions on
+func (api *PrivateRollupAPI) SetL2GasPrice(ctx context.Context, gasPrice hexutil.Big) error {
+	return api.b.SetL2GasPrice(ctx, (*big.Int)(&gasPrice))
 }
 
 // PublicDebugAPI is the collection of Ethereum APIs exposed over the public

l2geth/internal/ethapi/backend.go

@@ -94,10 +94,10 @@ type Backend interface {
 	GetRollupContext() (uint64, uint64, uint64)
 	GasLimit() uint64
 	GetDiff(*big.Int) (diffdb.Diff, error)
-	SuggestDataPrice(ctx context.Context) (*big.Int, error)
-	SetDataPrice(context.Context, *big.Int)
-	SuggestExecutionPrice(context.Context) (*big.Int, error)
-	SetExecutionPrice(context.Context, *big.Int)
+	SuggestL1GasPrice(ctx context.Context) (*big.Int, error)
+	SetL1GasPrice(context.Context, *big.Int) error
+	SuggestL2GasPrice(context.Context) (*big.Int, error)
+	SetL2GasPrice(context.Context, *big.Int) error
 	IngestTransactions([]*types.Transaction) error
 }
 

l2geth/les/api_backend.go

@@ -286,22 +286,22 @@ func (b *LesApiBackend) SuggestPrice(ctx context.Context) (*big.Int, error) {
 }
 
 // NB: Non sequencer nodes cannot suggest L1 gas prices.
-func (b *LesApiBackend) SuggestDataPrice(ctx context.Context) (*big.Int, error) {
-	panic("SuggestDataPrice not implemented")
+func (b *LesApiBackend) SuggestL1GasPrice(ctx context.Context) (*big.Int, error) {
+	panic("SuggestL1GasPrice not implemented")
 }
 
 // NB: Non sequencer nodes cannot suggest L2 execution gas prices.
-func (b *LesApiBackend) SuggestExecutionPrice(ctx context.Context) (*big.Int, error) {
-	panic("SuggestExecutionPrice not implemented")
+func (b *LesApiBackend) SuggestL2GasPrice(ctx context.Context) (*big.Int, error) {
+	panic("SuggestL2GasPrice not implemented")
 }
 
 // NB: Non sequencer nodes cannot set L1 gas prices.
-func (b *LesApiBackend) SetDataPrice(ctx context.Context, gasPrice *big.Int) {
+func (b *LesApiBackend) SetL1GasPrice(ctx context.Context, gasPrice *big.Int) error {
 	panic("SetDataPrice is not implemented")
 }
 
 // NB: Non sequencer nodes cannot set L2 execution prices.
-func (b *LesApiBackend) SetExecutionPrice(ctx context.Context, gasPrice *big.Int) {
+func (b *LesApiBackend) SetL2GasPrice(ctx context.Context, gasPrice *big.Int) error {
 	panic("SetExecutionPrice is not implemented")
 }
 

l2geth/rollup/config.go

@@ -25,6 +25,9 @@ type Config struct {
 	L1CrossDomainMessengerAddress common.Address
 	AddressManagerOwnerAddress    common.Address
 	L1ETHGatewayAddress           common.Address
+	GasPriceOracleAddress         common.Address
+	// Turns on checking of state for L2 gas price
+	EnableL2GasPolling bool
 	// Deployment Height of the canonical transaction chain
 	CanonicalTransactionChainDeployHeight *big.Int
 	// Path to the state dump
@@ -37,4 +40,6 @@ type Config struct {
 	DataPrice *big.Int
 	// The gas price to use for L2 congestion costs
 	ExecutionPrice *big.Int
+	// Only accept transactions with fees
+	EnforceFees bool
 }

l2geth/rollup/sync_service.go

@@ -10,7 +10,9 @@ import (
 	"sync/atomic"
 	"time"
 
+	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/core"
+	"github.com/ethereum/go-ethereum/core/state"
 	"github.com/ethereum/go-ethereum/ethdb"
 	"github.com/ethereum/go-ethereum/event"
 	"github.com/ethereum/go-ethereum/log"
@@ -28,6 +30,10 @@ type OVMContext struct {
 	timestamp   uint64
 }
 
+// L2GasPrice slot refers to the storage slot that the execution price is stored
+// in the L2 predeploy contract, the GasPriceOracle
+var l2GasPriceSlot = common.BigToHash(big.NewInt(1))
+
 // SyncService implements the verifier functionality as well as the reorg
 // protection for the sequencer.
 type SyncService struct {
@@ -49,6 +55,9 @@ type SyncService struct {
 	confirmationDepth         uint64
 	pollInterval              time.Duration
 	timestampRefreshThreshold time.Duration
+	gpoAddress                common.Address
+	enableL2GasPolling        bool
+	enforceFees               bool
 }
 
 // NewSyncService returns an initialized sync service
@@ -85,6 +94,7 @@ func NewSyncService(ctx context.Context, cfg Config, txpool *core.TxPool, bc *co
 	// Initialize the rollup client
 	client := NewClient(cfg.RollupClientHttp, chainID)
 	log.Info("Configured rollup client", "url", cfg.RollupClientHttp, "chain-id", chainID.Uint64(), "ctc-deploy-height", cfg.CanonicalTransactionChainDeployHeight)
+	log.Info("Enforce Fees", "set", cfg.EnforceFees)
 	service := SyncService{
 		ctx:                       ctx,
 		cancel:                    cancel,
@@ -99,6 +109,9 @@ func NewSyncService(ctx context.Context, cfg Config, txpool *core.TxPool, bc *co
 		db:                        db,
 		pollInterval:              pollInterval,
 		timestampRefreshThreshold: timestampRefreshThreshold,
+		gpoAddress:                cfg.GasPriceOracleAddress,
+		enableL2GasPolling:        cfg.EnableL2GasPolling,
+		enforceFees:               cfg.EnforceFees,
 	}
 
 	// Initial sync service setup if it is enabled. This code depends on
@@ -183,6 +196,8 @@ func (s *SyncService) Start() error {
 		return nil
 	}
 	log.Info("Initializing Sync Service", "eth1-chainid", s.eth1ChainId)
+	s.updateL2GasPrice(nil)
+	s.updateL1GasPrice()
 
 	// When a sequencer, be sure to sync to the tip of the ctc before allowing
 	// user transactions.
@@ -302,6 +317,9 @@ func (s *SyncService) VerifierLoop() {
 		if err := s.verify(); err != nil {
 			log.Error("Could not verify", "error", err)
 		}
+		if err := s.updateL2GasPrice(nil); err != nil {
+			log.Error("Cannot update L2 gas price", "msg", err)
+		}
 		time.Sleep(s.pollInterval)
 	}
 }
@@ -356,6 +374,9 @@ func (s *SyncService) SequencerLoop() {
 		}
 		s.txLock.Unlock()
 
+		if err := s.updateL2GasPrice(nil); err != nil {
+			log.Error("Cannot update L2 gas price", "msg", err)
+		}
 		if s.updateContext() != nil {
 			log.Error("Could not update execution context", "error", err)
 		}
@@ -447,8 +468,37 @@ func (s *SyncService) updateL1GasPrice() error {
 	if err != nil {
 		return err
 	}
-	s.RollupGpo.SetDataPrice(l1GasPrice)
-	log.Info("Adjusted L1 Gas Price", "gasprice", l1GasPrice)
+	s.RollupGpo.SetL1GasPrice(l1GasPrice)
+	return nil
+}
+
+// updateL2GasPrice accepts a state root and reads the gas price from the gas
+// price oracle at the state that corresponds to the state root. If no state
+// root is passed in, then the tip is used.
+func (s *SyncService) updateL2GasPrice(hash *common.Hash) error {
+	// TODO(mark): this is temporary and will be able to be rmoved when the
+	// OVM_GasPriceOracle is moved into the predeploy contracts
+	if !s.enableL2GasPolling {
+		return nil
+	}
+	var state *state.StateDB
+	var err error
+	if hash != nil {
+		state, err = s.bc.StateAt(*hash)
+	} else {
+		state, err = s.bc.State()
+	}
+	if err != nil {
+		return err
+	}
+	result := state.GetState(s.gpoAddress, l2GasPriceSlot)
+	gasPrice := result.Big()
+	if err := core.VerifyL2GasPrice(gasPrice); err != nil {
+		gp := core.RoundL2GasPrice(gasPrice)
+		log.Warn("Invalid gas price detected in state", "state", gasPrice, "using", gp)
+		gasPrice = gp
+	}
+	s.RollupGpo.SetL2GasPrice(gasPrice)
 	return nil
 }
 
@@ -710,6 +760,43 @@ func (s *SyncService) applyTransaction(tx *types.Transaction) error {
 	return nil
 }
 
+// verifyFee will verify that a valid fee is being paid.
+func (s *SyncService) verifyFee(tx *types.Transaction) error {
+	// Exit early if fees are enforced and the gasPrice is set to 0
+	if s.enforceFees && tx.GasPrice().Cmp(common.Big0) == 0 {
+		return errors.New("cannot accept 0 gas price transaction")
+	}
+
+	l1GasPrice, err := s.RollupGpo.SuggestL1GasPrice(context.Background())
+	if err != nil {
+		return err
+	}
+	l2GasPrice, err := s.RollupGpo.SuggestL2GasPrice(context.Background())
+	if err != nil {
+		return err
+	}
+	// Calculate the fee based on decoded L2 gas limit
+	gas := new(big.Int).SetUint64(tx.Gas())
+	l2GasLimit := core.DecodeL2GasLimit(gas)
+	fee, err := core.CalculateRollupFee(tx.Data(), l1GasPrice, l2GasLimit, l2GasPrice)
+	if err != nil {
+		return err
+	}
+	// If fees are not enforced and the gas price is 0, return early
+	if !s.enforceFees && tx.GasPrice().Cmp(common.Big0) == 0 {
+		return nil
+	}
+	// This should only happen if the transaction fee is greater than 18.44 ETH
+	if !fee.IsUint64() {
+		return fmt.Errorf("fee overflow: %s", fee.String())
+	}
+	// Make sure that the fee is paid
+	if tx.Gas() < fee.Uint64() {
+		return fmt.Errorf("fee too low: %d, use at least tx.gasLimit = %d and tx.gasPrice = 1", tx.Gas(), fee.Uint64())
+	}
+	return nil
+}
+
 // Higher level API for applying transactions. Should only be called for
 // queue origin sequencer transactions, as the contracts on L1 manage the same
 // validity checks that are done here.
@@ -717,6 +804,9 @@ func (s *SyncService) ApplyTransaction(tx *types.Transaction) error {
 	if tx == nil {
 		return fmt.Errorf("nil transaction passed to ApplyTransaction")
 	}
+	if err := s.verifyFee(tx); err != nil {
+		return err
+	}
 
 	log.Debug("Sending transaction to sync service", "hash", tx.Hash().Hex())
 	s.txLock.Lock()

l2geth/rollup/sync_service_test.go

@@ -154,13 +154,12 @@ func TestSyncServiceTransactionEnqueued(t *testing.T) {
 func TestSyncServiceL1GasPrice(t *testing.T) {
 	service, _, _, err := newTestSyncService(true)
 	setupMockClient(service, map[string]interface{}{})
-	service.RollupGpo = gasprice.NewRollupOracle(big.NewInt(0), big.NewInt(0))
 
 	if err != nil {
 		t.Fatal(err)
 	}
 
-	gasBefore, err := service.RollupGpo.SuggestDataPrice(context.Background())
+	gasBefore, err := service.RollupGpo.SuggestL1GasPrice(context.Background())
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -172,16 +171,53 @@ func TestSyncServiceL1GasPrice(t *testing.T) {
 	// Update the gas price
 	service.updateL1GasPrice()
 
-	gasAfter, err := service.RollupGpo.SuggestDataPrice(context.Background())
+	gasAfter, err := service.RollupGpo.SuggestL1GasPrice(context.Background())
 	if err != nil {
 		t.Fatal(err)
 	}
 
-	if gasAfter.Cmp(big.NewInt(100*int64(params.GWei))) != 0 {
+	if gasAfter.Cmp(core.RoundL1GasPrice(big.NewInt(1))) != 0 {
 		t.Fatal("expected 100 gas price, got", gasAfter)
 	}
 }
 
+func TestSyncServiceL2GasPrice(t *testing.T) {
+	service, _, _, err := newTestSyncService(true)
+	if err != nil {
+		t.Fatal(err)
+	}
+	service.enableL2GasPolling = true
+	service.gpoAddress = common.HexToAddress("0xF20b338752976878754518183873602902360704")
+
+	price, err := service.RollupGpo.SuggestL2GasPrice(context.Background())
+	if err != nil {
+		t.Fatal("Cannot fetch execution price")
+	}
+
+	if price.Cmp(common.Big0) != 0 {
+		t.Fatal("Incorrect gas price")
+	}
+
+	state, err := service.bc.State()
+	if err != nil {
+		t.Fatal("Cannot get state db")
+	}
+	l2GasPrice := big.NewInt(100000001)
+	state.SetState(service.gpoAddress, l2GasPriceSlot, common.BigToHash(l2GasPrice))
+	root, _ := state.Commit(false)
+
+	service.updateL2GasPrice(&root)
+
+	post, err := service.RollupGpo.SuggestL2GasPrice(context.Background())
+	if err != nil {
+		t.Fatal("Cannot fetch execution price")
+	}
+
+	if l2GasPrice.Cmp(post) != 0 {
+		t.Fatal("Gas price not updated")
+	}
+}
+
 // Pass true to set as a verifier
 func TestSyncServiceSync(t *testing.T) {
 	service, txCh, sub, err := newTestSyncService(true)
@@ -327,6 +363,7 @@ func newTestSyncService(isVerifier bool) (*SyncService, chan core.NewTxsEvent, e
 		return nil, nil, nil, fmt.Errorf("Cannot initialize syncservice: %w", err)
 	}
 
+	service.RollupGpo = gasprice.NewRollupOracle(big.NewInt(0), big.NewInt(0))
 	txCh := make(chan core.NewTxsEvent, 1)
 	sub := service.SubscribeNewTxsEvent(txCh)
 
@@ -443,5 +480,6 @@ func (m *mockClient) SyncStatus() (*SyncStatus, error) {
 }
 
 func (m *mockClient) GetL1GasPrice() (*big.Int, error) {
-	return big.NewInt(100 * int64(params.GWei)), nil
+	price := core.RoundL1GasPrice(big.NewInt(2))
+	return price, nil
 }

ops/envs/geth.env

@@ -6,6 +6,8 @@ ETH1_CONFIRMATION_DEPTH=0
 ROLLUP_CLIENT_HTTP=
 ROLLUP_STATE_DUMP_PATH=
 ROLLUP_POLL_INTERVAL_FLAG=500ms
+ROLLUP_ENABLE_L2_GAS_POLLING=true
+# ROLLUP_ENFORCE_FEES=
 
 RPC_ENABLE=true
 RPC_ADDR=0.0.0.0

packages/core-utils/src/fees.ts

+/**
+ * Fee related serialization and deserialization
+ */
+
+import { BigNumber } from 'ethers'
+import { remove0x } from './common'
+
+const hundredMillion = BigNumber.from(100_000_000)
+const txDataZeroGas = 4
+const txDataNonZeroGasEIP2028 = 16
+const overhead = 4200
+
+export interface EncodableL2GasLimit {
+  data: Buffer | string
+  l1GasPrice: BigNumber | number
+  l2GasLimit: BigNumber | number
+  l2GasPrice: BigNumber | number
+}
+
+function encode(input: EncodableL2GasLimit): BigNumber {
+  const { data } = input
+  let { l1GasPrice, l2GasLimit, l2GasPrice } = input
+  if (typeof l1GasPrice === 'number') {
+    l1GasPrice = BigNumber.from(l1GasPrice)
+  }
+  if (typeof l2GasLimit === 'number') {
+    l2GasLimit = BigNumber.from(l2GasLimit)
+  }
+  if (typeof l2GasPrice === 'number') {
+    l2GasPrice = BigNumber.from(l2GasPrice)
+  }
+
+  if (!verifyL2GasPrice(l2GasPrice)) {
+    throw new Error(`Invalid L2 Gas Price: ${l2GasPrice.toString()}`)
+  }
+  if (!verifyL1GasPrice(l1GasPrice)) {
+    throw new Error(`Invalid L1 Gas Price: ${l1GasPrice.toString()}`)
+  }
+  const l1GasLimit = calculateL1GasLimit(data)
+  const l1Fee = l1GasPrice.mul(l1GasLimit)
+  const l2Fee = l2GasLimit.mul(l2GasPrice)
+  return l1Fee.add(l2Fee)
+}
+
+function decode(fee: BigNumber | number): BigNumber {
+  if (typeof fee === 'number') {
+    fee = BigNumber.from(fee)
+  }
+  return fee.mod(hundredMillion)
+}
+
+export const L2GasLimit = {
+  encode,
+  decode,
+}
+
+export function verifyL2GasPrice(gasPrice: BigNumber | number): boolean {
+  if (typeof gasPrice === 'number') {
+    gasPrice = BigNumber.from(gasPrice)
+  }
+  // If the gas price is not equal to 0 and the gas price mod
+  // one hundred million is not one
+  if (!gasPrice.eq(0) && !gasPrice.mod(hundredMillion).eq(1)) {
+    return false
+  }
+  if (gasPrice.eq(0)) {
+    return false
+  }
+  return true
+}
+
+export function verifyL1GasPrice(gasPrice: BigNumber | number): boolean {
+  if (typeof gasPrice === 'number') {
+    gasPrice = BigNumber.from(gasPrice)
+  }
+  return gasPrice.mod(hundredMillion).eq(0)
+}
+
+export function calculateL1GasLimit(data: string | Buffer): number {
+  const [zeroes, ones] = zeroesAndOnes(data)
+  const zeroesCost = zeroes * txDataZeroGas
+  const onesCost = ones * txDataNonZeroGasEIP2028
+  const gasLimit = zeroesCost + onesCost + overhead
+  return gasLimit
+}
+
+export function zeroesAndOnes(data: Buffer | string): Array<number> {
+  if (typeof data === 'string') {
+    data = Buffer.from(remove0x(data), 'hex')
+  }
+  let zeros = 0
+  let ones = 0
+  for (const byte of data) {
+    if (byte === 0) {
+      zeros++
+    } else {
+      ones++
+    }
+  }
+  return [zeros, ones]
+}
+
+export function roundL1GasPrice(gasPrice: BigNumber | number): BigNumber {
+  if (typeof gasPrice === 'number') {
+    gasPrice = BigNumber.from(gasPrice)
+  }
+  return ceilModOneHundredMillion(gasPrice)
+}
+
+function ceilModOneHundredMillion(num: BigNumber): BigNumber {
+  if (num.mod(hundredMillion).eq(0)) {
+    return num
+  }
+  const sum = num.add(hundredMillion)
+  const mod = num.mod(hundredMillion)
+  return sum.sub(mod)
+}
+
+export function roundL2GasPrice(gasPrice: BigNumber | number): BigNumber {
+  if (typeof gasPrice === 'number') {
+    gasPrice = BigNumber.from(gasPrice)
+  }
+  if (gasPrice.eq(0)) {
+    return BigNumber.from(1)
+  }
+  if (gasPrice.eq(1)) {
+    return hundredMillion.add(1)
+  }
+  const gp = gasPrice.sub(1)
+  const mod = ceilModOneHundredMillion(gp)
+  return mod.add(1)
+}

packages/core-utils/src/index.ts

@@ -5,3 +5,4 @@ export * from './l2context'
 export * from './events'
 export * from './batches'
 export * from './bcfg'
+export * from './fees'

packages/core-utils/test/fees/fees.spec.ts

+import { expect } from '../setup'
+import * as fees from '../../src/fees'
+import { BigNumber } from 'ethers'
+
+describe('Fees', () => {
+  it('should count zeros and ones', () => {
+    const cases = [
+      { input: Buffer.from('0001', 'hex'), zeros: 1, ones: 1 },
+      { input: '0x0001', zeros: 1, ones: 1 },
+      { input: '0x', zeros: 0, ones: 0 },
+      { input: '0x1111', zeros: 0, ones: 2 },
+    ]
+
+    for (const test of cases) {
+      const [zeros, ones] = fees.zeroesAndOnes(test.input)
+      zeros.should.eq(test.zeros)
+      ones.should.eq(test.ones)
+    }
+  })
+
+  describe('Round L1 Gas Price', () => {
+    const roundL1GasPriceTests = [
+      { input: 10, expect: 10 ** 8, name: 'simple' },
+      { input: 10 ** 8 + 1, expect: 2 * 10 ** 8, name: 'one-over' },
+      { input: 10 ** 8, expect: 10 ** 8, name: 'exact' },
+      { input: 10 ** 8 - 1, expect: 10 ** 8, name: 'one-under' },
+      { input: 3, expect: 10 ** 8, name: 'small' },
+      { input: 2, expect: 10 ** 8, name: 'two' },
+      { input: 1, expect: 10 ** 8, name: 'one' },
+      { input: 0, expect: 0, name: 'zero' },
+    ]
+
+    for (const test of roundL1GasPriceTests) {
+      it(`should pass for ${test.name} case`, () => {
+        const got = fees.roundL1GasPrice(test.input)
+        const expected = BigNumber.from(test.expect)
+        expect(got).to.deep.equal(expected)
+      })
+    }
+  })
+
+  describe('Round L2 Gas Price', () => {
+    const roundL2GasPriceTests = [
+      { input: 10, expect: 10 ** 8 + 1, name: 'simple' },
+      { input: 10 ** 8 + 2, expect: 2 * 10 ** 8 + 1, name: 'one-over' },
+      { input: 10 ** 8 + 1, expect: 10 ** 8 + 1, name: 'exact' },
+      { input: 10 ** 8, expect: 10 ** 8 + 1, name: 'one-under' },
+      { input: 3, expect: 10 ** 8 + 1, name: 'small' },
+      { input: 2, expect: 10 ** 8 + 1, name: 'two' },
+      { input: 1, expect: 10 ** 8 + 1, name: 'one' },
+      { input: 0, expect: 1, name: 'zero' },
+    ]
+
+    for (const test of roundL2GasPriceTests) {
+      it(`should pass for ${test.name} case`, () => {
+        const got = fees.roundL2GasPrice(test.input)
+        const expected = BigNumber.from(test.expect)
+        expect(got).to.deep.equal(expected)
+      })
+    }
+  })
+
+  describe('Rollup Fees', () => {
+    const rollupFeesTests = [
+      {
+        name: 'simple',
+        dataLen: 10,
+        l1GasPrice: 100_000_000,
+        l2GasPrice: 100_000_001,
+        l2GasLimit: 437118,
+        error: false,
+      },
+      {
+        name: 'zero-l2-gasprice',
+        dataLen: 10,
+        l1GasPrice: 100_000_000,
+        l2GasPrice: 0,
+        l2GasLimit: 196205,
+        error: true,
+      },
+      {
+        name: 'one-l2-gasprice',
+        dataLen: 10,
+        l1GasPrice: 100_000_000,
+        l2GasPrice: 1,
+        l2GasLimit: 196205,
+        error: false,
+      },
+      {
+        name: 'zero-l1-gasprice',
+        dataLen: 10,
+        l1GasPrice: 0,
+        l2GasPrice: 100_000_001,
+        l2GasLimit: 196205,
+        error: false,
+      },
+      {
+        name: 'one-l1-gasprice',
+        dataLen: 10,
+        l1GasPrice: 1,
+        l2GasPrice: 23254,
+        l2GasLimit: 23255,
+        error: true,
+      },
+    ]
+
+    for (const test of rollupFeesTests) {
+      it(`should pass for ${test.name} case`, () => {
+        const data = Buffer.alloc(test.dataLen)
+
+        let got
+        let err = false
+        try {
+          got = fees.L2GasLimit.encode({
+            data,
+            l1GasPrice: test.l1GasPrice,
+            l2GasPrice: test.l2GasPrice,
+            l2GasLimit: test.l2GasLimit,
+          })
+        } catch (e) {
+          err = true
+        }
+
+        expect(err).to.equal(test.error)
+
+        if (!err) {
+          const decoded = fees.L2GasLimit.decode(got)
+          expect(decoded).to.deep.eq(BigNumber.from(test.l2GasLimit))
+        }
+      })
+    }
+  })
+})

packages/smock/src/smockit/smockit.ts

@@ -165,13 +165,11 @@ export const smockit = async (
   // We attach a wallet to the contract so that users can send transactions *from* a smock.
   await hre.network.provider.request({
     method: 'hardhat_impersonateAccount',
-    params: [contract.address]
+    params: [contract.address],
   })
 
   // Now we actually get the signer and attach it to the mock.
-  contract.wallet = await (hre as any).ethers.getSigner(
-    contract.address
-  )
+  contract.wallet = await (hre as any).ethers.getSigner(contract.address)
 
   // Start by smocking the fallback.
   contract.smocked = {

packages/smock/test/smockit/sending-from-mocks.spec.ts

@@ -11,16 +11,14 @@ describe('[smock]: sending transactions from smock contracts', () => {
 
   let TestHelpers_SenderAssertions: Contract
   before(async () => {
-    TestHelpers_SenderAssertions = await(
-      await ethers.getContractFactory(
-        'TestHelpers_SenderAssertions'
-      )
+    TestHelpers_SenderAssertions = await (
+      await ethers.getContractFactory('TestHelpers_SenderAssertions')
     ).deploy()
   })
 
   it('should attach a signer for a mock with a random address', async () => {
     const mock = await smockit('TestHelpers_BasicReturnContract')
-    
+
     expect(
       await TestHelpers_SenderAssertions.connect(mock.wallet).getSender()
     ).to.equal(mock.address)
@@ -28,7 +26,7 @@ describe('[smock]: sending transactions from smock contracts', () => {
 
   it('should attach a signer for a mock with a fixed address', async () => {
     const mock = await smockit('TestHelpers_BasicReturnContract', {
-      address: '0x1234123412341234123412341234123412341234'
+      address: '0x1234123412341234123412341234123412341234',
     })
 
     expect(