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Improve non-native currency fee tx handling (#2)
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Improves multi-currency fee support in the tx pool queue and pending lists.
Previously when paying for a tx in a non-native currency, the balance of the account
would only be checked when inserting the transaction into the tx pool, but as the
balance of the account can change after the tx is admitted, transactions are periodically
checked for validity in `txList.Filter`. This PR changes txList to properly track balances in
non-native currencies. This also adds support for checking the gas price minimum in the txList.

This PR also converts gas prices to CELO prior to comparing if a new transaction at the same
nonce should override an old transaction at the same nonce. It also refactors calculations
of `tx.Fee()`
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Joshua Gutow authored and Joshua Gutow committed Feb 5, 2021
1 parent e14be02 commit 3a2a2fc
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Showing 3 changed files with 194 additions and 31 deletions.
176 changes: 150 additions & 26 deletions core/tx_list.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -224,17 +224,23 @@ type txList struct {
strict bool // Whether nonces are strictly continuous or not
txs *txSortedMap // Heap indexed sorted hash map of the transactions

costcap *big.Int // Price of the highest costing transaction (reset only if exceeds balance)
gascap uint64 // Gas limit of the highest spending transaction (reset only if exceeds block limit)
nativecostcap *big.Int // Price of the highest costing transaction paid with native fees (reset only if exceeds balance)
feecaps map[common.Address]*big.Int // Price of the highest costing transaction per fee currency (reset only if exceeds balance)
nativegaspricefloor *big.Int // Lowest gas price minimum in the native currency
gaspricefloors map[common.Address]*big.Int // Lowest gas price minimum per currency (reset only if it is below the gpm)
gascap uint64 // Gas limit of the highest spending transaction (reset only if exceeds block limit)
}

// newTxList create a new transaction list for maintaining nonce-indexable fast,
// gapped, sortable transaction lists.
func newTxList(strict bool) *txList {
return &txList{
strict: strict,
txs: newTxSortedMap(),
costcap: new(big.Int),
strict: strict,
txs: newTxSortedMap(),
nativecostcap: new(big.Int),
feecaps: make(map[common.Address]*big.Int),
nativegaspricefloor: nil,
gaspricefloors: make(map[common.Address]*big.Int),
}
}

Expand All @@ -244,27 +250,75 @@ func (l *txList) Overlaps(tx *types.Transaction) bool {
return l.txs.Get(tx.Nonce()) != nil
}

// FeeCurrencies returns a list of each fee currency used to pay for gas in the txList
func (l *txList) FeeCurrencies() []common.Address {
var feeCurrencies []common.Address
for feeCurrency := range l.feecaps {
feeCurrencies = append(feeCurrencies, feeCurrency)
}
return feeCurrencies
}

// Add tries to insert a new transaction into the list, returning whether the
// transaction was accepted, and if yes, any previous transaction it replaced.
//
// If the new transaction is accepted into the list, the lists' cost and gas
// thresholds are also potentially updated.
// If the new transaction is accepted into the list, the lists' cost, gas and
// gasPriceMinimum thresholds are also potentially updated.
func (l *txList) Add(tx *types.Transaction, priceBump uint64) (bool, *types.Transaction) {
// If there's an older better transaction, abort
old := l.txs.Get(tx.Nonce())
var err error
if old != nil {
threshold := new(big.Int).Div(new(big.Int).Mul(old.GasPrice(), big.NewInt(100+int64(priceBump))), big.NewInt(100))
var oldPrice, newPrice *big.Int
// Short circuit conversion if both are the same currency
if old.FeeCurrency() == tx.FeeCurrency() {
oldPrice = old.GasPrice()
newPrice = tx.GasPrice()
} else {
if fc := old.FeeCurrency(); fc != nil {
if oldPrice, err = currency.ConvertToGold(old.GasPrice(), fc); err != nil {
return false, nil
}
} else {
oldPrice = old.GasPrice()
}
if fc := tx.FeeCurrency(); fc != nil {
if newPrice, err = currency.ConvertToGold(tx.GasPrice(), fc); err != nil {
return false, nil
}
} else {
newPrice = tx.GasPrice()
}
}
threshold := new(big.Int).Div(new(big.Int).Mul(oldPrice, big.NewInt(100+int64(priceBump))), big.NewInt(100))
// Have to ensure that the new gas price is higher than the old gas
// price as well as checking the percentage threshold to ensure that
// this is accurate for low (Wei-level) gas price replacements
if old.GasPrice().Cmp(tx.GasPrice()) >= 0 || threshold.Cmp(tx.GasPrice()) > 0 {
if oldPrice.Cmp(newPrice) >= 0 || threshold.Cmp(newPrice) > 0 {
return false, nil
}
}
// Otherwise overwrite the old transaction with the current one
// caps can only increase and floors can only decrease in this function
l.txs.Put(tx)
if cost := tx.Cost(); l.costcap.Cmp(cost) < 0 {
l.costcap = cost
if feeCurrency := tx.FeeCurrency(); feeCurrency == nil {
if cost := tx.Cost(); l.nativecostcap.Cmp(cost) < 0 {
l.nativecostcap = cost
}
if gasPrice := tx.GasPrice(); l.nativegaspricefloor == nil || l.nativegaspricefloor.Cmp(gasPrice) > 0 {
l.nativegaspricefloor = gasPrice
}
} else {
fee := tx.Fee()
if oldFee, ok := l.feecaps[*feeCurrency]; !ok || oldFee.Cmp(fee) < 0 {
l.feecaps[*feeCurrency] = fee
}
if gasFloor, ok := l.gaspricefloors[*feeCurrency]; !ok || gasFloor.Cmp(tx.GasPrice()) > 0 {
l.gaspricefloors[*feeCurrency] = tx.GasPrice()
}
if value := tx.Value(); l.nativecostcap.Cmp(value) < 0 {
l.nativecostcap = value
}
}
if gas := tx.Gas(); l.gascap < gas {
l.gascap = gas
Expand All @@ -287,29 +341,99 @@ func (l *txList) Forward(threshold uint64) types.Transactions {
// This method uses the cached costcap and gascap to quickly decide if there's even
// a point in calculating all the costs or if the balance covers all. If the threshold
// is lower than the costgas cap, the caps will be reset to a new high after removing
// the newly invalidated transactions.
func (l *txList) Filter(costLimit *big.Int, gasLimit uint64) (types.Transactions, types.Transactions) {
if costLimit == nil {
costLimit = l.costcap
func (l *txList) Filter(nativeCostLimit, nativeGasPriceMinimum *big.Int, feeLimits, gasPriceMinimums map[common.Address]*big.Int, gasLimit uint64) (types.Transactions, types.Transactions) {
// native gas price floor is not necessarily set in txList.Add unlike the rest of caps/floors
if l.nativegaspricefloor == nil {
l.nativegaspricefloor = new(big.Int).Set(nativeGasPriceMinimum)
}
// check if we can bail & lower caps & raise floors at the same time
canBail := true
// Ensure that the cost cap <= the cost limit
if l.nativecostcap.Cmp(nativeCostLimit) > 0 {
canBail = false
l.nativecostcap = new(big.Int).Set(nativeCostLimit)
}
// Ensure that native gas price floor >= the native gas price minimum
if l.nativegaspricefloor.Cmp(nativeGasPriceMinimum) < 0 {
canBail = false
l.nativegaspricefloor = new(big.Int).Set(nativeGasPriceMinimum)
}
// Ensure that the gas cap <= the gas limit
if l.gascap > gasLimit {
canBail = false
l.gascap = gasLimit
}
// Ensure that each cost cap <= the per currency cost limit.
for feeCurrency, feeLimit := range feeLimits {
if l.feecaps[feeCurrency].Cmp(feeLimit) > 0 {
canBail = false
l.feecaps[feeCurrency] = new(big.Int).Set(feeLimit)
}
}
// If all transactions are below the threshold, short circuit
if l.costcap.Cmp(costLimit) <= 0 && l.gascap <= gasLimit {
// Ensure that each gas price floor >= the gas price minimum.
for feeCurrency, gasPriceMinimum := range gasPriceMinimums {
if l.gaspricefloors[feeCurrency].Cmp(gasPriceMinimum) < 0 {
canBail = false
l.gaspricefloors[feeCurrency] = new(big.Int).Set(gasPriceMinimum)
}
}
if canBail {
return nil, nil
}
l.costcap = new(big.Int).Set(costLimit) // Lower the caps to the thresholds
l.gascap = gasLimit

// Filter out all the transactions above the account's funds
removed := l.txs.Filter(func(tx *types.Transaction) bool {
if tx.FeeCurrency() == nil {
log.Trace("Transaction Filter", "hash", tx.Hash(), "Fee currency", tx.FeeCurrency(), "Cost", tx.Cost(), "Cost Limit", costLimit, "Gas", tx.Gas(), "Gas Limit", gasLimit)
return tx.Cost().Cmp(costLimit) > 0 || tx.Gas() > gasLimit
if feeCurrency := tx.FeeCurrency(); feeCurrency == nil {
log.Trace("Transaction Filter", "hash", tx.Hash(), "Fee currency", tx.FeeCurrency(), "Cost", tx.Cost(), "Cost Limit", nativeCostLimit, "Gas", tx.Gas(), "Gas Limit", gasLimit)
return tx.Cost().Cmp(nativeCostLimit) > 0 || tx.Gas() > gasLimit || tx.GasPrice().Cmp(nativeGasPriceMinimum) < 0
} else {
// If the fees are being paid in the non-native currency, ensure that the `tx.Value` is less than costLimit
// as the fees will be deducted in the non-native currency.
log.Trace("Transaction Filter", "hash", tx.Hash(), "Fee currency", tx.FeeCurrency(), "Value", tx.Value(), "Cost Limit", costLimit, "Gas", tx.Gas(), "Gas Limit", gasLimit)
return tx.Value().Cmp(costLimit) > 0 || tx.Gas() > gasLimit
feeLimit := feeLimits[*feeCurrency]
fee := tx.Fee()
log.Trace("Transaction Filter", "hash", tx.Hash(), "Fee currency", tx.FeeCurrency(), "Value", tx.Value(), "Cost Limit", feeLimit, "Gas", tx.Gas(), "Gas Limit", gasLimit)
// If any of the following is true, the transaction is invalid
// The fees are greater than or equal to the balance in the currency
return fee.Cmp(feeLimit) >= 0 ||
// The value of the tx is greater than the native balance of the account
tx.Value().Cmp(nativeCostLimit) > 0 ||
// The gas price is less than the gas price minimum
tx.GasPrice().Cmp(gasPriceMinimums[*feeCurrency]) < 0 ||
// The gas used is greater than the gas limit
tx.Gas() > gasLimit
}
})

// If the list was strict, filter anything above the lowest nonce
var invalids types.Transactions

if l.strict && len(removed) > 0 {
lowest := uint64(math.MaxUint64)
for _, tx := range removed {
if nonce := tx.Nonce(); lowest > nonce {
lowest = nonce
}
}
invalids = l.txs.Filter(func(tx *types.Transaction) bool { return tx.Nonce() > lowest })
}
return removed, invalids
}

// FilterOnGasLimit removes all transactions from the list with a gas limit higher
// than the provided thresholds. Every removed transaction is returned for any
// post-removal maintenance. Strict-mode invalidated transactions are also
// returned.
//
// This method uses the cached gascap to quickly decide if there's even
// a point in calculating all the gas used
func (l *txList) FilterOnGasLimit(gasLimit uint64) (types.Transactions, types.Transactions) {
// We can bail if the gas cap <= the gas limit
if l.gascap <= gasLimit {
return nil, nil
}
l.gascap = gasLimit

// Filter out all the transactions above the account's funds
removed := l.txs.Filter(func(tx *types.Transaction) bool {
return tx.Gas() > gasLimit
})

// If the list was strict, filter anything above the lowest nonce
Expand Down
41 changes: 36 additions & 5 deletions core/tx_pool.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -492,7 +492,7 @@ func (pool *TxPool) SetGasLimit(gasLimit uint64) {
pool.demoteUnexecutables()

for _, list := range pool.queue {
rm, _ := list.Filter(nil, gasLimit)
rm, _ := list.FilterOnGasLimit(gasLimit)
for _, tx := range rm {
pool.removeTx(tx.Hash(), false)
}
Expand Down Expand Up @@ -1286,6 +1286,14 @@ func (pool *TxPool) reset(oldHead, newHead *types.Header) {
func (pool *TxPool) promoteExecutables(accounts []common.Address) []*types.Transaction {
// Track the promoted transactions to broadcast them at once
var promoted []*types.Transaction
// build gas price minimums
gasPriceMinimums := make(map[common.Address]*big.Int)
allCurrencies, _ := currency.CurrencyWhitelist(nil, nil)
for _, currency := range allCurrencies {
gasPriceMinimum, _ := gpm.GetGasPriceMinimum(&currency, nil, nil)
gasPriceMinimums[currency] = gasPriceMinimum
}
nativeGPM, _ := gpm.GetGasPriceMinimum(nil, nil, nil)

// Iterate over all accounts and promote any executable transactions
for _, addr := range accounts {
Expand All @@ -1300,8 +1308,15 @@ func (pool *TxPool) promoteExecutables(accounts []common.Address) []*types.Trans
pool.all.Remove(hash)
log.Trace("Removed old queued transaction", "hash", hash)
}
// Get balances in each currency
balances := make(map[common.Address]*big.Int)
allCurrencies := list.FeeCurrencies()
for _, feeCurrency := range allCurrencies {
feeCurrencyBalance, _, _ := currency.GetBalanceOf(addr, feeCurrency, params.MaxGasToReadErc20Balance, nil, nil)
balances[feeCurrency] = feeCurrencyBalance
}
// Drop all transactions that are too costly (low balance or out of gas)
drops, _ := list.Filter(pool.currentState.GetBalance(addr), pool.currentMaxGas)
drops, _ := list.Filter(pool.currentState.GetBalance(addr), nativeGPM, balances, gasPriceMinimums, pool.currentMaxGas)
for _, tx := range drops {
hash := tx.Hash()
pool.all.Remove(hash)
Expand Down Expand Up @@ -1482,6 +1497,15 @@ func (pool *TxPool) truncateQueue() {
// executable/pending queue and any subsequent transactions that become unexecutable
// are moved back into the future queue.
func (pool *TxPool) demoteUnexecutables() {
// build gas price minimums
gasPriceMinimums := make(map[common.Address]*big.Int)
allCurrencies, _ := currency.CurrencyWhitelist(nil, nil)
for _, currency := range allCurrencies {
gasPriceMinimum, _ := gpm.GetGasPriceMinimum(&currency, nil, nil)
gasPriceMinimums[currency] = gasPriceMinimum
}
nativeGPM, _ := gpm.GetGasPriceMinimum(nil, nil, nil)

// Iterate over all accounts and demote any non-executable transactions
for addr, list := range pool.pending {
nonce := pool.currentState.GetNonce(addr)
Expand All @@ -1493,8 +1517,15 @@ func (pool *TxPool) demoteUnexecutables() {
pool.all.Remove(hash)
log.Trace("Removed old pending transaction", "hash", hash)
}
// Get balances in each currency
balances := make(map[common.Address]*big.Int)
allCurrencies := list.FeeCurrencies()
for _, feeCurrency := range allCurrencies {
feeCurrencyBalance, _, _ := currency.GetBalanceOf(addr, feeCurrency, params.MaxGasToReadErc20Balance, nil, nil)
balances[feeCurrency] = feeCurrencyBalance
}
// Drop all transactions that are too costly (low balance or out of gas), and queue any invalids back for later
drops, invalids := list.Filter(pool.currentState.GetBalance(addr), pool.currentMaxGas)
drops, invalids := list.Filter(pool.currentState.GetBalance(addr), nativeGPM, balances, gasPriceMinimums, pool.currentMaxGas)
for _, tx := range drops {
hash := tx.Hash()
log.Trace("Removed unpayable pending transaction", "hash", hash)
Expand Down Expand Up @@ -1545,10 +1576,10 @@ func ValidateTransactorBalanceCoversTx(tx *types.Transaction, from common.Addres
return err
}

gasFee := new(big.Int).Mul(tx.GasPrice(), big.NewInt(int64(tx.Gas())))
// To match the logic in canPayFee() state_transition.go, we require the balance to be strictly greater than the fee,
// which means we reject the transaction if balance <= fee
if feeCurrencyBalance.Cmp(new(big.Int).Add(gasFee, tx.GatewayFee())) <= 0 {
fee := tx.Fee()
if feeCurrencyBalance.Cmp(fee) <= 0 {
log.Debug("validateTx insufficient fee currency", "feeCurrency", tx.FeeCurrency(), "feeCurrencyBalance", feeCurrencyBalance)
return ErrInsufficientFunds
}
Expand Down
8 changes: 8 additions & 0 deletions core/types/transaction.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -193,6 +193,10 @@ func (tx *Transaction) GatewayFee() *big.Int { return tx.data.Ga
func (tx *Transaction) Value() *big.Int { return new(big.Int).Set(tx.data.Amount) }
func (tx *Transaction) Nonce() uint64 { return tx.data.AccountNonce }
func (tx *Transaction) CheckNonce() bool { return true }
func (tx *Transaction) Fee() *big.Int {
gasFee := new(big.Int).Mul(tx.data.Price, big.NewInt(int64(tx.data.GasLimit)))
return gasFee.Add(gasFee, tx.data.GatewayFee)
}

// To returns the recipient address of the transaction.
// It returns nil if the transaction is a contract creation.
Expand Down Expand Up @@ -461,3 +465,7 @@ func (m Message) Gas() uint64 { return m.gasLimit }
func (m Message) Nonce() uint64 { return m.nonce }
func (m Message) Data() []byte { return m.data }
func (m Message) CheckNonce() bool { return m.checkNonce }
func (m Message) Fee() *big.Int {
gasFee := new(big.Int).Mul(m.gasPrice, big.NewInt(int64(m.gasLimit)))
return gasFee.Add(gasFee, m.gatewayFee)
}

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