cmd, eth, internal, les: add gasprice cap (ethereum#21212)

cmd/XDC/main.go

@@ -148,6 +148,7 @@ var (
 		utils.WSAllowedOriginsFlag,
 		utils.IPCDisabledFlag,
 		utils.IPCPathFlag,
+		utils.RPCGlobalTxFeeCap,
 	}
 
 	whisperFlags = []cli.Flag{

cmd/XDC/usage.go

@@ -156,6 +156,7 @@ var AppHelpFlagGroups = []flagGroup{
 			utils.IPCPathFlag,
 			utils.RPCCORSDomainFlag,
 			utils.RPCVirtualHostsFlag,
+			utils.RPCGlobalTxFeeCap,
 			utils.JSpathFlag,
 			utils.ExecFlag,
 			utils.PreloadJSFlag,

cmd/utils/flags.go

@@ -363,6 +363,11 @@ var (
 		Usage: "Sets a cap on gas that can be used in eth_call/estimateGas (0=infinite)",
 		Value: eth.DefaultConfig.RPCGasCap,
 	}
+	RPCGlobalTxFeeCap = cli.Float64Flag{
+		Name:  "rpc.txfeecap",
+		Usage: "Sets a cap on transaction fee (in ether) that can be sent via the RPC APIs (0 = no cap)",
+		Value: eth.DefaultConfig.RPCTxFeeCap,
+	}
 	// Logging and debug settings
 	EthStatsURLFlag = cli.StringFlag{
 		Name:  "ethstats",
@@ -1171,6 +1176,9 @@ func SetEthConfig(ctx *cli.Context, stack *node.Node, cfg *eth.Config) {
 	if ctx.GlobalIsSet(DocRootFlag.Name) {
 		cfg.DocRoot = ctx.GlobalString(DocRootFlag.Name)
 	}
+	if ctx.GlobalIsSet(RPCGlobalTxFeeCap.Name) {
+		cfg.RPCTxFeeCap = ctx.GlobalFloat64(RPCGlobalTxFeeCap.Name)
+	}
 	if ctx.GlobalIsSet(ExtraDataFlag.Name) {
 		cfg.ExtraData = []byte(ctx.GlobalString(ExtraDataFlag.Name))
 	}

eth/api_backend.go

@@ -356,6 +356,10 @@ func (b *EthApiBackend) AccountManager() *accounts.Manager {
 	return b.eth.AccountManager()
 }
 
+func (b *EthApiBackend) RPCTxFeeCap() float64 {
+	return b.eth.config.RPCTxFeeCap
+}
+
 func (b *EthApiBackend) BloomStatus() (uint64, uint64) {
 	sections, _, _ := b.eth.bloomIndexer.Sections()
 	return params.BloomBitsBlocks, sections

eth/config.go

@@ -56,6 +56,7 @@ var DefaultConfig = Config{
 		Blocks:     20,
 		Percentile: 60,
 	},
+	RPCTxFeeCap: 1, // 1 ether
 }
 
 func init() {
@@ -118,6 +119,10 @@ type Config struct {
 
 	// RPCGasCap is the global gas cap for eth-call variants.
 	RPCGasCap uint64
+
+	// RPCTxFeeCap is the global transaction fee(price * gaslimit) cap for
+	// send-transction variants. The unit is ether.
+	RPCTxFeeCap float64
 }
 
 type configMarshaling struct {

internal/ethapi/api.go

@@ -2372,6 +2372,14 @@ func SubmitTransaction(ctx context.Context, b Backend, tx *types.Transaction) (c
 	if tx.To() != nil && tx.IsSpecialTransaction() {
 		return common.Hash{}, errors.New("Dont allow transaction sent to BlockSigners & RandomizeSMC smart contract via API")
 	}
+
+	// If the transaction fee cap is already specified, ensure the
+	// fee of the given transaction is _reasonable_.
+	feeEth := new(big.Float).Quo(new(big.Float).SetInt(new(big.Int).Mul(tx.GasPrice(), new(big.Int).SetUint64(tx.Gas()))), new(big.Float).SetInt(big.NewInt(params.Ether)))
+	feeFloat, _ := feeEth.Float64()
+	if b.RPCTxFeeCap() != 0 && feeFloat > b.RPCTxFeeCap() {
+		return common.Hash{}, fmt.Errorf("tx fee (%.2f ether) exceeds the configured cap (%.2f ether)", feeFloat, b.RPCTxFeeCap())
+	}
 	if err := b.SendTx(ctx, tx); err != nil {
 		return common.Hash{}, err
 	}

internal/ethapi/backend.go

@@ -52,6 +52,7 @@ type Backend interface {
 	EventMux() *event.TypeMux
 	AccountManager() *accounts.Manager
 	RPCGasCap() uint64 // global gas cap for eth_call over rpc: DoS protection
+	RPCTxFeeCap() float64 // global tx fee cap for all transaction related APIs
 	XDCxService() *XDCx.XDCX
 	LendingService() *XDCxlending.Lending
 

les/api_backend.go

@@ -273,6 +273,10 @@ func (b *LesApiBackend) RPCGasCap() uint64 {
 	return b.eth.config.RPCGasCap
 }
 
+func (b *LesApiBackend) RPCTxFeeCap() float64 {
+	return b.eth.config.RPCTxFeeCap
+}
+
 func (b *LesApiBackend) BloomStatus() (uint64, uint64) {
 	if b.eth.bloomIndexer == nil {
 		return 0, 0