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

* cmd, eth, internal, les: add gasprice cap

* cmd/utils, eth: add default value for gasprice cap

* all: use txfee cap

* cmd, eth: add fix

* cmd, internal: address comments

eth/config.go

@@ -64,6 +64,7 @@ var DefaultConfig = Config{
 		Blocks:     20,
 		Percentile: 60,
 	},
+	RPCTxFeeCap: 1, // 1 ether
 }
 
 func init() {
@@ -159,6 +160,10 @@ type Config struct {
 	// RPCGasCap is the global gas cap for eth-call variants.
 	RPCGasCap *big.Int `toml:",omitempty"`
 
+	// RPCTxFeeCap is the global transaction fee(price * gaslimit) cap for
+	// send-transction variants. The unit is ether.
+	RPCTxFeeCap float64 `toml:",omitempty"`
+
 	// Checkpoint is a hardcoded checkpoint which can be nil.
 	Checkpoint *params.TrustedCheckpoint `toml:",omitempty"`