Merge pull request #34 from ava-labs/devv0.3.0-rc.5

Dev

3 files changed, 300 insertions, 121 deletions

diff --git a/internal/ethapi/addrlock.go b/internal/ethapi/addrlock.go
index ab96ae1..61ddff6 100644
--- a/internal/ethapi/addrlock.go
+++ b/internal/ethapi/addrlock.go
@@ -19,7 +19,7 @@ package ethapi
 import (
 	"sync"
 
-	"github.com/ava-labs/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/common"
 )
 
 type AddrLocker struct {
diff --git a/internal/ethapi/api.go b/internal/ethapi/api.go
index 8bc2f94..9915ad4 100644
--- a/internal/ethapi/api.go
+++ b/internal/ethapi/api.go
@@ -30,26 +30,22 @@ import (
 	"github.com/ava-labs/coreth/accounts/scwallet"
 	"github.com/ava-labs/coreth/consensus/ethash"
 	"github.com/ava-labs/coreth/core"
-	"github.com/ava-labs/coreth/core/rawdb"
 	"github.com/ava-labs/coreth/core/types"
 	"github.com/ava-labs/coreth/core/vm"
 	"github.com/ava-labs/coreth/params"
 	"github.com/ava-labs/coreth/rpc"
-	"github.com/ava-labs/go-ethereum/common"
-	"github.com/ava-labs/go-ethereum/common/hexutil"
-	"github.com/ava-labs/go-ethereum/common/math"
-	"github.com/ava-labs/go-ethereum/crypto"
-	"github.com/ava-labs/go-ethereum/log"
-	"github.com/ava-labs/go-ethereum/p2p"
-	"github.com/ava-labs/go-ethereum/rlp"
 	"github.com/davecgh/go-spew/spew"
+	"github.com/ethereum/go-ethereum/accounts/abi"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/common/hexutil"
+	"github.com/ethereum/go-ethereum/common/math"
+	"github.com/ethereum/go-ethereum/crypto"
+	"github.com/ethereum/go-ethereum/log"
+	"github.com/ethereum/go-ethereum/p2p"
+	"github.com/ethereum/go-ethereum/rlp"
 	"github.com/tyler-smith/go-bip39"
 )
 
-const (
-	defaultGasPrice = params.GWei
-)
-
 // PublicEthereumAPI provides an API to access Ethereum related information.
 // It offers only methods that operate on public data that is freely available to anyone.
 type PublicEthereumAPI struct {
@@ -279,7 +275,11 @@ func (s *PrivateAccountAPI) DeriveAccount(url string, path string, pin *bool) (a
 
 // NewAccount will create a new account and returns the address for the new account.
 func (s *PrivateAccountAPI) NewAccount(password string) (common.Address, error) {
-	acc, err := fetchKeystore(s.am).NewAccount(password)
+	ks, err := fetchKeystore(s.am)
+	if err != nil {
+		return common.Address{}, err
+	}
+	acc, err := ks.NewAccount(password)
 	if err == nil {
 		log.Info("Your new key was generated", "address", acc.Address)
 		log.Warn("Please backup your key file!", "path", acc.URL.Path)
@@ -289,9 +289,12 @@ func (s *PrivateAccountAPI) NewAccount(password string) (common.Address, error)
 	return common.Address{}, err
 }
 
-// fetchKeystore retrives the encrypted keystore from the account manager.
-func fetchKeystore(am *accounts.Manager) *keystore.KeyStore {
-	return am.Backends(keystore.KeyStoreType)[0].(*keystore.KeyStore)
+// fetchKeystore retrieves the encrypted keystore from the account manager.
+func fetchKeystore(am *accounts.Manager) (*keystore.KeyStore, error) {
+	if ks := am.Backends(keystore.KeyStoreType); len(ks) > 0 {
+		return ks[0].(*keystore.KeyStore), nil
+	}
+	return nil, errors.New("local keystore not used")
 }
 
 // ImportRawKey stores the given hex encoded ECDSA key into the key directory,
@@ -301,7 +304,11 @@ func (s *PrivateAccountAPI) ImportRawKey(privkey string, password string) (commo
 	if err != nil {
 		return common.Address{}, err
 	}
-	acc, err := fetchKeystore(s.am).ImportECDSA(key, password)
+	ks, err := fetchKeystore(s.am)
+	if err != nil {
+		return common.Address{}, err
+	}
+	acc, err := ks.ImportECDSA(key, password)
 	return acc.Address, err
 }
 
@@ -325,7 +332,11 @@ func (s *PrivateAccountAPI) UnlockAccount(ctx context.Context, addr common.Addre
 	} else {
 		d = time.Duration(*duration) * time.Second
 	}
-	err := fetchKeystore(s.am).TimedUnlock(accounts.Account{Address: addr}, password, d)
+	ks, err := fetchKeystore(s.am)
+	if err != nil {
+		return false, err
+	}
+	err = ks.TimedUnlock(accounts.Account{Address: addr}, password, d)
 	if err != nil {
 		log.Warn("Failed account unlock attempt", "address", addr, "err", err)
 	}
@@ -334,7 +345,10 @@ func (s *PrivateAccountAPI) UnlockAccount(ctx context.Context, addr common.Addre
 
 // LockAccount will lock the account associated with the given address when it's unlocked.
 func (s *PrivateAccountAPI) LockAccount(addr common.Address) bool {
-	return fetchKeystore(s.am).Lock(addr) == nil
+	if ks, err := fetchKeystore(s.am); err == nil {
+		return ks.Lock(addr) == nil
+	}
+	return false
 }
 
 // signTransaction sets defaults and signs the given transaction
@@ -391,6 +405,10 @@ func (s *PrivateAccountAPI) SignTransaction(ctx context.Context, args SendTxArgs
 	if args.Nonce == nil {
 		return nil, fmt.Errorf("nonce not specified")
 	}
+	// Before actually sign the transaction, ensure the transaction fee is reasonable.
+	if err := checkTxFee(args.GasPrice.ToInt(), uint64(*args.Gas), s.b.RPCTxFeeCap()); err != nil {
+		return nil, err
+	}
 	signed, err := s.signTransaction(ctx, &args, passwd)
 	if err != nil {
 		log.Warn("Failed transaction sign attempt", "from", args.From, "to", args.To, "value", args.Value.ToInt(), "err", err)
@@ -485,7 +503,7 @@ func (s *PrivateAccountAPI) InitializeWallet(ctx context.Context, url string) (s
 	case *scwallet.Wallet:
 		return mnemonic, wallet.Initialize(seed)
 	default:
-		return "", fmt.Errorf("Specified wallet does not support initialization")
+		return "", fmt.Errorf("specified wallet does not support initialization")
 	}
 }
 
@@ -500,7 +518,7 @@ func (s *PrivateAccountAPI) Unpair(ctx context.Context, url string, pin string)
 	case *scwallet.Wallet:
 		return wallet.Unpair([]byte(pin))
 	default:
-		return fmt.Errorf("Specified wallet does not support pairing")
+		return fmt.Errorf("specified wallet does not support pairing")
 	}
 }
 
@@ -529,8 +547,8 @@ func (s *PublicBlockChainAPI) BlockNumber() hexutil.Uint64 {
 // GetBalance returns the amount of wei for the given address in the state of the
 // given block number. The rpc.LatestBlockNumber and rpc.PendingBlockNumber meta
 // block numbers are also allowed.
-func (s *PublicBlockChainAPI) GetBalance(ctx context.Context, address common.Address, blockNr rpc.BlockNumber) (*hexutil.Big, error) {
-	state, _, err := s.b.StateAndHeaderByNumber(ctx, blockNr)
+func (s *PublicBlockChainAPI) GetBalance(ctx context.Context, address common.Address, blockNrOrHash rpc.BlockNumberOrHash) (*hexutil.Big, error) {
+	state, _, err := s.b.StateAndHeaderByNumberOrHash(ctx, blockNrOrHash)
 	if state == nil || err != nil {
 		return nil, err
 	}
@@ -554,8 +572,8 @@ type StorageResult struct {
 }
 
 // GetProof returns the Merkle-proof for a given account and optionally some storage keys.
-func (s *PublicBlockChainAPI) GetProof(ctx context.Context, address common.Address, storageKeys []string, blockNr rpc.BlockNumber) (*AccountResult, error) {
-	state, _, err := s.b.StateAndHeaderByNumber(ctx, blockNr)
+func (s *PublicBlockChainAPI) GetProof(ctx context.Context, address common.Address, storageKeys []string, blockNrOrHash rpc.BlockNumberOrHash) (*AccountResult, error) {
+	state, _, err := s.b.StateAndHeaderByNumberOrHash(ctx, blockNrOrHash)
 	if state == nil || err != nil {
 		return nil, err
 	}
@@ -609,7 +627,7 @@ func (s *PublicBlockChainAPI) GetProof(ctx context.Context, address common.Addre
 func (s *PublicBlockChainAPI) GetHeaderByNumber(ctx context.Context, number rpc.BlockNumber) (map[string]interface{}, error) {
 	header, err := s.b.HeaderByNumber(ctx, number)
 	if header != nil && err == nil {
-		response := s.rpcMarshalHeader(header)
+		response := s.rpcMarshalHeader(ctx, header)
 		if number == rpc.PendingBlockNumber {
 			// Pending header need to nil out a few fields
 			for _, field := range []string{"hash", "nonce", "miner"} {
@@ -625,7 +643,7 @@ func (s *PublicBlockChainAPI) GetHeaderByNumber(ctx context.Context, number rpc.
 func (s *PublicBlockChainAPI) GetHeaderByHash(ctx context.Context, hash common.Hash) map[string]interface{} {
 	header, _ := s.b.HeaderByHash(ctx, hash)
 	if header != nil {
-		return s.rpcMarshalHeader(header)
+		return s.rpcMarshalHeader(ctx, header)
 	}
 	return nil
 }
@@ -638,7 +656,7 @@ func (s *PublicBlockChainAPI) GetHeaderByHash(ctx context.Context, hash common.H
 func (s *PublicBlockChainAPI) GetBlockByNumber(ctx context.Context, number rpc.BlockNumber, fullTx bool) (map[string]interface{}, error) {
 	block, err := s.b.BlockByNumber(ctx, number)
 	if block != nil && err == nil {
-		response, err := s.rpcMarshalBlock(block, true, fullTx)
+		response, err := s.rpcMarshalBlock(ctx, block, true, fullTx)
 		if err == nil && number == rpc.PendingBlockNumber {
 			// Pending blocks need to nil out a few fields
 			for _, field := range []string{"hash", "nonce", "miner"} {
@@ -655,7 +673,7 @@ func (s *PublicBlockChainAPI) GetBlockByNumber(ctx context.Context, number rpc.B
 func (s *PublicBlockChainAPI) GetBlockByHash(ctx context.Context, hash common.Hash, fullTx bool) (map[string]interface{}, error) {
 	block, err := s.b.BlockByHash(ctx, hash)
 	if block != nil {
-		return s.rpcMarshalBlock(block, true, fullTx)
+		return s.rpcMarshalBlock(ctx, block, true, fullTx)
 	}
 	return nil, err
 }
@@ -671,7 +689,7 @@ func (s *PublicBlockChainAPI) GetUncleByBlockNumberAndIndex(ctx context.Context,
 			return nil, nil
 		}
 		block = types.NewBlockWithHeader(uncles[index])
-		return s.rpcMarshalBlock(block, false, false)
+		return s.rpcMarshalBlock(ctx, block, false, false)
 	}
 	return nil, err
 }
@@ -687,7 +705,7 @@ func (s *PublicBlockChainAPI) GetUncleByBlockHashAndIndex(ctx context.Context, b
 			return nil, nil
 		}
 		block = types.NewBlockWithHeader(uncles[index])
-		return s.rpcMarshalBlock(block, false, false)
+		return s.rpcMarshalBlock(ctx, block, false, false)
 	}
 	return nil, err
 }
@@ -711,8 +729,8 @@ func (s *PublicBlockChainAPI) GetUncleCountByBlockHash(ctx context.Context, bloc
 }
 
 // GetCode returns the code stored at the given address in the state for the given block number.
-func (s *PublicBlockChainAPI) GetCode(ctx context.Context, address common.Address, blockNr rpc.BlockNumber) (hexutil.Bytes, error) {
-	state, _, err := s.b.StateAndHeaderByNumber(ctx, blockNr)
+func (s *PublicBlockChainAPI) GetCode(ctx context.Context, address common.Address, blockNrOrHash rpc.BlockNumberOrHash) (hexutil.Bytes, error) {
+	state, _, err := s.b.StateAndHeaderByNumberOrHash(ctx, blockNrOrHash)
 	if state == nil || err != nil {
 		return nil, err
 	}
@@ -723,8 +741,8 @@ func (s *PublicBlockChainAPI) GetCode(ctx context.Context, address common.Addres
 // GetStorageAt returns the storage from the state at the given address, key and
 // block number. The rpc.LatestBlockNumber and rpc.PendingBlockNumber meta block
 // numbers are also allowed.
-func (s *PublicBlockChainAPI) GetStorageAt(ctx context.Context, address common.Address, key string, blockNr rpc.BlockNumber) (hexutil.Bytes, error) {
-	state, _, err := s.b.StateAndHeaderByNumber(ctx, blockNr)
+func (s *PublicBlockChainAPI) GetStorageAt(ctx context.Context, address common.Address, key string, blockNrOrHash rpc.BlockNumberOrHash) (hexutil.Bytes, error) {
+	state, _, err := s.b.StateAndHeaderByNumberOrHash(ctx, blockNrOrHash)
 	if state == nil || err != nil {
 		return nil, err
 	}
@@ -742,6 +760,45 @@ type CallArgs struct {
 	Data     *hexutil.Bytes  `json:"data"`
 }
 
+// ToMessage converts CallArgs to the Message type used by the core evm
+func (args *CallArgs) ToMessage(globalGasCap uint64) types.Message {
+	// Set sender address or use zero address if none specified.
+	var addr common.Address
+	if args.From != nil {
+		addr = *args.From
+	}
+
+	// Set default gas & gas price if none were set
+	gas := globalGasCap
+	if gas == 0 {
+		gas = uint64(math.MaxUint64 / 2)
+	}
+	if args.Gas != nil {
+		gas = uint64(*args.Gas)
+	}
+	if globalGasCap != 0 && globalGasCap < gas {
+		log.Warn("Caller gas above allowance, capping", "requested", gas, "cap", globalGasCap)
+		gas = globalGasCap
+	}
+	gasPrice := new(big.Int)
+	if args.GasPrice != nil {
+		gasPrice = args.GasPrice.ToInt()
+	}
+
+	value := new(big.Int)
+	if args.Value != nil {
+		value = args.Value.ToInt()
+	}
+
+	var data []byte
+	if args.Data != nil {
+		data = []byte(*args.Data)
+	}
+
+	msg := types.NewMessage(addr, args.To, 0, value, gas, gasPrice, data, false)
+	return msg
+}
+
 // account indicates the overriding fields of account during the execution of
 // a message call.
 // Note, state and stateDiff can't be specified at the same time. If state is
@@ -756,23 +813,12 @@ type account struct {
 	StateDiff *map[common.Hash]common.Hash `json:"stateDiff"`
 }
 
-func DoCall(ctx context.Context, b Backend, args CallArgs, blockNr rpc.BlockNumber, overrides map[common.Address]account, vmCfg vm.Config, timeout time.Duration, globalGasCap *big.Int) ([]byte, uint64, bool, error) {
+func DoCall(ctx context.Context, b Backend, args CallArgs, blockNrOrHash rpc.BlockNumberOrHash, overrides map[common.Address]account, vmCfg vm.Config, timeout time.Duration, globalGasCap uint64) (*core.ExecutionResult, error) {
 	defer func(start time.Time) { log.Debug("Executing EVM call finished", "runtime", time.Since(start)) }(time.Now())
 
-	state, header, err := b.StateAndHeaderByNumber(ctx, blockNr)
+	state, header, err := b.StateAndHeaderByNumberOrHash(ctx, blockNrOrHash)
 	if state == nil || err != nil {
-		return nil, 0, false, err
-	}
-	// Set sender address or use a default if none specified
-	var addr common.Address
-	if args.From == nil {
-		if wallets := b.AccountManager().Wallets(); len(wallets) > 0 {
-			if accounts := wallets[0].Accounts(); len(accounts) > 0 {
-				addr = accounts[0].Address
-			}
-		}
-	} else {
-		addr = *args.From
+		return nil, err
 	}
 	// Override the fields of specified contracts before execution.
 	for addr, account := range overrides {
@@ -789,7 +835,7 @@ func DoCall(ctx context.Context, b Backend, args CallArgs, blockNr rpc.BlockNumb
 			state.SetBalance(addr, (*big.Int)(*account.Balance))
 		}
 		if account.State != nil && account.StateDiff != nil {
-			return nil, 0, false, fmt.Errorf("account %s has both 'state' and 'stateDiff'", addr.Hex())
+			return nil, fmt.Errorf("account %s has both 'state' and 'stateDiff'", addr.Hex())
 		}
 		// Replace entire state if caller requires.
 		if account.State != nil {
@@ -802,33 +848,6 @@ func DoCall(ctx context.Context, b Backend, args CallArgs, blockNr rpc.BlockNumb
 			}
 		}
 	}
-	// Set default gas & gas price if none were set
-	gas := uint64(math.MaxUint64 / 2)
-	if args.Gas != nil {
-		gas = uint64(*args.Gas)
-	}
-	if globalGasCap != nil && globalGasCap.Uint64() < gas {
-		log.Warn("Caller gas above allowance, capping", "requested", gas, "cap", globalGasCap)
-		gas = globalGasCap.Uint64()
-	}
-	gasPrice := new(big.Int).SetUint64(defaultGasPrice)
-	if args.GasPrice != nil {
-		gasPrice = args.GasPrice.ToInt()
-	}
-
-	value := new(big.Int)
-	if args.Value != nil {
-		value = args.Value.ToInt()
-	}
-
-	var data []byte
-	if args.Data != nil {
-		data = []byte(*args.Data)
-	}
-
-	// Create new call message
-	msg := types.NewMessage(addr, args.To, 0, value, gas, gasPrice, data, false)
-
 	// Setup context so it may be cancelled the call has completed
 	// or, in case of unmetered gas, setup a context with a timeout.
 	var cancel context.CancelFunc
@@ -842,9 +861,10 @@ func DoCall(ctx context.Context, b Backend, args CallArgs, blockNr rpc.BlockNumb
 	defer cancel()
 
 	// Get a new instance of the EVM.
+	msg := args.ToMessage(globalGasCap)
 	evm, vmError, err := b.GetEVM(ctx, msg, state, header)
 	if err != nil {
-		return nil, 0, false, err
+		return nil, err
 	}
 	// Wait for the context to be done and cancel the evm. Even if the
 	// EVM has finished, cancelling may be done (repeatedly)
@@ -856,15 +876,48 @@ func DoCall(ctx context.Context, b Backend, args CallArgs, blockNr rpc.BlockNumb
 	// Setup the gas pool (also for unmetered requests)
 	// and apply the message.
 	gp := new(core.GasPool).AddGas(math.MaxUint64)
-	res, gas, failed, err := core.ApplyMessage(evm, msg, gp)
+	result, err := core.ApplyMessage(evm, msg, gp)
 	if err := vmError(); err != nil {
-		return nil, 0, false, err
+		return nil, err
 	}
 	// If the timer caused an abort, return an appropriate error message
 	if evm.Cancelled() {
-		return nil, 0, false, fmt.Errorf("execution aborted (timeout = %v)", timeout)
+		return nil, fmt.Errorf("execution aborted (timeout = %v)", timeout)
 	}
-	return res, gas, failed, err
+	if err != nil {
+		return result, fmt.Errorf("err: %w (supplied gas %d)", err, msg.Gas())
+	}
+	return result, nil
+}
+
+func newRevertError(result *core.ExecutionResult) *revertError {
+	reason, errUnpack := abi.UnpackRevert(result.Revert())
+	err := errors.New("execution reverted")
+	if errUnpack == nil {
+		err = fmt.Errorf("execution reverted: %v", reason)
+	}
+	return &revertError{
+		error:  err,
+		reason: hexutil.Encode(result.Revert()),
+	}
+}
+
+// revertError is an API error that encompassas an EVM revertal with JSON error
+// code and a binary data blob.
+type revertError struct {
+	error
+	reason string // revert reason hex encoded
+}
+
+// ErrorCode returns the JSON error code for a revertal.
+// See: https://github.com/ethereum/wiki/wiki/JSON-RPC-Error-Codes-Improvement-Proposal
+func (e *revertError) ErrorCode() int {
+	return 3
+}
+
+// ErrorData returns the hex encoded revert reason.
+func (e *revertError) ErrorData() interface{} {
+	return e.reason
 }
 
 // Call executes the given transaction on the state for the given block number.
@@ -873,52 +926,103 @@ func DoCall(ctx context.Context, b Backend, args CallArgs, blockNr rpc.BlockNumb
 //
 // Note, this function doesn't make and changes in the state/blockchain and is
 // useful to execute and retrieve values.
-func (s *PublicBlockChainAPI) Call(ctx context.Context, args CallArgs, blockNr rpc.BlockNumber, overrides *map[common.Address]account) (hexutil.Bytes, error) {
+func (s *PublicBlockChainAPI) Call(ctx context.Context, args CallArgs, blockNrOrHash rpc.BlockNumberOrHash, overrides *map[common.Address]account) (hexutil.Bytes, error) {
 	var accounts map[common.Address]account
 	if overrides != nil {
 		accounts = *overrides
 	}
-	result, _, _, err := DoCall(ctx, s.b, args, blockNr, accounts, vm.Config{}, 5*time.Second, s.b.RPCGasCap())
-	return (hexutil.Bytes)(result), err
+	result, err := DoCall(ctx, s.b, args, blockNrOrHash, accounts, vm.Config{}, 5*time.Second, s.b.RPCGasCap())
+	if err != nil {
+		return nil, err
+	}
+	// If the result contains a revert reason, try to unpack and return it.
+	if len(result.Revert()) > 0 {
+		return nil, newRevertError(result)
+	}
+	return result.Return(), result.Err
 }
 
-func DoEstimateGas(ctx context.Context, b Backend, args CallArgs, blockNr rpc.BlockNumber, gasCap *big.Int) (hexutil.Uint64, error) {
+func DoEstimateGas(ctx context.Context, b Backend, args CallArgs, blockNrOrHash rpc.BlockNumberOrHash, gasCap uint64) (hexutil.Uint64, error) {
 	// Binary search the gas requirement, as it may be higher than the amount used
 	var (
 		lo  uint64 = params.TxGas - 1
 		hi  uint64
 		cap uint64
 	)
+	// Use zero address if sender unspecified.
+	if args.From == nil {
+		args.From = new(common.Address)
+	}
+	// Determine the highest gas limit can be used during the estimation.
 	if args.Gas != nil && uint64(*args.Gas) >= params.TxGas {
 		hi = uint64(*args.Gas)
 	} else {
 		// Retrieve the block to act as the gas ceiling
-		block, err := b.BlockByNumber(ctx, blockNr)
+		block, err := b.BlockByNumberOrHash(ctx, blockNrOrHash)
 		if err != nil {
 			return 0, err
 		}
 		hi = block.GasLimit()
 	}
-	if gasCap != nil && hi > gasCap.Uint64() {
+	// Recap the highest gas limit with account's available balance.
+	if args.GasPrice != nil && args.GasPrice.ToInt().BitLen() != 0 {
+		state, _, err := b.StateAndHeaderByNumberOrHash(ctx, blockNrOrHash)
+		if err != nil {
+			return 0, err
+		}
+		balance := state.GetBalance(*args.From) // from can't be nil
+		available := new(big.Int).Set(balance)
+		if args.Value != nil {
+			if args.Value.ToInt().Cmp(available) >= 0 {
+				return 0, errors.New("insufficient funds for transfer")
+			}
+			available.Sub(available, args.Value.ToInt())
+		}
+		allowance := new(big.Int).Div(available, args.GasPrice.ToInt())
+
+		// If the allowance is larger than maximum uint64, skip checking
+		if allowance.IsUint64() && hi > allowance.Uint64() {
+			transfer := args.Value
+			if transfer == nil {
+				transfer = new(hexutil.Big)
+			}
+			log.Warn("Gas estimation capped by limited funds", "original", hi, "balance", balance,
+				"sent", transfer.ToInt(), "gasprice", args.GasPrice.ToInt(), "fundable", allowance)
+			hi = allowance.Uint64()
+		}
+	}
+	// Recap the highest gas allowance with specified gascap.
+	if gasCap != 0 && hi > gasCap {
 		log.Warn("Caller gas above allowance, capping", "requested", hi, "cap", gasCap)
-		hi = gasCap.Uint64()
+		hi = gasCap
 	}
 	cap = hi
 
 	// Create a helper to check if a gas allowance results in an executable transaction
-	executable := func(gas uint64) bool {
+	executable := func(gas uint64) (bool, *core.ExecutionResult, error) {
 		args.Gas = (*hexutil.Uint64)(&gas)
 
-		_, _, failed, err := DoCall(ctx, b, args, rpc.PendingBlockNumber, nil, vm.Config{}, 0, gasCap)
-		if err != nil || failed {
-			return false
+		result, err := DoCall(ctx, b, args, blockNrOrHash, nil, vm.Config{}, 0, gasCap)
+		if err != nil {
+			if errors.Is(err, core.ErrIntrinsicGas) {
+				return true, nil, nil // Special case, raise gas limit
+			}
+			return true, nil, err // Bail out
 		}
-		return true
+		return result.Failed(), result, nil
 	}
 	// Execute the binary search and hone in on an executable gas limit
 	for lo+1 < hi {
 		mid := (hi + lo) / 2
-		if !executable(mid) {
+		failed, _, err := executable(mid)
+
+		// If the error is not nil(consensus error), it means the provided message
+		// call or transaction will never be accepted no matter how much gas it is
+		// assigned. Return the error directly, don't struggle any more.
+		if err != nil {
+			return 0, err
+		}
+		if failed {
 			lo = mid
 		} else {
 			hi = mid
@@ -926,8 +1030,19 @@ func DoEstimateGas(ctx context.Context, b Backend, args CallArgs, blockNr rpc.Bl
 	}
 	// Reject the transaction as invalid if it still fails at the highest allowance
 	if hi == cap {
-		if !executable(hi) {
-			return 0, fmt.Errorf("gas required exceeds allowance (%d) or always failing transaction", cap)
+		failed, result, err := executable(hi)
+		if err != nil {
+			return 0, err
+		}
+		if failed {
+			if result != nil && result.Err != vm.ErrOutOfGas {
+				if len(result.Revert()) > 0 {
+					return 0, newRevertError(result)
+				}
+				return 0, result.Err
+			}
+			// Otherwise, the specified gas cap is too low
+			return 0, fmt.Errorf("gas required exceeds allowance (%d)", cap)
 		}
 	}
 	return hexutil.Uint64(hi), nil
@@ -936,7 +1051,8 @@ func DoEstimateGas(ctx context.Context, b Backend, args CallArgs, blockNr rpc.Bl
 // EstimateGas returns an estimate of the amount of gas needed to execute the
 // given transaction against the current pending block.
 func (s *PublicBlockChainAPI) EstimateGas(ctx context.Context, args CallArgs) (hexutil.Uint64, error) {
-	return DoEstimateGas(ctx, s.b, args, rpc.PendingBlockNumber, s.b.RPCGasCap())
+	blockNrOrHash := rpc.BlockNumberOrHashWithNumber(rpc.PendingBlockNumber)
+	return DoEstimateGas(ctx, s.b, args, blockNrOrHash, s.b.RPCGasCap())
 }
 
 // ExecutionResult groups all structured logs emitted by the EVM
@@ -1061,20 +1177,22 @@ func RPCMarshalBlock(block *types.Block, inclTx bool, fullTx bool) (map[string]i
 
 // rpcMarshalHeader uses the generalized output filler, then adds the total difficulty field, which requires
 // a `PublicBlockchainAPI`.
-func (s *PublicBlockChainAPI) rpcMarshalHeader(header *types.Header) map[string]interface{} {
+func (s *PublicBlockChainAPI) rpcMarshalHeader(ctx context.Context, header *types.Header) map[string]interface{} {
 	fields := RPCMarshalHeader(header)
-	fields["totalDifficulty"] = (*hexutil.Big)(s.b.GetTd(header.Hash()))
+	fields["totalDifficulty"] = (*hexutil.Big)(s.b.GetTd(ctx, header.Hash()))
 	return fields
 }
 
 // rpcMarshalBlock uses the generalized output filler, then adds the total difficulty field, which requires
 // a `PublicBlockchainAPI`.
-func (s *PublicBlockChainAPI) rpcMarshalBlock(b *types.Block, inclTx bool, fullTx bool) (map[string]interface{}, error) {
+func (s *PublicBlockChainAPI) rpcMarshalBlock(ctx context.Context, b *types.Block, inclTx bool, fullTx bool) (map[string]interface{}, error) {
 	fields, err := RPCMarshalBlock(b, inclTx, fullTx)
 	if err != nil {
 		return nil, err
 	}
-	fields["totalDifficulty"] = (*hexutil.Big)(s.b.GetTd(b.Hash()))
+	if inclTx {
+		fields["totalDifficulty"] = (*hexutil.Big)(s.b.GetTd(ctx, b.Hash()))
+	}
 	return fields, err
 }
 
@@ -1223,9 +1341,9 @@ func (s *PublicTransactionPoolAPI) GetRawTransactionByBlockHashAndIndex(ctx cont
 }
 
 // GetTransactionCount returns the number of transactions the given address has sent for the given block number
-func (s *PublicTransactionPoolAPI) GetTransactionCount(ctx context.Context, address common.Address, blockNr rpc.BlockNumber) (*hexutil.Uint64, error) {
+func (s *PublicTransactionPoolAPI) GetTransactionCount(ctx context.Context, address common.Address, blockNrOrHash rpc.BlockNumberOrHash) (*hexutil.Uint64, error) {
 	// Ask transaction pool for the nonce which includes pending transactions
-	if blockNr == rpc.PendingBlockNumber {
+	if blockNr, ok := blockNrOrHash.Number(); ok && blockNr == rpc.PendingBlockNumber {
 		nonce, err := s.b.GetPoolNonce(ctx, address)
 		if err != nil {
 			return nil, err
@@ -1233,7 +1351,7 @@ func (s *PublicTransactionPoolAPI) GetTransactionCount(ctx context.Context, addr
 		return (*hexutil.Uint64)(&nonce), nil
 	}
 	// Resolve block number and use its state to ask for the nonce
-	state, _, err := s.b.StateAndHeaderByNumber(ctx, blockNr)
+	state, _, err := s.b.StateAndHeaderByNumberOrHash(ctx, blockNrOrHash)
 	if state == nil || err != nil {
 		return nil, err
 	}
@@ -1279,8 +1397,8 @@ func (s *PublicTransactionPoolAPI) GetRawTransactionByHash(ctx context.Context,
 
 // GetTransactionReceipt returns the transaction receipt for the given transaction hash.
 func (s *PublicTransactionPoolAPI) GetTransactionReceipt(ctx context.Context, hash common.Hash) (map[string]interface{}, error) {
-	tx, blockHash, blockNumber, index := rawdb.ReadTransaction(s.b.ChainDb(), hash)
-	if tx == nil {
+	tx, blockHash, blockNumber, index, err := s.b.GetTransaction(ctx, hash)
+	if err != nil {
 		return nil, nil
 	}
 	receipts, err := s.b.GetReceipts(ctx, blockHash)
@@ -1375,7 +1493,7 @@ func (args *SendTxArgs) setDefaults(ctx context.Context, b Backend) error {
 		args.Nonce = (*hexutil.Uint64)(&nonce)
 	}
 	if args.Data != nil && args.Input != nil && !bytes.Equal(*args.Data, *args.Input) {
-		return errors.New(`Both "data" and "input" are set and not equal. Please use "input" to pass transaction call data.`)
+		return errors.New(`both "data" and "input" are set and not equal. Please use "input" to pass transaction call data`)
 	}
 	if args.To == nil {
 		// Contract creation
@@ -1404,7 +1522,8 @@ func (args *SendTxArgs) setDefaults(ctx context.Context, b Backend) error {
 			Value:    args.Value,
 			Data:     input,
 		}
-		estimated, err := DoEstimateGas(ctx, b, callArgs, rpc.PendingBlockNumber, b.RPCGasCap())
+		pendingBlockNr := rpc.BlockNumberOrHashWithNumber(rpc.PendingBlockNumber)
+		estimated, err := DoEstimateGas(ctx, b, callArgs, pendingBlockNr, b.RPCGasCap())
 		if err != nil {
 			return err
 		}
@@ -1429,6 +1548,11 @@ func (args *SendTxArgs) toTransaction() *types.Transaction {
 
 // SubmitTransaction is a helper function that submits tx to txPool and logs a message.
 func SubmitTransaction(ctx context.Context, b Backend, tx *types.Transaction) (common.Hash, error) {
+	// If the transaction fee cap is already specified, ensure the
+	// fee of the given transaction is _reasonable_.
+	if err := checkTxFee(tx.GasPrice(), tx.Gas(), b.RPCTxFeeCap()); err != nil {
+		return common.Hash{}, err
+	}
 	if err := b.SendTx(ctx, tx); err != nil {
 		return common.Hash{}, err
 	}
@@ -1478,6 +1602,22 @@ func (s *PublicTransactionPoolAPI) SendTransaction(ctx context.Context, args Sen
 	return SubmitTransaction(ctx, s.b, signed)
 }
 
+// FillTransaction fills the defaults (nonce, gas, gasPrice) on a given unsigned transaction,
+// and returns it to the caller for further processing (signing + broadcast)
+func (s *PublicTransactionPoolAPI) FillTransaction(ctx context.Context, args SendTxArgs) (*SignTransactionResult, error) {
+	// Set some sanity defaults and terminate on failure
+	if err := args.setDefaults(ctx, s.b); err != nil {
+		return nil, err
+	}
+	// Assemble the transaction and obtain rlp
+	tx := args.toTransaction()
+	data, err := rlp.EncodeToBytes(tx)
+	if err != nil {
+		return nil, err
+	}
+	return &SignTransactionResult{data, tx}, nil
+}
+
 // SendRawTransaction will add the signed transaction to the transaction pool.
 // The sender is responsible for signing the transaction and using the correct nonce.
 func (s *PublicTransactionPoolAPI) SendRawTransaction(ctx context.Context, encodedTx hexutil.Bytes) (common.Hash, error) {
@@ -1535,6 +1675,10 @@ func (s *PublicTransactionPoolAPI) SignTransaction(ctx context.Context, args Sen
 	if err := args.setDefaults(ctx, s.b); err != nil {
 		return nil, err
 	}
+	// Before actually sign the transaction, ensure the transaction fee is reasonable.
+	if err := checkTxFee(args.GasPrice.ToInt(), uint64(*args.Gas), s.b.RPCTxFeeCap()); err != nil {
+		return nil, err
+	}
 	tx, err := s.sign(args.From, args.toTransaction())
 	if err != nil {
 		return nil, err
@@ -1583,11 +1727,24 @@ func (s *PublicTransactionPoolAPI) Resend(ctx context.Context, sendArgs SendTxAr
 		return common.Hash{}, err
 	}
 	matchTx := sendArgs.toTransaction()
+
+	// Before replacing the old transaction, ensure the _new_ transaction fee is reasonable.
+	var price = matchTx.GasPrice()
+	if gasPrice != nil {
+		price = gasPrice.ToInt()
+	}
+	var gas = matchTx.Gas()
+	if gasLimit != nil {
+		gas = uint64(*gasLimit)
+	}
+	if err := checkTxFee(price, gas, s.b.RPCTxFeeCap()); err != nil {
+		return common.Hash{}, err
+	}
+	// Iterate the pending list for replacement
 	pending, err := s.b.GetPoolTransactions()
 	if err != nil {
 		return common.Hash{}, err
 	}
-
 	for _, p := range pending {
 		var signer types.Signer = types.HomesteadSigner{}
 		if p.Protected() {
@@ -1614,7 +1771,7 @@ func (s *PublicTransactionPoolAPI) Resend(ctx context.Context, sendArgs SendTxAr
 		}
 	}
 
-	return common.Hash{}, fmt.Errorf("Transaction %#x not found", matchTx.Hash())
+	return common.Hash{}, fmt.Errorf("transaction %#x not found", matchTx.Hash())
 }
 
 // PublicDebugAPI is the collection of Ethereum APIs exposed over the public
@@ -1725,3 +1882,18 @@ func (s *PublicNetAPI) PeerCount() hexutil.Uint {
 func (s *PublicNetAPI) Version() string {
 	return fmt.Sprintf("%d", s.networkVersion)
 }
+
+// checkTxFee is an internal function used to check whether the fee of
+// the given transaction is _reasonable_(under the cap).
+func checkTxFee(gasPrice *big.Int, gas uint64, cap float64) error {
+	// Short circuit if there is no cap for transaction fee at all.
+	if cap == 0 {
+		return nil
+	}
+	feeEth := new(big.Float).Quo(new(big.Float).SetInt(new(big.Int).Mul(gasPrice, new(big.Int).SetUint64(gas))), new(big.Float).SetInt(big.NewInt(params.Ether)))
+	feeFloat, _ := feeEth.Float64()
+	if feeFloat > cap {
+		return fmt.Errorf("tx fee (%.2f ether) exceeds the configured cap (%.2f ether)", feeFloat, cap)
+	}
+	return nil
+}
diff --git a/internal/ethapi/backend.go b/internal/ethapi/backend.go
index fb38034..f89a3aa 100644
--- a/internal/ethapi/backend.go
+++ b/internal/ethapi/backend.go
@@ -22,17 +22,18 @@ import (
 	"math/big"
 
 	"github.com/ava-labs/coreth/accounts"
+	"github.com/ava-labs/coreth/consensus"
 	"github.com/ava-labs/coreth/core"
+	"github.com/ava-labs/coreth/core/bloombits"
 	"github.com/ava-labs/coreth/core/state"
 	"github.com/ava-labs/coreth/core/types"
 	"github.com/ava-labs/coreth/core/vm"
 	"github.com/ava-labs/coreth/params"
 	"github.com/ava-labs/coreth/rpc"
-	"github.com/ava-labs/go-ethereum/common"
-	"github.com/ava-labs/go-ethereum/core/bloombits"
-	"github.com/ava-labs/go-ethereum/eth/downloader"
-	"github.com/ava-labs/go-ethereum/ethdb"
-	"github.com/ava-labs/go-ethereum/event"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/eth/downloader"
+	"github.com/ethereum/go-ethereum/ethdb"
+	"github.com/ethereum/go-ethereum/event"
 )
 
 // Backend interface provides the common API services (that are provided by
@@ -43,20 +44,25 @@ type Backend interface {
 	ProtocolVersion() int
 	SuggestPrice(ctx context.Context) (*big.Int, error)
 	ChainDb() ethdb.Database
-	EventMux() *event.TypeMux
 	AccountManager() *accounts.Manager
 	ExtRPCEnabled() bool
-	RPCGasCap() *big.Int // global gas cap for eth_call over rpc: DoS protection
+	RPCGasCap() uint64    // global gas cap for eth_call over rpc: DoS protection
+	RPCTxFeeCap() float64 // global tx fee cap for all transaction related APIs
 
 	// Blockchain API
 	SetHead(number uint64)
 	HeaderByNumber(ctx context.Context, number rpc.BlockNumber) (*types.Header, error)
 	HeaderByHash(ctx context.Context, hash common.Hash) (*types.Header, error)
+	HeaderByNumberOrHash(ctx context.Context, blockNrOrHash rpc.BlockNumberOrHash) (*types.Header, error)
+	CurrentHeader() *types.Header
+	CurrentBlock() *types.Block
 	BlockByNumber(ctx context.Context, number rpc.BlockNumber) (*types.Block, error)
 	BlockByHash(ctx context.Context, hash common.Hash) (*types.Block, error)
+	BlockByNumberOrHash(ctx context.Context, blockNrOrHash rpc.BlockNumberOrHash) (*types.Block, error)
 	StateAndHeaderByNumber(ctx context.Context, number rpc.BlockNumber) (*state.StateDB, *types.Header, error)
+	StateAndHeaderByNumberOrHash(ctx context.Context, blockNrOrHash rpc.BlockNumberOrHash) (*state.StateDB, *types.Header, error)
 	GetReceipts(ctx context.Context, hash common.Hash) (types.Receipts, error)
-	GetTd(hash common.Hash) *big.Int
+	GetTd(ctx context.Context, hash common.Hash) *big.Int
 	GetEVM(ctx context.Context, msg core.Message, state *state.StateDB, header *types.Header) (*vm.EVM, func() error, error)
 	SubscribeChainEvent(ch chan<- core.ChainEvent) event.Subscription
 	SubscribeChainHeadEvent(ch chan<- core.ChainHeadEvent) event.Subscription
@@ -77,10 +83,11 @@ type Backend interface {
 	GetLogs(ctx context.Context, blockHash common.Hash) ([][]*types.Log, error)
 	ServiceFilter(ctx context.Context, session *bloombits.MatcherSession)
 	SubscribeLogsEvent(ch chan<- []*types.Log) event.Subscription
+	SubscribePendingLogsEvent(ch chan<- []*types.Log) event.Subscription
 	SubscribeRemovedLogsEvent(ch chan<- core.RemovedLogsEvent) event.Subscription
 
 	ChainConfig() *params.ChainConfig
-	CurrentBlock() *types.Block
+	Engine() consensus.Engine
 	AcceptedBlock() *types.Block
 }