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package common
import (
"encoding/binary"
"fmt"
"math/big"
ethCommon "github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/crypto"
"github.com/iden3/go-iden3-crypto/babyjub"
)
const (
// L1UserTxBytesLen is the length of the byte array that represents the L1Tx
L1UserTxBytesLen = 72
// L1CoordinatorTxBytesLen is the length of the byte array that represents the L1CoordinatorTx
L1CoordinatorTxBytesLen = 101
)
// L1Tx is a struct that represents a L1 tx
type L1Tx struct {
// Stored in DB: mandatory fileds
// TxID (12 bytes) for L1Tx is:
// bytes: | 1 | 8 | 2 | 1 |
// values: | type | ToForgeL1TxsNum | Position | 0 (padding) |
// where type:
// - L1UserTx: 0
// - L1CoordinatorTx: 1
TxID TxID `meddler:"id"`
ToForgeL1TxsNum *int64 `meddler:"to_forge_l1_txs_num"` // toForgeL1TxsNum in which the tx was forged / will be forged
Position int `meddler:"position"`
UserOrigin bool `meddler:"user_origin"` // true if the tx was originated by a user, false if it was aoriginated by a coordinator. Note that this differ from the spec for implementation simplification purpposes
FromIdx Idx `meddler:"from_idx,zeroisnull"` // FromIdx is used by L1Tx/Deposit to indicate the Idx receiver of the L1Tx.LoadAmount (deposit)
FromEthAddr ethCommon.Address `meddler:"from_eth_addr,zeroisnull"`
FromBJJ *babyjub.PublicKey `meddler:"from_bjj,zeroisnull"`
ToIdx Idx `meddler:"to_idx"` // ToIdx is ignored in L1Tx/Deposit, but used in the L1Tx/DepositAndTransfer
TokenID TokenID `meddler:"token_id"`
Amount *big.Int `meddler:"amount,bigint"`
LoadAmount *big.Int `meddler:"load_amount,bigint"`
EthBlockNum int64 `meddler:"eth_block_num"` // Ethereum Block Number in which this L1Tx was added to the queue
Type TxType `meddler:"type"`
BatchNum *BatchNum `meddler:"batch_num"`
}
// NewL1Tx returns the given L1Tx with the TxId & Type parameters calculated
// from the L1Tx values
func NewL1Tx(l1Tx *L1Tx) (*L1Tx, error) {
// calculate TxType
var txType TxType
if l1Tx.FromIdx == 0 {
if l1Tx.ToIdx == Idx(0) {
txType = TxTypeCreateAccountDeposit
} else if l1Tx.ToIdx >= IdxUserThreshold {
txType = TxTypeCreateAccountDepositTransfer
} else {
return l1Tx, fmt.Errorf("Can not determine type of L1Tx, invalid ToIdx value: %d", l1Tx.ToIdx)
}
} else if l1Tx.FromIdx >= IdxUserThreshold {
if l1Tx.ToIdx == Idx(0) {
txType = TxTypeDeposit
} else if l1Tx.ToIdx == Idx(1) {
txType = TxTypeForceExit
} else if l1Tx.ToIdx >= IdxUserThreshold {
if l1Tx.LoadAmount.Int64() == int64(0) {
txType = TxTypeForceTransfer
} else {
txType = TxTypeDepositTransfer
}
} else {
return l1Tx, fmt.Errorf("Can not determine type of L1Tx, invalid ToIdx value: %d", l1Tx.ToIdx)
}
} else {
return l1Tx, fmt.Errorf("Can not determine type of L1Tx, invalid FromIdx value: %d", l1Tx.FromIdx)
}
if l1Tx.Type != "" && l1Tx.Type != txType {
return l1Tx, fmt.Errorf("L1Tx.Type: %s, should be: %s", l1Tx.Type, txType)
}
l1Tx.Type = txType
txID, err := l1Tx.CalcTxID()
if err != nil {
return nil, err
}
l1Tx.TxID = *txID
return l1Tx, nil
}
// CalcTxID calculates the TxId of the L1Tx
func (tx *L1Tx) CalcTxID() (*TxID, error) {
var txID TxID
if tx.UserOrigin {
if tx.ToForgeL1TxsNum == nil {
return nil, fmt.Errorf("L1Tx.UserOrigin == true && L1Tx.ToForgeL1TxsNum == nil")
}
txID[0] = TxIDPrefixL1UserTx
var toForgeL1TxsNumBytes [8]byte
binary.BigEndian.PutUint64(toForgeL1TxsNumBytes[:], uint64(*tx.ToForgeL1TxsNum))
copy(txID[1:9], toForgeL1TxsNumBytes[:])
} else {
if tx.BatchNum == nil {
return nil, fmt.Errorf("L1Tx.UserOrigin == false && L1Tx.BatchNum == nil")
}
txID[0] = TxIDPrefixL1CoordTx
var batchNumBytes [8]byte
binary.BigEndian.PutUint64(batchNumBytes[:], uint64(*tx.BatchNum))
copy(txID[1:9], batchNumBytes[:])
}
var positionBytes [2]byte
binary.BigEndian.PutUint16(positionBytes[:], uint16(tx.Position))
copy(txID[9:11], positionBytes[:])
return &txID, nil
}
// Tx returns a *Tx from the L1Tx
func (tx L1Tx) Tx() Tx {
f := new(big.Float).SetInt(tx.Amount)
amountFloat, _ := f.Float64()
userOrigin := new(bool)
*userOrigin = tx.UserOrigin
genericTx := Tx{
IsL1: true,
TxID: tx.TxID,
Type: tx.Type,
Position: tx.Position,
FromIdx: tx.FromIdx,
ToIdx: tx.ToIdx,
Amount: tx.Amount,
AmountFloat: amountFloat,
TokenID: tx.TokenID,
ToForgeL1TxsNum: tx.ToForgeL1TxsNum,
UserOrigin: userOrigin,
FromEthAddr: tx.FromEthAddr,
FromBJJ: tx.FromBJJ,
LoadAmount: tx.LoadAmount,
EthBlockNum: tx.EthBlockNum,
}
if tx.LoadAmount != nil {
lf := new(big.Float).SetInt(tx.LoadAmount)
loadAmountFloat, _ := lf.Float64()
genericTx.LoadAmountFloat = &loadAmountFloat
}
return genericTx
}
// TxCompressedData spec:
// [ 1 bits ] empty (toBJJSign) // 1 byte
// [ 8 bits ] empty (userFee) // 1 byte
// [ 40 bits ] empty (nonce) // 5 bytes
// [ 32 bits ] tokenID // 4 bytes
// [ 16 bits ] amountFloat16 // 2 bytes
// [ 48 bits ] toIdx // 6 bytes
// [ 48 bits ] fromIdx // 6 bytes
// [ 16 bits ] chainId // 2 bytes
// [ 32 bits ] empty (signatureConstant) // 4 bytes
// Total bits compressed data: 241 bits // 31 bytes in *big.Int representation
func (tx L1Tx) TxCompressedData() (*big.Int, error) {
amountFloat16, err := NewFloat16(tx.Amount)
if err != nil {
return nil, err
}
var b [31]byte
// b[0:7] empty: no fee neither nonce
copy(b[7:11], tx.TokenID.Bytes())
copy(b[11:13], amountFloat16.Bytes())
toIdxBytes, err := tx.ToIdx.Bytes()
if err != nil {
return nil, err
}
copy(b[13:19], toIdxBytes[:])
fromIdxBytes, err := tx.FromIdx.Bytes()
if err != nil {
return nil, err
}
copy(b[19:25], fromIdxBytes[:])
copy(b[25:27], []byte{0, 1}) // TODO this will be generated by the ChainID config parameter
// b[27:] empty: no signature
bi := new(big.Int).SetBytes(b[:])
return bi, nil
}
// BytesGeneric returns the generic representation of a L1Tx. This method is
// used to compute the []byte representation of a L1UserTx, and also to compute
// the L1TxData for the ZKInputs (at the HashGlobalInputs), using this method
// for L1CoordinatorTxs & L1UserTxs (for the ZKInputs case).
func (tx *L1Tx) BytesGeneric() ([]byte, error) {
var b [L1UserTxBytesLen]byte
copy(b[0:20], tx.FromEthAddr.Bytes())
if tx.FromBJJ != nil {
pkCompL := tx.FromBJJ.Compress()
pkCompB := SwapEndianness(pkCompL[:])
copy(b[20:52], pkCompB[:])
}
fromIdxBytes, err := tx.FromIdx.Bytes()
if err != nil {
return nil, err
}
copy(b[52:58], fromIdxBytes[:])
loadAmountFloat16, err := NewFloat16(tx.LoadAmount)
if err != nil {
return nil, err
}
copy(b[58:60], loadAmountFloat16.Bytes())
amountFloat16, err := NewFloat16(tx.Amount)
if err != nil {
return nil, err
}
copy(b[60:62], amountFloat16.Bytes())
copy(b[62:66], tx.TokenID.Bytes())
toIdxBytes, err := tx.ToIdx.Bytes()
if err != nil {
return nil, err
}
copy(b[66:72], toIdxBytes[:])
return b[:], nil
}
// BytesUser encodes a L1UserTx into []byte
func (tx *L1Tx) BytesUser() ([]byte, error) {
if !tx.UserOrigin {
return nil, fmt.Errorf("Can not calculate BytesUser() for a L1CoordinatorTx")
}
return tx.BytesGeneric()
}
// BytesCoordinatorTx encodes a L1CoordinatorTx into []byte
func (tx *L1Tx) BytesCoordinatorTx(compressedSignatureBytes []byte) ([]byte, error) {
if tx.UserOrigin {
return nil, fmt.Errorf("Can not calculate BytesCoordinatorTx() for a L1UserTx")
}
var b [L1CoordinatorTxBytesLen]byte
v := compressedSignatureBytes[64]
s := compressedSignatureBytes[32:64]
r := compressedSignatureBytes[0:32]
b[0] = v
copy(b[1:33], s)
copy(b[33:65], r)
pkCompL := tx.FromBJJ.Compress()
pkCompB := SwapEndianness(pkCompL[:])
copy(b[65:97], pkCompB[:])
copy(b[97:101], tx.TokenID.Bytes())
return b[:], nil
}
// L1UserTxFromBytes decodes a L1Tx from []byte
func L1UserTxFromBytes(b []byte) (*L1Tx, error) {
if len(b) != L1UserTxBytesLen {
return nil, fmt.Errorf("Can not parse L1Tx bytes, expected length %d, current: %d", 68, len(b))
}
tx := &L1Tx{
UserOrigin: true,
}
var err error
tx.FromEthAddr = ethCommon.BytesToAddress(b[0:20])
pkCompB := b[20:52]
pkCompL := SwapEndianness(pkCompB)
var pkComp babyjub.PublicKeyComp
copy(pkComp[:], pkCompL)
tx.FromBJJ, err = pkComp.Decompress()
if err != nil {
return nil, err
}
fromIdx, err := IdxFromBytes(b[52:58])
if err != nil {
return nil, err
}
tx.FromIdx = fromIdx
tx.LoadAmount = Float16FromBytes(b[58:60]).BigInt()
tx.Amount = Float16FromBytes(b[60:62]).BigInt()
tx.TokenID, err = TokenIDFromBytes(b[62:66])
if err != nil {
return nil, err
}
tx.ToIdx, err = IdxFromBytes(b[66:72])
if err != nil {
return nil, err
}
return tx, nil
}
func signHash(data []byte) []byte {
msg := fmt.Sprintf("\x19Ethereum Signed Message:\n%d%s", len(data), data)
return crypto.Keccak256([]byte(msg))
}
// L1CoordinatorTxFromBytes decodes a L1Tx from []byte
func L1CoordinatorTxFromBytes(b []byte, chainID *big.Int, hermezAddress ethCommon.Address) (*L1Tx, error) {
if len(b) != L1CoordinatorTxBytesLen {
return nil, fmt.Errorf("Can not parse L1CoordinatorTx bytes, expected length %d, current: %d", 101, len(b))
}
bytesMessage := []byte("I authorize this babyjubjub key for hermez rollup account creation")
tx := &L1Tx{
UserOrigin: false,
}
var err error
v := b[0]
s := b[1:33]
r := b[33:65]
pkCompB := b[65:97]
pkCompL := SwapEndianness(pkCompB)
var pkComp babyjub.PublicKeyComp
copy(pkComp[:], pkCompL)
tx.FromBJJ, err = pkComp.Decompress()
if err != nil {
return nil, err
}
tx.TokenID, err = TokenIDFromBytes(b[97:101])
if err != nil {
return nil, err
}
tx.Amount = big.NewInt(0)
tx.LoadAmount = big.NewInt(0)
if int(v) > 0 {
// L1CoordinatorTX ETH
// Ethereum adds 27 to v
v = b[0] - byte(27) //nolint:gomnd
chainIDBytes := ethCommon.LeftPadBytes(chainID.Bytes(), 2)
var data []byte
data = append(data, bytesMessage...)
data = append(data, pkCompB...)
data = append(data, chainIDBytes[:]...)
data = append(data, hermezAddress.Bytes()...)
var signature []byte
signature = append(signature, r[:]...)
signature = append(signature, s[:]...)
signature = append(signature, v)
hash := signHash(data)
pubKeyBytes, err := crypto.Ecrecover(hash, signature)
if err != nil {
return nil, err
}
pubKey, err := crypto.UnmarshalPubkey(pubKeyBytes)
if err != nil {
return nil, err
}
tx.FromEthAddr = crypto.PubkeyToAddress(*pubKey)
} else {
// L1Coordinator Babyjub
tx.FromEthAddr = RollupConstEthAddressInternalOnly
}
return tx, nil
}