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package common
import (
"encoding/binary"
"errors"
"fmt"
"math/big"
"time"
ethCommon "github.com/ethereum/go-ethereum/common"
"github.com/hermeznetwork/tracerr"
"github.com/iden3/go-iden3-crypto/babyjub"
"github.com/iden3/go-iden3-crypto/poseidon"
)
// EmptyBJJComp contains the 32 byte array of a empty BabyJubJub PublicKey
// Compressed. It is a valid point in the BabyJubJub curve, so does not give
// errors when being decompressed.
var EmptyBJJComp = babyjub.PublicKeyComp([32]byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0})
// PoolL2Tx is a struct that represents a L2Tx sent by an account to the
// coordinator that is waiting to be forged
type PoolL2Tx struct {
// Stored in DB: mandatory fileds
// TxID (12 bytes) for L2Tx is:
// bytes: | 1 | 6 | 5 |
// values: | type | FromIdx | Nonce |
TxID TxID `meddler:"tx_id"`
FromIdx Idx `meddler:"from_idx"`
ToIdx Idx `meddler:"to_idx,zeroisnull"`
// AuxToIdx is only used internally at the StateDB to avoid repeated
// computation when processing transactions (from Synchronizer,
// TxSelector, BatchBuilder)
AuxToIdx Idx `meddler:"-"`
ToEthAddr ethCommon.Address `meddler:"to_eth_addr,zeroisnull"`
ToBJJ babyjub.PublicKeyComp `meddler:"to_bjj,zeroisnull"`
TokenID TokenID `meddler:"token_id"`
Amount *big.Int `meddler:"amount,bigint"`
Fee FeeSelector `meddler:"fee"`
Nonce Nonce `meddler:"nonce"` // effective 40 bits used
State PoolL2TxState `meddler:"state"`
// Info contains information about the status & State of the
// transaction. As for example, if the Tx has not been selected in the
// last batch due not enough Balance at the Sender account, this reason
// would appear at this parameter.
Info string `meddler:"info,zeroisnull"`
Signature babyjub.SignatureComp `meddler:"signature"` // tx signature
Timestamp time.Time `meddler:"timestamp,utctime"` // time when added to the tx pool
// Stored in DB: optional fileds, may be uninitialized
RqFromIdx Idx `meddler:"rq_from_idx,zeroisnull"`
RqToIdx Idx `meddler:"rq_to_idx,zeroisnull"`
RqToEthAddr ethCommon.Address `meddler:"rq_to_eth_addr,zeroisnull"`
RqToBJJ babyjub.PublicKeyComp `meddler:"rq_to_bjj,zeroisnull"`
RqTokenID TokenID `meddler:"rq_token_id,zeroisnull"`
RqAmount *big.Int `meddler:"rq_amount,bigintnull"`
RqFee FeeSelector `meddler:"rq_fee,zeroisnull"`
RqNonce Nonce `meddler:"rq_nonce,zeroisnull"` // effective 48 bits used
AbsoluteFee float64 `meddler:"fee_usd,zeroisnull"`
AbsoluteFeeUpdate time.Time `meddler:"usd_update,utctimez"`
Type TxType `meddler:"tx_type"`
// Extra metadata, may be uninitialized
RqTxCompressedData []byte `meddler:"-"` // 253 bits, optional for atomic txs
}
// NewPoolL2Tx returns the given L2Tx with the TxId & Type parameters calculated
// from the L2Tx values
func NewPoolL2Tx(tx *PoolL2Tx) (*PoolL2Tx, error) {
txTypeOld := tx.Type
if err := tx.SetType(); err != nil {
return nil, tracerr.Wrap(err)
}
// If original Type doesn't match the correct one, return error
if txTypeOld != "" && txTypeOld != tx.Type {
return nil, tracerr.Wrap(fmt.Errorf("L2Tx.Type: %s, should be: %s",
tx.Type, txTypeOld))
}
txIDOld := tx.TxID
if err := tx.SetID(); err != nil {
return nil, tracerr.Wrap(err)
}
// If original TxID doesn't match the correct one, return error
if txIDOld != (TxID{}) && txIDOld != tx.TxID {
return tx, tracerr.Wrap(fmt.Errorf("PoolL2Tx.TxID: %s, should be: %s",
tx.TxID.String(), txIDOld.String()))
}
return tx, nil
}
// SetType sets the type of the transaction
func (tx *PoolL2Tx) SetType() error {
if tx.ToIdx >= IdxUserThreshold {
tx.Type = TxTypeTransfer
} else if tx.ToIdx == 1 {
tx.Type = TxTypeExit
} else if tx.ToIdx == 0 {
if tx.ToBJJ != EmptyBJJComp && tx.ToEthAddr == FFAddr {
tx.Type = TxTypeTransferToBJJ
} else if tx.ToEthAddr != FFAddr && tx.ToEthAddr != EmptyAddr {
tx.Type = TxTypeTransferToEthAddr
}
} else {
return tracerr.Wrap(errors.New("malformed transaction"))
}
return nil
}
// SetID sets the ID of the transaction
func (tx *PoolL2Tx) SetID() error {
txID, err := tx.L2Tx().CalculateTxID()
if err != nil {
return tracerr.Wrap(err)
}
tx.TxID = txID
return nil
}
// TxCompressedData spec:
// [ 1 bits ] toBJJSign // 1 byte
// [ 8 bits ] userFee // 1 byte
// [ 40 bits ] nonce // 5 bytes
// [ 32 bits ] tokenID // 4 bytes
// [ 48 bits ] toIdx // 6 bytes
// [ 48 bits ] fromIdx // 6 bytes
// [ 16 bits ] chainId // 2 bytes
// [ 32 bits ] signatureConstant // 4 bytes
// Total bits compressed data: 225 bits // 29 bytes in *big.Int representation
func (tx *PoolL2Tx) TxCompressedData(chainID uint16) (*big.Int, error) {
var b [29]byte
toBJJSign := byte(0)
pkSign, _ := babyjub.UnpackSignY(tx.ToBJJ)
if pkSign {
toBJJSign = byte(1)
}
b[0] = toBJJSign
b[1] = byte(tx.Fee)
nonceBytes, err := tx.Nonce.Bytes()
if err != nil {
return nil, tracerr.Wrap(err)
}
copy(b[2:7], nonceBytes[:])
copy(b[7:11], tx.TokenID.Bytes())
toIdxBytes, err := tx.ToIdx.Bytes()
if err != nil {
return nil, tracerr.Wrap(err)
}
copy(b[11:17], toIdxBytes[:])
fromIdxBytes, err := tx.FromIdx.Bytes()
if err != nil {
return nil, tracerr.Wrap(err)
}
copy(b[17:23], fromIdxBytes[:])
binary.BigEndian.PutUint16(b[23:25], chainID)
copy(b[25:29], SignatureConstantBytes[:])
bi := new(big.Int).SetBytes(b[:])
return bi, nil
}
// TxCompressedDataEmpty calculates the TxCompressedData of an empty
// transaction
func TxCompressedDataEmpty(chainID uint16) *big.Int {
var b [29]byte
binary.BigEndian.PutUint16(b[23:25], chainID)
copy(b[25:29], SignatureConstantBytes[:])
bi := new(big.Int).SetBytes(b[:])
return bi
}
// TxCompressedDataV2 spec:
// [ 1 bits ] toBJJSign // 1 byte
// [ 8 bits ] userFee // 1 byte
// [ 40 bits ] nonce // 5 bytes
// [ 32 bits ] tokenID // 4 bytes
// [ 40 bits ] amountFloat40 // 5 bytes
// [ 48 bits ] toIdx // 6 bytes
// [ 48 bits ] fromIdx // 6 bytes
// Total bits compressed data: 217 bits // 28 bytes in *big.Int representation
func (tx *PoolL2Tx) TxCompressedDataV2() (*big.Int, error) {
if tx.Amount == nil {
tx.Amount = big.NewInt(0)
}
amountFloat40, err := NewFloat40(tx.Amount)
if err != nil {
return nil, tracerr.Wrap(err)
}
amountFloat40Bytes, err := amountFloat40.Bytes()
if err != nil {
return nil, tracerr.Wrap(err)
}
var b [28]byte
toBJJSign := byte(0)
if tx.ToBJJ != EmptyBJJComp {
sign, _ := babyjub.UnpackSignY(tx.ToBJJ)
if sign {
toBJJSign = byte(1)
}
}
b[0] = toBJJSign
b[1] = byte(tx.Fee)
nonceBytes, err := tx.Nonce.Bytes()
if err != nil {
return nil, tracerr.Wrap(err)
}
copy(b[2:7], nonceBytes[:])
copy(b[7:11], tx.TokenID.Bytes())
copy(b[11:16], amountFloat40Bytes)
toIdxBytes, err := tx.ToIdx.Bytes()
if err != nil {
return nil, tracerr.Wrap(err)
}
copy(b[16:22], toIdxBytes[:])
fromIdxBytes, err := tx.FromIdx.Bytes()
if err != nil {
return nil, tracerr.Wrap(err)
}
copy(b[22:28], fromIdxBytes[:])
bi := new(big.Int).SetBytes(b[:])
return bi, nil
}
// RqTxCompressedDataV2 is like the TxCompressedDataV2 but using the 'Rq'
// parameters. In a future iteration of the hermez-node, the 'Rq' parameters
// can be inside a struct, which contains the 'Rq' transaction grouped inside,
// so then computing the 'RqTxCompressedDataV2' would be just calling
// 'tx.Rq.TxCompressedDataV2()'.
// RqTxCompressedDataV2 spec:
// [ 1 bits ] rqToBJJSign // 1 byte
// [ 8 bits ] rqUserFee // 1 byte
// [ 40 bits ] rqNonce // 5 bytes
// [ 32 bits ] rqTokenID // 4 bytes
// [ 40 bits ] rqAmountFloat40 // 5 bytes
// [ 48 bits ] rqToIdx // 6 bytes
// [ 48 bits ] rqFromIdx // 6 bytes
// Total bits compressed data: 217 bits // 28 bytes in *big.Int representation
func (tx *PoolL2Tx) RqTxCompressedDataV2() (*big.Int, error) {
if tx.RqAmount == nil {
tx.RqAmount = big.NewInt(0)
}
amountFloat40, err := NewFloat40(tx.RqAmount)
if err != nil {
return nil, tracerr.Wrap(err)
}
amountFloat40Bytes, err := amountFloat40.Bytes()
if err != nil {
return nil, tracerr.Wrap(err)
}
var b [28]byte
rqToBJJSign := byte(0)
if tx.RqToBJJ != EmptyBJJComp {
sign, _ := babyjub.UnpackSignY(tx.RqToBJJ)
if sign {
rqToBJJSign = byte(1)
}
}
b[0] = rqToBJJSign
b[1] = byte(tx.RqFee)
nonceBytes, err := tx.RqNonce.Bytes()
if err != nil {
return nil, tracerr.Wrap(err)
}
copy(b[2:7], nonceBytes[:])
copy(b[7:11], tx.RqTokenID.Bytes())
copy(b[11:16], amountFloat40Bytes)
toIdxBytes, err := tx.RqToIdx.Bytes()
if err != nil {
return nil, tracerr.Wrap(err)
}
copy(b[16:22], toIdxBytes[:])
fromIdxBytes, err := tx.RqFromIdx.Bytes()
if err != nil {
return nil, tracerr.Wrap(err)
}
copy(b[22:28], fromIdxBytes[:])
bi := new(big.Int).SetBytes(b[:])
return bi, nil
}
// HashToSign returns the computed Poseidon hash from the *PoolL2Tx that will
// be signed by the sender.
func (tx *PoolL2Tx) HashToSign(chainID uint16) (*big.Int, error) {
toCompressedData, err := tx.TxCompressedData(chainID)
if err != nil {
return nil, tracerr.Wrap(err)
}
// e1: [5 bytes AmountFloat40 | 20 bytes ToEthAddr]
var e1B [25]byte
amountFloat40, err := NewFloat40(tx.Amount)
if err != nil {
return nil, tracerr.Wrap(err)
}
amountFloat40Bytes, err := amountFloat40.Bytes()
if err != nil {
return nil, tracerr.Wrap(err)
}
copy(e1B[0:5], amountFloat40Bytes)
toEthAddr := EthAddrToBigInt(tx.ToEthAddr)
copy(e1B[5:25], toEthAddr.Bytes())
e1 := new(big.Int).SetBytes(e1B[:])
rqToEthAddr := EthAddrToBigInt(tx.RqToEthAddr)
_, toBJJY := babyjub.UnpackSignY(tx.ToBJJ)
rqTxCompressedDataV2, err := tx.RqTxCompressedDataV2()
if err != nil {
return nil, tracerr.Wrap(err)
}
_, rqToBJJY := babyjub.UnpackSignY(tx.RqToBJJ)
return poseidon.Hash([]*big.Int{toCompressedData, e1, toBJJY, rqTxCompressedDataV2, rqToEthAddr, rqToBJJY})
}
// VerifySignature returns true if the signature verification is correct for the given PublicKeyComp
func (tx *PoolL2Tx) VerifySignature(chainID uint16, pkComp babyjub.PublicKeyComp) bool {
h, err := tx.HashToSign(chainID)
if err != nil {
return false
}
s, err := tx.Signature.Decompress()
if err != nil {
return false
}
pk, err := pkComp.Decompress()
if err != nil {
return false
}
return pk.VerifyPoseidon(h, s)
}
// L2Tx returns a *L2Tx from the PoolL2Tx
func (tx PoolL2Tx) L2Tx() L2Tx {
var toIdx Idx
if tx.ToIdx == Idx(0) {
toIdx = tx.AuxToIdx
} else {
toIdx = tx.ToIdx
}
return L2Tx{
TxID: tx.TxID,
FromIdx: tx.FromIdx,
ToIdx: toIdx,
TokenID: tx.TokenID,
Amount: tx.Amount,
Fee: tx.Fee,
Nonce: tx.Nonce,
Type: tx.Type,
}
}
// Tx returns a *Tx from the PoolL2Tx
func (tx PoolL2Tx) Tx() Tx {
return Tx{
TxID: tx.TxID,
FromIdx: tx.FromIdx,
ToIdx: tx.ToIdx,
Amount: tx.Amount,
TokenID: tx.TokenID,
Nonce: &tx.Nonce,
Fee: &tx.Fee,
Type: tx.Type,
}
}
// PoolL2TxsToL2Txs returns an array of []L2Tx from an array of []PoolL2Tx
func PoolL2TxsToL2Txs(txs []PoolL2Tx) ([]L2Tx, error) {
l2Txs := make([]L2Tx, len(txs))
for i, poolTx := range txs {
l2Txs[i] = poolTx.L2Tx()
}
return l2Txs, nil
}
// TxIDsFromPoolL2Txs returns an array of TxID from the []PoolL2Tx
func TxIDsFromPoolL2Txs(txs []PoolL2Tx) []TxID {
txIDs := make([]TxID, len(txs))
for i, tx := range txs {
txIDs[i] = tx.TxID
}
return txIDs
}
// PoolL2TxState is a string that represents the status of a L2 transaction
type PoolL2TxState string
const (
// PoolL2TxStatePending represents a valid L2Tx that hasn't started the
// forging process
PoolL2TxStatePending PoolL2TxState = "pend"
// PoolL2TxStateForging represents a valid L2Tx that has started the
// forging process
PoolL2TxStateForging PoolL2TxState = "fing"
// PoolL2TxStateForged represents a L2Tx that has already been forged
PoolL2TxStateForged PoolL2TxState = "fged"
// PoolL2TxStateInvalid represents a L2Tx that has been invalidated
PoolL2TxStateInvalid PoolL2TxState = "invl"
)