optimize cet verification

Author: suefay

api/side/lending/lending.pulsar.go

@@ -255,6 +255,7 @@ message CetInfo {
   uint32 outcome_index = 2;
   string signature_point = 3;
   LeafScript script = 4 [(gogoproto.nullable) = false];
+  uint32 sighash_type = 5;
 }
 
 message LiquidationCet {

proto/side/lending/lending.proto

@@ -41,6 +41,7 @@ func (k Keeper) UpdateDLCMeta(ctx sdk.Context, loanId string, depositTxs []*psbt
 	dlcMeta := k.GetDLCMeta(ctx, loanId)
 
 	vaultPkScript, _ := types.GetPkScriptFromAddress(loanId)
+	dcmPkScript, _ := types.GetPkScriptFromPubKey(loan.DCM)
 
 	vaultUtxos, err := types.GetVaultUtxos(depositTxs, vaultPkScript)
 	if err != nil {
@@ -63,7 +64,6 @@ func (k Keeper) UpdateDLCMeta(ctx sdk.Context, loanId string, depositTxs []*psbt
 	repaymentScript, repaymentScriptControlBlock, _ := types.UnwrapLeafScript(dlcMeta.RepaymentScript)
 
 	for i := range liquidationCetPsbt.Inputs {
-		liquidationCetPsbt.Inputs[i].SighashType = txscript.SigHashDefault
 		liquidationCetPsbt.Inputs[i].TaprootInternalKey = internalKey
 		liquidationCetPsbt.Inputs[i].TaprootLeafScript = []*psbt.TaprootTapLeafScript{
 			{
@@ -74,8 +74,18 @@ func (k Keeper) UpdateDLCMeta(ctx sdk.Context, loanId string, depositTxs []*psbt
 		}
 	}
 
+	// get fee rate
+	feeRate := k.btcbridgeKeeper.GetFeeRate(ctx)
+	if err := k.btcbridgeKeeper.CheckFeeRate(ctx, feeRate); err != nil {
+		return err
+	}
+
+	// add DCM output to liquidation cet
+	if err := types.AddDCMOutputToLiquidationCet(liquidationCetPsbt, liquidationScript, liquidationScriptControlBlock, dcmPkScript, feeRate.Value); err != nil {
+		return err
+	}
+
 	for i := range repaymentCetPsbt.Inputs {
-		repaymentCetPsbt.Inputs[i].SighashType = txscript.SigHashDefault
 		repaymentCetPsbt.Inputs[i].TaprootInternalKey = internalKey
 		repaymentCetPsbt.Inputs[i].TaprootLeafScript = []*psbt.TaprootTapLeafScript{
 			{
@@ -101,12 +111,7 @@ func (k Keeper) UpdateDLCMeta(ctx sdk.Context, loanId string, depositTxs []*psbt
 		return err
 	}
 
-	// get fee rate
-	feeRate := k.BtcBridgeKeeper().GetFeeRate(ctx)
-	if feeRate.Value == 0 {
-		feeRate.Value = types.DefaultFeeRate
-	}
-
+	// timeout refund transaction can be generated offchain as needed
 	timeoutRefundTx, err := types.CreateTimeoutRefundTransaction(depositTxs, vaultPkScript, borrowerPkScript, internalKey, dlcMeta.TimeoutRefundScript, feeRate.Value)
 	if err != nil {
 		return err
@@ -179,9 +184,9 @@ func (k Keeper) GetCetInfos(ctx sdk.Context, loanId string, collateralAmount sdk
 		k.UpdateDLCEventLiquidatedOutcome(ctx, loan, dlcEvent, liquidationPrice)
 	}
 
-	liquidationCetInfo, _ := types.GetCetInfo(dlcEvent, types.LiquidatedOutcomeIndex, liquidationScript, liquidationScriptControlBlock)
-	defaultLiquidationCetInfo, _ := types.GetCetInfo(dlcEvent, types.DefaultLiquidatedOutcomeIndex, liquidationScript, liquidationScriptControlBlock)
-	repaymentCetInfo, _ := types.GetCetInfo(dlcEvent, types.RepaidOutcomeIndex, repaymentScript, repaymentScriptControlBlock)
+	liquidationCetInfo, _ := types.GetCetInfo(dlcEvent, types.LiquidatedOutcomeIndex, liquidationScript, liquidationScriptControlBlock, types.BorrowerLiquidationCetSigHashType)
+	defaultLiquidationCetInfo, _ := types.GetCetInfo(dlcEvent, types.DefaultLiquidatedOutcomeIndex, liquidationScript, liquidationScriptControlBlock, types.BorrowerLiquidationCetSigHashType)
+	repaymentCetInfo, _ := types.GetCetInfo(dlcEvent, types.RepaidOutcomeIndex, repaymentScript, repaymentScriptControlBlock, types.DefaultSigHashType)
 
 	return []*types.CetInfo{
 		liquidationCetInfo,

x/lending/keeper/dlc.go

@@ -199,7 +199,7 @@ func (m msgServer) SubmitCets(goCtx context.Context, msg *types.MsgSubmitCets) (
 	m.UpdateDLCEventLiquidatedOutcome(ctx, loan, dlcEvent, liquidationPrice)
 
 	// verify cets
-	if err := types.VerifyCets(depositTxs, vaultPkScript, loan.BorrowerPubKey, loan.BorrowerAuthPubKey, loan.DCM, dlcEvent, msg.LiquidationCet, msg.LiquidationAdaptorSignatures, msg.DefaultLiquidationAdaptorSignatures, msg.RepaymentCet, msg.RepaymentSignatures); err != nil {
+	if err := types.VerifyCets(m.GetDLCMeta(ctx, msg.LoanId), depositTxs, vaultPkScript, loan.BorrowerPubKey, loan.BorrowerAuthPubKey, loan.DCM, dlcEvent, msg.LiquidationCet, msg.LiquidationAdaptorSignatures, msg.DefaultLiquidationAdaptorSignatures, msg.RepaymentCet, msg.RepaymentSignatures); err != nil {
 		return nil, err
 	}
 

x/lending/keeper/msg_server_loan.go

@@ -257,7 +257,7 @@ func handleLiquidatedLoans(ctx sdk.Context, k keeper.Keeper) {
 
 		// build signed liquidation cet if both borrower adapted signatures(obviously exist) and DCM signatures already exist
 		if len(cet.DCMSignatures) != 0 {
-			signedTx, txHash, err := types.BuildSignedCet(cet.Tx, loan.BorrowerAuthPubKey, cet.BorrowerAdaptedSignatures, loan.DCM, cet.DCMSignatures)
+			signedTx, txHash, err := types.BuildSignedCet(cet.Tx, loan.BorrowerAuthPubKey, cet.BorrowerAdaptedSignatures, loan.DCM, cet.DCMSignatures, cetType)
 			if err != nil {
 				k.Logger(ctx).Info("failed to build signed liquidation cet", "loan id", loan.VaultAddress, "err", err)
 			} else {
@@ -331,7 +331,7 @@ func handleRepayments(ctx sdk.Context, k keeper.Keeper) {
 		}
 
 		// build signed repayment cet
-		signedTx, txHash, err := types.BuildSignedCet(dlcMeta.RepaymentCet.Tx, loan.BorrowerPubKey, dlcMeta.RepaymentCet.BorrowerSignatures, loan.DCM, dlcMeta.RepaymentCet.DCMAdaptedSignatures)
+		signedTx, txHash, err := types.BuildSignedCet(dlcMeta.RepaymentCet.Tx, loan.BorrowerPubKey, dlcMeta.RepaymentCet.BorrowerSignatures, loan.DCM, dlcMeta.RepaymentCet.DCMAdaptedSignatures, types.CetType_REPAYMENT)
 		if err != nil {
 			k.Logger(ctx).Info("failed to build signed repayment cet", "loan id", loan.VaultAddress, "err", err)
 		} else {

x/lending/module/abci.go

@@ -1,9 +1,11 @@
 package types
 
 import (
+	"github.com/btcsuite/btcd/blockchain"
+	"github.com/btcsuite/btcd/btcutil"
 	"github.com/btcsuite/btcd/btcutil/psbt"
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
-	"github.com/btcsuite/btcd/txscript"
+	"github.com/btcsuite/btcd/mempool"
 	"github.com/btcsuite/btcd/wire"
 
 	btcbridgetypes "github.com/sideprotocol/side/x/btcbridge/types"
@@ -13,18 +15,15 @@ const (
 	// default tx version
 	TxVersion = 2
 
-	// default sig hash type
-	DefaultSigHashType = txscript.SigHashDefault
-
-	// default fee rate
-	DefaultFeeRate = int64(1)
+	// default maximum allowed transaction weight
+	MaxTransactionWeight = 400000
 )
 
 // BuildPsbt builds a psbt from the given params
-func BuildPsbt(utxos []*btcbridgetypes.UTXO, recipientPkScript []byte, feeRate int64) (*psbt.Packet, error) {
+func BuildPsbt(utxos []*btcbridgetypes.UTXO, recipientPkScript []byte, feeRate int64, witnessSize int) (*psbt.Packet, error) {
 	txOut := wire.NewTxOut(0, recipientPkScript)
 
-	unsignedTx, err := BuildUnsignedTransaction(utxos, txOut, feeRate)
+	unsignedTx, err := BuildUnsignedTransaction(utxos, txOut, feeRate, witnessSize)
 	if err != nil {
 		return nil, err
 	}
@@ -35,15 +34,14 @@ func BuildPsbt(utxos []*btcbridgetypes.UTXO, recipientPkScript []byte, feeRate i
 	}
 
 	for i, utxo := range utxos {
-		p.Inputs[i].SighashType = DefaultSigHashType
 		p.Inputs[i].WitnessUtxo = wire.NewTxOut(int64(utxo.Amount), utxo.PubKeyScript)
 	}
 
 	return p, nil
 }
 
 // BuildUnsignedTransaction builds an unsigned tx from the given params
-func BuildUnsignedTransaction(utxos []*btcbridgetypes.UTXO, txOut *wire.TxOut, feeRate int64) (*wire.MsgTx, error) {
+func BuildUnsignedTransaction(utxos []*btcbridgetypes.UTXO, txOut *wire.TxOut, feeRate int64, witnessSize int) (*wire.MsgTx, error) {
 	tx := wire.NewMsgTx(TxVersion)
 
 	inAmount := int64(0)
@@ -56,19 +54,19 @@ func BuildUnsignedTransaction(utxos []*btcbridgetypes.UTXO, txOut *wire.TxOut, f
 
 	tx.AddTxOut(txOut)
 
-	fee := btcbridgetypes.GetTxVirtualSize(tx, utxos) * feeRate
+	fee := GetTxVirtualSize(tx, witnessSize) * feeRate
 
 	change := inAmount - outAmount - fee
 	if change <= 0 {
-		return nil, ErrFailedToBuildTx
+		return nil, ErrInsufficientUTXOs
 	}
 
 	txOut.Value += change
 	if btcbridgetypes.IsDustOut(txOut) {
-		return nil, ErrFailedToBuildTx
+		return nil, ErrDustOutput
 	}
 
-	if err := btcbridgetypes.CheckTransactionWeight(tx, utxos); err != nil {
+	if err := CheckTransactionWeight(tx, witnessSize); err != nil {
 		return nil, err
 	}
 
@@ -89,3 +87,36 @@ func AddUTXOToTx(tx *wire.MsgTx, utxo *btcbridgetypes.UTXO) {
 
 	tx.AddTxIn(txIn)
 }
+
+// GetTxVirtualSize gets the virtual size of the given tx.
+func GetTxVirtualSize(tx *wire.MsgTx, witnessSize int) int64 {
+	newTx := PopulateTxWithDummyWitness(tx, witnessSize)
+
+	return mempool.GetTxVirtualSize(btcutil.NewTx(newTx))
+}
+
+// CheckTransactionWeight checks if the weight of the given tx exceeds the allowed maximum weight
+func CheckTransactionWeight(tx *wire.MsgTx, witnessSize int) error {
+	newTx := PopulateTxWithDummyWitness(tx, witnessSize)
+
+	weight := blockchain.GetTransactionWeight(btcutil.NewTx(newTx))
+	if weight > MaxTransactionWeight {
+		return ErrMaxTransactionWeightExceeded
+	}
+
+	return nil
+}
+
+// PopulateTxWithDummyWitness populates the given tx with the dummy witness
+func PopulateTxWithDummyWitness(tx *wire.MsgTx, witnessSize int) *wire.MsgTx {
+	newTx := tx.Copy()
+
+	for _, txIn := range newTx.TxIn {
+		if len(txIn.Witness) == 0 {
+			dummyWitness := make([]byte, witnessSize)
+			txIn.Witness = wire.TxWitness{dummyWitness}
+		}
+	}
+
+	return newTx
+}