lnd: label the tx to make it easier to audit

Ensure that all lnd transactions related to peerswaps are identifiable
by the label `peerswap`.
This makes it easier to audit the transactions from faraday.
This is performed by LND's LabelTransaction RPC.
Since CLN has no such function, no label is assigned.
Since label recording is not an essential requirement for swap,
if it fails, it is logged and subsequent processing is continued.

clightning/clightning_wallet.go

@@ -199,6 +199,14 @@ func (cl *ClightningClient) CreateCoopSpendingTransaction(swapParams *swap.Openi
 	return spendingTx.TxHash().String(), txHex, nil
 }
 
+func (cl *ClightningClient) LabelTransaction(txId, label string) error {
+	// todo implement
+	// This function assigns an identifiable label to the target transaction based on the txid.
+	// Currently no such functionality is available, so it has not been implemented.
+	// Supported by lnd only.
+	return nil
+}
+
 func (cl *ClightningClient) NewAddress() (string, error) {
 	newAddr, err := cl.glightning.NewAddr()
 	if err != nil {

lnd/lnd_wallet.go

@@ -7,6 +7,7 @@ import (
 	"encoding/hex"
 
 	"github.com/btcsuite/btcd/btcutil/psbt"
+	"github.com/btcsuite/btcd/chaincfg/chainhash"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/elementsproject/peerswap/lightning"
 	"github.com/elementsproject/peerswap/onchain"
@@ -207,6 +208,22 @@ func (l *Client) CreateCoopSpendingTransaction(swapParams *swap.OpeningParams, c
 	return spendingTx.TxHash().String(), txHex, nil
 }
 
+// LabelTransaction labels a transaction with a given label.
+// This makes it easier to audit the transactions from faraday.
+// This is performed by LND's LabelTransaction RPC.
+func (l *Client) LabelTransaction(txID, label string) error {
+	txIDHash, err := chainhash.NewHashFromStr(txID)
+	if err != nil {
+		return err
+	}
+	_, err = l.walletClient.LabelTransaction(l.ctx,
+		&walletrpc.LabelTransactionRequest{
+			Txid:      txIDHash.CloneBytes(),
+			Label:     label,
+			Overwrite: true})
+	return err
+}
+
 func (l *Client) GetOnchainBalance() (uint64, error) {
 	res, err := l.lndClient.WalletBalance(l.ctx, &lnrpc.WalletBalanceRequest{})
 	if err != nil {

onchain/bitcoin.go

@@ -254,6 +254,14 @@ func (b *BitcoinOnChain) PrepareSpendingTransaction(swapParams *swap.OpeningPara
 	return spendingTx, sigHash, redeemScript, nil
 }
 
+func (b *BitcoinOnChain) LabelTransaction(txID, label string) error {
+	// TODO: implement
+	// This function assigns an identifiable label to the target transaction based on the txid.
+	// Currently no such functionality is available, so it has not been implemented.
+	// Supported by lnd only.
+	return nil
+}
+
 func (b *BitcoinOnChain) CreateOpeningAddress(params *swap.OpeningParams, csv uint32) (string, error) {
 	redeemScript, err := ParamsToTxScript(params, csv)
 	if err != nil {

onchain/liquid.go

@@ -220,6 +220,14 @@ func (l *LiquidOnChain) CreateCoopSpendingTransaction(swapParams *swap.OpeningPa
 	return txId, txHex, nil
 }
 
+func (l *LiquidOnChain) LabelTransaction(txID, label string) error {
+	// TODO: implement
+	// This function assigns an identifiable label to the target transaction based on the txid.
+	// Currently no such functionality is available, so it has not been implemented.
+	// Supported by lnd only.
+	return nil
+}
+
 func (l *LiquidOnChain) AddBlindingRandomFactors(claimParams *swap.ClaimParams) (err error) {
 	claimParams.OutputAssetBlindingFactor = generateRandom32Bytes()
 	claimParams.BlindingSeed = generateRandom32Bytes()

swap/actions.go

@@ -18,8 +18,9 @@ import (
 )
 
 const (
-	BitcoinCsv = 1008
-	LiquidCsv  = 60
+	BitcoinCsv    = 1008
+	LiquidCsv     = 60
+	peerswapLabel = "peerswap"
 )
 
 type CheckRequestWrapperAction struct {
@@ -194,6 +195,10 @@ func (s *ClaimSwapTransactionWithPreimageAction) Execute(services *SwapServices,
 			return Event_OnRetry
 		}
 		swap.ClaimTxId = txId
+		err = wallet.LabelTransaction(txId, peerswapLabel)
+		if err != nil {
+			log.Infof("Error labeling trnasaction %v", err)
+		}
 	}
 
 	return Event_ActionSucceeded
@@ -249,6 +254,10 @@ func (c *CreateAndBroadcastOpeningTransaction) Execute(services *SwapServices, s
 		// todo: idempotent states
 		return swap.HandleError(err)
 	}
+	err = wallet.LabelTransaction(txId, peerswapLabel)
+	if err != nil {
+		log.Infof("Error labeling trnasaction %v", err)
+	}
 	startingHeight, err := txWatcher.GetBlockHeight()
 	if err != nil {
 		return swap.HandleError(err)
@@ -437,6 +446,10 @@ func (c *ClaimSwapTransactionWithCsv) Execute(services *SwapServices, swap *Swap
 			return Event_OnRetry
 		}
 		swap.ClaimTxId = txId
+		err = wallet.LabelTransaction(txId, peerswapLabel)
+		if err != nil {
+			log.Infof("Error labeling trnasaction %v", err)
+		}
 	}
 
 	return Event_ActionSucceeded
@@ -463,6 +476,10 @@ func (c *ClaimSwapTransactionCoop) Execute(services *SwapServices, swap *SwapDat
 			return swap.HandleError(err)
 		}
 		swap.ClaimTxId = txId
+		err = wallet.LabelTransaction(txId, peerswapLabel)
+		if err != nil {
+			log.Infof("Error labeling trnasaction %v", err)
+		}
 	}
 
 	return Event_ActionSucceeded

swap/services.go

@@ -74,6 +74,7 @@ type Wallet interface {
 	CreatePreimageSpendingTransaction(swapParams *OpeningParams, claimParams *ClaimParams) (string, string, error)
 	CreateCsvSpendingTransaction(swapParams *OpeningParams, claimParams *ClaimParams) (txId, txHex string, error error)
 	CreateCoopSpendingTransaction(swapParams *OpeningParams, claimParams *ClaimParams, takerSigner Signer) (txId, txHex string, error error)
+	LabelTransaction(txId, label string) error
 	GetOutputScript(params *OpeningParams) ([]byte, error)
 	NewAddress() (string, error)
 	GetRefundFee() (uint64, error)

swap/swap_out_sender_test.go

@@ -458,6 +458,10 @@ func (d *dummyChain) AddWaitForConfirmationTx(swapId, txId string, vout, startin
 
 }
 
+func (d *dummyChain) LabelTransaction(txId, label string) error {
+	return nil
+}
+
 func (d *dummyChain) AddWaitForCsvTx(swapId, txId string, vout uint32, startingHeight uint32, wantscript []byte) {
 
 }