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.

#254

clightning/clightning_wallet.go

@@ -199,6 +199,11 @@ func (cl *ClightningClient) CreateCoopSpendingTransaction(swapParams *swap.Openi
 	return spendingTx.TxHash().String(), txHex, nil
 }
 
+func (cl *ClightningClient) LabelTransaction(txId, label string) error {
+	// todo implement
+	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 +208,19 @@ func (l *Client) CreateCoopSpendingTransaction(swapParams *swap.OpeningParams, c
 	return spendingTx.TxHash().String(), txHex, nil
 }
 
+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 +254,11 @@ func (b *BitcoinOnChain) PrepareSpendingTransaction(swapParams *swap.OpeningPara
 	return spendingTx, sigHash, redeemScript, nil
 }
 
+func (b *BitcoinOnChain) LabelTransaction(txID, label string) error {
+	// TODO: implement label transaction
+	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 +220,11 @@ func (l *LiquidOnChain) CreateCoopSpendingTransaction(swapParams *swap.OpeningPa
 	return txId, txHex, nil
 }
 
+func (l *LiquidOnChain) LabelTransaction(txID, label string) error {
+	// TODO: implement label transaction
+	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 +195,11 @@ 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_OnRetry
+		}
 	}
 
 	return Event_ActionSucceeded
@@ -249,6 +255,10 @@ func (c *CreateAndBroadcastOpeningTransaction) Execute(services *SwapServices, s
 		// todo: idempotent states
 		return swap.HandleError(err)
 	}
+	err = wallet.LabelTransaction(txId, peerswapLabel)
+	if err != nil {
+		return swap.HandleError(err)
+	}
 	startingHeight, err := txWatcher.GetBlockHeight()
 	if err != nil {
 		return swap.HandleError(err)
@@ -437,6 +447,11 @@ func (c *ClaimSwapTransactionWithCsv) Execute(services *SwapServices, swap *Swap
 			return Event_OnRetry
 		}
 		swap.ClaimTxId = txId
+		err = wallet.LabelTransaction(txId, peerswapLabel)
+		if err != nil {
+			swap.HandleError(err)
+			return Event_OnRetry
+		}
 	}
 
 	return Event_ActionSucceeded
@@ -463,6 +478,10 @@ func (c *ClaimSwapTransactionCoop) Execute(services *SwapServices, swap *SwapDat
 			return swap.HandleError(err)
 		}
 		swap.ClaimTxId = txId
+		err = wallet.LabelTransaction(txId, peerswapLabel)
+		if err != nil {
+			return swap.HandleError(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) {
 
 }