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.

Need to check with integration test,
but LND needs to be upgraded to use GetTransaction RPC,
To do so, it is necessary to upgrade the LND version.
Therefore, this will be handled separately.

ElementsProject#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 +208,18 @@ 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})
+	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) {
 
 }