multi: thread new config values through client

client.go

@@ -79,8 +79,8 @@ type Client struct {
 
 // NewClient returns a new instance to initiate swaps with.
 func NewClient(dbDir string, serverAddress string, insecure bool,
-	tlsPathServer string, lnd *lndclient.LndServices) (*Client, func(),
-	error) {
+	tlsPathServer string, lnd *lndclient.LndServices, maxLSATCost,
+	maxLSATFee btcutil.Amount) (*Client, func(), error) {
 
 	store, err := loopdb.NewBoltSwapStore(dbDir, lnd.ChainParams)
 	if err != nil {
@@ -93,6 +93,7 @@ func NewClient(dbDir string, serverAddress string, insecure bool,
 
 	swapServerClient, err := newSwapServerClient(
 		serverAddress, insecure, tlsPathServer, lsatStore, lnd,
+		maxLSATCost, maxLSATFee,
 	)
 	if err != nil {
 		return nil, nil, err

loopd/daemon.go

@@ -56,10 +56,7 @@ func daemon(config *config, lisCfg *listenerCfg) error {
 	log.Infof("Swap server address: %v", config.SwapServer)
 
 	// Create an instance of the loop client library.
-	swapClient, cleanup, err := getClient(
-		config.Network, config.SwapServer, config.Insecure,
-		config.TLSPathSwapSrv, &lnd.LndServices,
-	)
+	swapClient, cleanup, err := getClient(config, &lnd.LndServices)
 	if err != nil {
 		return err
 	}

loopd/utils.go

@@ -4,21 +4,24 @@ import (
 	"os"
 	"path/filepath"
 
+	"github.com/btcsuite/btcutil"
 	"github.com/lightninglabs/loop"
 	"github.com/lightninglabs/loop/lndclient"
 )
 
 // getClient returns an instance of the swap client.
-func getClient(network, swapServer string, insecure bool, tlsPathServer string,
-	lnd *lndclient.LndServices) (*loop.Client, func(), error) {
+func getClient(config *config, lnd *lndclient.LndServices) (*loop.Client,
+	func(), error) {
 
-	storeDir, err := getStoreDir(network)
+	storeDir, err := getStoreDir(config.Network)
 	if err != nil {
 		return nil, nil, err
 	}
 
 	swapClient, cleanUp, err := loop.NewClient(
-		storeDir, swapServer, insecure, tlsPathServer, lnd,
+		storeDir, config.SwapServer, config.Insecure,
+		config.TLSPathSwapSrv, lnd, btcutil.Amount(config.MaxLSATCost),
+		btcutil.Amount(config.MaxLSATFee),
 	)
 	if err != nil {
 		return nil, nil, err

loopd/view.go

@@ -23,10 +23,7 @@ func view(config *config, lisCfg *listenerCfg) error {
 	}
 	defer lnd.Close()
 
-	swapClient, cleanup, err := getClient(
-		config.Network, config.SwapServer, config.Insecure,
-		config.TLSPathSwapSrv, &lnd.LndServices,
-	)
+	swapClient, cleanup, err := getClient(config, &lnd.LndServices)
 	if err != nil {
 		return err
 	}

lsat/interceptor.go

@@ -8,6 +8,7 @@ import (
 	"sync"
 	"time"
 
+	"github.com/btcsuite/btcutil"
 	"github.com/lightninglabs/loop/lndclient"
 	"github.com/lightningnetwork/lnd/lnrpc/routerrpc"
 	"github.com/lightningnetwork/lnd/lnwire"
@@ -67,6 +68,8 @@ type Interceptor struct {
 	lnd         *lndclient.LndServices
 	store       Store
 	callTimeout time.Duration
+	maxCost     btcutil.Amount
+	maxFee      btcutil.Amount
 	lock        sync.Mutex
 }
 
@@ -74,12 +77,15 @@ type Interceptor struct {
 // lnd connection to automatically acquire and pay for LSAT tokens, unless the
 // indicated store already contains a usable token.
 func NewInterceptor(lnd *lndclient.LndServices, store Store,
-	rpcCallTimeout time.Duration) *Interceptor {
+	rpcCallTimeout time.Duration, maxCost,
+	maxFee btcutil.Amount) *Interceptor {
 
 	return &Interceptor{
 		lnd:         lnd,
 		store:       store,
 		callTimeout: rpcCallTimeout,
+		maxCost:     maxCost,
+		maxFee:      maxFee,
 	}
 }
 
@@ -226,6 +232,14 @@ func (i *Interceptor) payLsatToken(ctx context.Context, md *metadata.MD) (
 		return nil, fmt.Errorf("unable to decode invoice: %v", err)
 	}
 
+	// Check that the charged amount does not exceed our maximum cost.
+	maxCostMsat := lnwire.NewMSatFromSatoshis(i.maxCost)
+	if invoice.MilliSat != nil && *invoice.MilliSat > maxCostMsat {
+		return nil, fmt.Errorf("cannot pay for LSAT automatically, "+
+			"cost of %d msat exceeds configured max cost of %d "+
+			"msat", *invoice.MilliSat, maxCostMsat)
+	}
+
 	// Create and store the pending token so we can resume the payment in
 	// case the payment is interrupted somehow.
 	token, err := tokenFromChallenge(macBytes, invoice.PaymentHash)
@@ -242,7 +256,7 @@ func (i *Interceptor) payLsatToken(ctx context.Context, md *metadata.MD) (
 	payCtx, cancel := context.WithTimeout(ctx, PaymentTimeout)
 	defer cancel()
 	respChan := i.lnd.Client.PayInvoice(
-		payCtx, invoiceStr, DefaultMaxRoutingFeeSats, nil,
+		payCtx, invoiceStr, i.maxFee, nil,
 	)
 	select {
 	case result := <-respChan:

swap_server_client.go

@@ -52,13 +52,13 @@ type grpcSwapServerClient struct {
 var _ swapServerClient = (*grpcSwapServerClient)(nil)
 
 func newSwapServerClient(address string, insecure bool, tlsPath string,
-	lsatStore lsat.Store, lnd *lndclient.LndServices) (
-	*grpcSwapServerClient, error) {
+	lsatStore lsat.Store, lnd *lndclient.LndServices,
+	maxLSATCost, maxLSATFee btcutil.Amount) (*grpcSwapServerClient, error) {
 
 	// Create the server connection with the interceptor that will handle
 	// the LSAT protocol for us.
 	clientInterceptor := lsat.NewInterceptor(
-		lnd, lsatStore, serverRPCTimeout,
+		lnd, lsatStore, serverRPCTimeout, maxLSATCost, maxLSATFee,
 	)
 	serverConn, err := getSwapServerConn(
 		address, insecure, tlsPath, clientInterceptor,