staticaddr: configurable max htlc tx fee

Author: hieblmi

client.go

@@ -131,6 +131,22 @@ type ClientConfig struct {
 	// MaxPaymentRetries is the maximum times we retry an off-chain payment
 	// (used in loop out).
 	MaxPaymentRetries int
+
+	// MaxStaticAddrHtlcFeePercentage is the percentage of the swap amount
+	// that we allow the server to charge for the htlc transaction.
+	// Although highly unlikely, this is a defense against the server
+	// publishing the htlc without paying the swap invoice, forcing us to
+	// sweep the timeout path.
+	MaxStaticAddrHtlcFeePercentage float64
+
+	// MaxStaticAddrHtlcBackupFeePercentage is the percentage of the swap
+	// amount that we allow the server to charge for the htlc backup
+	// transactions. This is a defense against the server publishing the
+	// htlc backup without paying the swap invoice, forcing us to sweep the
+	// timeout path. This value is elevated compared to
+	// MaxStaticAddrHtlcFeePercentage since it serves the server as backup
+	// transaction in case of fee spikes.
+	MaxStaticAddrHtlcBackupFeePercentage float64
 }
 
 // NewClient returns a new instance to initiate swaps with.

loopd/config.go

@@ -42,11 +42,13 @@ var (
 		LoopDirBase, DefaultNetwork, defaultSqliteDatabaseFileName,
 	)
 
-	defaultMaxLogFiles         = 3
-	defaultMaxLogFileSize      = 10
-	defaultLoopOutMaxParts     = uint32(5)
-	defaultTotalPaymentTimeout = time.Minute * 60
-	defaultMaxPaymentRetries   = 3
+	defaultMaxLogFiles                          = 3
+	defaultMaxLogFileSize                       = 10
+	defaultLoopOutMaxParts                      = uint32(5)
+	defaultTotalPaymentTimeout                  = time.Minute * 60
+	defaultMaxPaymentRetries                    = 3
+	defaultMaxStaticAddrHtlcFeePercentage       = 0.2
+	defaultMaxStaticAddrHtlcBackupFeePercentage = 0.5
 
 	// defaultRPCBatchSize is the default batch size to use for RPC calls
 	// we make to LND during migrations. If operations on the LND side are
@@ -183,6 +185,9 @@ type Config struct {
 	TotalPaymentTimeout time.Duration `long:"totalpaymenttimeout" description:"The timeout to use for off-chain payments."`
 	MaxPaymentRetries   int           `long:"maxpaymentretries" description:"The maximum number of times an off-chain payment may be retried."`
 
+	MaxStaticAddrHtlcFeePercentage       float64 `long:"maxstaticaddrhtlcfeepercentage" description:"The maximum fee percentage that the server can charge for the htlc tx."`
+	MaxStaticAddrHtlcBackupFeePercentage float64 `long:"maxstaticaddrhtlcbackupfeepercentage" description:"The maximum fee percentage that the server can charge for the htlc backup tx."`
+
 	EnableExperimental bool `long:"experimental" description:"Enable experimental features: reservations"`
 
 	MigrationRPCBatchSize int `long:"migrationrpcbatchsize" description:"The RPC batch size to use during migrations."`
@@ -215,21 +220,23 @@ func DefaultConfig() Config {
 		Sqlite: &loopdb.SqliteConfig{
 			DatabaseFileName: defaultSqliteDatabasePath,
 		},
-		LogDir:                defaultLogDir,
-		MaxLogFiles:           defaultMaxLogFiles,
-		MaxLogFileSize:        defaultMaxLogFileSize,
-		DebugLevel:            defaultLogLevel,
-		TLSCertPath:           DefaultTLSCertPath,
-		TLSKeyPath:            DefaultTLSKeyPath,
-		TLSValidity:           DefaultAutogenValidity,
-		MacaroonPath:          DefaultMacaroonPath,
-		MaxL402Cost:           l402.DefaultMaxCostSats,
-		MaxL402Fee:            l402.DefaultMaxRoutingFeeSats,
-		LoopOutMaxParts:       defaultLoopOutMaxParts,
-		TotalPaymentTimeout:   defaultTotalPaymentTimeout,
-		MaxPaymentRetries:     defaultMaxPaymentRetries,
-		EnableExperimental:    false,
-		MigrationRPCBatchSize: defaultRPCBatchSize,
+		LogDir:                               defaultLogDir,
+		MaxLogFiles:                          defaultMaxLogFiles,
+		MaxLogFileSize:                       defaultMaxLogFileSize,
+		DebugLevel:                           defaultLogLevel,
+		TLSCertPath:                          DefaultTLSCertPath,
+		TLSKeyPath:                           DefaultTLSKeyPath,
+		TLSValidity:                          DefaultAutogenValidity,
+		MacaroonPath:                         DefaultMacaroonPath,
+		MaxL402Cost:                          l402.DefaultMaxCostSats,
+		MaxL402Fee:                           l402.DefaultMaxRoutingFeeSats,
+		LoopOutMaxParts:                      defaultLoopOutMaxParts,
+		TotalPaymentTimeout:                  defaultTotalPaymentTimeout,
+		MaxPaymentRetries:                    defaultMaxPaymentRetries,
+		MaxStaticAddrHtlcFeePercentage:       defaultMaxStaticAddrHtlcFeePercentage,
+		MaxStaticAddrHtlcBackupFeePercentage: defaultMaxStaticAddrHtlcBackupFeePercentage,
+		EnableExperimental:                   false,
+		MigrationRPCBatchSize:                defaultRPCBatchSize,
 		Lnd: &lndConfig{
 			Host:         "localhost:10009",
 			MacaroonPath: DefaultLndMacaroonPath,

loopd/utils.go

@@ -40,16 +40,18 @@ func getClient(cfg *Config, swapDb loopdb.SwapStore,
 	}
 
 	clientConfig := &loop.ClientConfig{
-		ServerAddress:       cfg.Server.Host,
-		ProxyAddress:        cfg.Server.Proxy,
-		SwapServerNoTLS:     cfg.Server.NoTLS,
-		TLSPathServer:       cfg.Server.TLSPath,
-		Lnd:                 lnd,
-		MaxL402Cost:         btcutil.Amount(cfg.MaxL402Cost),
-		MaxL402Fee:          btcutil.Amount(cfg.MaxL402Fee),
-		LoopOutMaxParts:     cfg.LoopOutMaxParts,
-		TotalPaymentTimeout: cfg.TotalPaymentTimeout,
-		MaxPaymentRetries:   cfg.MaxPaymentRetries,
+		ServerAddress:                        cfg.Server.Host,
+		ProxyAddress:                         cfg.Server.Proxy,
+		SwapServerNoTLS:                      cfg.Server.NoTLS,
+		TLSPathServer:                        cfg.Server.TLSPath,
+		Lnd:                                  lnd,
+		MaxL402Cost:                          btcutil.Amount(cfg.MaxL402Cost),
+		MaxL402Fee:                           btcutil.Amount(cfg.MaxL402Fee),
+		LoopOutMaxParts:                      cfg.LoopOutMaxParts,
+		TotalPaymentTimeout:                  cfg.TotalPaymentTimeout,
+		MaxPaymentRetries:                    cfg.MaxPaymentRetries,
+		MaxStaticAddrHtlcFeePercentage:       cfg.MaxStaticAddrHtlcFeePercentage,
+		MaxStaticAddrHtlcBackupFeePercentage: cfg.MaxStaticAddrHtlcBackupFeePercentage,
 	}
 
 	if cfg.MaxL402Cost == defaultCost && cfg.MaxLSATCost != 0 {