package feature import ( "fmt" "github.com/lightningnetwork/lnd/lnwire" ) // Config houses any runtime modifications to the default set descriptors. For // our purposes, this typically means disabling certain features to test legacy // protocol interoperability or functionality. type Config struct { // NoTLVOnion unsets any optional or required TLVOnionPaylod bits from // all feature sets. NoTLVOnion bool // NoStaticRemoteKey unsets any optional or required StaticRemoteKey // bits from all feature sets. NoStaticRemoteKey bool // NoAnchors unsets any bits signaling support for anchor outputs. NoAnchors bool } // Manager is responsible for generating feature vectors for different requested // feature sets. type Manager struct { // fsets is a static map of feature set to raw feature vectors. Requests // are fulfilled by cloning these interal feature vectors. fsets map[Set]*lnwire.RawFeatureVector } // NewManager creates a new feature Manager, applying any custom modifications // to its feature sets before returning. func NewManager(cfg Config) (*Manager, error) { return newManager(cfg, defaultSetDesc) } // newManager creates a new feeature Manager, applying any custom modifications // to its feature sets before returning. This method accepts the setDesc as its // own parameter so that it can be unit tested. func newManager(cfg Config, desc setDesc) (*Manager, error) { // First build the default feature vector for all known sets. fsets := make(map[Set]*lnwire.RawFeatureVector) for bit, sets := range desc { for set := range sets { // Fetch the feature vector for this set, allocating a // new one if it doesn't exist. fv, ok := fsets[set] if !ok { fv = lnwire.NewRawFeatureVector() } // Set the configured bit on the feature vector, // ensuring that we don't set two feature bits for the // same pair. err := fv.SafeSet(bit) if err != nil { return nil, fmt.Errorf("unable to set "+ "%v in %v: %v", bit, set, err) } // Write the updated feature vector under its set. fsets[set] = fv } } // Now, remove any features as directed by the config. for set, raw := range fsets { if cfg.NoTLVOnion { raw.Unset(lnwire.TLVOnionPayloadOptional) raw.Unset(lnwire.TLVOnionPayloadRequired) raw.Unset(lnwire.PaymentAddrOptional) raw.Unset(lnwire.PaymentAddrRequired) raw.Unset(lnwire.MPPOptional) raw.Unset(lnwire.MPPRequired) } if cfg.NoStaticRemoteKey { raw.Unset(lnwire.StaticRemoteKeyOptional) raw.Unset(lnwire.StaticRemoteKeyRequired) } if cfg.NoAnchors { raw.Unset(lnwire.AnchorsOptional) raw.Unset(lnwire.AnchorsRequired) } // Ensure that all of our feature sets properly set any // dependent features. fv := lnwire.NewFeatureVector(raw, lnwire.Features) err := ValidateDeps(fv) if err != nil { return nil, fmt.Errorf("invalid feature set %v: %v", set, err) } } return &Manager{ fsets: fsets, }, nil } // GetRaw returns a raw feature vector for the passed set. If no set is known, // an empty raw feature vector is returned. func (m *Manager) GetRaw(set Set) *lnwire.RawFeatureVector { if fv, ok := m.fsets[set]; ok { return fv.Clone() } return lnwire.NewRawFeatureVector() } // Get returns a feature vector for the passed set. If no set is known, an empty // feature vector is returned. func (m *Manager) Get(set Set) *lnwire.FeatureVector { raw := m.GetRaw(set) return lnwire.NewFeatureVector(raw, lnwire.Features) } // ListSets returns a list of the feature sets that our node supports. func (m *Manager) ListSets() []Set { var sets []Set for set := range m.fsets { sets = append(sets, set) } return sets }