package routing import ( "github.com/lightningnetwork/lnd/channeldb" "github.com/lightningnetwork/lnd/channeldb/kvdb" "github.com/lightningnetwork/lnd/lnwire" "github.com/lightningnetwork/lnd/routing/route" ) // routingGraph is an abstract interface that provides information about nodes // and edges to pathfinding. type routingGraph interface { // forEachNodeChannel calls the callback for every channel of the given node. forEachNodeChannel(nodePub route.Vertex, cb func(*channeldb.ChannelEdgeInfo, *channeldb.ChannelEdgePolicy, *channeldb.ChannelEdgePolicy) error) error // sourceNode returns the source node of the graph. sourceNode() route.Vertex // fetchNodeFeatures returns the features of the given node. fetchNodeFeatures(nodePub route.Vertex) (*lnwire.FeatureVector, error) } // dbRoutingTx is a routingGraph implementation that retrieves from the // database. type dbRoutingTx struct { graph *channeldb.ChannelGraph tx kvdb.ReadTx source route.Vertex } // newDbRoutingTx instantiates a new db-connected routing graph. It implictly // instantiates a new read transaction. func newDbRoutingTx(graph *channeldb.ChannelGraph) (*dbRoutingTx, error) { sourceNode, err := graph.SourceNode() if err != nil { return nil, err } tx, err := graph.Database().BeginReadTx() if err != nil { return nil, err } return &dbRoutingTx{ graph: graph, tx: tx, source: sourceNode.PubKeyBytes, }, nil } // close closes the underlying db transaction. func (g *dbRoutingTx) close() error { return g.tx.Rollback() } // forEachNodeChannel calls the callback for every channel of the given node. // // NOTE: Part of the routingGraph interface. func (g *dbRoutingTx) forEachNodeChannel(nodePub route.Vertex, cb func(*channeldb.ChannelEdgeInfo, *channeldb.ChannelEdgePolicy, *channeldb.ChannelEdgePolicy) error) error { txCb := func(_ kvdb.ReadTx, info *channeldb.ChannelEdgeInfo, p1, p2 *channeldb.ChannelEdgePolicy) error { return cb(info, p1, p2) } return g.graph.ForEachNodeChannel(g.tx, nodePub[:], txCb) } // sourceNode returns the source node of the graph. // // NOTE: Part of the routingGraph interface. func (g *dbRoutingTx) sourceNode() route.Vertex { return g.source } // fetchNodeFeatures returns the features of the given node. If the node is // unknown, assume no additional features are supported. // // NOTE: Part of the routingGraph interface. func (g *dbRoutingTx) fetchNodeFeatures(nodePub route.Vertex) ( *lnwire.FeatureVector, error) { targetNode, err := g.graph.FetchLightningNode(g.tx, nodePub) switch err { // If the node exists and has features, return them directly. case nil: return targetNode.Features, nil // If we couldn't find a node announcement, populate a blank feature // vector. case channeldb.ErrGraphNodeNotFound: return lnwire.EmptyFeatureVector(), nil // Otherwise bubble the error up. default: return nil, err } }