package discovery import ( "time" "github.com/btcsuite/btcd/chaincfg/chainhash" "github.com/lightningnetwork/lnd/channeldb" "github.com/lightningnetwork/lnd/lnwire" "github.com/lightningnetwork/lnd/netann" "github.com/lightningnetwork/lnd/routing/route" ) // ChannelGraphTimeSeries is an interface that provides time and block based // querying into our view of the channel graph. New channels will have // monotonically increasing block heights, and new channel updates will have // increasing timestamps. Once we connect to a peer, we'll use the methods in // this interface to determine if we're already in sync, or need to request // some new information from them. type ChannelGraphTimeSeries interface { // HighestChanID should return the channel ID of the channel we know of // that's furthest in the target chain. This channel will have a block // height that's close to the current tip of the main chain as we // know it. We'll use this to start our QueryChannelRange dance with // the remote node. HighestChanID(chain chainhash.Hash) (*lnwire.ShortChannelID, error) // UpdatesInHorizon returns all known channel and node updates with an // update timestamp between the start time and end time. We'll use this // to catch up a remote node to the set of channel updates that they // may have missed out on within the target chain. UpdatesInHorizon(chain chainhash.Hash, startTime time.Time, endTime time.Time) ([]lnwire.Message, error) // FilterKnownChanIDs takes a target chain, and a set of channel ID's, // and returns a filtered set of chan ID's. This filtered set of chan // ID's represents the ID's that we don't know of which were in the // passed superSet. FilterKnownChanIDs(chain chainhash.Hash, superSet []lnwire.ShortChannelID) ([]lnwire.ShortChannelID, error) // FilterChannelRange returns the set of channels that we created // between the start height and the end height. We'll use this to to a // remote peer's QueryChannelRange message. FilterChannelRange(chain chainhash.Hash, startHeight, endHeight uint32) ([]lnwire.ShortChannelID, error) // FetchChanAnns returns a full set of channel announcements as well as // their updates that match the set of specified short channel ID's. // We'll use this to reply to a QueryShortChanIDs message sent by a // remote peer. The response will contain a unique set of // ChannelAnnouncements, the latest ChannelUpdate for each of the // announcements, and a unique set of NodeAnnouncements. FetchChanAnns(chain chainhash.Hash, shortChanIDs []lnwire.ShortChannelID) ([]lnwire.Message, error) // FetchChanUpdates returns the latest channel update messages for the // specified short channel ID. If no channel updates are known for the // channel, then an empty slice will be returned. FetchChanUpdates(chain chainhash.Hash, shortChanID lnwire.ShortChannelID) ([]*lnwire.ChannelUpdate, error) } // ChanSeries is an implementation of the ChannelGraphTimeSeries // interface backed by the channeldb ChannelGraph database. We'll provide this // implementation to the AuthenticatedGossiper so it can properly use the // in-protocol channel range queries to quickly and efficiently synchronize our // channel state with all peers. type ChanSeries struct { graph *channeldb.ChannelGraph } // NewChanSeries constructs a new ChanSeries backed by a channeldb.ChannelGraph. // The returned ChanSeries implements the ChannelGraphTimeSeries interface. func NewChanSeries(graph *channeldb.ChannelGraph) *ChanSeries { return &ChanSeries{ graph: graph, } } // HighestChanID should return is the channel ID of the channel we know of // that's furthest in the target chain. This channel will have a block height // that's close to the current tip of the main chain as we know it. We'll use // this to start our QueryChannelRange dance with the remote node. // // NOTE: This is part of the ChannelGraphTimeSeries interface. func (c *ChanSeries) HighestChanID(chain chainhash.Hash) (*lnwire.ShortChannelID, error) { chanID, err := c.graph.HighestChanID() if err != nil { return nil, err } shortChanID := lnwire.NewShortChanIDFromInt(chanID) return &shortChanID, nil } // UpdatesInHorizon returns all known channel and node updates with an update // timestamp between the start time and end time. We'll use this to catch up a // remote node to the set of channel updates that they may have missed out on // within the target chain. // // NOTE: This is part of the ChannelGraphTimeSeries interface. func (c *ChanSeries) UpdatesInHorizon(chain chainhash.Hash, startTime time.Time, endTime time.Time) ([]lnwire.Message, error) { var updates []lnwire.Message // First, we'll query for all the set of channels that have an update // that falls within the specified horizon. chansInHorizon, err := c.graph.ChanUpdatesInHorizon( startTime, endTime, ) if err != nil { return nil, err } for _, channel := range chansInHorizon { // If the channel hasn't been fully advertised yet, or is a // private channel, then we'll skip it as we can't construct a // full authentication proof if one is requested. if channel.Info.AuthProof == nil { continue } chanAnn, edge1, edge2, err := netann.CreateChanAnnouncement( channel.Info.AuthProof, channel.Info, channel.Policy1, channel.Policy2, ) if err != nil { return nil, err } updates = append(updates, chanAnn) if edge1 != nil { updates = append(updates, edge1) } if edge2 != nil { updates = append(updates, edge2) } } // Next, we'll send out all the node announcements that have an update // within the horizon as well. We send these second to ensure that they // follow any active channels they have. nodeAnnsInHorizon, err := c.graph.NodeUpdatesInHorizon( startTime, endTime, ) if err != nil { return nil, err } for _, nodeAnn := range nodeAnnsInHorizon { // Ensure we only forward nodes that are publicly advertised to // prevent leaking information about nodes. isNodePublic, err := c.graph.IsPublicNode(nodeAnn.PubKeyBytes) if err != nil { log.Errorf("Unable to determine if node %x is "+ "advertised: %v", nodeAnn.PubKeyBytes, err) continue } if !isNodePublic { log.Tracef("Skipping forwarding announcement for "+ "node %x due to being unadvertised", nodeAnn.PubKeyBytes) continue } nodeUpdate, err := nodeAnn.NodeAnnouncement(true) if err != nil { return nil, err } updates = append(updates, nodeUpdate) } return updates, nil } // FilterKnownChanIDs takes a target chain, and a set of channel ID's, and // returns a filtered set of chan ID's. This filtered set of chan ID's // represents the ID's that we don't know of which were in the passed superSet. // // NOTE: This is part of the ChannelGraphTimeSeries interface. func (c *ChanSeries) FilterKnownChanIDs(chain chainhash.Hash, superSet []lnwire.ShortChannelID) ([]lnwire.ShortChannelID, error) { chanIDs := make([]uint64, 0, len(superSet)) for _, chanID := range superSet { chanIDs = append(chanIDs, chanID.ToUint64()) } newChanIDs, err := c.graph.FilterKnownChanIDs(chanIDs) if err != nil { return nil, err } filteredIDs := make([]lnwire.ShortChannelID, 0, len(newChanIDs)) for _, chanID := range newChanIDs { filteredIDs = append( filteredIDs, lnwire.NewShortChanIDFromInt(chanID), ) } return filteredIDs, nil } // FilterChannelRange returns the set of channels that we created between the // start height and the end height. We'll use this respond to a remote peer's // QueryChannelRange message. // // NOTE: This is part of the ChannelGraphTimeSeries interface. func (c *ChanSeries) FilterChannelRange(chain chainhash.Hash, startHeight, endHeight uint32) ([]lnwire.ShortChannelID, error) { chansInRange, err := c.graph.FilterChannelRange(startHeight, endHeight) if err != nil { return nil, err } chanResp := make([]lnwire.ShortChannelID, 0, len(chansInRange)) for _, chanID := range chansInRange { chanResp = append( chanResp, lnwire.NewShortChanIDFromInt(chanID), ) } return chanResp, nil } // FetchChanAnns returns a full set of channel announcements as well as their // updates that match the set of specified short channel ID's. We'll use this // to reply to a QueryShortChanIDs message sent by a remote peer. The response // will contain a unique set of ChannelAnnouncements, the latest ChannelUpdate // for each of the announcements, and a unique set of NodeAnnouncements. // // NOTE: This is part of the ChannelGraphTimeSeries interface. func (c *ChanSeries) FetchChanAnns(chain chainhash.Hash, shortChanIDs []lnwire.ShortChannelID) ([]lnwire.Message, error) { chanIDs := make([]uint64, 0, len(shortChanIDs)) for _, chanID := range shortChanIDs { chanIDs = append(chanIDs, chanID.ToUint64()) } channels, err := c.graph.FetchChanInfos(chanIDs) if err != nil { return nil, err } // We'll use this map to ensure we don't send the same node // announcement more than one time as one node may have many channel // anns we'll need to send. nodePubsSent := make(map[route.Vertex]struct{}) chanAnns := make([]lnwire.Message, 0, len(channels)*3) for _, channel := range channels { // If the channel doesn't have an authentication proof, then we // won't send it over as it may not yet be finalized, or be a // non-advertised channel. if channel.Info.AuthProof == nil { continue } chanAnn, edge1, edge2, err := netann.CreateChanAnnouncement( channel.Info.AuthProof, channel.Info, channel.Policy1, channel.Policy2, ) if err != nil { return nil, err } chanAnns = append(chanAnns, chanAnn) if edge1 != nil { chanAnns = append(chanAnns, edge1) // If this edge has a validated node announcement, that // we haven't yet sent, then we'll send that as well. nodePub := channel.Policy1.Node.PubKeyBytes hasNodeAnn := channel.Policy1.Node.HaveNodeAnnouncement if _, ok := nodePubsSent[nodePub]; !ok && hasNodeAnn { nodeAnn, err := channel.Policy1.Node.NodeAnnouncement(true) if err != nil { return nil, err } chanAnns = append(chanAnns, nodeAnn) nodePubsSent[nodePub] = struct{}{} } } if edge2 != nil { chanAnns = append(chanAnns, edge2) // If this edge has a validated node announcement, that // we haven't yet sent, then we'll send that as well. nodePub := channel.Policy2.Node.PubKeyBytes hasNodeAnn := channel.Policy2.Node.HaveNodeAnnouncement if _, ok := nodePubsSent[nodePub]; !ok && hasNodeAnn { nodeAnn, err := channel.Policy2.Node.NodeAnnouncement(true) if err != nil { return nil, err } chanAnns = append(chanAnns, nodeAnn) nodePubsSent[nodePub] = struct{}{} } } } return chanAnns, nil } // FetchChanUpdates returns the latest channel update messages for the // specified short channel ID. If no channel updates are known for the channel, // then an empty slice will be returned. // // NOTE: This is part of the ChannelGraphTimeSeries interface. func (c *ChanSeries) FetchChanUpdates(chain chainhash.Hash, shortChanID lnwire.ShortChannelID) ([]*lnwire.ChannelUpdate, error) { chanInfo, e1, e2, err := c.graph.FetchChannelEdgesByID( shortChanID.ToUint64(), ) if err != nil { return nil, err } chanUpdates := make([]*lnwire.ChannelUpdate, 0, 2) if e1 != nil { chanUpdate, err := netann.ChannelUpdateFromEdge(chanInfo, e1) if err != nil { return nil, err } chanUpdates = append(chanUpdates, chanUpdate) } if e2 != nil { chanUpdate, err := netann.ChannelUpdateFromEdge(chanInfo, e2) if err != nil { return nil, err } chanUpdates = append(chanUpdates, chanUpdate) } return chanUpdates, nil } // A compile-time assertion to ensure that ChanSeries meets the // ChannelGraphTimeSeries interface. var _ ChannelGraphTimeSeries = (*ChanSeries)(nil)