package channeldb import ( "bytes" "crypto/sha256" "encoding/binary" "fmt" "image/color" "io" "math" "net" "time" "github.com/btcsuite/btcd/btcec" "github.com/btcsuite/btcd/chaincfg/chainhash" "github.com/btcsuite/btcd/txscript" "github.com/btcsuite/btcd/wire" "github.com/btcsuite/btcutil" "github.com/coreos/bbolt" "github.com/lightningnetwork/lnd/lnwire" ) var ( // nodeBucket is a bucket which houses all the vertices or nodes within // the channel graph. This bucket has a single-sub bucket which adds an // additional index from pubkey -> alias. Within the top-level of this // bucket, the key space maps a node's compressed public key to the // serialized information for that node. Additionally, there's a // special key "source" which stores the pubkey of the source node. The // source node is used as the starting point for all graph/queries and // traversals. The graph is formed as a star-graph with the source node // at the center. // // maps: pubKey -> nodeInfo // maps: source -> selfPubKey nodeBucket = []byte("graph-node") // nodeUpdateIndexBucket is a sub-bucket of the nodeBucket. This bucket // will be used to quickly look up the "freshness" of a node's last // update to the network. The bucket only contains keys, and no values, // it's mapping: // // maps: updateTime || nodeID -> nil nodeUpdateIndexBucket = []byte("graph-node-update-index") // sourceKey is a special key that resides within the nodeBucket. The // sourceKey maps a key to the public key of the "self node". sourceKey = []byte("source") // aliasIndexBucket is a sub-bucket that's nested within the main // nodeBucket. This bucket maps the public key of a node to its // current alias. This bucket is provided as it can be used within a // future UI layer to add an additional degree of confirmation. aliasIndexBucket = []byte("alias") // edgeBucket is a bucket which houses all of the edge or channel // information within the channel graph. This bucket essentially acts // as an adjacency list, which in conjunction with a range scan, can be // used to iterate over all the incoming and outgoing edges for a // particular node. Key in the bucket use a prefix scheme which leads // with the node's public key and sends with the compact edge ID. // For each chanID, there will be two entries within the bucket, as the // graph is directed: nodes may have different policies w.r.t to fees // for their respective directions. // // maps: pubKey || chanID -> channel edge policy for node edgeBucket = []byte("graph-edge") // unknownPolicy is represented as an empty slice. It is // used as the value in edgeBucket for unknown channel edge policies. // Unknown policies are still stored in the database to enable efficient // lookup of incoming channel edges. unknownPolicy = []byte{} // chanStart is an array of all zero bytes which is used to perform // range scans within the edgeBucket to obtain all of the outgoing // edges for a particular node. chanStart [8]byte // edgeIndexBucket is an index which can be used to iterate all edges // in the bucket, grouping them according to their in/out nodes. // Additionally, the items in this bucket also contain the complete // edge information for a channel. The edge information includes the // capacity of the channel, the nodes that made the channel, etc. This // bucket resides within the edgeBucket above. Creation of an edge // proceeds in two phases: first the edge is added to the edge index, // afterwards the edgeBucket can be updated with the latest details of // the edge as they are announced on the network. // // maps: chanID -> pubKey1 || pubKey2 || restofEdgeInfo edgeIndexBucket = []byte("edge-index") // edgeUpdateIndexBucket is a sub-bucket of the main edgeBucket. This // bucket contains an index which allows us to gauge the "freshness" of // a channel's last updates. // // maps: updateTime || chanID -> nil edgeUpdateIndexBucket = []byte("edge-update-index") // channelPointBucket maps a channel's full outpoint (txid:index) to // its short 8-byte channel ID. This bucket resides within the // edgeBucket above, and can be used to quickly remove an edge due to // the outpoint being spent, or to query for existence of a channel. // // maps: outPoint -> chanID channelPointBucket = []byte("chan-index") // graphMetaBucket is a top-level bucket which stores various meta-deta // related to the on-disk channel graph. Data stored in this bucket // includes the block to which the graph has been synced to, the total // number of channels, etc. graphMetaBucket = []byte("graph-meta") // pruneLogBucket is a bucket within the graphMetaBucket that stores // a mapping from the block height to the hash for the blocks used to // prune the graph. // Once a new block is discovered, any channels that have been closed // (by spending the outpoint) can safely be removed from the graph, and // the block is added to the prune log. We need to keep such a log for // the case where a reorg happens, and we must "rewind" the state of the // graph by removing channels that were previously confirmed. In such a // case we'll remove all entries from the prune log with a block height // that no longer exists. pruneLogBucket = []byte("prune-log") edgeBloomKey = []byte("edge-bloom") nodeBloomKey = []byte("node-bloom") ) const ( // MaxAllowedExtraOpaqueBytes is the largest amount of opaque bytes that // we'll permit to be written to disk. We limit this as otherwise, it // would be possible for a node to create a ton of updates and slowly // fill our disk, and also waste bandwidth due to relaying. MaxAllowedExtraOpaqueBytes = 10000 ) // ChannelGraph is a persistent, on-disk graph representation of the Lightning // Network. This struct can be used to implement path finding algorithms on top // of, and also to update a node's view based on information received from the // p2p network. Internally, the graph is stored using a modified adjacency list // representation with some added object interaction possible with each // serialized edge/node. The graph is stored is directed, meaning that are two // edges stored for each channel: an inbound/outbound edge for each node pair. // Nodes, edges, and edge information can all be added to the graph // independently. Edge removal results in the deletion of all edge information // for that edge. type ChannelGraph struct { db *DB // TODO(roasbeef): store and update bloom filter to reduce disk access // due to current gossip model // * LRU cache for edges? } // Database returns a pointer to the underlying database. func (c *ChannelGraph) Database() *DB { return c.db } // ForEachChannel iterates through all the channel edges stored within the // graph and invokes the passed callback for each edge. The callback takes two // edges as since this is a directed graph, both the in/out edges are visited. // If the callback returns an error, then the transaction is aborted and the // iteration stops early. // // NOTE: If an edge can't be found, or wasn't advertised, then a nil pointer // for that particular channel edge routing policy will be passed into the // callback. func (c *ChannelGraph) ForEachChannel(cb func(*ChannelEdgeInfo, *ChannelEdgePolicy, *ChannelEdgePolicy) error) error { // TODO(roasbeef): ptr map to reduce # of allocs? no duplicates return c.db.View(func(tx *bolt.Tx) error { // First, grab the node bucket. This will be used to populate // the Node pointers in each edge read from disk. nodes := tx.Bucket(nodeBucket) if nodes == nil { return ErrGraphNotFound } // Next, grab the edge bucket which stores the edges, and also // the index itself so we can group the directed edges together // logically. edges := tx.Bucket(edgeBucket) if edges == nil { return ErrGraphNoEdgesFound } edgeIndex := edges.Bucket(edgeIndexBucket) if edgeIndex == nil { return ErrGraphNoEdgesFound } // For each edge pair within the edge index, we fetch each edge // itself and also the node information in order to fully // populated the object. return edgeIndex.ForEach(func(chanID, edgeInfoBytes []byte) error { infoReader := bytes.NewReader(edgeInfoBytes) edgeInfo, err := deserializeChanEdgeInfo(infoReader) if err != nil { return err } edgeInfo.db = c.db edge1, edge2, err := fetchChanEdgePolicies( edgeIndex, edges, nodes, chanID, c.db, ) if err != nil { return err } // With both edges read, execute the call back. IF this // function returns an error then the transaction will // be aborted. return cb(&edgeInfo, edge1, edge2) }) }) } // ForEachNode iterates through all the stored vertices/nodes in the graph, // executing the passed callback with each node encountered. If the callback // returns an error, then the transaction is aborted and the iteration stops // early. // // If the caller wishes to re-use an existing boltdb transaction, then it // should be passed as the first argument. Otherwise the first argument should // be nil and a fresh transaction will be created to execute the graph // traversal // // TODO(roasbeef): add iterator interface to allow for memory efficient graph // traversal when graph gets mega func (c *ChannelGraph) ForEachNode(tx *bolt.Tx, cb func(*bolt.Tx, *LightningNode) error) error { traversal := func(tx *bolt.Tx) error { // First grab the nodes bucket which stores the mapping from // pubKey to node information. nodes := tx.Bucket(nodeBucket) if nodes == nil { return ErrGraphNotFound } return nodes.ForEach(func(pubKey, nodeBytes []byte) error { // If this is the source key, then we skip this // iteration as the value for this key is a pubKey // rather than raw node information. if bytes.Equal(pubKey, sourceKey) || len(pubKey) != 33 { return nil } nodeReader := bytes.NewReader(nodeBytes) node, err := deserializeLightningNode(nodeReader) if err != nil { return err } node.db = c.db // Execute the callback, the transaction will abort if // this returns an error. return cb(tx, &node) }) } // If no transaction was provided, then we'll create a new transaction // to execute the transaction within. if tx == nil { return c.db.View(traversal) } // Otherwise, we re-use the existing transaction to execute the graph // traversal. return traversal(tx) } // SourceNode returns the source node of the graph. The source node is treated // as the center node within a star-graph. This method may be used to kick off // a path finding algorithm in order to explore the reachability of another // node based off the source node. func (c *ChannelGraph) SourceNode() (*LightningNode, error) { var source *LightningNode err := c.db.View(func(tx *bolt.Tx) error { node, err := c.sourceNode(tx) if err != nil { return err } source = node return nil }) if err != nil { return nil, err } return source, nil } // sourceNode uses an existing database transaction and returns the source node // of the graph. The source node is treated as the center node within a // star-graph. This method may be used to kick off a path finding algorithm in // order to explore the reachability of another node based off the source node. func (c *ChannelGraph) sourceNode(tx *bolt.Tx) (*LightningNode, error) { // First grab the nodes bucket which stores the mapping from // pubKey to node information. nodes := tx.Bucket(nodeBucket) if nodes == nil { return nil, ErrGraphNotFound } selfPub := nodes.Get(sourceKey) if selfPub == nil { return nil, ErrSourceNodeNotSet } // With the pubKey of the source node retrieved, we're able to // fetch the full node information. node, err := fetchLightningNode(nodes, selfPub) if err != nil { return nil, err } node.db = c.db return &node, nil } // SetSourceNode sets the source node within the graph database. The source // node is to be used as the center of a star-graph within path finding // algorithms. func (c *ChannelGraph) SetSourceNode(node *LightningNode) error { nodePubBytes := node.PubKeyBytes[:] return c.db.Update(func(tx *bolt.Tx) error { // First grab the nodes bucket which stores the mapping from // pubKey to node information. nodes, err := tx.CreateBucketIfNotExists(nodeBucket) if err != nil { return err } // Next we create the mapping from source to the targeted // public key. if err := nodes.Put(sourceKey, nodePubBytes); err != nil { return err } // Finally, we commit the information of the lightning node // itself. return addLightningNode(tx, node) }) } // AddLightningNode adds a vertex/node to the graph database. If the node is not // in the database from before, this will add a new, unconnected one to the // graph. If it is present from before, this will update that node's // information. Note that this method is expected to only be called to update // an already present node from a node announcement, or to insert a node found // in a channel update. // // TODO(roasbeef): also need sig of announcement func (c *ChannelGraph) AddLightningNode(node *LightningNode) error { return c.db.Update(func(tx *bolt.Tx) error { return addLightningNode(tx, node) }) } func addLightningNode(tx *bolt.Tx, node *LightningNode) error { nodes, err := tx.CreateBucketIfNotExists(nodeBucket) if err != nil { return err } aliases, err := nodes.CreateBucketIfNotExists(aliasIndexBucket) if err != nil { return err } updateIndex, err := nodes.CreateBucketIfNotExists( nodeUpdateIndexBucket, ) if err != nil { return err } return putLightningNode(nodes, aliases, updateIndex, node) } // LookupAlias attempts to return the alias as advertised by the target node. // TODO(roasbeef): currently assumes that aliases are unique... func (c *ChannelGraph) LookupAlias(pub *btcec.PublicKey) (string, error) { var alias string err := c.db.View(func(tx *bolt.Tx) error { nodes := tx.Bucket(nodeBucket) if nodes == nil { return ErrGraphNodesNotFound } aliases := nodes.Bucket(aliasIndexBucket) if aliases == nil { return ErrGraphNodesNotFound } nodePub := pub.SerializeCompressed() a := aliases.Get(nodePub) if a == nil { return ErrNodeAliasNotFound } // TODO(roasbeef): should actually be using the utf-8 // package... alias = string(a) return nil }) if err != nil { return "", err } return alias, nil } // DeleteLightningNode starts a new database transaction to remove a vertex/node // from the database according to the node's public key. func (c *ChannelGraph) DeleteLightningNode(nodePub *btcec.PublicKey) error { // TODO(roasbeef): ensure dangling edges are removed... return c.db.Update(func(tx *bolt.Tx) error { return c.deleteLightningNode(tx, nodePub.SerializeCompressed()) }) } // deleteLightningNode uses an existing database transaction to remove a // vertex/node from the database according to the node's public key. func (c *ChannelGraph) deleteLightningNode(tx *bolt.Tx, compressedPubKey []byte) error { nodes := tx.Bucket(nodeBucket) if nodes == nil { return ErrGraphNodesNotFound } aliases := nodes.Bucket(aliasIndexBucket) if aliases == nil { return ErrGraphNodesNotFound } if err := aliases.Delete(compressedPubKey); err != nil { return err } // Before we delete the node, we'll fetch its current state so we can // determine when its last update was to clear out the node update // index. node, err := fetchLightningNode(nodes, compressedPubKey) if err != nil { return err } if err := nodes.Delete(compressedPubKey); err != nil { return err } // Finally, we'll delete the index entry for the node within the // nodeUpdateIndexBucket as this node is no longer active, so we don't // need to track its last update. nodeUpdateIndex := nodes.Bucket(nodeUpdateIndexBucket) if nodeUpdateIndex == nil { return ErrGraphNodesNotFound } // In order to delete the entry, we'll need to reconstruct the key for // its last update. updateUnix := uint64(node.LastUpdate.Unix()) var indexKey [8 + 33]byte byteOrder.PutUint64(indexKey[:8], updateUnix) copy(indexKey[8:], compressedPubKey) return nodeUpdateIndex.Delete(indexKey[:]) } // AddChannelEdge adds a new (undirected, blank) edge to the graph database. An // undirected edge from the two target nodes are created. The information // stored denotes the static attributes of the channel, such as the channelID, // the keys involved in creation of the channel, and the set of features that // the channel supports. The chanPoint and chanID are used to uniquely identify // the edge globally within the database. func (c *ChannelGraph) AddChannelEdge(edge *ChannelEdgeInfo) error { // Construct the channel's primary key which is the 8-byte channel ID. var chanKey [8]byte binary.BigEndian.PutUint64(chanKey[:], edge.ChannelID) return c.db.Update(func(tx *bolt.Tx) error { nodes, err := tx.CreateBucketIfNotExists(nodeBucket) if err != nil { return err } edges, err := tx.CreateBucketIfNotExists(edgeBucket) if err != nil { return err } edgeIndex, err := edges.CreateBucketIfNotExists(edgeIndexBucket) if err != nil { return err } chanIndex, err := edges.CreateBucketIfNotExists(channelPointBucket) if err != nil { return err } // First, attempt to check if this edge has already been // created. If so, then we can exit early as this method is // meant to be idempotent. if edgeInfo := edgeIndex.Get(chanKey[:]); edgeInfo != nil { return ErrEdgeAlreadyExist } // Before we insert the channel into the database, we'll ensure // that both nodes already exist in the channel graph. If // either node doesn't, then we'll insert a "shell" node that // just includes its public key, so subsequent validation and // queries can work properly. _, node1Err := fetchLightningNode(nodes, edge.NodeKey1Bytes[:]) switch { case node1Err == ErrGraphNodeNotFound: node1Shell := LightningNode{ PubKeyBytes: edge.NodeKey1Bytes, HaveNodeAnnouncement: false, } err := addLightningNode(tx, &node1Shell) if err != nil { return fmt.Errorf("unable to create shell node "+ "for: %x", edge.NodeKey1Bytes) } case node1Err != nil: return err } _, node2Err := fetchLightningNode(nodes, edge.NodeKey2Bytes[:]) switch { case node2Err == ErrGraphNodeNotFound: node2Shell := LightningNode{ PubKeyBytes: edge.NodeKey2Bytes, HaveNodeAnnouncement: false, } err := addLightningNode(tx, &node2Shell) if err != nil { return fmt.Errorf("unable to create shell node "+ "for: %x", edge.NodeKey2Bytes) } case node2Err != nil: return err } // If the edge hasn't been created yet, then we'll first add it // to the edge index in order to associate the edge between two // nodes and also store the static components of the channel. if err := putChanEdgeInfo(edgeIndex, edge, chanKey); err != nil { return err } // Mark edge policies for both sides as unknown. This is to // enable efficient incoming channel lookup for a node. for _, key := range []*[33]byte{&edge.NodeKey1Bytes, &edge.NodeKey2Bytes} { err := putChanEdgePolicyUnknown(edges, edge.ChannelID, key[:]) if err != nil { return err } } // Finally we add it to the channel index which maps channel // points (outpoints) to the shorter channel ID's. var b bytes.Buffer if err := writeOutpoint(&b, &edge.ChannelPoint); err != nil { return err } return chanIndex.Put(b.Bytes(), chanKey[:]) }) } // HasChannelEdge returns true if the database knows of a channel edge with the // passed channel ID, and false otherwise. If an edge with that ID is found // within the graph, then two time stamps representing the last time the edge // was updated for both directed edges are returned along with the boolean. func (c *ChannelGraph) HasChannelEdge(chanID uint64) (time.Time, time.Time, bool, error) { // TODO(roasbeef): check internal bloom filter first var ( node1UpdateTime time.Time node2UpdateTime time.Time exists bool ) if err := c.db.View(func(tx *bolt.Tx) error { edges := tx.Bucket(edgeBucket) if edges == nil { return ErrGraphNoEdgesFound } edgeIndex := edges.Bucket(edgeIndexBucket) if edgeIndex == nil { return ErrGraphNoEdgesFound } var channelID [8]byte byteOrder.PutUint64(channelID[:], chanID) if edgeIndex.Get(channelID[:]) == nil { exists = false return nil } exists = true // If the channel has been found in the graph, then retrieve // the edges itself so we can return the last updated // timestamps. nodes := tx.Bucket(nodeBucket) if nodes == nil { return ErrGraphNodeNotFound } e1, e2, err := fetchChanEdgePolicies(edgeIndex, edges, nodes, channelID[:], c.db) if err != nil { return err } // As we may have only one of the edges populated, only set the // update time if the edge was found in the database. if e1 != nil { node1UpdateTime = e1.LastUpdate } if e2 != nil { node2UpdateTime = e2.LastUpdate } return nil }); err != nil { return time.Time{}, time.Time{}, exists, err } return node1UpdateTime, node2UpdateTime, exists, nil } // UpdateChannelEdge retrieves and update edge of the graph database. Method // only reserved for updating an edge info after its already been created. // In order to maintain this constraints, we return an error in the scenario // that an edge info hasn't yet been created yet, but someone attempts to update // it. func (c *ChannelGraph) UpdateChannelEdge(edge *ChannelEdgeInfo) error { // Construct the channel's primary key which is the 8-byte channel ID. var chanKey [8]byte binary.BigEndian.PutUint64(chanKey[:], edge.ChannelID) return c.db.Update(func(tx *bolt.Tx) error { edges, err := tx.CreateBucketIfNotExists(edgeBucket) if err != nil { return err } edgeIndex, err := edges.CreateBucketIfNotExists(edgeIndexBucket) if err != nil { return err } if edgeInfo := edgeIndex.Get(chanKey[:]); edgeInfo == nil { return ErrEdgeNotFound } return putChanEdgeInfo(edgeIndex, edge, chanKey) }) } const ( // pruneTipBytes is the total size of the value which stores a prune // entry of the graph in the prune log. The "prune tip" is the last // entry in the prune log, and indicates if the channel graph is in // sync with the current UTXO state. The structure of the value // is: blockHash, taking 32 bytes total. pruneTipBytes = 32 ) // PruneGraph prunes newly closed channels from the channel graph in response // to a new block being solved on the network. Any transactions which spend the // funding output of any known channels within he graph will be deleted. // Additionally, the "prune tip", or the last block which has been used to // prune the graph is stored so callers can ensure the graph is fully in sync // with the current UTXO state. A slice of channels that have been closed by // the target block are returned if the function succeeds without error. func (c *ChannelGraph) PruneGraph(spentOutputs []*wire.OutPoint, blockHash *chainhash.Hash, blockHeight uint32) ([]*ChannelEdgeInfo, error) { var chansClosed []*ChannelEdgeInfo err := c.db.Update(func(tx *bolt.Tx) error { // First grab the edges bucket which houses the information // we'd like to delete edges, err := tx.CreateBucketIfNotExists(edgeBucket) if err != nil { return err } // Next grab the two edge indexes which will also need to be updated. edgeIndex, err := edges.CreateBucketIfNotExists(edgeIndexBucket) if err != nil { return err } chanIndex, err := edges.CreateBucketIfNotExists(channelPointBucket) if err != nil { return err } nodes, err := tx.CreateBucketIfNotExists(nodeBucket) if err != nil { return err } // For each of the outpoints that have been spent within the // block, we attempt to delete them from the graph as if that // outpoint was a channel, then it has now been closed. for _, chanPoint := range spentOutputs { // TODO(roasbeef): load channel bloom filter, continue // if NOT if filter var opBytes bytes.Buffer if err := writeOutpoint(&opBytes, chanPoint); err != nil { return nil } // First attempt to see if the channel exists within // the database, if not, then we can exit early. chanID := chanIndex.Get(opBytes.Bytes()) if chanID == nil { continue } // However, if it does, then we'll read out the full // version so we can add it to the set of deleted // channels. edgeInfo, err := fetchChanEdgeInfo(edgeIndex, chanID) if err != nil { return err } // Attempt to delete the channel, an ErrEdgeNotFound // will be returned if that outpoint isn't known to be // a channel. If no error is returned, then a channel // was successfully pruned. err = delChannelByEdge( edges, edgeIndex, chanIndex, nodes, chanPoint, ) if err != nil && err != ErrEdgeNotFound { return err } chansClosed = append(chansClosed, &edgeInfo) } metaBucket, err := tx.CreateBucketIfNotExists(graphMetaBucket) if err != nil { return err } pruneBucket, err := metaBucket.CreateBucketIfNotExists(pruneLogBucket) if err != nil { return err } // With the graph pruned, add a new entry to the prune log, // which can be used to check if the graph is fully synced with // the current UTXO state. var blockHeightBytes [4]byte byteOrder.PutUint32(blockHeightBytes[:], blockHeight) var newTip [pruneTipBytes]byte copy(newTip[:], blockHash[:]) err = pruneBucket.Put(blockHeightBytes[:], newTip[:]) if err != nil { return err } // Now that the graph has been pruned, we'll also attempt to // prune any nodes that have had a channel closed within the // latest block. return c.pruneGraphNodes(tx, nodes, edgeIndex) }) if err != nil { return nil, err } return chansClosed, nil } // PruneGraphNodes is a garbage collection method which attempts to prune out // any nodes from the channel graph that are currently unconnected. This ensure // that we only maintain a graph of reachable nodes. In the event that a pruned // node gains more channels, it will be re-added back to the graph. func (c *ChannelGraph) PruneGraphNodes() error { return c.db.Update(func(tx *bolt.Tx) error { nodes, err := tx.CreateBucketIfNotExists(nodeBucket) if err != nil { return err } edges := tx.Bucket(edgeBucket) if edges == nil { return ErrGraphNotFound } edgeIndex := edges.Bucket(edgeIndexBucket) if edgeIndex == nil { return ErrGraphNoEdgesFound } return c.pruneGraphNodes(tx, nodes, edgeIndex) }) } // pruneGraphNodes attempts to remove any nodes from the graph who have had a // channel closed within the current block. If the node still has existing // channels in the graph, this will act as a no-op. func (c *ChannelGraph) pruneGraphNodes(tx *bolt.Tx, nodes *bolt.Bucket, edgeIndex *bolt.Bucket) error { log.Trace("Pruning nodes from graph with no open channels") // We'll retrieve the graph's source node to ensure we don't remove it // even if it no longer has any open channels. sourceNode, err := c.sourceNode(tx) if err != nil { return err } // We'll use this map to keep count the number of references to a node // in the graph. A node should only be removed once it has no more // references in the graph. nodeRefCounts := make(map[[33]byte]int) err = nodes.ForEach(func(pubKey, nodeBytes []byte) error { // If this is the source key, then we skip this // iteration as the value for this key is a pubKey // rather than raw node information. if bytes.Equal(pubKey, sourceKey) || len(pubKey) != 33 { return nil } var nodePub [33]byte copy(nodePub[:], pubKey) nodeRefCounts[nodePub] = 0 return nil }) if err != nil { return err } // To ensure we never delete the source node, we'll start off by // bumping its ref count to 1. nodeRefCounts[sourceNode.PubKeyBytes] = 1 // Next, we'll run through the edgeIndex which maps a channel ID to the // edge info. We'll use this scan to populate our reference count map // above. err = edgeIndex.ForEach(func(chanID, edgeInfoBytes []byte) error { // The first 66 bytes of the edge info contain the pubkeys of // the nodes that this edge attaches. We'll extract them, and // add them to the ref count map. var node1, node2 [33]byte copy(node1[:], edgeInfoBytes[:33]) copy(node2[:], edgeInfoBytes[33:]) // With the nodes extracted, we'll increase the ref count of // each of the nodes. nodeRefCounts[node1]++ nodeRefCounts[node2]++ return nil }) if err != nil { return err } // Finally, we'll make a second pass over the set of nodes, and delete // any nodes that have a ref count of zero. var numNodesPruned int for nodePubKey, refCount := range nodeRefCounts { // If the ref count of the node isn't zero, then we can safely // skip it as it still has edges to or from it within the // graph. if refCount != 0 { continue } // If we reach this point, then there are no longer any edges // that connect this node, so we can delete it. if err := c.deleteLightningNode(tx, nodePubKey[:]); err != nil { log.Warnf("Unable to prune node %x from the "+ "graph: %v", nodePubKey, err) continue } log.Infof("Pruned unconnected node %x from channel graph", nodePubKey[:]) numNodesPruned++ } if numNodesPruned > 0 { log.Infof("Pruned %v unconnected nodes from the channel graph", numNodesPruned) } return nil } // DisconnectBlockAtHeight is used to indicate that the block specified // by the passed height has been disconnected from the main chain. This // will "rewind" the graph back to the height below, deleting channels // that are no longer confirmed from the graph. The prune log will be // set to the last prune height valid for the remaining chain. // Channels that were removed from the graph resulting from the // disconnected block are returned. func (c *ChannelGraph) DisconnectBlockAtHeight(height uint32) ([]*ChannelEdgeInfo, error) { // Every channel having a ShortChannelID starting at 'height' // will no longer be confirmed. startShortChanID := lnwire.ShortChannelID{ BlockHeight: height, } // Delete everything after this height from the db. endShortChanID := lnwire.ShortChannelID{ BlockHeight: math.MaxUint32 & 0x00ffffff, TxIndex: math.MaxUint32 & 0x00ffffff, TxPosition: math.MaxUint16, } // The block height will be the 3 first bytes of the channel IDs. var chanIDStart [8]byte byteOrder.PutUint64(chanIDStart[:], startShortChanID.ToUint64()) var chanIDEnd [8]byte byteOrder.PutUint64(chanIDEnd[:], endShortChanID.ToUint64()) // Keep track of the channels that are removed from the graph. var removedChans []*ChannelEdgeInfo if err := c.db.Update(func(tx *bolt.Tx) error { edges, err := tx.CreateBucketIfNotExists(edgeBucket) if err != nil { return err } edgeIndex, err := edges.CreateBucketIfNotExists(edgeIndexBucket) if err != nil { return err } chanIndex, err := edges.CreateBucketIfNotExists(channelPointBucket) if err != nil { return err } nodes, err := tx.CreateBucketIfNotExists(nodeBucket) if err != nil { return err } // Scan from chanIDStart to chanIDEnd, deleting every // found edge. cursor := edgeIndex.Cursor() for k, v := cursor.Seek(chanIDStart[:]); k != nil && bytes.Compare(k, chanIDEnd[:]) <= 0; k, v = cursor.Next() { edgeInfoReader := bytes.NewReader(v) edgeInfo, err := deserializeChanEdgeInfo(edgeInfoReader) if err != nil { return err } err = delChannelByEdge( edges, edgeIndex, chanIndex, nodes, &edgeInfo.ChannelPoint, ) if err != nil && err != ErrEdgeNotFound { return err } removedChans = append(removedChans, &edgeInfo) } // Delete all the entries in the prune log having a height // greater or equal to the block disconnected. metaBucket, err := tx.CreateBucketIfNotExists(graphMetaBucket) if err != nil { return err } pruneBucket, err := metaBucket.CreateBucketIfNotExists(pruneLogBucket) if err != nil { return err } var pruneKeyStart [4]byte byteOrder.PutUint32(pruneKeyStart[:], height) var pruneKeyEnd [4]byte byteOrder.PutUint32(pruneKeyEnd[:], math.MaxUint32) pruneCursor := pruneBucket.Cursor() for k, _ := pruneCursor.Seek(pruneKeyStart[:]); k != nil && bytes.Compare(k, pruneKeyEnd[:]) <= 0; k, _ = pruneCursor.Next() { if err := pruneCursor.Delete(); err != nil { return err } } return nil }); err != nil { return nil, err } return removedChans, nil } // PruneTip returns the block height and hash of the latest block that has been // used to prune channels in the graph. Knowing the "prune tip" allows callers // to tell if the graph is currently in sync with the current best known UTXO // state. func (c *ChannelGraph) PruneTip() (*chainhash.Hash, uint32, error) { var ( tipHash chainhash.Hash tipHeight uint32 ) err := c.db.View(func(tx *bolt.Tx) error { graphMeta := tx.Bucket(graphMetaBucket) if graphMeta == nil { return ErrGraphNotFound } pruneBucket := graphMeta.Bucket(pruneLogBucket) if pruneBucket == nil { return ErrGraphNeverPruned } pruneCursor := pruneBucket.Cursor() // The prune key with the largest block height will be our // prune tip. k, v := pruneCursor.Last() if k == nil { return ErrGraphNeverPruned } // Once we have the prune tip, the value will be the block hash, // and the key the block height. copy(tipHash[:], v[:]) tipHeight = byteOrder.Uint32(k[:]) return nil }) if err != nil { return nil, 0, err } return &tipHash, tipHeight, nil } // DeleteChannelEdge removes an edge from the database as identified by its // funding outpoint. If the edge does not exist within the database, then // ErrEdgeNotFound will be returned. func (c *ChannelGraph) DeleteChannelEdge(chanPoint *wire.OutPoint) error { // TODO(roasbeef): possibly delete from node bucket if node has no more // channels // TODO(roasbeef): don't delete both edges? return c.db.Update(func(tx *bolt.Tx) error { // First grab the edges bucket which houses the information // we'd like to delete edges, err := tx.CreateBucketIfNotExists(edgeBucket) if err != nil { return err } // Next grab the two edge indexes which will also need to be updated. edgeIndex, err := edges.CreateBucketIfNotExists(edgeIndexBucket) if err != nil { return err } chanIndex, err := edges.CreateBucketIfNotExists(channelPointBucket) if err != nil { return err } nodes, err := tx.CreateBucketIfNotExists(nodeBucket) if err != nil { return err } return delChannelByEdge(edges, edgeIndex, chanIndex, nodes, chanPoint) }) } // ChannelID attempt to lookup the 8-byte compact channel ID which maps to the // passed channel point (outpoint). If the passed channel doesn't exist within // the database, then ErrEdgeNotFound is returned. func (c *ChannelGraph) ChannelID(chanPoint *wire.OutPoint) (uint64, error) { var chanID uint64 var b bytes.Buffer if err := writeOutpoint(&b, chanPoint); err != nil { return 0, nil } if err := c.db.View(func(tx *bolt.Tx) error { edges := tx.Bucket(edgeBucket) if edges == nil { return ErrGraphNoEdgesFound } chanIndex := edges.Bucket(channelPointBucket) if chanIndex == nil { return ErrGraphNoEdgesFound } chanIDBytes := chanIndex.Get(b.Bytes()) if chanIDBytes == nil { return ErrEdgeNotFound } chanID = byteOrder.Uint64(chanIDBytes) return nil }); err != nil { return 0, err } return chanID, nil } // TODO(roasbeef): allow updates to use Batch? // HighestChanID returns the "highest" known channel ID in the channel graph. // This represents the "newest" channel from the PoV of the chain. This method // can be used by peers to quickly determine if they're graphs are in sync. func (c *ChannelGraph) HighestChanID() (uint64, error) { var cid uint64 err := c.db.View(func(tx *bolt.Tx) error { edges := tx.Bucket(edgeBucket) if edges == nil { return ErrGraphNoEdgesFound } edgeIndex := edges.Bucket(edgeIndexBucket) if edgeIndex == nil { return ErrGraphNoEdgesFound } // In order to find the highest chan ID, we'll fetch a cursor // and use that to seek to the "end" of our known rage. cidCursor := edgeIndex.Cursor() lastChanID, _ := cidCursor.Last() // If there's no key, then this means that we don't actually // know of any channels, so we'll return a predicable error. if lastChanID == nil { return ErrGraphNoEdgesFound } // Otherwise, we'll de serialize the channel ID and return it // to the caller. cid = byteOrder.Uint64(lastChanID) return nil }) if err != nil && err != ErrGraphNoEdgesFound { return 0, err } return cid, nil } // ChannelEdge represents the complete set of information for a channel edge in // the known channel graph. This struct couples the core information of the // edge as well as each of the known advertised edge policies. type ChannelEdge struct { // Info contains all the static information describing the channel. Info *ChannelEdgeInfo // Policy1 points to the "first" edge policy of the channel containing // the dynamic information required to properly route through the edge. Policy1 *ChannelEdgePolicy // Policy2 points to the "second" edge policy of the channel containing // the dynamic information required to properly route through the edge. Policy2 *ChannelEdgePolicy } // ChanUpdatesInHorizon returns all the known channel edges which have at least // one edge that has an update timestamp within the specified horizon. func (c *ChannelGraph) ChanUpdatesInHorizon(startTime, endTime time.Time) ([]ChannelEdge, error) { // To ensure we don't return duplicate ChannelEdges, we'll use an // additional map to keep track of the edges already seen to prevent // re-adding it. edgesSeen := make(map[uint64]struct{}) var edgesInHorizon []ChannelEdge err := c.db.View(func(tx *bolt.Tx) error { edges := tx.Bucket(edgeBucket) if edges == nil { return ErrGraphNoEdgesFound } edgeIndex := edges.Bucket(edgeIndexBucket) if edgeIndex == nil { return ErrGraphNoEdgesFound } edgeUpdateIndex := edges.Bucket(edgeUpdateIndexBucket) if edgeUpdateIndex == nil { return ErrGraphNoEdgesFound } nodes := tx.Bucket(nodeBucket) if nodes == nil { return ErrGraphNodesNotFound } // We'll now obtain a cursor to perform a range query within // the index to find all channels within the horizon. updateCursor := edgeUpdateIndex.Cursor() var startTimeBytes, endTimeBytes [8 + 8]byte byteOrder.PutUint64( startTimeBytes[:8], uint64(startTime.Unix()), ) byteOrder.PutUint64( endTimeBytes[:8], uint64(endTime.Unix()), ) // With our start and end times constructed, we'll step through // the index collecting the info and policy of each update of // each channel that has a last update within the time range. for indexKey, _ := updateCursor.Seek(startTimeBytes[:]); indexKey != nil && bytes.Compare(indexKey, endTimeBytes[:]) <= 0; indexKey, _ = updateCursor.Next() { // We have a new eligible entry, so we'll slice of the // chan ID so we can query it in the DB. chanID := indexKey[8:] // If we've already retrieved the info and policies for // this edge, then we can skip it as we don't need to do // so again. chanIDInt := byteOrder.Uint64(chanID) if _, ok := edgesSeen[chanIDInt]; ok { continue } // First, we'll fetch the static edge information. edgeInfo, err := fetchChanEdgeInfo(edgeIndex, chanID) if err != nil { chanID := byteOrder.Uint64(chanID) return fmt.Errorf("unable to fetch info for "+ "edge with chan_id=%v: %v", chanID, err) } edgeInfo.db = c.db // With the static information obtained, we'll now // fetch the dynamic policy info. edge1, edge2, err := fetchChanEdgePolicies( edgeIndex, edges, nodes, chanID, c.db, ) if err != nil { chanID := byteOrder.Uint64(chanID) return fmt.Errorf("unable to fetch policies "+ "for edge with chan_id=%v: %v", chanID, err) } // Finally, we'll collate this edge with the rest of // edges to be returned. edgesSeen[chanIDInt] = struct{}{} edgesInHorizon = append(edgesInHorizon, ChannelEdge{ Info: &edgeInfo, Policy1: edge1, Policy2: edge2, }) } return nil }) switch { case err == ErrGraphNoEdgesFound: fallthrough case err == ErrGraphNodesNotFound: break case err != nil: return nil, err } return edgesInHorizon, nil } // NodeUpdatesInHorizon returns all the known lightning node which have an // update timestamp within the passed range. This method can be used by two // nodes to quickly determine if they have the same set of up to date node // announcements. func (c *ChannelGraph) NodeUpdatesInHorizon(startTime, endTime time.Time) ([]LightningNode, error) { var nodesInHorizon []LightningNode err := c.db.View(func(tx *bolt.Tx) error { nodes := tx.Bucket(nodeBucket) if nodes == nil { return ErrGraphNodesNotFound } nodeUpdateIndex := nodes.Bucket(nodeUpdateIndexBucket) if nodeUpdateIndex == nil { return ErrGraphNodesNotFound } // We'll now obtain a cursor to perform a range query within // the index to find all node announcements within the horizon. updateCursor := nodeUpdateIndex.Cursor() var startTimeBytes, endTimeBytes [8 + 33]byte byteOrder.PutUint64( startTimeBytes[:8], uint64(startTime.Unix()), ) byteOrder.PutUint64( endTimeBytes[:8], uint64(endTime.Unix()), ) // With our start and end times constructed, we'll step through // the index collecting info for each node within the time // range. for indexKey, _ := updateCursor.Seek(startTimeBytes[:]); indexKey != nil && bytes.Compare(indexKey, endTimeBytes[:]) <= 0; indexKey, _ = updateCursor.Next() { nodePub := indexKey[8:] node, err := fetchLightningNode(nodes, nodePub) if err != nil { return err } node.db = c.db nodesInHorizon = append(nodesInHorizon, node) } return nil }) switch { case err == ErrGraphNoEdgesFound: fallthrough case err == ErrGraphNodesNotFound: break case err != nil: return nil, err } return nodesInHorizon, nil } // FilterKnownChanIDs takes a set of channel IDs and return the subset of chan // ID's that we don't know of in the passed set. In other words, we perform a // set difference of our set of chan ID's and the ones passed in. This method // can be used by callers to determine the set of channels ta peer knows of // that we don't. func (c *ChannelGraph) FilterKnownChanIDs(chanIDs []uint64) ([]uint64, error) { var newChanIDs []uint64 err := c.db.View(func(tx *bolt.Tx) error { edges := tx.Bucket(edgeBucket) if edges == nil { return ErrGraphNoEdgesFound } edgeIndex := edges.Bucket(edgeIndexBucket) if edgeIndex == nil { return ErrGraphNoEdgesFound } // We'll run through the set of chanIDs and collate only the // set of channel that are unable to be found within our db. var cidBytes [8]byte for _, cid := range chanIDs { byteOrder.PutUint64(cidBytes[:], cid) if v := edgeIndex.Get(cidBytes[:]); v == nil { newChanIDs = append(newChanIDs, cid) } } return nil }) switch { // If we don't know of any edges yet, then we'll return the entire set // of chan IDs specified. case err == ErrGraphNoEdgesFound: return chanIDs, nil case err != nil: return nil, err } return newChanIDs, nil } // FilterChannelRange returns the channel ID's of all known channels which were // mined in a block height within the passed range. This method can be used to // quickly share with a peer the set of channels we know of within a particular // range to catch them up after a period of time offline. func (c *ChannelGraph) FilterChannelRange(startHeight, endHeight uint32) ([]uint64, error) { var chanIDs []uint64 startChanID := &lnwire.ShortChannelID{ BlockHeight: startHeight, } endChanID := lnwire.ShortChannelID{ BlockHeight: endHeight, TxIndex: math.MaxUint32 & 0x00ffffff, TxPosition: math.MaxUint16, } // As we need to perform a range scan, we'll convert the starting and // ending height to their corresponding values when encoded using short // channel ID's. var chanIDStart, chanIDEnd [8]byte byteOrder.PutUint64(chanIDStart[:], startChanID.ToUint64()) byteOrder.PutUint64(chanIDEnd[:], endChanID.ToUint64()) err := c.db.View(func(tx *bolt.Tx) error { edges := tx.Bucket(edgeBucket) if edges == nil { return ErrGraphNoEdgesFound } edgeIndex := edges.Bucket(edgeIndexBucket) if edgeIndex == nil { return ErrGraphNoEdgesFound } cursor := edgeIndex.Cursor() // We'll now iterate through the database, and find each // channel ID that resides within the specified range. var cid uint64 for k, _ := cursor.Seek(chanIDStart[:]); k != nil && bytes.Compare(k, chanIDEnd[:]) <= 0; k, _ = cursor.Next() { // This channel ID rests within the target range, so // we'll convert it into an integer and add it to our // returned set. cid = byteOrder.Uint64(k) chanIDs = append(chanIDs, cid) } return nil }) switch { // If we don't know of any channels yet, then there's nothing to // filter, so we'll return an empty slice. case err == ErrGraphNoEdgesFound: return chanIDs, nil case err != nil: return nil, err } return chanIDs, nil } // FetchChanInfos returns the set of channel edges that correspond to the // passed channel ID's. This can be used to respond to peer queries that are // seeking to fill in gaps in their view of the channel graph. func (c *ChannelGraph) FetchChanInfos(chanIDs []uint64) ([]ChannelEdge, error) { // TODO(roasbeef): sort cids? var ( chanEdges []ChannelEdge cidBytes [8]byte ) err := c.db.View(func(tx *bolt.Tx) error { edges := tx.Bucket(edgeBucket) if edges == nil { return ErrGraphNoEdgesFound } edgeIndex := edges.Bucket(edgeIndexBucket) if edgeIndex == nil { return ErrGraphNoEdgesFound } nodes := tx.Bucket(nodeBucket) if nodes == nil { return ErrGraphNotFound } for _, cid := range chanIDs { byteOrder.PutUint64(cidBytes[:], cid) // First, we'll fetch the static edge information. edgeInfo, err := fetchChanEdgeInfo( edgeIndex, cidBytes[:], ) if err != nil { return err } edgeInfo.db = c.db // With the static information obtained, we'll now // fetch the dynamic policy info. edge1, edge2, err := fetchChanEdgePolicies( edgeIndex, edges, nodes, cidBytes[:], c.db, ) if err != nil { return err } chanEdges = append(chanEdges, ChannelEdge{ Info: &edgeInfo, Policy1: edge1, Policy2: edge2, }) } return nil }) if err != nil { return nil, err } return chanEdges, nil } func delEdgeUpdateIndexEntry(edgesBucket *bolt.Bucket, chanID uint64, edge1, edge2 *ChannelEdgePolicy) error { // First, we'll fetch the edge update index bucket which currently // stores an entry for the channel we're about to delete. updateIndex, err := edgesBucket.CreateBucketIfNotExists( edgeUpdateIndexBucket, ) if err != nil { return err } // Now that we have the bucket, we'll attempt to construct a template // for the index key: updateTime || chanid. var indexKey [8 + 8]byte byteOrder.PutUint64(indexKey[8:], chanID) // With the template constructed, we'll attempt to delete an entry that // would have been created by both edges: we'll alternate the update // times, as one may had overridden the other. if edge1 != nil { byteOrder.PutUint64(indexKey[:8], uint64(edge1.LastUpdate.Unix())) if err := updateIndex.Delete(indexKey[:]); err != nil { return err } } // We'll also attempt to delete the entry that may have been created by // the second edge. if edge2 != nil { byteOrder.PutUint64(indexKey[:8], uint64(edge2.LastUpdate.Unix())) if err := updateIndex.Delete(indexKey[:]); err != nil { return err } } return nil } func delChannelByEdge(edges *bolt.Bucket, edgeIndex *bolt.Bucket, chanIndex *bolt.Bucket, nodes *bolt.Bucket, chanPoint *wire.OutPoint) error { var b bytes.Buffer if err := writeOutpoint(&b, chanPoint); err != nil { return err } // If the channel's outpoint doesn't exist within the outpoint index, // then the edge does not exist. chanID := chanIndex.Get(b.Bytes()) if chanID == nil { return ErrEdgeNotFound } // Otherwise we obtain the two public keys from the mapping: chanID -> // pubKey1 || pubKey2. With this, we can construct the keys which house // both of the directed edges for this channel. nodeKeys := edgeIndex.Get(chanID) if nodeKeys == nil { return fmt.Errorf("could not find nodekeys for chanID %v", chanID) } // We'll also remove the entry in the edge update index bucket before // we delete the edges themselves so we can access their last update // times. cid := byteOrder.Uint64(chanID) edge1, edge2, err := fetchChanEdgePolicies( edgeIndex, edges, nodes, chanID, nil, ) if err != nil { return err } err = delEdgeUpdateIndexEntry(edges, cid, edge1, edge2) if err != nil { return err } // The edge key is of the format pubKey || chanID. First we construct // the latter half, populating the channel ID. var edgeKey [33 + 8]byte copy(edgeKey[33:], chanID) // With the latter half constructed, copy over the first public key to // delete the edge in this direction, then the second to delete the // edge in the opposite direction. copy(edgeKey[:33], nodeKeys[:33]) if edges.Get(edgeKey[:]) != nil { if err := edges.Delete(edgeKey[:]); err != nil { return err } } copy(edgeKey[:33], nodeKeys[33:]) if edges.Get(edgeKey[:]) != nil { if err := edges.Delete(edgeKey[:]); err != nil { return err } } // Finally, with the edge data deleted, we can purge the information // from the two edge indexes. if err := edgeIndex.Delete(chanID); err != nil { return err } return chanIndex.Delete(b.Bytes()) } // UpdateEdgePolicy updates the edge routing policy for a single directed edge // within the database for the referenced channel. The `flags` attribute within // the ChannelEdgePolicy determines which of the directed edges are being // updated. If the flag is 1, then the first node's information is being // updated, otherwise it's the second node's information. The node ordering is // determined by the lexicographical ordering of the identity public keys of // the nodes on either side of the channel. func (c *ChannelGraph) UpdateEdgePolicy(edge *ChannelEdgePolicy) error { return c.db.Update(func(tx *bolt.Tx) error { edges, err := tx.CreateBucketIfNotExists(edgeBucket) if err != nil { return err } edgeIndex, err := edges.CreateBucketIfNotExists(edgeIndexBucket) if err != nil { return err } nodes, err := tx.CreateBucketIfNotExists(nodeBucket) if err != nil { return err } return updateEdgePolicy(edges, edgeIndex, nodes, edge) }) } // updateEdgePolicy attempts to update an edge's policy within the relevant // buckets using an existing database transaction. func updateEdgePolicy(edges, edgeIndex, nodes *bolt.Bucket, edge *ChannelEdgePolicy) error { // Create the channelID key be converting the channel ID // integer into a byte slice. var chanID [8]byte byteOrder.PutUint64(chanID[:], edge.ChannelID) // With the channel ID, we then fetch the value storing the two // nodes which connect this channel edge. nodeInfo := edgeIndex.Get(chanID[:]) if nodeInfo == nil { return ErrEdgeNotFound } // Depending on the flags value passed above, either the first // or second edge policy is being updated. var fromNode, toNode []byte if edge.Flags&lnwire.ChanUpdateDirection == 0 { fromNode = nodeInfo[:33] toNode = nodeInfo[33:66] } else { fromNode = nodeInfo[33:66] toNode = nodeInfo[:33] } // Finally, with the direction of the edge being updated // identified, we update the on-disk edge representation. return putChanEdgePolicy(edges, nodes, edge, fromNode, toNode) } // LightningNode represents an individual vertex/node within the channel graph. // A node is connected to other nodes by one or more channel edges emanating // from it. As the graph is directed, a node will also have an incoming edge // attached to it for each outgoing edge. type LightningNode struct { // PubKeyBytes is the raw bytes of the public key of the target node. PubKeyBytes [33]byte pubKey *btcec.PublicKey // HaveNodeAnnouncement indicates whether we received a node // announcement for this particular node. If true, the remaining fields // will be set, if false only the PubKey is known for this node. HaveNodeAnnouncement bool // LastUpdate is the last time the vertex information for this node has // been updated. LastUpdate time.Time // Address is the TCP address this node is reachable over. Addresses []net.Addr // Color is the selected color for the node. Color color.RGBA // Alias is a nick-name for the node. The alias can be used to confirm // a node's identity or to serve as a short ID for an address book. Alias string // AuthSigBytes is the raw signature under the advertised public key // which serves to authenticate the attributes announced by this node. AuthSigBytes []byte // Features is the list of protocol features supported by this node. Features *lnwire.FeatureVector // ExtraOpaqueData is the set of data that was appended to this // message, some of which we may not actually know how to iterate or // parse. By holding onto this data, we ensure that we're able to // properly validate the set of signatures that cover these new fields, // and ensure we're able to make upgrades to the network in a forwards // compatible manner. ExtraOpaqueData []byte db *DB // TODO(roasbeef): discovery will need storage to keep it's last IP // address and re-announce if interface changes? // TODO(roasbeef): add update method and fetch? } // PubKey is the node's long-term identity public key. This key will be used to // authenticated any advertisements/updates sent by the node. // // NOTE: By having this method to access an attribute, we ensure we only need // to fully deserialize the pubkey if absolutely necessary. func (l *LightningNode) PubKey() (*btcec.PublicKey, error) { if l.pubKey != nil { return l.pubKey, nil } key, err := btcec.ParsePubKey(l.PubKeyBytes[:], btcec.S256()) if err != nil { return nil, err } l.pubKey = key l.pubKey.Curve = nil return key, nil } // AuthSig is a signature under the advertised public key which serves to // authenticate the attributes announced by this node. // // NOTE: By having this method to access an attribute, we ensure we only need // to fully deserialize the signature if absolutely necessary. func (l *LightningNode) AuthSig() (*btcec.Signature, error) { return btcec.ParseSignature(l.AuthSigBytes, btcec.S256()) } // AddPubKey is a setter-link method that can be used to swap out the public // key for a node. func (l *LightningNode) AddPubKey(key *btcec.PublicKey) { l.pubKey = key copy(l.PubKeyBytes[:], key.SerializeCompressed()) } // FetchLightningNode attempts to look up a target node by its identity public // key. If the node isn't found in the database, then ErrGraphNodeNotFound is // returned. func (c *ChannelGraph) FetchLightningNode(pub *btcec.PublicKey) (*LightningNode, error) { var node *LightningNode nodePub := pub.SerializeCompressed() err := c.db.View(func(tx *bolt.Tx) error { // First grab the nodes bucket which stores the mapping from // pubKey to node information. nodes := tx.Bucket(nodeBucket) if nodes == nil { return ErrGraphNotFound } // If a key for this serialized public key isn't found, then // the target node doesn't exist within the database. nodeBytes := nodes.Get(nodePub) if nodeBytes == nil { return ErrGraphNodeNotFound } // If the node is found, then we can de deserialize the node // information to return to the user. nodeReader := bytes.NewReader(nodeBytes) n, err := deserializeLightningNode(nodeReader) if err != nil { return err } n.db = c.db node = &n return nil }) if err != nil { return nil, err } return node, nil } // HasLightningNode determines if the graph has a vertex identified by the // target node identity public key. If the node exists in the database, a // timestamp of when the data for the node was lasted updated is returned along // with a true boolean. Otherwise, an empty time.Time is returned with a false // boolean. func (c *ChannelGraph) HasLightningNode(nodePub [33]byte) (time.Time, bool, error) { var ( updateTime time.Time exists bool ) err := c.db.View(func(tx *bolt.Tx) error { // First grab the nodes bucket which stores the mapping from // pubKey to node information. nodes := tx.Bucket(nodeBucket) if nodes == nil { return ErrGraphNotFound } // If a key for this serialized public key isn't found, we can // exit early. nodeBytes := nodes.Get(nodePub[:]) if nodeBytes == nil { exists = false return nil } // Otherwise we continue on to obtain the time stamp // representing the last time the data for this node was // updated. nodeReader := bytes.NewReader(nodeBytes) node, err := deserializeLightningNode(nodeReader) if err != nil { return err } exists = true updateTime = node.LastUpdate return nil }) if err != nil { return time.Time{}, exists, nil } return updateTime, exists, nil } // ForEachChannel iterates through all channels of this node, executing the // passed callback with an edge info structure and the policies of each end // of the channel. The first edge policy is the outgoing edge *to* the // the connecting node, while the second is the incoming edge *from* the // connecting node. If the callback returns an error, then the iteration is // halted with the error propagated back up to the caller. // // Unknown policies are passed into the callback as nil values. // // If the caller wishes to re-use an existing boltdb transaction, then it // should be passed as the first argument. Otherwise the first argument should // be nil and a fresh transaction will be created to execute the graph // traversal. func (l *LightningNode) ForEachChannel(tx *bolt.Tx, cb func(*bolt.Tx, *ChannelEdgeInfo, *ChannelEdgePolicy, *ChannelEdgePolicy) error) error { nodePub := l.PubKeyBytes[:] traversal := func(tx *bolt.Tx) error { nodes := tx.Bucket(nodeBucket) if nodes == nil { return ErrGraphNotFound } edges := tx.Bucket(edgeBucket) if edges == nil { return ErrGraphNotFound } edgeIndex := edges.Bucket(edgeIndexBucket) if edgeIndex == nil { return ErrGraphNoEdgesFound } // In order to reach all the edges for this node, we take // advantage of the construction of the key-space within the // edge bucket. The keys are stored in the form: pubKey || // chanID. Therefore, starting from a chanID of zero, we can // scan forward in the bucket, grabbing all the edges for the // node. Once the prefix no longer matches, then we know we're // done. var nodeStart [33 + 8]byte copy(nodeStart[:], nodePub) copy(nodeStart[33:], chanStart[:]) // Starting from the key pubKey || 0, we seek forward in the // bucket until the retrieved key no longer has the public key // as its prefix. This indicates that we've stepped over into // another node's edges, so we can terminate our scan. edgeCursor := edges.Cursor() for nodeEdge, _ := edgeCursor.Seek(nodeStart[:]); bytes.HasPrefix(nodeEdge, nodePub); nodeEdge, _ = edgeCursor.Next() { // If the prefix still matches, the channel id is // returned in nodeEdge. Channel id is used to lookup // the node at the other end of the channel and both // edge policies. chanID := nodeEdge[33:] edgeInfo, err := fetchChanEdgeInfo(edgeIndex, chanID) if err != nil { return err } edgeInfo.db = l.db outgoingPolicy, err := fetchChanEdgePolicy( edges, chanID, nodePub, nodes, ) if err != nil { return err } otherNode, err := edgeInfo.OtherNodeKeyBytes(nodePub) if err != nil { return err } incomingPolicy, err := fetchChanEdgePolicy( edges, chanID, otherNode, nodes, ) if err != nil { return err } // Finally, we execute the callback. err = cb(tx, &edgeInfo, outgoingPolicy, incomingPolicy) if err != nil { return err } } return nil } // If no transaction was provided, then we'll create a new transaction // to execute the transaction within. if tx == nil { return l.db.View(traversal) } // Otherwise, we re-use the existing transaction to execute the graph // traversal. return traversal(tx) } // ChannelEdgeInfo represents a fully authenticated channel along with all its // unique attributes. Once an authenticated channel announcement has been // processed on the network, then an instance of ChannelEdgeInfo encapsulating // the channels attributes is stored. The other portions relevant to routing // policy of a channel are stored within a ChannelEdgePolicy for each direction // of the channel. type ChannelEdgeInfo struct { // ChannelID is the unique channel ID for the channel. The first 3 // bytes are the block height, the next 3 the index within the block, // and the last 2 bytes are the output index for the channel. ChannelID uint64 // ChainHash is the hash that uniquely identifies the chain that this // channel was opened within. // // TODO(roasbeef): need to modify db keying for multi-chain // * must add chain hash to prefix as well ChainHash chainhash.Hash // NodeKey1Bytes is the raw public key of the first node. NodeKey1Bytes [33]byte nodeKey1 *btcec.PublicKey // NodeKey2Bytes is the raw public key of the first node. NodeKey2Bytes [33]byte nodeKey2 *btcec.PublicKey // BitcoinKey1Bytes is the raw public key of the first node. BitcoinKey1Bytes [33]byte bitcoinKey1 *btcec.PublicKey // BitcoinKey2Bytes is the raw public key of the first node. BitcoinKey2Bytes [33]byte bitcoinKey2 *btcec.PublicKey // Features is an opaque byte slice that encodes the set of channel // specific features that this channel edge supports. Features []byte // AuthProof is the authentication proof for this channel. This proof // contains a set of signatures binding four identities, which attests // to the legitimacy of the advertised channel. AuthProof *ChannelAuthProof // ChannelPoint is the funding outpoint of the channel. This can be // used to uniquely identify the channel within the channel graph. ChannelPoint wire.OutPoint // Capacity is the total capacity of the channel, this is determined by // the value output in the outpoint that created this channel. Capacity btcutil.Amount // ExtraOpaqueData is the set of data that was appended to this // message, some of which we may not actually know how to iterate or // parse. By holding onto this data, we ensure that we're able to // properly validate the set of signatures that cover these new fields, // and ensure we're able to make upgrades to the network in a forwards // compatible manner. ExtraOpaqueData []byte db *DB } // AddNodeKeys is a setter-like method that can be used to replace the set of // keys for the target ChannelEdgeInfo. func (c *ChannelEdgeInfo) AddNodeKeys(nodeKey1, nodeKey2, bitcoinKey1, bitcoinKey2 *btcec.PublicKey) { c.nodeKey1 = nodeKey1 copy(c.NodeKey1Bytes[:], c.nodeKey1.SerializeCompressed()) c.nodeKey2 = nodeKey2 copy(c.NodeKey2Bytes[:], nodeKey2.SerializeCompressed()) c.bitcoinKey1 = bitcoinKey1 copy(c.BitcoinKey1Bytes[:], c.bitcoinKey1.SerializeCompressed()) c.bitcoinKey2 = bitcoinKey2 copy(c.BitcoinKey2Bytes[:], bitcoinKey2.SerializeCompressed()) } // NodeKey1 is the identity public key of the "first" node that was involved in // the creation of this channel. A node is considered "first" if the // lexicographical ordering the its serialized public key is "smaller" than // that of the other node involved in channel creation. // // NOTE: By having this method to access an attribute, we ensure we only need // to fully deserialize the pubkey if absolutely necessary. func (c *ChannelEdgeInfo) NodeKey1() (*btcec.PublicKey, error) { if c.nodeKey1 != nil { return c.nodeKey1, nil } key, err := btcec.ParsePubKey(c.NodeKey1Bytes[:], btcec.S256()) if err != nil { return nil, err } c.nodeKey1 = key return key, nil } // NodeKey2 is the identity public key of the "second" node that was // involved in the creation of this channel. A node is considered // "second" if the lexicographical ordering the its serialized public // key is "larger" than that of the other node involved in channel // creation. // // NOTE: By having this method to access an attribute, we ensure we only need // to fully deserialize the pubkey if absolutely necessary. func (c *ChannelEdgeInfo) NodeKey2() (*btcec.PublicKey, error) { if c.nodeKey2 != nil { return c.nodeKey2, nil } key, err := btcec.ParsePubKey(c.NodeKey2Bytes[:], btcec.S256()) if err != nil { return nil, err } c.nodeKey2 = key return key, nil } // BitcoinKey1 is the Bitcoin multi-sig key belonging to the first // node, that was involved in the funding transaction that originally // created the channel that this struct represents. // // NOTE: By having this method to access an attribute, we ensure we only need // to fully deserialize the pubkey if absolutely necessary. func (c *ChannelEdgeInfo) BitcoinKey1() (*btcec.PublicKey, error) { if c.bitcoinKey1 != nil { return c.bitcoinKey1, nil } key, err := btcec.ParsePubKey(c.BitcoinKey1Bytes[:], btcec.S256()) if err != nil { return nil, err } c.bitcoinKey1 = key return key, nil } // BitcoinKey2 is the Bitcoin multi-sig key belonging to the second // node, that was involved in the funding transaction that originally // created the channel that this struct represents. // // NOTE: By having this method to access an attribute, we ensure we only need // to fully deserialize the pubkey if absolutely necessary. func (c *ChannelEdgeInfo) BitcoinKey2() (*btcec.PublicKey, error) { if c.bitcoinKey2 != nil { return c.bitcoinKey2, nil } key, err := btcec.ParsePubKey(c.BitcoinKey2Bytes[:], btcec.S256()) if err != nil { return nil, err } c.bitcoinKey2 = key return key, nil } // OtherNodeKeyBytes returns the node key bytes of the other end of // the channel. func (c *ChannelEdgeInfo) OtherNodeKeyBytes(thisNodeKey []byte) ( []byte, error) { switch { case bytes.Equal(c.NodeKey1Bytes[:], thisNodeKey): return c.NodeKey2Bytes[:], nil case bytes.Equal(c.NodeKey2Bytes[:], thisNodeKey): return c.NodeKey1Bytes[:], nil default: return nil, fmt.Errorf("node not participating in this channel") } } // FetchOtherNode attempts to fetch the full LightningNode that's opposite of // the target node in the channel. This is useful when one knows the pubkey of // one of the nodes, and wishes to obtain the full LightningNode for the other // end of the channel. func (c *ChannelEdgeInfo) FetchOtherNode(tx *bolt.Tx, thisNodeKey []byte) (*LightningNode, error) { // Ensure that the node passed in is actually a member of the channel. var targetNodeBytes [33]byte switch { case bytes.Equal(c.NodeKey1Bytes[:], thisNodeKey): targetNodeBytes = c.NodeKey2Bytes case bytes.Equal(c.NodeKey2Bytes[:], thisNodeKey): targetNodeBytes = c.NodeKey1Bytes default: return nil, fmt.Errorf("node not participating in this channel") } var targetNode *LightningNode fetchNodeFunc := func(tx *bolt.Tx) error { // First grab the nodes bucket which stores the mapping from // pubKey to node information. nodes := tx.Bucket(nodeBucket) if nodes == nil { return ErrGraphNotFound } node, err := fetchLightningNode(nodes, targetNodeBytes[:]) if err != nil { return err } node.db = c.db targetNode = &node return nil } // If the transaction is nil, then we'll need to create a new one, // otherwise we can use the existing db transaction. var err error if tx == nil { err = c.db.View(fetchNodeFunc) } else { err = fetchNodeFunc(tx) } return targetNode, err } // ChannelAuthProof is the authentication proof (the signature portion) for a // channel. Using the four signatures contained in the struct, and some // auxiliary knowledge (the funding script, node identities, and outpoint) nodes // on the network are able to validate the authenticity and existence of a // channel. Each of these signatures signs the following digest: chanID || // nodeID1 || nodeID2 || bitcoinKey1|| bitcoinKey2 || 2-byte-feature-len || // features. type ChannelAuthProof struct { // nodeSig1 is a cached instance of the first node signature. nodeSig1 *btcec.Signature // NodeSig1Bytes are the raw bytes of the first node signature encoded // in DER format. NodeSig1Bytes []byte // nodeSig2 is a cached instance of the second node signature. nodeSig2 *btcec.Signature // NodeSig2Bytes are the raw bytes of the second node signature // encoded in DER format. NodeSig2Bytes []byte // bitcoinSig1 is a cached instance of the first bitcoin signature. bitcoinSig1 *btcec.Signature // BitcoinSig1Bytes are the raw bytes of the first bitcoin signature // encoded in DER format. BitcoinSig1Bytes []byte // bitcoinSig2 is a cached instance of the second bitcoin signature. bitcoinSig2 *btcec.Signature // BitcoinSig2Bytes are the raw bytes of the second bitcoin signature // encoded in DER format. BitcoinSig2Bytes []byte } // Node1Sig is the signature using the identity key of the node that is first // in a lexicographical ordering of the serialized public keys of the two nodes // that created the channel. // // NOTE: By having this method to access an attribute, we ensure we only need // to fully deserialize the signature if absolutely necessary. func (c *ChannelAuthProof) Node1Sig() (*btcec.Signature, error) { if c.nodeSig1 != nil { return c.nodeSig1, nil } sig, err := btcec.ParseSignature(c.NodeSig1Bytes, btcec.S256()) if err != nil { return nil, err } c.nodeSig1 = sig return sig, nil } // Node2Sig is the signature using the identity key of the node that is second // in a lexicographical ordering of the serialized public keys of the two nodes // that created the channel. // // NOTE: By having this method to access an attribute, we ensure we only need // to fully deserialize the signature if absolutely necessary. func (c *ChannelAuthProof) Node2Sig() (*btcec.Signature, error) { if c.nodeSig2 != nil { return c.nodeSig2, nil } sig, err := btcec.ParseSignature(c.NodeSig2Bytes, btcec.S256()) if err != nil { return nil, err } c.nodeSig2 = sig return sig, nil } // BitcoinSig1 is the signature using the public key of the first node that was // used in the channel's multi-sig output. // // NOTE: By having this method to access an attribute, we ensure we only need // to fully deserialize the signature if absolutely necessary. func (c *ChannelAuthProof) BitcoinSig1() (*btcec.Signature, error) { if c.bitcoinSig1 != nil { return c.bitcoinSig1, nil } sig, err := btcec.ParseSignature(c.BitcoinSig1Bytes, btcec.S256()) if err != nil { return nil, err } c.bitcoinSig1 = sig return sig, nil } // BitcoinSig2 is the signature using the public key of the second node that // was used in the channel's multi-sig output. // // NOTE: By having this method to access an attribute, we ensure we only need // to fully deserialize the signature if absolutely necessary. func (c *ChannelAuthProof) BitcoinSig2() (*btcec.Signature, error) { if c.bitcoinSig2 != nil { return c.bitcoinSig2, nil } sig, err := btcec.ParseSignature(c.BitcoinSig2Bytes, btcec.S256()) if err != nil { return nil, err } c.bitcoinSig2 = sig return sig, nil } // IsEmpty check is the authentication proof is empty Proof is empty if at // least one of the signatures are equal to nil. func (c *ChannelAuthProof) IsEmpty() bool { return len(c.NodeSig1Bytes) == 0 || len(c.NodeSig2Bytes) == 0 || len(c.BitcoinSig1Bytes) == 0 || len(c.BitcoinSig2Bytes) == 0 } // ChannelEdgePolicy represents a *directed* edge within the channel graph. For // each channel in the database, there are two distinct edges: one for each // possible direction of travel along the channel. The edges themselves hold // information concerning fees, and minimum time-lock information which is // utilized during path finding. type ChannelEdgePolicy struct { // SigBytes is the raw bytes of the signature of the channel edge // policy. We'll only parse these if the caller needs to access the // signature for validation purposes. SigBytes []byte // sig is a cached fully parsed signature. sig *btcec.Signature // ChannelID is the unique channel ID for the channel. The first 3 // bytes are the block height, the next 3 the index within the block, // and the last 2 bytes are the output index for the channel. ChannelID uint64 // LastUpdate is the last time an authenticated edge for this channel // was received. LastUpdate time.Time // Flags is a bitfield which signals the capabilities of the channel as // well as the directed edge this update applies to. Flags lnwire.ChanUpdateFlag // TimeLockDelta is the number of blocks this node will subtract from // the expiry of an incoming HTLC. This value expresses the time buffer // the node would like to HTLC exchanges. TimeLockDelta uint16 // MinHTLC is the smallest value HTLC this node will accept, expressed // in millisatoshi. MinHTLC lnwire.MilliSatoshi // FeeBaseMSat is the base HTLC fee that will be charged for forwarding // ANY HTLC, expressed in mSAT's. FeeBaseMSat lnwire.MilliSatoshi // FeeProportionalMillionths is the rate that the node will charge for // HTLCs for each millionth of a satoshi forwarded. FeeProportionalMillionths lnwire.MilliSatoshi // Node is the LightningNode that this directed edge leads to. Using // this pointer the channel graph can further be traversed. Node *LightningNode // ExtraOpaqueData is the set of data that was appended to this // message, some of which we may not actually know how to iterate or // parse. By holding onto this data, we ensure that we're able to // properly validate the set of signatures that cover these new fields, // and ensure we're able to make upgrades to the network in a forwards // compatible manner. ExtraOpaqueData []byte db *DB } // Signature is a channel announcement signature, which is needed for proper // edge policy announcement. // // NOTE: By having this method to access an attribute, we ensure we only need // to fully deserialize the signature if absolutely necessary. func (c *ChannelEdgePolicy) Signature() (*btcec.Signature, error) { if c.sig != nil { return c.sig, nil } sig, err := btcec.ParseSignature(c.SigBytes, btcec.S256()) if err != nil { return nil, err } c.sig = sig return sig, nil } // FetchChannelEdgesByOutpoint attempts to lookup the two directed edges for // the channel identified by the funding outpoint. If the channel can't be // found, then ErrEdgeNotFound is returned. A struct which houses the general // information for the channel itself is returned as well as two structs that // contain the routing policies for the channel in either direction. func (c *ChannelGraph) FetchChannelEdgesByOutpoint(op *wire.OutPoint) (*ChannelEdgeInfo, *ChannelEdgePolicy, *ChannelEdgePolicy, error) { var ( edgeInfo *ChannelEdgeInfo policy1 *ChannelEdgePolicy policy2 *ChannelEdgePolicy ) err := c.db.View(func(tx *bolt.Tx) error { // First, grab the node bucket. This will be used to populate // the Node pointers in each edge read from disk. nodes := tx.Bucket(nodeBucket) if nodes == nil { return ErrGraphNotFound } // Next, grab the edge bucket which stores the edges, and also // the index itself so we can group the directed edges together // logically. edges := tx.Bucket(edgeBucket) if edges == nil { return ErrGraphNoEdgesFound } edgeIndex := edges.Bucket(edgeIndexBucket) if edgeIndex == nil { return ErrGraphNoEdgesFound } // If the channel's outpoint doesn't exist within the outpoint // index, then the edge does not exist. chanIndex := edges.Bucket(channelPointBucket) if chanIndex == nil { return ErrGraphNoEdgesFound } var b bytes.Buffer if err := writeOutpoint(&b, op); err != nil { return err } chanID := chanIndex.Get(b.Bytes()) if chanID == nil { return ErrEdgeNotFound } // If the channel is found to exists, then we'll first retrieve // the general information for the channel. edge, err := fetchChanEdgeInfo(edgeIndex, chanID) if err != nil { return err } edgeInfo = &edge edgeInfo.db = c.db // Once we have the information about the channels' parameters, // we'll fetch the routing policies for each for the directed // edges. e1, e2, err := fetchChanEdgePolicies( edgeIndex, edges, nodes, chanID, c.db, ) if err != nil { return err } policy1 = e1 policy2 = e2 return nil }) if err != nil { return nil, nil, nil, err } return edgeInfo, policy1, policy2, nil } // FetchChannelEdgesByID attempts to lookup the two directed edges for the // channel identified by the channel ID. If the channel can't be found, then // ErrEdgeNotFound is returned. A struct which houses the general information // for the channel itself is returned as well as two structs that contain the // routing policies for the channel in either direction. func (c *ChannelGraph) FetchChannelEdgesByID(chanID uint64) (*ChannelEdgeInfo, *ChannelEdgePolicy, *ChannelEdgePolicy, error) { var ( edgeInfo *ChannelEdgeInfo policy1 *ChannelEdgePolicy policy2 *ChannelEdgePolicy channelID [8]byte ) err := c.db.View(func(tx *bolt.Tx) error { // First, grab the node bucket. This will be used to populate // the Node pointers in each edge read from disk. nodes := tx.Bucket(nodeBucket) if nodes == nil { return ErrGraphNotFound } // Next, grab the edge bucket which stores the edges, and also // the index itself so we can group the directed edges together // logically. edges := tx.Bucket(edgeBucket) if edges == nil { return ErrGraphNoEdgesFound } edgeIndex := edges.Bucket(edgeIndexBucket) if edgeIndex == nil { return ErrGraphNoEdgesFound } byteOrder.PutUint64(channelID[:], chanID) edge, err := fetchChanEdgeInfo(edgeIndex, channelID[:]) if err != nil { return err } edgeInfo = &edge edgeInfo.db = c.db e1, e2, err := fetchChanEdgePolicies( edgeIndex, edges, nodes, channelID[:], c.db, ) if err != nil { return err } policy1 = e1 policy2 = e2 return nil }) if err != nil { return nil, nil, nil, err } return edgeInfo, policy1, policy2, nil } // genMultiSigP2WSH generates the p2wsh'd multisig script for 2 of 2 pubkeys. func genMultiSigP2WSH(aPub, bPub []byte) ([]byte, error) { if len(aPub) != 33 || len(bPub) != 33 { return nil, fmt.Errorf("Pubkey size error. Compressed " + "pubkeys only") } // Swap to sort pubkeys if needed. Keys are sorted in lexicographical // order. The signatures within the scriptSig must also adhere to the // order, ensuring that the signatures for each public key appears in // the proper order on the stack. if bytes.Compare(aPub, bPub) == 1 { aPub, bPub = bPub, aPub } // First, we'll generate the witness script for the multi-sig. bldr := txscript.NewScriptBuilder() bldr.AddOp(txscript.OP_2) bldr.AddData(aPub) // Add both pubkeys (sorted). bldr.AddData(bPub) bldr.AddOp(txscript.OP_2) bldr.AddOp(txscript.OP_CHECKMULTISIG) witnessScript, err := bldr.Script() if err != nil { return nil, err } // With the witness script generated, we'll now turn it into a p2sh // script: // * OP_0 bldr = txscript.NewScriptBuilder() bldr.AddOp(txscript.OP_0) scriptHash := sha256.Sum256(witnessScript) bldr.AddData(scriptHash[:]) return bldr.Script() } // EdgePoint couples the outpoint of a channel with the funding script that it // creates. The FilteredChainView will use this to watch for spends of this // edge point on chain. We require both of these values as depending on the // concrete implementation, either the pkScript, or the out point will be used. type EdgePoint struct { // FundingPkScript is the p2wsh multi-sig script of the target channel. FundingPkScript []byte // OutPoint is the outpoint of the target channel. OutPoint wire.OutPoint } // String returns a human readable version of the target EdgePoint. We return // the outpoint directly as it is enough to uniquely identify the edge point. func (e *EdgePoint) String() string { return e.OutPoint.String() } // ChannelView returns the verifiable edge information for each active channel // within the known channel graph. The set of UTXO's (along with their scripts) // returned are the ones that need to be watched on chain to detect channel // closes on the resident blockchain. func (c *ChannelGraph) ChannelView() ([]EdgePoint, error) { var edgePoints []EdgePoint if err := c.db.View(func(tx *bolt.Tx) error { // We're going to iterate over the entire channel index, so // we'll need to fetch the edgeBucket to get to the index as // it's a sub-bucket. edges := tx.Bucket(edgeBucket) if edges == nil { return ErrGraphNoEdgesFound } chanIndex := edges.Bucket(channelPointBucket) if chanIndex == nil { return ErrGraphNoEdgesFound } edgeIndex := edges.Bucket(edgeIndexBucket) if edgeIndex == nil { return ErrGraphNoEdgesFound } // Once we have the proper bucket, we'll range over each key // (which is the channel point for the channel) and decode it, // accumulating each entry. return chanIndex.ForEach(func(chanPointBytes, chanID []byte) error { chanPointReader := bytes.NewReader(chanPointBytes) var chanPoint wire.OutPoint err := readOutpoint(chanPointReader, &chanPoint) if err != nil { return err } edgeInfo, err := fetchChanEdgeInfo( edgeIndex, chanID, ) if err != nil { return err } pkScript, err := genMultiSigP2WSH( edgeInfo.BitcoinKey1Bytes[:], edgeInfo.BitcoinKey2Bytes[:], ) if err != nil { return err } edgePoints = append(edgePoints, EdgePoint{ FundingPkScript: pkScript, OutPoint: chanPoint, }) return nil }) }); err != nil { return nil, err } return edgePoints, nil } // NewChannelEdgePolicy returns a new blank ChannelEdgePolicy. func (c *ChannelGraph) NewChannelEdgePolicy() *ChannelEdgePolicy { return &ChannelEdgePolicy{db: c.db} } func putLightningNode(nodeBucket *bolt.Bucket, aliasBucket *bolt.Bucket, updateIndex *bolt.Bucket, node *LightningNode) error { var ( scratch [16]byte b bytes.Buffer ) pub, err := node.PubKey() if err != nil { return err } nodePub := pub.SerializeCompressed() // If the node has the update time set, write it, else write 0. updateUnix := uint64(0) if node.LastUpdate.Unix() > 0 { updateUnix = uint64(node.LastUpdate.Unix()) } byteOrder.PutUint64(scratch[:8], updateUnix) if _, err := b.Write(scratch[:8]); err != nil { return err } if _, err := b.Write(nodePub); err != nil { return err } // If we got a node announcement for this node, we will have the rest // of the data available. If not we don't have more data to write. if !node.HaveNodeAnnouncement { // Write HaveNodeAnnouncement=0. byteOrder.PutUint16(scratch[:2], 0) if _, err := b.Write(scratch[:2]); err != nil { return err } return nodeBucket.Put(nodePub, b.Bytes()) } // Write HaveNodeAnnouncement=1. byteOrder.PutUint16(scratch[:2], 1) if _, err := b.Write(scratch[:2]); err != nil { return err } if err := binary.Write(&b, byteOrder, node.Color.R); err != nil { return err } if err := binary.Write(&b, byteOrder, node.Color.G); err != nil { return err } if err := binary.Write(&b, byteOrder, node.Color.B); err != nil { return err } if err := wire.WriteVarString(&b, 0, node.Alias); err != nil { return err } if err := node.Features.Encode(&b); err != nil { return err } numAddresses := uint16(len(node.Addresses)) byteOrder.PutUint16(scratch[:2], numAddresses) if _, err := b.Write(scratch[:2]); err != nil { return err } for _, address := range node.Addresses { if err := serializeAddr(&b, address); err != nil { return err } } err = wire.WriteVarBytes(&b, 0, node.AuthSigBytes) if err != nil { return err } if len(node.ExtraOpaqueData) > MaxAllowedExtraOpaqueBytes { return ErrTooManyExtraOpaqueBytes(len(node.ExtraOpaqueData)) } err = wire.WriteVarBytes(&b, 0, node.ExtraOpaqueData) if err != nil { return err } if err := aliasBucket.Put(nodePub, []byte(node.Alias)); err != nil { return err } // With the alias bucket updated, we'll now update the index that // tracks the time series of node updates. var indexKey [8 + 33]byte byteOrder.PutUint64(indexKey[:8], updateUnix) copy(indexKey[8:], nodePub) // If there was already an old index entry for this node, then we'll // delete the old one before we write the new entry. if nodeBytes := nodeBucket.Get(nodePub); nodeBytes != nil { // Extract out the old update time to we can reconstruct the // prior index key to delete it from the index. oldUpdateTime := nodeBytes[:8] var oldIndexKey [8 + 33]byte copy(oldIndexKey[:8], oldUpdateTime) copy(oldIndexKey[8:], nodePub) if err := updateIndex.Delete(oldIndexKey[:]); err != nil { return err } } if err := updateIndex.Put(indexKey[:], nil); err != nil { return err } return nodeBucket.Put(nodePub, b.Bytes()) } func fetchLightningNode(nodeBucket *bolt.Bucket, nodePub []byte) (LightningNode, error) { nodeBytes := nodeBucket.Get(nodePub) if nodeBytes == nil { return LightningNode{}, ErrGraphNodeNotFound } nodeReader := bytes.NewReader(nodeBytes) return deserializeLightningNode(nodeReader) } func deserializeLightningNode(r io.Reader) (LightningNode, error) { var ( node LightningNode scratch [8]byte err error ) if _, err := r.Read(scratch[:]); err != nil { return LightningNode{}, err } unix := int64(byteOrder.Uint64(scratch[:])) node.LastUpdate = time.Unix(unix, 0) if _, err := io.ReadFull(r, node.PubKeyBytes[:]); err != nil { return LightningNode{}, err } if _, err := r.Read(scratch[:2]); err != nil { return LightningNode{}, err } hasNodeAnn := byteOrder.Uint16(scratch[:2]) if hasNodeAnn == 1 { node.HaveNodeAnnouncement = true } else { node.HaveNodeAnnouncement = false } // The rest of the data is optional, and will only be there if we got a node // announcement for this node. if !node.HaveNodeAnnouncement { return node, nil } // We did get a node announcement for this node, so we'll have the rest // of the data available. if err := binary.Read(r, byteOrder, &node.Color.R); err != nil { return LightningNode{}, err } if err := binary.Read(r, byteOrder, &node.Color.G); err != nil { return LightningNode{}, err } if err := binary.Read(r, byteOrder, &node.Color.B); err != nil { return LightningNode{}, err } node.Alias, err = wire.ReadVarString(r, 0) if err != nil { return LightningNode{}, err } fv := lnwire.NewFeatureVector(nil, lnwire.GlobalFeatures) err = fv.Decode(r) if err != nil { return LightningNode{}, err } node.Features = fv if _, err := r.Read(scratch[:2]); err != nil { return LightningNode{}, err } numAddresses := int(byteOrder.Uint16(scratch[:2])) var addresses []net.Addr for i := 0; i < numAddresses; i++ { address, err := deserializeAddr(r) if err != nil { return LightningNode{}, err } addresses = append(addresses, address) } node.Addresses = addresses node.AuthSigBytes, err = wire.ReadVarBytes(r, 0, 80, "sig") if err != nil { return LightningNode{}, err } // We'll try and see if there are any opaque bytes left, if not, then // we'll ignore the EOF error and return the node as is. node.ExtraOpaqueData, err = wire.ReadVarBytes( r, 0, MaxAllowedExtraOpaqueBytes, "blob", ) switch { case err == io.ErrUnexpectedEOF: case err == io.EOF: case err != nil: return LightningNode{}, err } return node, nil } func putChanEdgeInfo(edgeIndex *bolt.Bucket, edgeInfo *ChannelEdgeInfo, chanID [8]byte) error { var b bytes.Buffer if _, err := b.Write(edgeInfo.NodeKey1Bytes[:]); err != nil { return err } if _, err := b.Write(edgeInfo.NodeKey2Bytes[:]); err != nil { return err } if _, err := b.Write(edgeInfo.BitcoinKey1Bytes[:]); err != nil { return err } if _, err := b.Write(edgeInfo.BitcoinKey2Bytes[:]); err != nil { return err } if err := wire.WriteVarBytes(&b, 0, edgeInfo.Features); err != nil { return err } authProof := edgeInfo.AuthProof var nodeSig1, nodeSig2, bitcoinSig1, bitcoinSig2 []byte if authProof != nil { nodeSig1 = authProof.NodeSig1Bytes nodeSig2 = authProof.NodeSig2Bytes bitcoinSig1 = authProof.BitcoinSig1Bytes bitcoinSig2 = authProof.BitcoinSig2Bytes } if err := wire.WriteVarBytes(&b, 0, nodeSig1); err != nil { return err } if err := wire.WriteVarBytes(&b, 0, nodeSig2); err != nil { return err } if err := wire.WriteVarBytes(&b, 0, bitcoinSig1); err != nil { return err } if err := wire.WriteVarBytes(&b, 0, bitcoinSig2); err != nil { return err } if err := writeOutpoint(&b, &edgeInfo.ChannelPoint); err != nil { return err } if err := binary.Write(&b, byteOrder, uint64(edgeInfo.Capacity)); err != nil { return err } if _, err := b.Write(chanID[:]); err != nil { return err } if _, err := b.Write(edgeInfo.ChainHash[:]); err != nil { return err } if len(edgeInfo.ExtraOpaqueData) > MaxAllowedExtraOpaqueBytes { return ErrTooManyExtraOpaqueBytes(len(edgeInfo.ExtraOpaqueData)) } err := wire.WriteVarBytes(&b, 0, edgeInfo.ExtraOpaqueData) if err != nil { return err } return edgeIndex.Put(chanID[:], b.Bytes()) } func fetchChanEdgeInfo(edgeIndex *bolt.Bucket, chanID []byte) (ChannelEdgeInfo, error) { edgeInfoBytes := edgeIndex.Get(chanID) if edgeInfoBytes == nil { return ChannelEdgeInfo{}, ErrEdgeNotFound } edgeInfoReader := bytes.NewReader(edgeInfoBytes) return deserializeChanEdgeInfo(edgeInfoReader) } func deserializeChanEdgeInfo(r io.Reader) (ChannelEdgeInfo, error) { var ( err error edgeInfo ChannelEdgeInfo ) if _, err := io.ReadFull(r, edgeInfo.NodeKey1Bytes[:]); err != nil { return ChannelEdgeInfo{}, err } if _, err := io.ReadFull(r, edgeInfo.NodeKey2Bytes[:]); err != nil { return ChannelEdgeInfo{}, err } if _, err := io.ReadFull(r, edgeInfo.BitcoinKey1Bytes[:]); err != nil { return ChannelEdgeInfo{}, err } if _, err := io.ReadFull(r, edgeInfo.BitcoinKey2Bytes[:]); err != nil { return ChannelEdgeInfo{}, err } edgeInfo.Features, err = wire.ReadVarBytes(r, 0, 900, "features") if err != nil { return ChannelEdgeInfo{}, err } proof := &ChannelAuthProof{} proof.NodeSig1Bytes, err = wire.ReadVarBytes(r, 0, 80, "sigs") if err != nil { return ChannelEdgeInfo{}, err } proof.NodeSig2Bytes, err = wire.ReadVarBytes(r, 0, 80, "sigs") if err != nil { return ChannelEdgeInfo{}, err } proof.BitcoinSig1Bytes, err = wire.ReadVarBytes(r, 0, 80, "sigs") if err != nil { return ChannelEdgeInfo{}, err } proof.BitcoinSig2Bytes, err = wire.ReadVarBytes(r, 0, 80, "sigs") if err != nil { return ChannelEdgeInfo{}, err } if !proof.IsEmpty() { edgeInfo.AuthProof = proof } edgeInfo.ChannelPoint = wire.OutPoint{} if err := readOutpoint(r, &edgeInfo.ChannelPoint); err != nil { return ChannelEdgeInfo{}, err } if err := binary.Read(r, byteOrder, &edgeInfo.Capacity); err != nil { return ChannelEdgeInfo{}, err } if err := binary.Read(r, byteOrder, &edgeInfo.ChannelID); err != nil { return ChannelEdgeInfo{}, err } if _, err := io.ReadFull(r, edgeInfo.ChainHash[:]); err != nil { return ChannelEdgeInfo{}, err } // We'll try and see if there are any opaque bytes left, if not, then // we'll ignore the EOF error and return the edge as is. edgeInfo.ExtraOpaqueData, err = wire.ReadVarBytes( r, 0, MaxAllowedExtraOpaqueBytes, "blob", ) switch { case err == io.ErrUnexpectedEOF: case err == io.EOF: case err != nil: return ChannelEdgeInfo{}, err } return edgeInfo, nil } func putChanEdgePolicy(edges, nodes *bolt.Bucket, edge *ChannelEdgePolicy, from, to []byte) error { var edgeKey [33 + 8]byte copy(edgeKey[:], from) byteOrder.PutUint64(edgeKey[33:], edge.ChannelID) var b bytes.Buffer err := wire.WriteVarBytes(&b, 0, edge.SigBytes) if err != nil { return err } if err := binary.Write(&b, byteOrder, edge.ChannelID); err != nil { return err } var scratch [8]byte updateUnix := uint64(edge.LastUpdate.Unix()) byteOrder.PutUint64(scratch[:], updateUnix) if _, err := b.Write(scratch[:]); err != nil { return err } if err := binary.Write(&b, byteOrder, edge.Flags); err != nil { return err } if err := binary.Write(&b, byteOrder, edge.TimeLockDelta); err != nil { return err } if err := binary.Write(&b, byteOrder, uint64(edge.MinHTLC)); err != nil { return err } if err := binary.Write(&b, byteOrder, uint64(edge.FeeBaseMSat)); err != nil { return err } if err := binary.Write(&b, byteOrder, uint64(edge.FeeProportionalMillionths)); err != nil { return err } if _, err := b.Write(to); err != nil { return err } if len(edge.ExtraOpaqueData) > MaxAllowedExtraOpaqueBytes { return ErrTooManyExtraOpaqueBytes(len(edge.ExtraOpaqueData)) } if err := wire.WriteVarBytes(&b, 0, edge.ExtraOpaqueData); err != nil { return err } // Before we write out the new edge, we'll create a new entry in the // update index in order to keep it fresh. var indexKey [8 + 8]byte copy(indexKey[:], scratch[:]) byteOrder.PutUint64(indexKey[8:], edge.ChannelID) updateIndex, err := edges.CreateBucketIfNotExists(edgeUpdateIndexBucket) if err != nil { return err } // If there was already an entry for this edge, then we'll need to // delete the old one to ensure we don't leave around any after-images. // An unknown policy value does not have a update time recorded, so // it also does not need to be removed. if edgeBytes := edges.Get(edgeKey[:]); edgeBytes != nil && !bytes.Equal(edgeBytes[:], unknownPolicy) { // In order to delete the old entry, we'll need to obtain the // *prior* update time in order to delete it. To do this, we'll // need to deserialize the existing policy within the database // (now outdated by the new one), and delete its corresponding // entry within the update index. oldEdgePolicy, err := deserializeChanEdgePolicy( bytes.NewReader(edgeBytes), nodes, ) if err != nil { return err } oldUpdateTime := uint64(oldEdgePolicy.LastUpdate.Unix()) var oldIndexKey [8 + 8]byte byteOrder.PutUint64(oldIndexKey[:8], oldUpdateTime) byteOrder.PutUint64(oldIndexKey[8:], edge.ChannelID) if err := updateIndex.Delete(oldIndexKey[:]); err != nil { return err } } if err := updateIndex.Put(indexKey[:], nil); err != nil { return err } return edges.Put(edgeKey[:], b.Bytes()[:]) } // putChanEdgePolicyUnknown marks the edge policy as unknown // in the edges bucket. func putChanEdgePolicyUnknown(edges *bolt.Bucket, channelID uint64, from []byte) error { var edgeKey [33 + 8]byte copy(edgeKey[:], from) byteOrder.PutUint64(edgeKey[33:], channelID) if edges.Get(edgeKey[:]) != nil { return fmt.Errorf("Cannot write unknown policy for channel %v "+ " when there is already a policy present", channelID) } return edges.Put(edgeKey[:], unknownPolicy) } func fetchChanEdgePolicy(edges *bolt.Bucket, chanID []byte, nodePub []byte, nodes *bolt.Bucket) (*ChannelEdgePolicy, error) { var edgeKey [33 + 8]byte copy(edgeKey[:], nodePub) copy(edgeKey[33:], chanID[:]) edgeBytes := edges.Get(edgeKey[:]) if edgeBytes == nil { return nil, ErrEdgeNotFound } // No need to deserialize unknown policy. if bytes.Equal(edgeBytes[:], unknownPolicy) { return nil, nil } edgeReader := bytes.NewReader(edgeBytes) return deserializeChanEdgePolicy(edgeReader, nodes) } func fetchChanEdgePolicies(edgeIndex *bolt.Bucket, edges *bolt.Bucket, nodes *bolt.Bucket, chanID []byte, db *DB) (*ChannelEdgePolicy, *ChannelEdgePolicy, error) { edgeInfo := edgeIndex.Get(chanID) if edgeInfo == nil { return nil, nil, ErrEdgeNotFound } // The first node is contained within the first half of the edge // information. We only propagate the error here and below if it's // something other than edge non-existence. node1Pub := edgeInfo[:33] edge1, err := fetchChanEdgePolicy(edges, chanID, node1Pub, nodes) if err != nil { return nil, nil, err } // As we may have a single direction of the edge but not the other, // only fill in the database pointers if the edge is found. if edge1 != nil { edge1.db = db edge1.Node.db = db } // Similarly, the second node is contained within the latter // half of the edge information. node2Pub := edgeInfo[33:66] edge2, err := fetchChanEdgePolicy(edges, chanID, node2Pub, nodes) if err != nil { return nil, nil, err } if edge2 != nil { edge2.db = db edge2.Node.db = db } return edge1, edge2, nil } func deserializeChanEdgePolicy(r io.Reader, nodes *bolt.Bucket) (*ChannelEdgePolicy, error) { edge := &ChannelEdgePolicy{} var err error edge.SigBytes, err = wire.ReadVarBytes(r, 0, 80, "sig") if err != nil { return nil, err } if err := binary.Read(r, byteOrder, &edge.ChannelID); err != nil { return nil, err } var scratch [8]byte if _, err := r.Read(scratch[:]); err != nil { return nil, err } unix := int64(byteOrder.Uint64(scratch[:])) edge.LastUpdate = time.Unix(unix, 0) if err := binary.Read(r, byteOrder, &edge.Flags); err != nil { return nil, err } if err := binary.Read(r, byteOrder, &edge.TimeLockDelta); err != nil { return nil, err } var n uint64 if err := binary.Read(r, byteOrder, &n); err != nil { return nil, err } edge.MinHTLC = lnwire.MilliSatoshi(n) if err := binary.Read(r, byteOrder, &n); err != nil { return nil, err } edge.FeeBaseMSat = lnwire.MilliSatoshi(n) if err := binary.Read(r, byteOrder, &n); err != nil { return nil, err } edge.FeeProportionalMillionths = lnwire.MilliSatoshi(n) var pub [33]byte if _, err := r.Read(pub[:]); err != nil { return nil, err } node, err := fetchLightningNode(nodes, pub[:]) if err != nil { return nil, fmt.Errorf("unable to fetch node: %x, %v", pub[:], err) } // We'll try and see if there are any opaque bytes left, if not, then // we'll ignore the EOF error and return the edge as is. edge.ExtraOpaqueData, err = wire.ReadVarBytes( r, 0, MaxAllowedExtraOpaqueBytes, "blob", ) switch { case err == io.ErrUnexpectedEOF: case err == io.EOF: case err != nil: return nil, err } edge.Node = &node return edge, nil }