package channeldb import ( "bytes" "encoding/binary" "image/color" "io" "net" "time" "github.com/boltdb/bolt" "github.com/roasbeef/btcd/btcec" "github.com/roasbeef/btcd/chaincfg/chainhash" "github.com/roasbeef/btcd/wire" "github.com/roasbeef/btcutil" ) 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 -> nofInfo // maps: source -> selfPubKey nodeBucket = []byte("graph-node") // 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 it's // 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 _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 edgeID, // 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 || edgeID -> edge for node edgeBucket = []byte("graph-edge") // 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. This // bucket resides within the edgeBucket above. Creation of a 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 -> pub1 || pub2 edgeIndexBucket = []byte("edge-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 strored in this bucket // includes the block to which the graph has been synced to, the total // number of channels, etc. graphMetaBucket = []byte("graph-meta") // pruneTipKey is a key within the above graphMetaBucket that stores // the best known blockhash+height that the channel graph has been // known to be pruned to. Once a new block is discovered, any channels // that have been closed (by spending the outpoint) can safely be // removed from the graph. pruneTipKey = []byte("prune-tip") edgeBloomKey = []byte("edge-bloom") nodeBloomKey = []byte("node-bloom") ) // 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? } // 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, ro wasn't advertised, then a nil pointer // will be passed into the callback. func (c *ChannelGraph) ForEachChannel(cb func(*ChannelEdge, *ChannelEdge) 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 objecvt. return edgeIndex.ForEach(func(chanID, edgeInfo []byte) error { // The first node is contained within the first half of // the edge information. node1Pub := edgeInfo[:33] edge1, err := fetchChannelEdge(edges, chanID, node1Pub, nodes) if err != nil && err != ErrEdgeNotFound && err != ErrGraphNodeNotFound { return err } // The targeted edge may have not been advertised // within the network, so we ensure it's non-nil before // deferencing its attributes. if edge1 != nil { edge1.db = c.db if edge1.Node != nil { edge1.Node.db = c.db } } // Similarly, the second node is contained within the // latter half of the edge information. node2Pub := edgeInfo[33:] edge2, err := fetchChannelEdge(edges, chanID, node2Pub, nodes) if err != nil && err != ErrEdgeNotFound && err != ErrGraphNodeNotFound { return err } // The targeted edge may have not been advertised // within the network, so we ensure it's non-nil before // deferencing its attributes. if edge2 != nil { edge2.db = c.db if edge2.Node != nil { edge2.Node.db = c.db } } // With both edges read, execute the call back. IF this // function returns an error then the transaction will // be aborted. return cb(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. func (c *ChannelGraph) ForEachNode(cb func(*LightningNode) error) error { // TODO(roasbeef): need to also pass in a transaction? or reverse order // to get all in memory THEN execute callback? return 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 } 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(node) }) }) } // 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 { // First grab the nodes bucket which stores the mapping from // pubKey to node information. nodes := tx.Bucket(nodeBucket) if nodes == nil { return ErrGraphNotFound } selfPub := nodes.Get(sourceKey) if selfPub == nil { return 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 err } source = node source.db = c.db return nil }) if err != nil { return nil, err } return source, 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 { nodePub := node.PubKey.SerializeCompressed() 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, nodePub); err != nil { return err } // Finally, we commit the information of the lightning node // itself. return addLightningNode(tx, node) }) } // AddLightningNode adds a new (unconnected) vertex/node to the graph database. // When adding an edge, each node must be added before the edge can be // inserted. Afterwards the edge information can then be updated. // 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 } return putLightningNode(nodes, aliases, 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 removes a vertex/node from the database according to the // node's public key. func (c *ChannelGraph) DeleteLightningNode(nodePub *btcec.PublicKey) error { pub := nodePub.SerializeCompressed() // TODO(roasbeef): ensure dangling edges are removed... return c.db.Update(func(tx *bolt.Tx) error { nodes, err := tx.CreateBucketIfNotExists(nodeBucket) if err != nil { return err } aliases, err := tx.CreateBucketIfNotExists(aliasIndexBucket) if err != nil { return err } if err := aliases.Delete(pub); err != nil { return err } return nodes.Delete(pub) }) } // AddChannelEdge adds a new (undirected, blank) edge to the graph database. An // undirected edge from the two target nodes are created. The chanPoint and // chanID are used to uniquely identify the edge globally within the database. func (c *ChannelGraph) AddChannelEdge(from, to *btcec.PublicKey, chanPoint *wire.OutPoint, chanID uint64) error { // Construct the channel's primary key which is the 8-byte channel ID. var chanKey [8]byte binary.BigEndian.PutUint64(chanKey[:], chanID) var ( node1 []byte node2 []byte ) fromBytes := from.SerializeCompressed() toBytes := to.SerializeCompressed() // On-disk, we order the value for the edge's key with the "smaller" // pubkey coming before the larger one. This ensures that all edges // have a deterministic ordering. if bytes.Compare(fromBytes, toBytes) == -1 { node1 = fromBytes node2 = toBytes } else { node1 = toBytes node2 = fromBytes } 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 } 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 nil } // 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. var edgeInfo [66]byte copy(edgeInfo[:33], node1) copy(edgeInfo[33:], node2) if err := edgeIndex.Put(chanKey[:], edgeInfo[:]); 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, chanPoint); 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 the 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 // timestmaps. nodes := tx.Bucket(nodeBucket) if nodes == nil { return ErrGraphNodeNotFound } e1, e2, err := fetchEdges(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 } const ( // pruneTipBytes is the total size of the value which stores the // current prune tip of the graph. The prune tip indicates if the // channel graph is in sync with the current UTXO state. The structure // is: blockHash || blockHeight, taking 36 bytes total. pruneTipBytes = 32 + 4 ) // 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. An integer is returned which reflects the // number of channels pruned due to the new incoming block. func (c *ChannelGraph) PruneGraph(spentOutputs []*wire.OutPoint, blockHash *chainhash.Hash, blockHeight uint32) (uint32, error) { var numChans uint32 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 } // For each of the outpoints that've 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 // Attempt to delete the channel, and 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, chanPoint) if err != nil && err != ErrEdgeNotFound { return err } else if err == nil { numChans += 1 } } metaBucket, err := tx.CreateBucketIfNotExists(graphMetaBucket) if err != nil { return err } // With the graph pruned, update the current "prune tip" which // can eb used to check if the graph is fully synced with the // current UTXO state. var newTip [pruneTipBytes]byte copy(newTip[:], blockHash[:]) byteOrder.PutUint32(newTip[32:], uint32(blockHeight)) return metaBucket.Put(pruneTipKey, newTip[:]) }) if err != nil { return 0, err } return numChans, 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 ( currentTip [pruneTipBytes]byte tipHash chainhash.Hash tipHeight uint32 ) err := c.db.View(func(tx *bolt.Tx) error { graphMeta := tx.Bucket(graphMetaBucket) if graphMeta == nil { return ErrGraphNotFound } tipBytes := graphMeta.Get(pruneTipKey) if tipBytes == nil { return ErrGraphNeverPruned } copy(currentTip[:], tipBytes) return nil }) if err != nil { return nil, 0, err } // Once we have the prune tip, the first 32 bytes are the block hash, // with the latter 4 bytes being the block height. copy(tipHash[:], currentTip[:32]) tipHeight = byteOrder.Uint32(currentTip[32:]) return &tipHash, tipHeight, nil } // DeleteChannelEdge removes an edge from the database as identified by it's // funding outpoint. If the edge does not exist within the database, then this 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 } return delChannelByEdge(edges, edgeIndex, chanIndex, 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 edges == 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 } func delChannelByEdge(edges *bolt.Bucket, edgeIndex *bolt.Bucket, chanIndex *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) // 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()) } // UpdateEdgeInfo updates the edge information for a single directed edge // within the database for the referenced channel. The `flags` attribute within // the ChannelEdge 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. func (r *ChannelGraph) UpdateEdgeInfo(edge *ChannelEdge) error { return r.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 } // 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 parsed above, either the first // or second node is being updated. var fromNode, toNode []byte if edge.Flags == 0 { fromNode = nodeInfo[:33] toNode = nodeInfo[33:] } else { fromNode = nodeInfo[33:] toNode = nodeInfo[:33] } // Finally, with the direction of the edge being updated // identified, we update the on-disk edge representation. return putChannelEdge(edges, 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 { // 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. Address *net.TCPAddr // PubKey is the node's long-term identity public key. This key will be // used to authenticated any advertisements/updates sent by the node. PubKey *btcec.PublicKey // 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 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? } // FetchLightningNode attempts to look up a target node by its identity public // key. If the node iwn'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(pub *btcec.PublicKey) (time.Time, bool, error) { var ( updateTime time.Time exists bool ) 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, 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 the outgoing channel edges from this // node, executing the passed callback with each edge as its sole argument. If // the callback returns an error, then the iteration is halted with the error // propagated back up to the caller. 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(*ChannelEdge) error) error { // TODO(roasbeef): remove the option to pass in a transaction after // all? nodePub := l.PubKey.SerializeCompressed() traversal := func(tx *bolt.Tx) error { nodes := tx.Bucket(nodeBucket) if nodes == nil { return ErrGraphNotFound } edges := tx.Bucket(edgeBucket) if edges == nil { return ErrGraphNotFound } // 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, edgeInfo := edgeCursor.Seek(nodeStart[:]); bytes.HasPrefix(nodeEdge, nodePub); nodeEdge, edgeInfo = edgeCursor.Next() { // If the prefix still matches, then the value is the // raw edge information. So we can now serialize the // edge info and fetch the outgoing node in order to // retrieve the full channel edge. edgeReader := bytes.NewReader(edgeInfo) edge, err := deserializeChannelEdge(edgeReader, nodes) if err != nil { return err } edge.db = l.db edge.Node.db = l.db // Finally, we execute the callback. if err := cb(edge); 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) } // ChannelEdge 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 ChannelEdge 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. // TODO(roasbeef): spell out and use index of channel ID to do fast look // ups? ChannelID uint64 // ChannelPoint is the funding outpoint of the channel. This can be // used to uniquely identify the channel within the channel graph. ChannelPoint wire.OutPoint // 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 directe edge this update applies to. // TODO(roasbeef): make into wire struct Flags uint16 // Expiry 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. Expiry uint16 // MinHTLC is the smallest value HTLC this node will accept, expressed // in millisatoshi. MinHTLC btcutil.Amount // FeeBaseMSat is the base HTLC fee that will be charged for forwarding // ANY HTLC, expressed in mSAT's. FeeBaseMSat btcutil.Amount // FeeProportionalMillionths is the rate that the node will charge for // HTLCs for each millionth of a satoshi forwarded. FeeProportionalMillionths btcutil.Amount // 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 // Node is the LightningNode that this directed edge leads to. Using // this pointer the channel graph can further be traversed. Node *LightningNode db *DB } // 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. func (c *ChannelGraph) FetchChannelEdgesByOutpoint(op *wire.OutPoint) (*ChannelEdge, *ChannelEdge, error) { var ( edge1 *ChannelEdge edge2 *ChannelEdge ) err := c.db.Update(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, err := tx.CreateBucketIfNotExists(nodeBucket) if err != nil { return err } // Next, grab the edge bucket which stores the edges, and also // the index itself so we can group the directed edges together // logically. edges, err := tx.CreateBucketIfNotExists(edgeBucket) if err != nil { return err } edgeIndex, err := edges.CreateBucketIfNotExists(edgeIndexBucket) if err != nil { return err } // If the channel's outpoint doesn't exist within the outpoint // index, then the edge does not exist. chanIndex, err := edges.CreateBucketIfNotExists(channelPointBucket) if err != nil { return err } var b bytes.Buffer if err := writeOutpoint(&b, op); err != nil { return err } chanID := chanIndex.Get(b.Bytes()) if chanID == nil { return ErrEdgeNotFound } e1, e2, err := fetchEdges(edgeIndex, edges, nodes, chanID, c.db) if err != nil { return err } edge1 = e1 edge2 = e2 return nil }) if err != nil { return nil, nil, err } return edge1, edge2, 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. func (c *ChannelGraph) FetchChannelEdgesByID(chanID uint64) (*ChannelEdge, *ChannelEdge, error) { var ( edge1 *ChannelEdge edge2 *ChannelEdge 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) e1, e2, err := fetchEdges(edgeIndex, edges, nodes, channelID[:], c.db) if err != nil { return err } edge1 = e1 edge2 = e2 return nil }) if err != nil { return nil, nil, err } return edge1, edge2, nil } // NewChannelEdge returns a new blank ChannelEdge. func (c *ChannelGraph) NewChannelEdge() *ChannelEdge { return &ChannelEdge{db: c.db} } func putLightningNode(nodeBucket *bolt.Bucket, aliasBucket *bolt.Bucket, node *LightningNode) error { var ( scratch [8]byte b bytes.Buffer ) nodePub := node.PubKey.SerializeCompressed() if err := aliasBucket.Put(nodePub, []byte(node.Alias)); err != nil { return err } updateUnix := uint64(node.LastUpdate.Unix()) byteOrder.PutUint64(scratch[:], updateUnix) if _, err := b.Write(scratch[:]); err != nil { return err } addrString := node.Address.String() if err := wire.WriteVarString(&b, 0, addrString); err != nil { return err } if _, err := b.Write(nodePub); 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 } return nodeBucket.Put(nodePub, b.Bytes()) } func fetchLightningNode(nodeBucket *bolt.Bucket, nodePub []byte) (*LightningNode, error) { nodeBytes := nodeBucket.Get(nodePub) if nodeBytes == nil { return nil, ErrGraphNodeNotFound } nodeReader := bytes.NewReader(nodeBytes) return deserializeLightningNode(nodeReader) } func deserializeLightningNode(r io.Reader) (*LightningNode, error) { node := &LightningNode{} var scratch [8]byte if _, err := r.Read(scratch[:]); err != nil { return nil, err } unix := int64(byteOrder.Uint64(scratch[:])) node.LastUpdate = time.Unix(unix, 0) addrString, err := wire.ReadVarString(r, 0) if err != nil { return nil, err } node.Address, err = net.ResolveTCPAddr("tcp", addrString) if err != nil { return nil, err } var pub [33]byte if _, err := r.Read(pub[:]); err != nil { return nil, err } node.PubKey, err = btcec.ParsePubKey(pub[:], btcec.S256()) if err != nil { return nil, err } if err := binary.Read(r, byteOrder, &node.Color.R); err != nil { return nil, err } if err := binary.Read(r, byteOrder, &node.Color.G); err != nil { return nil, err } if err := binary.Read(r, byteOrder, &node.Color.B); err != nil { return nil, err } node.Alias, err = wire.ReadVarString(r, 0) if err != nil { return nil, err } return node, nil } func putChannelEdge(edges *bolt.Bucket, edge *ChannelEdge, from, to []byte) error { var edgeKey [33 + 8]byte copy(edgeKey[:], from) byteOrder.PutUint64(edgeKey[33:], edge.ChannelID) var b bytes.Buffer if err := binary.Write(&b, byteOrder, edge.ChannelID); err != nil { return err } if err := writeOutpoint(&b, &edge.ChannelPoint); 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.Expiry); 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 := binary.Write(&b, byteOrder, uint64(edge.Capacity)); err != nil { return err } if _, err := b.Write(to); err != nil { return err } return edges.Put(edgeKey[:], b.Bytes()[:]) } func fetchEdges(edgeIndex *bolt.Bucket, edges *bolt.Bucket, nodes *bolt.Bucket, chanID []byte, db *DB) (*ChannelEdge, *ChannelEdge, 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 := fetchChannelEdge(edges, chanID, node1Pub, nodes) if err != nil && err != ErrEdgeNotFound { 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:] edge2, err := fetchChannelEdge(edges, chanID, node2Pub, nodes) if err != nil && err != ErrEdgeNotFound { return nil, nil, err } if edge2 != nil { edge2.db = db edge2.Node.db = db } return edge1, edge2, nil } func fetchChannelEdge(edges *bolt.Bucket, chanID []byte, nodePub []byte, nodes *bolt.Bucket) (*ChannelEdge, error) { var edgeKey [33 + 8]byte copy(edgeKey[:], nodePub) copy(edgeKey[33:], chanID[:]) edgeBytes := edges.Get(edgeKey[:]) if edgeBytes == nil { return nil, ErrEdgeNotFound } edgeReader := bytes.NewReader(edgeBytes) return deserializeChannelEdge(edgeReader, nodes) } func deserializeChannelEdge(r io.Reader, nodes *bolt.Bucket) (*ChannelEdge, error) { edge := &ChannelEdge{} if err := binary.Read(r, byteOrder, &edge.ChannelID); err != nil { return nil, err } edge.ChannelPoint = wire.OutPoint{} if err := readOutpoint(r, &edge.ChannelPoint); 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.Expiry); err != nil { return nil, err } var n uint64 if err := binary.Read(r, byteOrder, &n); err != nil { return nil, err } edge.MinHTLC = btcutil.Amount(n) if err := binary.Read(r, byteOrder, &n); err != nil { return nil, err } edge.FeeBaseMSat = btcutil.Amount(n) if err := binary.Read(r, byteOrder, &n); err != nil { return nil, err } edge.FeeProportionalMillionths = btcutil.Amount(n) if err := binary.Read(r, byteOrder, &n); err != nil { return nil, err } edge.Capacity = btcutil.Amount(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, err } edge.Node = node return edge, nil }