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utils: use SelectHopHints from LND
This commit is contained in:
Andras Banki-Horvath
parent
db2fba6f0d
commit
31f7b5947a
2 changed files with 127 additions and 456 deletions
286
utils.go
286
utils.go
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@ -2,202 +2,170 @@ package loop
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import (
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"context"
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"fmt"
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"strconv"
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"strings"
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"github.com/btcsuite/btcd/btcec"
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"github.com/btcsuite/btcd/chaincfg/chainhash"
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"github.com/btcsuite/btcd/wire"
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"github.com/btcsuite/btcutil"
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"github.com/lightninglabs/lndclient"
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"github.com/lightningnetwork/lnd/channeldb"
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"github.com/lightningnetwork/lnd/lnrpc/invoicesrpc"
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"github.com/lightningnetwork/lnd/lnwire"
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"github.com/lightningnetwork/lnd/routing/route"
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"github.com/lightningnetwork/lnd/zpay32"
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"google.golang.org/grpc/codes"
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"google.golang.org/grpc/status"
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)
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var (
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// DefaultMaxHopHints is set to 20 as that is the default set in LND
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// DefaultMaxHopHints is set to 20 as that is the default set in LND.
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DefaultMaxHopHints = 20
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)
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// SelectHopHints is a direct port of the SelectHopHints found in lnd. It was
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// reimplemented because the current implementation in LND relies on internals
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// not externalized through the API. Hopefully in the future SelectHopHints
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// will be refactored to allow for custom data sources. It iterates through all
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// the active and public channels available and returns eligible channels.
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// Eligibility requirements are simple: does the channel have enough liquidity
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// to fulfill the request and is the node whitelisted (if specified)
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// isPublicNode checks if a node is public, by simply checking if there's any
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// channels reported to the node.
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func isPublicNode(ctx context.Context, lnd *lndclient.LndServices,
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pubKey [33]byte) (bool, error) {
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// GetNodeInfo doesn't report our private channels with the queried node
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// so we can use it to determine if the node is considered public.
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nodeInfo, err := lnd.Client.GetNodeInfo(
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ctx, pubKey, true,
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)
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if err != nil {
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return false, err
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}
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return (nodeInfo.ChannelCount > 0), nil
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}
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// fetchChannelEdgesByID fetches the edge info for the passed channel and
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// returns the channeldb structs filled with the data that is needed for
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// LND's SelectHopHints implementation.
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func fetchChannelEdgesByID(ctx context.Context, lnd *lndclient.LndServices,
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chanID uint64) (*channeldb.ChannelEdgeInfo, *channeldb.ChannelEdgePolicy,
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*channeldb.ChannelEdgePolicy, error) {
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chanInfo, err := lnd.Client.GetChanInfo(ctx, chanID)
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if err != nil {
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return nil, nil, nil, err
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}
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edgeInfo := &channeldb.ChannelEdgeInfo{
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ChannelID: chanID,
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NodeKey1Bytes: chanInfo.Node1,
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NodeKey2Bytes: chanInfo.Node2,
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}
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policy1 := &channeldb.ChannelEdgePolicy{
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FeeBaseMSat: lnwire.MilliSatoshi(
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chanInfo.Node1Policy.FeeBaseMsat,
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),
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FeeProportionalMillionths: lnwire.MilliSatoshi(
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chanInfo.Node1Policy.FeeRateMilliMsat,
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),
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TimeLockDelta: uint16(chanInfo.Node1Policy.TimeLockDelta),
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}
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policy2 := &channeldb.ChannelEdgePolicy{
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FeeBaseMSat: lnwire.MilliSatoshi(
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chanInfo.Node2Policy.FeeBaseMsat,
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),
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FeeProportionalMillionths: lnwire.MilliSatoshi(
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chanInfo.Node2Policy.FeeRateMilliMsat,
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),
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TimeLockDelta: uint16(chanInfo.Node2Policy.TimeLockDelta),
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}
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return edgeInfo, policy1, policy2, nil
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}
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// parseOutPoint attempts to parse an outpoint from the passed in string.
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func parseOutPoint(s string) (*wire.OutPoint, error) {
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split := strings.Split(s, ":")
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if len(split) != 2 {
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return nil, fmt.Errorf("expecting outpoint to be in format "+
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"of txid:index: %s", s)
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}
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index, err := strconv.ParseInt(split[1], 10, 32)
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if err != nil {
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return nil, fmt.Errorf("unable to decode output index: %v", err)
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}
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txid, err := chainhash.NewHashFromStr(split[0])
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if err != nil {
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return nil, fmt.Errorf("unable to parse hex string: %v", err)
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}
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return &wire.OutPoint{
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Hash: *txid,
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Index: uint32(index),
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}, nil
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}
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// SelectHopHints calls into LND's exposed SelectHopHints prefiltered to the
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// includeNodes map (unless it's empty).
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func SelectHopHints(ctx context.Context, lnd *lndclient.LndServices,
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amtMSat btcutil.Amount, numMaxHophints int,
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amt btcutil.Amount, numMaxHophints int,
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includeNodes map[route.Vertex]struct{}) ([][]zpay32.HopHint, error) {
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cfg := &invoicesrpc.SelectHopHintsCfg{
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IsPublicNode: func(pubKey [33]byte) (bool, error) {
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return isPublicNode(ctx, lnd, pubKey)
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},
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FetchChannelEdgesByID: func(chanID uint64) (
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*channeldb.ChannelEdgeInfo, *channeldb.ChannelEdgePolicy,
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*channeldb.ChannelEdgePolicy, error) {
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return fetchChannelEdgesByID(ctx, lnd, chanID)
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},
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}
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// Fetch all active and public channels.
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openChannels, err := lnd.Client.ListChannels(ctx, false, false)
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channels, err := lnd.Client.ListChannels(ctx, false, false)
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if err != nil {
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return nil, err
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}
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// We'll add our hop hints in two passes, first we'll add all channels
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// that are eligible to be hop hints, and also have a local balance
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// above the payment amount.
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var totalHintBandwidth btcutil.Amount
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// chanInfoCache is a simple cache for any information we retrieve
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// through GetChanInfo
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chanInfoCache := make(map[uint64]*lndclient.ChannelEdge)
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// skipCache is a simple cache which holds the indice of any
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// channel we've added to final hopHints
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skipCache := make(map[int]struct{})
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hopHints := make([][]zpay32.HopHint, 0, numMaxHophints)
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for i, channel := range openChannels {
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// In this first pass, we'll ignore all channels in
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// isolation that can't satisfy this payment.
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// Retrieve extra info for each channel not available in
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// listChannels
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chanInfo, err := lnd.Client.GetChanInfo(ctx, channel.ChannelID)
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if err != nil {
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return nil, err
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}
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// Cache the GetChanInfo result since it might be useful
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chanInfoCache[channel.ChannelID] = chanInfo
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// Skip if channel can't forward payment
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if channel.RemoteBalance < amtMSat {
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log.Debugf(
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"Skipping ChannelID: %v for hints as "+
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"remote balance (%v sats) "+
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"insufficient appears to be private",
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channel.ChannelID, channel.RemoteBalance,
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)
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continue
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}
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// If includeNodes is set, we'll only add channels with peers in
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// includeNodes. This is done to respect the last_hop parameter.
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openChannels := []*invoicesrpc.HopHintInfo{}
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for _, channel := range channels {
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if len(includeNodes) > 0 {
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if _, ok := includeNodes[channel.PubKeyBytes]; !ok {
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continue
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}
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}
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// Mark the index to skip so we can skip it on the next
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// iteration if needed. We'll skip all channels that make
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// it past this point as they'll likely belong to private
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// nodes or be selected.
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skipCache[i] = struct{}{}
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// We want to prevent leaking private nodes, which we define as
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// nodes with only private channels.
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//
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// GetNodeInfo will never return private channels, even if
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// they're somehow known to us. If there are any channels
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// returned, we can consider the node to be public.
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nodeInfo, err := lnd.Client.GetNodeInfo(
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ctx, channel.PubKeyBytes, true,
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)
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// If the error is node isn't found, just iterate. Otherwise,
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// fail.
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status, ok := status.FromError(err)
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if ok && status.Code() == codes.NotFound {
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log.Warnf("Skipping ChannelID: %v for hints as peer "+
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"(NodeID: %v) is not found: %v",
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channel.ChannelID, channel.PubKeyBytes.String(),
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err)
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continue
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} else if err != nil {
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outPoint, err := parseOutPoint(channel.ChannelPoint)
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if err != nil {
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return nil, err
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}
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if len(nodeInfo.Channels) == 0 {
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log.Infof(
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"Skipping ChannelID: %v for hints as peer "+
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"(NodeID: %v) appears to be private",
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channel.ChannelID, channel.PubKeyBytes.String(),
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)
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continue
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}
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nodeID, err := btcec.ParsePubKey(
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remotePubkey, err := btcec.ParsePubKey(
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channel.PubKeyBytes[:], btcec.S256(),
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)
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if err != nil {
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return nil, err
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}
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// Now that we now this channel use usable, add it as a hop
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// hint and the indexes we'll use later.
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hopHints = append(hopHints, []zpay32.HopHint{{
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NodeID: nodeID,
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ChannelID: channel.ChannelID,
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FeeBaseMSat: uint32(chanInfo.Node2Policy.FeeBaseMsat),
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FeeProportionalMillionths: uint32(
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chanInfo.Node2Policy.FeeRateMilliMsat,
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),
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CLTVExpiryDelta: uint16(
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chanInfo.Node2Policy.TimeLockDelta),
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}})
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totalHintBandwidth += channel.RemoteBalance
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openChannels = append(
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openChannels, &invoicesrpc.HopHintInfo{
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IsPublic: !channel.Private,
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IsActive: channel.Active,
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FundingOutpoint: *outPoint,
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RemotePubkey: remotePubkey,
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RemoteBalance: lnwire.MilliSatoshi(
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channel.RemoteBalance * 1000,
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),
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ShortChannelID: channel.ChannelID,
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},
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)
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}
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// If we have enough hop hints at this point, then we'll exit early.
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// Otherwise, we'll continue to add more that may help out mpp users.
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if len(hopHints) >= numMaxHophints {
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return hopHints, nil
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}
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routeHints := invoicesrpc.SelectHopHints(
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lnwire.MilliSatoshi(amt*1000), cfg, openChannels, numMaxHophints,
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)
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// In this second pass we'll add channels, and we'll either stop when
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// we have 20 hop hints, we've run through all the available channels,
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// or if the sum of available bandwidth in the routing hints exceeds 2x
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// the payment amount. We do 2x here to account for a margin of error
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// if some of the selected channels no longer become operable.
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hopHintFactor := btcutil.Amount(lnwire.MilliSatoshi(2))
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for i := 0; i < len(openChannels); i++ {
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// If we hit either of our early termination conditions, then
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// we'll break the loop here.
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if totalHintBandwidth > amtMSat*hopHintFactor ||
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len(hopHints) >= numMaxHophints {
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break
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}
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// Skip the channel if we already selected it.
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if _, ok := skipCache[i]; ok {
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continue
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}
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channel := openChannels[i]
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chanInfo := chanInfoCache[channel.ChannelID]
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nodeID, err := btcec.ParsePubKey(
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channel.PubKeyBytes[:], btcec.S256())
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if err != nil {
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continue
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}
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// Include the route hint in our set of options that will be
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// used when creating the invoice.
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hopHints = append(hopHints, []zpay32.HopHint{{
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NodeID: nodeID,
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ChannelID: channel.ChannelID,
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FeeBaseMSat: uint32(chanInfo.Node2Policy.FeeBaseMsat),
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FeeProportionalMillionths: uint32(
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chanInfo.Node2Policy.FeeRateMilliMsat,
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),
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CLTVExpiryDelta: uint16(
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chanInfo.Node2Policy.TimeLockDelta),
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}})
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// As we've just added a new hop hint, we'll accumulate it's
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// available balance now to update our tally.
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//
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// TODO(roasbeef): have a cut off based on min bandwidth?
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totalHintBandwidth += channel.RemoteBalance
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}
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return hopHints, nil
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return routeHints, nil
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}
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