lnd.xprv/discovery/gossiper.go

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package discovery
import (
"bytes"
"fmt"
"sync"
"sync/atomic"
"time"
"github.com/davecgh/go-spew/spew"
"github.com/go-errors/errors"
"github.com/lightningnetwork/lnd/chainntnfs"
"github.com/lightningnetwork/lnd/channeldb"
"github.com/lightningnetwork/lnd/lnwallet"
"github.com/lightningnetwork/lnd/lnwire"
"github.com/lightningnetwork/lnd/routing"
"github.com/roasbeef/btcd/btcec"
"github.com/roasbeef/btcd/chaincfg/chainhash"
"github.com/roasbeef/btcd/wire"
)
// networkMsg couples a routing related wire message with the peer that
// originally sent it.
type networkMsg struct {
peer *btcec.PublicKey
msg lnwire.Message
isRemote bool
err chan error
}
// syncRequest represents a request from an outside subsystem to the wallet to
// sync a new node to the latest graph state.
type syncRequest struct {
node *btcec.PublicKey
}
// feeUpdateRequest is a request that is sent to the server when a caller
// wishes to update the fees for a particular set of channels. New UpdateFee
// messages will be crafted to be sent out during the next broadcast epoch and
// the fee updates committed to the lower layer.
type feeUpdateRequest struct {
targetChans []wire.OutPoint
newSchema routing.FeeSchema
errResp chan error
}
// Config defines the configuration for the service. ALL elements within the
// configuration MUST be non-nil for the service to carry out its duties.
type Config struct {
// ChainHash is a hash that indicates which resident chain of the
// AuthenticatedGossiper. Any announcements that don't match this
// chain hash will be ignored.
//
// TODO(roasbeef): eventually make into map so can de-multiplex
// incoming announcements
// * also need to do same for Notifier
ChainHash chainhash.Hash
// Router is the subsystem which is responsible for managing the
// topology of lightning network. After incoming channel, node, channel
// updates announcements are validated they are sent to the router in
// order to be included in the LN graph.
Router routing.ChannelGraphSource
// Notifier is used for receiving notifications of incoming blocks.
// With each new incoming block found we process previously premature
// announcements.
//
// TODO(roasbeef): could possibly just replace this with an epoch
// channel.
Notifier chainntnfs.ChainNotifier
// Broadcast broadcasts a particular set of announcements to all peers
// that the daemon is connected to. If supplied, the exclude parameter
// indicates that the target peer should be excluded from the
// broadcast.
Broadcast func(exclude *btcec.PublicKey, msg ...lnwire.Message) error
// SendToPeer is a function which allows the service to send a set of
// messages to a particular peer identified by the target public key.
SendToPeer func(target *btcec.PublicKey, msg ...lnwire.Message) error
// ProofMatureDelta the number of confirmations which is needed before
// exchange the channel announcement proofs.
ProofMatureDelta uint32
// TrickleDelay the period of trickle timer which flushing to the
// network the pending batch of new announcements we've received since
// the last trickle tick.
TrickleDelay time.Duration
// RetransmitDelay is the period of a timer which indicates that we
// should check if we need re-broadcast any of our personal channels.
RetransmitDelay time.Duration
// DB is a global boltdb instance which is needed to pass it in waiting
// proof storage to make waiting proofs persistent.
DB *channeldb.DB
// AnnSigner is an instance of the MessageSigner interface which will
// be used to manually sign any outgoing channel updates. The signer
// implementation should be backed by the public key of the backing
// Lightning node.
//
// TODO(roasbeef): extract ann crafting + sign from fundingMgr into
// here?
AnnSigner lnwallet.MessageSigner
}
// AuthenticatedGossiper is a subsystem which is responsible for receiving
// announcements validate them and apply the changes to router, syncing
// lightning network with newly connected nodes, broadcasting announcements
// after validation, negotiating the channel announcement proofs exchange and
// handling the premature announcements. All outgoing announcements are
// expected to be properly signed as dictated in BOLT#7, additionally, all
// incoming message are expected to be well formed and signed. Invalid messages
// will be rejected by this struct.
type AuthenticatedGossiper struct {
// Parameters which are needed to properly handle the start and stop of
// the service.
started uint32
stopped uint32
quit chan struct{}
wg sync.WaitGroup
// cfg is a copy of the configuration struct that the gossiper service
// was initialized with.
cfg *Config
// newBlocks is a channel in which new blocks connected to the end of
// the main chain are sent over.
newBlocks <-chan *chainntnfs.BlockEpoch
// prematureAnnouncements maps a block height to a set of network
// messages which are "premature" from our PoV. An message is premature
// if it claims to be anchored in a block which is beyond the current
// main chain tip as we know it. Premature network messages will be
// processed once the chain tip as we know it extends to/past the
// premature height.
//
// TODO(roasbeef): limit premature networkMsgs to N
prematureAnnouncements map[uint32][]*networkMsg
// waitingProofs is a persistent storage of partial channel proof
// announcement messages. We use it to buffer half of the material
// needed to reconstruct a full authenticated channel announcement. Once
// we receive the other half the channel proof, we'll be able to
// properly validate it an re-broadcast it out to the network.
waitingProofs *channeldb.WaitingProofStore
// networkMsgs is a channel that carries new network broadcasted
// message from outside the gossiper service to be processed by the
// networkHandler.
networkMsgs chan *networkMsg
// syncRequests is a channel that carries requests to synchronize newly
// connected peers to the state of the lightning network topology from
// our PoV.
syncRequests chan *syncRequest
// feeUpdates is a channel that requests to update the fee schedule of
// a set of channels is sent over.
feeUpdates chan *feeUpdateRequest
// bestHeight is the height of the block at the tip of the main chain
// as we know it.
bestHeight uint32
// selfKey is the identity public key of the backing Lighting node.
selfKey *btcec.PublicKey
}
// New creates a new AuthenticatedGossiper instance, initialized with the
// passed configuration parameters.
func New(cfg Config, selfKey *btcec.PublicKey) (*AuthenticatedGossiper, error) {
storage, err := channeldb.NewWaitingProofStore(cfg.DB)
if err != nil {
return nil, err
}
return &AuthenticatedGossiper{
selfKey: selfKey,
cfg: &cfg,
networkMsgs: make(chan *networkMsg),
quit: make(chan struct{}),
syncRequests: make(chan *syncRequest),
feeUpdates: make(chan *feeUpdateRequest),
prematureAnnouncements: make(map[uint32][]*networkMsg),
waitingProofs: storage,
}, nil
}
// SynchronizeNode sends a message to the service indicating it should
// synchronize lightning topology state with the target node. This method is to
// be utilized when a node connections for the first time to provide it with
// the latest topology update state.
func (d *AuthenticatedGossiper) SynchronizeNode(pub *btcec.PublicKey) {
select {
case d.syncRequests <- &syncRequest{
node: pub,
}:
case <-d.quit:
return
}
}
// PropagateFeeUpdate signals the AuthenticatedGossiper to update the fee
// schema for the specified channels. If no channels are specified, then the
// fee update will be applied to all outgoing channels from the source node.
// Fee updates are done in two stages: first, the AuthenticatedGossiper ensures
// the updated has been committed by dependant sub-systems, then it signs and
// broadcasts new updates to the network.
func (d *AuthenticatedGossiper) PropagateFeeUpdate(newSchema routing.FeeSchema,
chanPoints ...wire.OutPoint) error {
errChan := make(chan error, 1)
feeUpdate := &feeUpdateRequest{
targetChans: chanPoints,
newSchema: newSchema,
errResp: errChan,
}
select {
case d.feeUpdates <- feeUpdate:
return <-errChan
case <-d.quit:
return fmt.Errorf("AuthenticatedGossiper shutting down")
}
}
// Start spawns network messages handler goroutine and registers on new block
// notifications in order to properly handle the premature announcements.
func (d *AuthenticatedGossiper) Start() error {
if !atomic.CompareAndSwapUint32(&d.started, 0, 1) {
return nil
}
log.Info("Authenticated Gossiper is starting")
// First we register for new notifications of newly discovered blocks.
// We do this immediately so we'll later be able to consume any/all
// blocks which were discovered.
blockEpochs, err := d.cfg.Notifier.RegisterBlockEpochNtfn()
if err != nil {
return err
}
d.newBlocks = blockEpochs.Epochs
height, err := d.cfg.Router.CurrentBlockHeight()
if err != nil {
return err
}
d.bestHeight = height
d.wg.Add(1)
go d.networkHandler()
return nil
}
// Stop signals any active goroutines for a graceful closure.
func (d *AuthenticatedGossiper) Stop() {
if !atomic.CompareAndSwapUint32(&d.stopped, 0, 1) {
return
}
log.Info("Authenticated Gossiper is stopping")
close(d.quit)
d.wg.Wait()
}
// ProcessRemoteAnnouncement sends a new remote announcement message along with
// the peer that sent the routing message. The announcement will be processed
// then added to a queue for batched trickled announcement to all connected
// peers. Remote channel announcements should contain the announcement proof
// and be fully validated.
func (d *AuthenticatedGossiper) ProcessRemoteAnnouncement(msg lnwire.Message,
src *btcec.PublicKey) chan error {
nMsg := &networkMsg{
msg: msg,
isRemote: true,
peer: src,
err: make(chan error, 1),
}
select {
case d.networkMsgs <- nMsg:
case <-d.quit:
nMsg.err <- errors.New("gossiper has shut down")
}
return nMsg.err
}
// ProcessLocalAnnouncement sends a new remote announcement message along with
// the peer that sent the routing message. The announcement will be processed
// then added to a queue for batched trickled announcement to all connected
// peers. Local channel announcements don't contain the announcement proof and
// will not be fully validated. Once the channel proofs are received, the
// entire channel announcement and update messages will be re-constructed and
// broadcast to the rest of the network.
func (d *AuthenticatedGossiper) ProcessLocalAnnouncement(msg lnwire.Message,
src *btcec.PublicKey) chan error {
nMsg := &networkMsg{
msg: msg,
isRemote: false,
peer: src,
err: make(chan error, 1),
}
select {
case d.networkMsgs <- nMsg:
case <-d.quit:
nMsg.err <- errors.New("gossiper has shut down")
}
return nMsg.err
}
// networkHandler is the primary goroutine that drives this service. The roles
// of this goroutine includes answering queries related to the state of the
// network, syncing up newly connected peers, and also periodically
// broadcasting our latest topology state to all connected peers.
//
// NOTE: This MUST be run as a goroutine.
func (d *AuthenticatedGossiper) networkHandler() {
defer d.wg.Done()
// TODO(roasbeef): changes for spec compliance
// * make into de-duplicated struct
// * always send chan ann -> node ann -> chan update
// * buffer recv'd node ann until after chan ann that includes is
// created
// * can use mostly empty struct in db as place holder
var announcementBatch []lnwire.Message
retransmitTimer := time.NewTicker(d.cfg.RetransmitDelay)
defer retransmitTimer.Stop()
trickleTimer := time.NewTicker(d.cfg.TrickleDelay)
defer trickleTimer.Stop()
// To start, we'll first check to see if there're any stale channels
// that we need to re-transmit.
if err := d.retransmitStaleChannels(); err != nil {
log.Errorf("unable to rebroadcast stale channels: %v",
err)
}
for {
select {
// A new fee update has arrived. We'll commit it to the
// sub-systems below us, then craft, sign, and broadcast a new
// ChannelUpdate for the set of affected clients.
case feeUpdate := <-d.feeUpdates:
// First, we'll now create new fully signed updates for
// the affected channels and also update the underlying
// graph with the new state.
newChanUpdates, err := d.processFeeChanUpdate(feeUpdate)
if err != nil {
log.Errorf("Unable to craft fee updates: %v", err)
feeUpdate.errResp <- err
continue
}
// Finally, with the updates committed, we'll now add
// them to the announcement batch to be flushed at the
// start of the next epoch.
announcementBatch = append(announcementBatch,
newChanUpdates...)
feeUpdate.errResp <- nil
case announcement := <-d.networkMsgs:
// Process the network announcement to determine if
// this is either a new announcement from our PoV or an
// edges to a prior vertex/edge we previously
// proceeded.
emittedAnnouncements := d.processNetworkAnnouncement(announcement)
// If the announcement was accepted, then add the
// emitted announcements to our announce batch to be
// broadcast once the trickle timer ticks gain.
if emittedAnnouncements != nil {
// TODO(roasbeef): exclude peer that sent
announcementBatch = append(
announcementBatch,
emittedAnnouncements...,
)
}
// A new block has arrived, so we can re-process the previously
// premature announcements.
case newBlock, ok := <-d.newBlocks:
// If the channel has been closed, then this indicates
// the daemon is shutting down, so we exit ourselves.
if !ok {
return
}
// Once a new block arrives, we updates our running
// track of the height of the chain tip.
blockHeight := uint32(newBlock.Height)
d.bestHeight = blockHeight
// Next we check if we have any premature announcements
// for this height, if so, then we process them once
// more as normal announcements.
prematureAnns := d.prematureAnnouncements[uint32(newBlock.Height)]
if len(prematureAnns) != 0 {
log.Infof("Re-processing %v premature "+
"announcements for height %v",
len(prematureAnns), blockHeight)
}
for _, ann := range prematureAnns {
emittedAnnouncements := d.processNetworkAnnouncement(ann)
if emittedAnnouncements != nil {
announcementBatch = append(
announcementBatch,
emittedAnnouncements...,
)
}
}
delete(d.prematureAnnouncements, blockHeight)
// The trickle timer has ticked, which indicates we should
// flush to the network the pending batch of new announcements
// we've received since the last trickle tick.
case <-trickleTimer.C:
// If the current announcements batch is nil, then we
// have no further work here.
if len(announcementBatch) == 0 {
continue
}
log.Infof("Broadcasting batch of %v new announcements",
len(announcementBatch))
// If we have new things to announce then broadcast
// them to all our immediately connected peers.
err := d.cfg.Broadcast(nil, announcementBatch...)
if err != nil {
log.Errorf("unable to send batch "+
"announcements: %v", err)
continue
}
// If we're able to broadcast the current batch
// successfully, then we reset the batch for a new
// round of announcements.
announcementBatch = nil
// The retransmission timer has ticked which indicates that we
// should check if we need to prune or re-broadcast any of our
// personal channels. This addresses the case of "zombie" channels and
// channel advertisements that have been dropped, or not properly
// propagated through the network.
case <-retransmitTimer.C:
if err := d.retransmitStaleChannels(); err != nil {
log.Errorf("unable to rebroadcast stale "+
"channels: %v", err)
}
// We've just received a new request to synchronize a peer with
// our latest lightning network topology state. This indicates
// that a peer has just connected for the first time, so for
// now we dump our entire network graph and allow them to sift
// through the (subjectively) new information on their own.
case syncReq := <-d.syncRequests:
nodePub := syncReq.node.SerializeCompressed()
if err := d.synchronizeWithNode(syncReq); err != nil {
log.Errorf("unable to sync graph state with %x: %v",
nodePub, err)
}
// The gossiper has been signalled to exit, to we exit our
// main loop so the wait group can be decremented.
case <-d.quit:
return
}
}
}
// retransmitStaleChannels eaxmines all outgoing channels that the source node
// is known to maintain to check to see if any of them are "stale". A channel
// is stale iff, the last timestamp of it's rebroadcast is older then
// broadcastInterval.
func (d *AuthenticatedGossiper) retransmitStaleChannels() error {
// Iterate over all of our channels and check if any of them fall
// within the prune interval or re-broadcast interval.
type updateTuple struct {
info *channeldb.ChannelEdgeInfo
edge *channeldb.ChannelEdgePolicy
}
var edgesToUpdate []updateTuple
err := d.cfg.Router.ForAllOutgoingChannels(func(
info *channeldb.ChannelEdgeInfo,
edge *channeldb.ChannelEdgePolicy) error {
const broadcastInterval = time.Hour * 24
timeElapsed := time.Since(edge.LastUpdate)
// If it's been a full day since we've re-broadcasted the
// channel, add the channel to the set of edges we need to
// update.
if timeElapsed >= broadcastInterval {
edgesToUpdate = append(edgesToUpdate, updateTuple{
info: info,
edge: edge,
})
}
return nil
})
if err != nil {
return fmt.Errorf("error while retrieving outgoing "+
"channels: %v", err)
}
var signedUpdates []lnwire.Message
for _, chanToUpdate := range edgesToUpdate {
// Re-sign and update the channel on disk and retrieve our
// ChannelUpdate to broadcast.
chanAnn, chanUpdate, err := d.updateChannel(chanToUpdate.info,
chanToUpdate.edge)
if err != nil {
return fmt.Errorf("unable to update channel: %v", err)
}
// If we have a valid announcement to transmit, then we'll send
// that along with the update.
if chanAnn != nil {
signedUpdates = append(signedUpdates, chanAnn)
}
signedUpdates = append(signedUpdates, chanUpdate)
}
// If we don't have any channels to re-broadcast, then we'll exit
// early.
if len(signedUpdates) == 0 {
return nil
}
log.Infof("Retransmitting %v outgoing channels", len(edgesToUpdate))
// With all the wire announcements properly crafted, we'll broadcast
// our known outgoing channels to all our immediate peers.
if err := d.cfg.Broadcast(nil, signedUpdates...); err != nil {
return fmt.Errorf("unable to re-broadcast channels: %v", err)
}
return nil
}
// processFeeChanUpdate generates a new set of channel updates with the new fee
// schema applied for each specified channel identified by its channel point.
// In the case that no channel points are specified, then the fee update will
// be applied to all channels. Finally, the backing ChannelGraphSource is
// updated with the latest information reflecting the applied fee updates.
//
// TODO(roasbeef): generalize into generic for any channel update
func (d *AuthenticatedGossiper) processFeeChanUpdate(feeUpdate *feeUpdateRequest) ([]lnwire.Message, error) {
// First, we'll construct a set of all the channels that need to be
// updated.
chansToUpdate := make(map[wire.OutPoint]struct{})
for _, chanPoint := range feeUpdate.targetChans {
chansToUpdate[chanPoint] = struct{}{}
}
haveChanFilter := len(chansToUpdate) != 0
var chanUpdates []lnwire.Message
// Next, we'll loop over all the outgoing channels the router knows of.
// If we have a filter then we'll only collected those channels,
// otherwise we'll collect them all.
err := d.cfg.Router.ForAllOutgoingChannels(func(info *channeldb.ChannelEdgeInfo,
edge *channeldb.ChannelEdgePolicy) error {
// If we have a channel filter, and this channel isn't a part
// of it, then we'll skip it.
if _, ok := chansToUpdate[info.ChannelPoint]; !ok && haveChanFilter {
return nil
}
// Apply the new fee schema to the edge.
edge.FeeBaseMSat = feeUpdate.newSchema.BaseFee
edge.FeeProportionalMillionths = lnwire.MilliSatoshi(
feeUpdate.newSchema.FeeRate,
)
// Re-sign and update the backing ChannelGraphSource, and
// retrieve our ChannelUpdate to broadcast.
_, chanUpdate, err := d.updateChannel(info, edge)
if err != nil {
return err
}
chanUpdates = append(chanUpdates, chanUpdate)
return nil
})
if err != nil {
return nil, err
}
return chanUpdates, nil
}
// processNetworkAnnouncement processes a new network relate authenticated
// channel or node announcement or announcements proofs. If the announcement
// didn't affect the internal state due to either being out of date, invalid,
// or redundant, then nil is returned. Otherwise, the set of announcements will
// be returned which should be broadcasted to the rest of the network.
func (d *AuthenticatedGossiper) processNetworkAnnouncement(nMsg *networkMsg) []lnwire.Message {
isPremature := func(chanID lnwire.ShortChannelID, delta uint32) bool {
// TODO(roasbeef) make height delta 6
// * or configurable
return chanID.BlockHeight+delta > d.bestHeight
}
var announcements []lnwire.Message
switch msg := nMsg.msg.(type) {
// A new node announcement has arrived which either presents new
// information about a node in one of the channels we know about, or a
// updating previously advertised information.
case *lnwire.NodeAnnouncement:
if nMsg.isRemote {
if err := d.validateNodeAnn(msg); err != nil {
err := errors.Errorf("unable to validate "+
"node announcement: %v", err)
log.Error(err)
nMsg.err <- err
return nil
}
}
node := &channeldb.LightningNode{
HaveNodeAnnouncement: true,
LastUpdate: time.Unix(int64(msg.Timestamp), 0),
Addresses: msg.Addresses,
PubKey: msg.NodeID,
Alias: msg.Alias.String(),
AuthSig: msg.Signature,
Features: msg.Features,
}
if err := d.cfg.Router.AddNode(node); err != nil {
if routing.IsError(err, routing.ErrOutdated,
routing.ErrIgnored) {
log.Debug(err)
} else {
log.Error(err)
}
nMsg.err <- err
return nil
}
// Node announcement was successfully proceeded and know it
// might be broadcast to other connected nodes.
announcements = append(announcements, msg)
nMsg.err <- nil
// TODO(roasbeef): get rid of the above
return announcements
// A new channel announcement has arrived, this indicates the
// *creation* of a new channel within the network. This only advertises
// the existence of a channel and not yet the routing policies in
// either direction of the channel.
case *lnwire.ChannelAnnouncement:
// We'll ignore any channel announcements that target any chain
// other than the set of chains we know of.
if !bytes.Equal(msg.ChainHash[:], d.cfg.ChainHash[:]) {
log.Error("Ignoring ChannelAnnouncement from "+
"chain=%v, gossiper on chain=%v", msg.ChainHash,
d.cfg.ChainHash)
return nil
}
// If the advertised inclusionary block is beyond our knowledge
// of the chain tip, then we'll put the announcement in limbo
// to be fully verified once we advance forward in the chain.
if isPremature(msg.ShortChannelID, 0) {
blockHeight := msg.ShortChannelID.BlockHeight
log.Infof("Announcement for chan_id=(%v), is premature: "+
"advertises height %v, only height %v is known",
msg.ShortChannelID.ToUint64(),
msg.ShortChannelID.BlockHeight, d.bestHeight)
d.prematureAnnouncements[blockHeight] = append(
d.prematureAnnouncements[blockHeight],
nMsg,
)
return nil
}
// If this is a remote channel announcement, then we'll validate
// all the signatures within the proof as it should be well
// formed.
var proof *channeldb.ChannelAuthProof
if nMsg.isRemote {
if err := d.validateChannelAnn(msg); err != nil {
err := errors.Errorf("unable to validate "+
"announcement: %v", err)
log.Error(err)
nMsg.err <- err
return nil
}
// If the proof checks out, then we'll save the proof
// itself to the database so we can fetch it later when
// gossiping with other nodes.
proof = &channeldb.ChannelAuthProof{
NodeSig1: msg.NodeSig1,
NodeSig2: msg.NodeSig2,
BitcoinSig1: msg.BitcoinSig1,
BitcoinSig2: msg.BitcoinSig2,
}
}
// With the proof validate (if necessary), we can now store it
// within the database for our path finding and syncing needs.
var featureBuf bytes.Buffer
if err := msg.Features.Encode(&featureBuf); err != nil {
2017-08-22 11:00:07 +03:00
log.Errorf("unable to encode features: %v", err)
nMsg.err <- err
return nil
}
edge := &channeldb.ChannelEdgeInfo{
ChannelID: msg.ShortChannelID.ToUint64(),
ChainHash: msg.ChainHash,
NodeKey1: msg.NodeID1,
NodeKey2: msg.NodeID2,
BitcoinKey1: msg.BitcoinKey1,
BitcoinKey2: msg.BitcoinKey2,
AuthProof: proof,
Features: featureBuf.Bytes(),
}
// We will add the edge to the channel router. If the nodes
// present in this channel are not present in the database, a
// partial node will be added to represent each node while we
// wait for a node announcement.
if err := d.cfg.Router.AddEdge(edge); err != nil {
if routing.IsError(err, routing.ErrOutdated,
routing.ErrIgnored) {
log.Debugf("Router rejected channel edge: %v",
err)
} else {
log.Errorf("Router rejected channel edge: %v",
err)
}
nMsg.err <- err
return nil
}
// Channel announcement was successfully proceeded and know it
// might be broadcast to other connected nodes if it was
// announcement with proof (remote).
if proof != nil {
announcements = append(announcements, msg)
}
nMsg.err <- nil
return announcements
// A new authenticated channel edge update has arrived. This indicates
// that the directional information for an already known channel has
// been updated.
case *lnwire.ChannelUpdate:
// We'll ignore any channel announcements that target any chain
// other than the set of chains we know of.
if !bytes.Equal(msg.ChainHash[:], d.cfg.ChainHash[:]) {
log.Error("Ignoring ChannelUpdate from "+
"chain=%v, gossiper on chain=%v", msg.ChainHash,
d.cfg.ChainHash)
return nil
}
blockHeight := msg.ShortChannelID.BlockHeight
shortChanID := msg.ShortChannelID.ToUint64()
// If the advertised inclusionary block is beyond our knowledge
// of the chain tip, then we'll put the announcement in limbo
// to be fully verified once we advance forward in the chain.
if isPremature(msg.ShortChannelID, 0) {
log.Infof("Update announcement for "+
"short_chan_id(%v), is premature: advertises "+
"height %v, only height %v is known",
shortChanID, blockHeight, d.bestHeight)
d.prematureAnnouncements[blockHeight] = append(
d.prematureAnnouncements[blockHeight],
nMsg,
)
return nil
}
// Get the node pub key as far as we don't have it in channel
// update announcement message. We'll need this to properly
// verify message signature.
chanInfo, _, _, err := d.cfg.Router.GetChannelByID(msg.ShortChannelID)
if err != nil {
err := errors.Errorf("unable to validate "+
"channel update short_chan_id=%v: %v",
shortChanID, err)
log.Error(err)
nMsg.err <- err
return nil
}
// The flag on the channel update announcement tells us "which"
// side of the channels directed edge is being updated.
var pubKey *btcec.PublicKey
switch msg.Flags {
case 0:
pubKey = chanInfo.NodeKey1
case 1:
pubKey = chanInfo.NodeKey2
}
// Validate the channel announcement with the expected public
// key, In the case of an invalid channel , we'll return an
// error to the caller and exit early.
if err := d.validateChannelUpdateAnn(pubKey, msg); err != nil {
rErr := errors.Errorf("unable to validate channel "+
"update announcement for short_chan_id=%v: %v",
spew.Sdump(msg.ShortChannelID), err)
log.Error(rErr)
nMsg.err <- rErr
return nil
}
update := &channeldb.ChannelEdgePolicy{
Signature: msg.Signature,
ChannelID: shortChanID,
LastUpdate: time.Unix(int64(msg.Timestamp), 0),
Flags: msg.Flags,
TimeLockDelta: msg.TimeLockDelta,
MinHTLC: msg.HtlcMinimumMsat,
FeeBaseMSat: lnwire.MilliSatoshi(msg.BaseFee),
FeeProportionalMillionths: lnwire.MilliSatoshi(msg.FeeRate),
}
if err := d.cfg.Router.UpdateEdge(update); err != nil {
if routing.IsError(err, routing.ErrOutdated, routing.ErrIgnored) {
log.Debug(err)
} else {
log.Error(err)
}
nMsg.err <- err
return nil
}
// Channel update announcement was successfully processed and
// now it can be broadcast to the rest of the network. However,
// we'll only broadcast the channel update announcement if it
// has an attached authentication proof.
if chanInfo.AuthProof != nil {
announcements = append(announcements, msg)
}
nMsg.err <- nil
return announcements
// A new signature announcement has been received. This indicates
// willingness of nodes involved in the funding of a channel to
// announce this new channel to the rest of the world.
case *lnwire.AnnounceSignatures:
needBlockHeight := msg.ShortChannelID.BlockHeight + d.cfg.ProofMatureDelta
shortChanID := msg.ShortChannelID.ToUint64()
prefix := "local"
if nMsg.isRemote {
prefix = "remote"
}
log.Infof("Received new channel announcement: %v", spew.Sdump(msg))
// By the specification, channel announcement proofs should be
// sent after some number of confirmations after channel was
// registered in bitcoin blockchain. Therefore, we check if the
// proof is premature. If so we'll halt processing until the
// expected announcement height. This allows us to be tolerant
// to other clients if this constraint was changed.
if isPremature(msg.ShortChannelID, d.cfg.ProofMatureDelta) {
d.prematureAnnouncements[needBlockHeight] = append(
d.prematureAnnouncements[needBlockHeight],
nMsg,
)
log.Infof("Premature proof announcement, "+
"current block height lower than needed: %v <"+
" %v, add announcement to reprocessing batch",
d.bestHeight, needBlockHeight)
return nil
}
// Ensure that we know of a channel with the target channel ID
// before proceeding further.
chanInfo, e1, e2, err := d.cfg.Router.GetChannelByID(msg.ShortChannelID)
if err != nil {
// TODO(andrew.shvv) this is dangerous because remote
// node might rewrite the waiting proof.
proof := channeldb.NewWaitingProof(nMsg.isRemote, msg)
if err := d.waitingProofs.Add(proof); err != nil {
err := errors.Errorf("unable to store "+
"the proof for short_chan_id=%v: %v",
shortChanID, err)
log.Error(err)
nMsg.err <- err
return nil
}
log.Infof("Orphan %v proof announcement with "+
"short_chan_id=%v, adding"+
"to waiting batch", prefix, shortChanID)
nMsg.err <- nil
return nil
}
isFirstNode := bytes.Equal(nMsg.peer.SerializeCompressed(),
chanInfo.NodeKey1.SerializeCompressed())
isSecondNode := bytes.Equal(nMsg.peer.SerializeCompressed(),
chanInfo.NodeKey2.SerializeCompressed())
// Ensure that channel that was retrieved belongs to the peer
// which sent the proof announcement.
if !(isFirstNode || isSecondNode) {
err := errors.Errorf("channel that was received not "+
"belongs to the peer which sent the proof, "+
"short_chan_id=%v", shortChanID)
log.Error(err)
nMsg.err <- err
return nil
}
// Check that we received the opposite proof. If so, then we're
// now able to construct the full proof, and create the channel
// announcement. If we didn't receive the opposite half of the
// proof than we should store it this one, and wait for
// opposite to be received.
proof := channeldb.NewWaitingProof(nMsg.isRemote, msg)
oppositeProof, err := d.waitingProofs.Get(proof.OppositeKey())
if err != nil && err != channeldb.ErrWaitingProofNotFound {
err := errors.Errorf("unable to get "+
"the opposite proof for short_chan_id=%v: %v",
shortChanID, err)
log.Error(err)
nMsg.err <- err
return nil
}
if err == channeldb.ErrWaitingProofNotFound {
if err := d.waitingProofs.Add(proof); err != nil {
err := errors.Errorf("unable to store "+
"the proof for short_chan_id=%v: %v",
shortChanID, err)
log.Error(err)
nMsg.err <- err
return nil
}
// If proof was sent by a local sub-system, then we'll
// send the announcement signature to the remote node
// so they can also reconstruct the full channel
// announcement.
if !nMsg.isRemote {
// Check that first node of the channel info
// corresponds to us.
var remotePeer *btcec.PublicKey
if isFirstNode {
remotePeer = chanInfo.NodeKey2
} else {
remotePeer = chanInfo.NodeKey1
}
err := d.cfg.SendToPeer(remotePeer, msg)
if err != nil {
log.Errorf("unable to send "+
"announcement message to peer: %x",
remotePeer.SerializeCompressed())
}
log.Infof("Sent channel announcement proof "+
"for short_chan_id=%v to remote peer: "+
"%x", shortChanID,
remotePeer.SerializeCompressed())
}
log.Infof("1/2 of channel ann proof received for "+
"short_chan_id=%v, waiting for other half",
shortChanID)
nMsg.err <- nil
return nil
}
// If we now have both halves of the channel announcement
// proof, then we'll reconstruct the initial announcement so we
// can validate it shortly below.
var dbProof channeldb.ChannelAuthProof
if isFirstNode {
dbProof.NodeSig1 = msg.NodeSignature
dbProof.NodeSig2 = oppositeProof.NodeSignature
dbProof.BitcoinSig1 = msg.BitcoinSignature
dbProof.BitcoinSig2 = oppositeProof.BitcoinSignature
} else {
dbProof.NodeSig1 = oppositeProof.NodeSignature
dbProof.NodeSig2 = msg.NodeSignature
dbProof.BitcoinSig1 = oppositeProof.BitcoinSignature
dbProof.BitcoinSig2 = msg.BitcoinSignature
}
chanAnn, e1Ann, e2Ann := createChanAnnouncement(&dbProof, chanInfo, e1, e2)
// With all the necessary components assembled validate the
// full channel announcement proof.
if err := d.validateChannelAnn(chanAnn); err != nil {
err := errors.Errorf("channel announcement proof "+
"for short_chan_id=%v isn't valid: %v",
shortChanID, err)
log.Error(err)
nMsg.err <- err
return nil
}
// If the channel was returned by the router it means that
// existence of funding point and inclusion of nodes bitcoin
// keys in it already checked by the router. In this stage we
// should check that node keys are attest to the bitcoin keys
// by validating the signatures of announcement. If proof is
// valid then we'll populate the channel edge with it, so we
// can announce it on peer connect.
err = d.cfg.Router.AddProof(msg.ShortChannelID, &dbProof)
if err != nil {
err := errors.Errorf("unable add proof to the "+
"channel chanID=%v: %v", msg.ChannelID, err)
log.Error(err)
nMsg.err <- err
return nil
}
if err := d.waitingProofs.Remove(proof.OppositeKey()); err != nil {
err := errors.Errorf("unable remove opposite proof "+
"for the channel with chanID=%v: %v", msg.ChannelID, err)
log.Error(err)
nMsg.err <- err
return nil
}
// Proof was successfully created and now can announce the
// channel to the remain network.
log.Infof("Fully valid channel proof for short_chan_id=%v "+
"constructed, adding to next ann batch",
shortChanID)
// Assemble the necessary announcements to add to the next
// broadcasting batch.
announcements = append(announcements, chanAnn)
if e1Ann != nil {
announcements = append(announcements, e1Ann)
}
if e2Ann != nil {
announcements = append(announcements, e2Ann)
}
// If this a local announcement, then we'll send it to the
// remote side so they can reconstruct the full channel
// announcement proof.
if !nMsg.isRemote {
var remotePeer *btcec.PublicKey
if isFirstNode {
remotePeer = chanInfo.NodeKey2
} else {
remotePeer = chanInfo.NodeKey1
}
if err = d.cfg.SendToPeer(remotePeer, msg); err != nil {
log.Errorf("unable to send announcement "+
"message to peer: %x",
remotePeer.SerializeCompressed())
}
}
nMsg.err <- nil
return announcements
default:
nMsg.err <- errors.New("wrong type of the announcement")
return nil
}
}
// synchronizeWithNode attempts to synchronize the target node in the syncReq
// to the latest channel graph state. In order to accomplish this, (currently)
// the entire network graph is read from disk, then serialized to the format
// defined within the current wire protocol. This cache of graph data is then
// sent directly to the target node.
func (d *AuthenticatedGossiper) synchronizeWithNode(syncReq *syncRequest) error {
targetNode := syncReq.node
// TODO(roasbeef): need to also store sig data in db
// * will be nice when we switch to pairing sigs would only need one ^_^
// We'll collate all the gathered routing messages into a single slice
// containing all the messages to be sent to the target peer.
var announceMessages []lnwire.Message
// As peers are expecting channel announcements before node
// announcements, we first retrieve the initial announcement, as well as
// the latest channel update announcement for both of the directed edges
// that make up each channel, and queue these to be sent to the peer.
var numEdges uint32
if err := d.cfg.Router.ForEachChannel(func(chanInfo *channeldb.ChannelEdgeInfo,
e1, e2 *channeldb.ChannelEdgePolicy) error {
// First, using the parameters of the channel, along with the
// channel authentication proof, we'll create re-create the
// original authenticated channel announcement.
if chanInfo.AuthProof != nil {
chanAnn, e1Ann, e2Ann := createChanAnnouncement(
chanInfo.AuthProof, chanInfo, e1, e2)
announceMessages = append(announceMessages, chanAnn)
if e1Ann != nil {
announceMessages = append(announceMessages, e1Ann)
}
if e2Ann != nil {
announceMessages = append(announceMessages, e2Ann)
}
numEdges++
}
return nil
}); err != nil && err != channeldb.ErrGraphNoEdgesFound {
log.Errorf("unable to sync infos with peer: %v", err)
return err
}
// Run through all the vertexes in the graph, retrieving the data for
// the node announcements we originally retrieved.
var numNodes uint32
if err := d.cfg.Router.ForEachNode(func(node *channeldb.LightningNode) error {
// If this is a node we never received a node announcement for,
// we skip it.
if !node.HaveNodeAnnouncement {
return nil
}
alias, err := lnwire.NewNodeAlias(node.Alias)
if err != nil {
return err
}
ann := &lnwire.NodeAnnouncement{
Signature: node.AuthSig,
Timestamp: uint32(node.LastUpdate.Unix()),
Addresses: node.Addresses,
NodeID: node.PubKey,
Alias: alias,
Features: node.Features,
}
announceMessages = append(announceMessages, ann)
numNodes++
return nil
}); err != nil {
return err
}
log.Infof("Syncing channel graph state with %x, sending %v "+
"vertexes and %v edges", targetNode.SerializeCompressed(),
numNodes, numEdges)
// With all the announcement messages gathered, send them all in a
// single batch to the target peer.
return d.cfg.SendToPeer(targetNode, announceMessages...)
}
// updateChannel creates a new fully signed update for the channel, and updates
// the underlying graph with the new state.
func (d *AuthenticatedGossiper) updateChannel(info *channeldb.ChannelEdgeInfo,
edge *channeldb.ChannelEdgePolicy) (*lnwire.ChannelAnnouncement, *lnwire.ChannelUpdate, error) {
edge.LastUpdate = time.Now()
chanUpdate := &lnwire.ChannelUpdate{
Signature: edge.Signature,
ChainHash: info.ChainHash,
ShortChannelID: lnwire.NewShortChanIDFromInt(edge.ChannelID),
Timestamp: uint32(edge.LastUpdate.Unix()),
Flags: edge.Flags,
TimeLockDelta: edge.TimeLockDelta,
HtlcMinimumMsat: edge.MinHTLC,
BaseFee: uint32(edge.FeeBaseMSat),
FeeRate: uint32(edge.FeeProportionalMillionths),
}
// With the update applied, we'll generate a new signature over a
// digest of the channel announcement itself.
sig, err := SignAnnouncement(d.cfg.AnnSigner, d.selfKey, chanUpdate)
if err != nil {
return nil, nil, err
}
// Next, we'll set the new signature in place, and update the reference
// in the backing slice.
edge.Signature = sig
chanUpdate.Signature = sig
// To ensure that our signature is valid, we'll verify it ourself
// before committing it to the slice returned.
err = d.validateChannelUpdateAnn(d.selfKey, chanUpdate)
if err != nil {
return nil, nil, fmt.Errorf("generated invalid channel "+
"update sig: %v", err)
}
// Finally, we'll write the new edge policy to disk.
edge.Node.PubKey.Curve = nil
if err := d.cfg.Router.UpdateEdge(edge); err != nil {
return nil, nil, err
}
// We'll also create the original channel announcement so the two can
// be broadcast along side each other (if necessary), but only if we
// have a full channel announcement for this channel.
var chanAnn *lnwire.ChannelAnnouncement
if info.AuthProof != nil {
chanID := lnwire.NewShortChanIDFromInt(info.ChannelID)
chanAnn = &lnwire.ChannelAnnouncement{
NodeSig1: info.AuthProof.NodeSig1,
NodeSig2: info.AuthProof.NodeSig2,
ShortChannelID: chanID,
BitcoinSig1: info.AuthProof.BitcoinSig1,
BitcoinSig2: info.AuthProof.BitcoinSig2,
NodeID1: info.NodeKey1,
NodeID2: info.NodeKey2,
ChainHash: info.ChainHash,
BitcoinKey1: info.BitcoinKey1,
Features: lnwire.NewFeatureVector([]lnwire.Feature{}),
BitcoinKey2: info.BitcoinKey2,
}
}
return chanAnn, chanUpdate, err
}