lnd.xprv/peer.go

1786 lines
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package main
import (
"bytes"
"container/list"
"crypto/sha256"
"fmt"
"net"
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"sync"
"sync/atomic"
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"time"
"github.com/davecgh/go-spew/spew"
"github.com/go-errors/errors"
"github.com/lightningnetwork/lightning-onion"
"github.com/lightningnetwork/lnd/channeldb"
"github.com/lightningnetwork/lnd/lnrpc"
"github.com/lightningnetwork/lnd/lnwallet"
"github.com/lightningnetwork/lnd/lnwire"
"github.com/roasbeef/btcd/btcec"
"github.com/roasbeef/btcd/chaincfg/chainhash"
"github.com/roasbeef/btcd/connmgr"
"github.com/roasbeef/btcd/txscript"
"github.com/roasbeef/btcd/wire"
"github.com/roasbeef/btcutil"
)
var (
numNodes int32
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)
const (
// pingInterval is the interval at which ping messages are sent.
pingInterval = 1 * time.Minute
// outgoingQueueLen is the buffer size of the channel which houses
// messages to be sent across the wire, requested by objects outside
// this struct.
outgoingQueueLen = 50
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)
// outgoinMsg packages an lnwire.Message to be sent out on the wire, along with
// a buffered channel which will be sent upon once the write is complete. This
// buffered channel acts as a semaphore to be used for synchronization purposes.
type outgoinMsg struct {
msg lnwire.Message
sentChan chan struct{} // MUST be buffered.
}
// newChannelMsg packages a lnwallet.LightningChannel with a channel that
// allows the receiver of the request to report when the funding transaction
// has been confirmed and the channel creation process completed.
type newChannelMsg struct {
channel *lnwallet.LightningChannel
done chan struct{}
}
// chanSnapshotReq is a message sent by outside subsystems to a peer in order
// to gain a snapshot of the peer's currently active channels.
type chanSnapshotReq struct {
resp chan []*channeldb.ChannelSnapshot
}
// peer is an active peer on the Lightning Network. This struct is responsible
// for managing any channel state related to this peer. To do so, it has
// several helper goroutines to handle events such as HTLC timeouts, new
// funding workflow, and detecting an uncooperative closure of any active
// channels.
// TODO(roasbeef): proper reconnection logic
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type peer struct {
// The following fields are only meant to be used *atomically*
bytesReceived uint64
bytesSent uint64
// pingTime is a rough estimate of the RTT (round-trip-time) between us
// and the connected peer. This time is expressed in micro seconds.
// TODO(roasbeef): also use a WMA or EMA?
pingTime int64
// pingLastSend is the Unix time expressed in nanoseconds when we sent
// our last ping message.
pingLastSend int64
// MUST be used atomically.
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started int32
disconnect int32
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connReq *connmgr.ConnReq
conn net.Conn
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addr *lnwire.NetAddress
lightningID chainhash.Hash
inbound bool
id int32
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// This mutex protects all the stats below it.
sync.RWMutex
timeConnected time.Time
lastSend time.Time
lastRecv time.Time
// sendQueue is the channel which is used to queue outgoing to be
// written onto the wire. Note that this channel is unbuffered.
sendQueue chan outgoinMsg
// outgoingQueue is a buffered channel which allows second/third party
// objects to queue messages to be sent out on the wire.
outgoingQueue chan outgoinMsg
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// sendQueueSync is used as a semaphore to synchronize writes between
// the writeHandler and the queueHandler.
sendQueueSync chan struct{}
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// activeChannels is a map which stores the state machines of all
// active channels. Channels are indexed into the map by the txid of
// the funding transaction which opened the channel.
activeChanMtx sync.RWMutex
activeChannels map[lnwire.ChannelID]*lnwallet.LightningChannel
chanSnapshotReqs chan *chanSnapshotReq
htlcManMtx sync.RWMutex
htlcManagers map[lnwire.ChannelID]chan lnwire.Message
// newChannels is used by the fundingManager to send fully opened
// channels to the source peer which handled the funding workflow.
newChannels chan *newChannelMsg
// localCloseChanReqs is a channel in which any local requests to close
// a particular channel are sent over.
localCloseChanReqs chan *closeLinkReq
// remoteCloseChanReqs is a channel in which any remote requests
// (initiated by the remote peer) close a particular channel are sent
// over.
remoteCloseChanReqs chan *lnwire.CloseRequest
server *server
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// localSharedFeatures is a product of comparison of our and their
// local features vectors which consist of features which are present
// on both sides.
localSharedFeatures *lnwire.SharedFeatures
// globalSharedFeatures is a product of comparison of our and their
// global features vectors which consist of features which are present
// on both sides.
globalSharedFeatures *lnwire.SharedFeatures
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queueQuit chan struct{}
quit chan struct{}
wg sync.WaitGroup
}
// newPeer creates a new peer from an establish connection object, and a
// pointer to the main server.
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func newPeer(conn net.Conn, connReq *connmgr.ConnReq, server *server,
addr *lnwire.NetAddress, inbound bool) (*peer, error) {
nodePub := addr.IdentityKey
p := &peer{
conn: conn,
lightningID: chainhash.Hash(sha256.Sum256(nodePub.SerializeCompressed())),
addr: addr,
id: atomic.AddInt32(&numNodes, 1),
inbound: inbound,
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connReq: connReq,
server: server,
sendQueueSync: make(chan struct{}, 1),
sendQueue: make(chan outgoinMsg, 1),
outgoingQueue: make(chan outgoinMsg, outgoingQueueLen),
activeChannels: make(map[lnwire.ChannelID]*lnwallet.LightningChannel),
htlcManagers: make(map[lnwire.ChannelID]chan lnwire.Message),
chanSnapshotReqs: make(chan *chanSnapshotReq),
newChannels: make(chan *newChannelMsg, 1),
localCloseChanReqs: make(chan *closeLinkReq),
remoteCloseChanReqs: make(chan *lnwire.CloseRequest),
localSharedFeatures: nil,
globalSharedFeatures: nil,
queueQuit: make(chan struct{}),
quit: make(chan struct{}),
}
// Fetch and then load all the active channels we have with this
// remote peer from the database.
activeChans, err := server.chanDB.FetchOpenChannels(p.addr.IdentityKey)
if err != nil {
peerLog.Errorf("unable to fetch active chans "+
"for peer %v: %v", p, err)
return nil, err
}
peerLog.Debugf("Loaded %v active channels from database with peerID(%v)",
len(activeChans), p.id)
if err := p.loadActiveChannels(activeChans); err != nil {
return nil, err
}
return p, nil
}
// loadActiveChannels creates indexes within the peer for tracking all active
// channels returned by the database.
func (p *peer) loadActiveChannels(chans []*channeldb.OpenChannel) error {
for _, dbChan := range chans {
if dbChan.IsPending {
continue
}
lnChan, err := lnwallet.NewLightningChannel(p.server.lnwallet.Signer,
p.server.chainNotifier, dbChan)
if err != nil {
return err
}
chanPoint := *dbChan.ChanID
chanID := lnwire.NewChanIDFromOutPoint(&chanPoint)
p.activeChanMtx.Lock()
p.activeChannels[chanID] = lnChan
p.activeChanMtx.Unlock()
peerLog.Infof("peerID(%v) loaded ChannelPoint(%v)", p.id, chanPoint)
p.server.breachArbiter.newContracts <- lnChan
// Register this new channel link with the HTLC Switch. This is
// necessary to properly route multi-hop payments, and forward
// new payments triggered by RPC clients.
downstreamLink := make(chan *htlcPacket, 10)
plexChan := p.server.htlcSwitch.RegisterLink(p,
dbChan.Snapshot(), downstreamLink)
upstreamLink := make(chan lnwire.Message, 10)
p.htlcManMtx.Lock()
p.htlcManagers[chanID] = upstreamLink
p.htlcManMtx.Unlock()
p.wg.Add(1)
go p.htlcManager(lnChan, plexChan, downstreamLink, upstreamLink)
}
return nil
}
// Start starts all helper goroutines the peer needs for normal operations. In
// the case this peer has already been started, then this function is a loop.
func (p *peer) Start() error {
if atomic.AddInt32(&p.started, 1) != 1 {
return nil
}
peerLog.Tracef("peer %v starting", p)
// Exchange local and global features, the init message should be very
// first between two nodes.
if err := p.sendInitMsg(); err != nil {
return err
}
// Before we launch any of the helper goroutines off the peer struct,
// we'll first ensure proper adherence to the p2p protocl. The init
// message MUST be sent before any other message.
readErr := make(chan error, 1)
msgChan := make(chan lnwire.Message, 1)
go func() {
msg, _, err := p.readNextMessage()
if err != nil {
readErr <- err
msgChan <- nil
}
readErr <- nil
msgChan <- msg
}()
select {
// In order to avoid blocking indefinitely, we'll give the other peer
// an upper timeout of 15 seconds to respond before we bail out early.
case <-time.After(time.Second * 15):
return fmt.Errorf("peer did not complete handshake within 5 " +
"seconds")
case err := <-readErr:
if err != nil {
return err
}
}
msg := <-msgChan
if msg, ok := msg.(*lnwire.Init); ok {
if err := p.handleInitMsg(msg); err != nil {
return err
}
} else {
return errors.New("very first message between nodes " +
"must be init message")
}
p.wg.Add(5)
go p.queueHandler()
go p.writeHandler()
go p.readHandler()
go p.channelManager()
go p.pingHandler()
return nil
}
// Stop signals the peer for a graceful shutdown. All active goroutines will be
// signaled to wrap up any final actions. This function will also block until
// all goroutines have exited.
func (p *peer) Stop() error {
// If we're already disconnecting, just exit.
if !atomic.CompareAndSwapInt32(&p.disconnect, 0, 1) {
return nil
}
// Ensure that the TCP connection is properly closed before continuing.
p.conn.Close()
// Signal all worker goroutines to gracefully exit.
close(p.quit)
p.wg.Wait()
return nil
}
// TODO(roasbeef): add WaitForShutdown method
// Disconnect terminates the connection with the remote peer. Additionally, a
// signal is sent to the server and htlcSwitch indicating the resources
// allocated to the peer can now be cleaned up.
func (p *peer) Disconnect() {
if !atomic.CompareAndSwapInt32(&p.disconnect, 0, 1) {
return
}
peerLog.Tracef("Disconnecting %s", p)
// Ensure that the TCP connection is properly closed before continuing.
p.conn.Close()
close(p.quit)
// If this connection was established persistently, then notify the
// connection manager that the peer has been disconnected.
if p.connReq != nil {
p.server.connMgr.Disconnect(p.connReq.ID())
}
// Launch a goroutine to clean up the remaining resources.
go func() {
// Tell the switch to unregister all links associated with this
// peer. Passing nil as the target link indicates that all
// links associated with this interface should be closed.
p.server.htlcSwitch.UnregisterLink(p.addr.IdentityKey, nil)
p.server.donePeers <- p
}()
}
// String returns the string representation of this peer.
func (p *peer) String() string {
return p.conn.RemoteAddr().String()
}
// readNextMessage reads, and returns the next message on the wire along with
// any additional raw payload.
func (p *peer) readNextMessage() (lnwire.Message, []byte, error) {
// TODO(roasbeef): use our own net magic?
n, nextMsg, rawPayload, err := lnwire.ReadMessage(p.conn, 0,
p.addr.ChainNet)
atomic.AddUint64(&p.bytesReceived, uint64(n))
if err != nil {
return nil, nil, err
}
// TODO(roasbeef): add message summaries
p.logWireMessage(nextMsg, true)
return nextMsg, rawPayload, nil
}
// readHandler is responsible for reading messages off the wire in series, then
// properly dispatching the handling of the message to the proper subsystem.
//
// NOTE: This method MUST be run as a goroutine.
func (p *peer) readHandler() {
var activeChanMtx sync.Mutex
activeChanStreams := make(map[lnwire.ChannelID]struct{})
out:
for atomic.LoadInt32(&p.disconnect) == 0 {
nextMsg, _, err := p.readNextMessage()
if err != nil {
peerLog.Infof("unable to read message from %v: %v",
p, err)
switch err.(type) {
// If this is just a message we don't yet recognize,
// we'll continue processing as normal as this allows
// us to introduce new messages in a forwards
// compatible manner.
case *lnwire.UnknownMessage:
continue
// If the error we encountered wasn't just a message we
// didn't recognize, then we'll stop all processing s
// this is a fatal error.
default:
break out
}
}
var (
isChanUpdate bool
targetChan lnwire.ChannelID
)
switch msg := nextMsg.(type) {
case *lnwire.Pong:
// When we receive a Pong message in response to our
// last ping message, we'll use the time in which we
// sent the ping message to measure a rough estimate of
// round trip time.
pingSendTime := atomic.LoadInt64(&p.pingLastSend)
delay := (time.Now().UnixNano() - pingSendTime) / 1000
atomic.StoreInt64(&p.pingTime, delay)
case *lnwire.Ping:
pongBytes := make([]byte, msg.NumPongBytes)
p.queueMsg(lnwire.NewPong(pongBytes), nil)
case *lnwire.SingleFundingRequest:
p.server.fundingMgr.processFundingRequest(msg, p.addr)
case *lnwire.SingleFundingResponse:
p.server.fundingMgr.processFundingResponse(msg, p.addr)
case *lnwire.SingleFundingComplete:
p.server.fundingMgr.processFundingComplete(msg, p.addr)
case *lnwire.SingleFundingSignComplete:
p.server.fundingMgr.processFundingSignComplete(msg, p.addr)
case *lnwire.FundingLocked:
p.server.fundingMgr.processFundingLocked(msg, p.addr)
case *lnwire.CloseRequest:
p.remoteCloseChanReqs <- msg
case *lnwire.Error:
p.server.fundingMgr.processFundingError(msg, p.addr)
// TODO(roasbeef): create ChanUpdater interface for the below
case *lnwire.UpdateAddHTLC:
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isChanUpdate = true
targetChan = msg.ChanID
case *lnwire.UpdateFufillHTLC:
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isChanUpdate = true
targetChan = msg.ChanID
case *lnwire.UpdateFailHTLC:
isChanUpdate = true
targetChan = msg.ChanID
case *lnwire.RevokeAndAck:
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isChanUpdate = true
targetChan = msg.ChanID
case *lnwire.CommitSig:
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isChanUpdate = true
targetChan = msg.ChanID
case *lnwire.ChannelUpdateAnnouncement,
*lnwire.ChannelAnnouncement,
*lnwire.NodeAnnouncement,
*lnwire.AnnounceSignatures:
p.server.discoverSrv.ProcessRemoteAnnouncement(msg,
p.addr.IdentityKey)
default:
peerLog.Errorf("unknown message received from peer "+
"%v", p)
}
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if isChanUpdate {
sendUpdate := func() {
// Dispatch the commitment update message to
// the proper active goroutine dedicated to
// this channel.
p.htlcManMtx.RLock()
channel, ok := p.htlcManagers[targetChan]
p.htlcManMtx.RUnlock()
if !ok {
peerLog.Errorf("recv'd update for unknown "+
"channel %v from %v", targetChan, p)
return
}
channel <- nextMsg
}
// Check the map of active channel streams, if this map
// has an entry, then this means the channel is fully
// open. In this case, we can send the channel update
// directly without any further waiting.
activeChanMtx.Lock()
_, ok := activeChanStreams[targetChan]
activeChanMtx.Unlock()
if ok {
sendUpdate()
continue
}
// Otherwise, we'll launch a goroutine to synchronize
// the processing of this message, with the opening of
// the channel as marked by the funding manage.
go func() {
// Block until the channel is marked open.
p.server.fundingMgr.waitUntilChannelOpen(targetChan)
// Once the channel is open, we'll mark the
// stream as active and send the update to the
// channel. Marking the stream lets us take the
// fast path above, skipping the check to the
// funding manager.
activeChanMtx.Lock()
activeChanStreams[targetChan] = struct{}{}
sendUpdate()
activeChanMtx.Unlock()
}()
}
}
p.Disconnect()
p.wg.Done()
peerLog.Tracef("readHandler for peer %v done", p)
}
// logWireMessage logs the receipt or sending of particular wire message. This
// function is used rather than just logging the message in order to produce
// less spammy log messages in trace mode by setting the 'Curve" parameter to
// nil. Doing this avoids printing out each of the field elements in the curve
// parameters for secp256k1.
func (p *peer) logWireMessage(msg lnwire.Message, read bool) {
switch m := msg.(type) {
case *lnwire.RevokeAndAck:
m.NextRevocationKey.Curve = nil
case *lnwire.NodeAnnouncement:
m.NodeID.Curve = nil
case *lnwire.ChannelAnnouncement:
m.NodeID1.Curve = nil
m.NodeID2.Curve = nil
m.BitcoinKey1.Curve = nil
m.BitcoinKey2.Curve = nil
case *lnwire.SingleFundingComplete:
m.RevocationKey.Curve = nil
case *lnwire.SingleFundingRequest:
m.CommitmentKey.Curve = nil
m.ChannelDerivationPoint.Curve = nil
case *lnwire.SingleFundingResponse:
m.ChannelDerivationPoint.Curve = nil
m.CommitmentKey.Curve = nil
m.RevocationKey.Curve = nil
case *lnwire.FundingLocked:
m.NextPerCommitmentPoint.Curve = nil
}
prefix := "readMessage from"
if !read {
prefix = "writeMessage to"
}
peerLog.Tracef(prefix+" %v: %v", p, newLogClosure(func() string {
return spew.Sdump(msg)
}))
}
// writeMessage writes the target lnwire.Message to the remote peer.
func (p *peer) writeMessage(msg lnwire.Message) error {
// Simply exit if we're shutting down.
if atomic.LoadInt32(&p.disconnect) != 0 {
return nil
}
// TODO(roasbeef): add message summaries
p.logWireMessage(msg, false)
n, err := lnwire.WriteMessage(p.conn, msg, 0, p.addr.ChainNet)
atomic.AddUint64(&p.bytesSent, uint64(n))
return err
}
// writeHandler is a goroutine dedicated to reading messages off of an incoming
// queue, and writing them out to the wire. This goroutine coordinates with the
// queueHandler in order to ensure the incoming message queue is quickly drained.
//
// NOTE: This method MUST be run as a goroutine.
func (p *peer) writeHandler() {
defer func() {
p.wg.Done()
peerLog.Tracef("writeHandler for peer %v done", p)
}()
for {
select {
case outMsg := <-p.sendQueue:
switch outMsg.msg.(type) {
// If we're about to send a ping message, then log the
// exact time in which we send the message so we can
// use the delay as a rough estimate of latency to the
// remote peer.
case *lnwire.Ping:
// TODO(roasbeef): do this before the write?
// possibly account for processing within func?
now := time.Now().UnixNano()
atomic.StoreInt64(&p.pingLastSend, now)
}
// Write out the message to the socket, closing the
// 'sentChan' if it's non-nil, The 'sentChan' allows
// callers to optionally synchronize sends with the
// writeHandler.
err := p.writeMessage(outMsg.msg)
if outMsg.sentChan != nil {
close(outMsg.sentChan)
}
if err != nil {
peerLog.Errorf("unable to write message: %v",
err)
p.Disconnect()
return
}
case <-p.quit:
return
}
}
}
// queueHandler is responsible for accepting messages from outside subsystems
// to be eventually sent out on the wire by the writeHandler.
//
// NOTE: This method MUST be run as a goroutine.
func (p *peer) queueHandler() {
defer p.wg.Done()
pendingMsgs := list.New()
for {
// Before add a queue'd message our pending message queue,
// we'll first try to aggressively empty out our pending list of
// messaging.
for {
// Examine the front of the queue. If this message is
// nil, then we've emptied out the queue and can accept
// new messages from outside sub-systems.
elem := pendingMsgs.Front()
if elem == nil {
break
}
select {
case p.sendQueue <- elem.Value.(outgoinMsg):
pendingMsgs.Remove(elem)
case <-p.quit:
return
default:
break
}
}
// If there weren't any messages to send, or the writehandler
// is still blocked, then we'll accept a new message into the
// queue from outside sub-systems.
select {
case <-p.quit:
return
case msg := <-p.outgoingQueue:
pendingMsgs.PushBack(msg)
}
}
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}
// pingHandler is responsible for periodically sending ping messages to the
// remote peer in order to keep the connection alive and/or determine if the
// connection is still active.
//
// NOTE: This method MUST be run as a goroutine.
func (p *peer) pingHandler() {
pingTicker := time.NewTicker(pingInterval)
defer pingTicker.Stop()
// TODO(roasbeef): make dynamic in order to create fake cover traffic
const numPingBytes = 16
out:
for {
select {
case <-pingTicker.C:
p.queueMsg(lnwire.NewPing(numPingBytes), nil)
case <-p.quit:
break out
}
}
p.wg.Done()
}
// PingTime returns the estimated ping time to the peer in microseconds.
func (p *peer) PingTime() int64 {
return atomic.LoadInt64(&p.pingTime)
}
// queueMsg queues a new lnwire.Message to be eventually sent out on the
// wire.
func (p *peer) queueMsg(msg lnwire.Message, doneChan chan struct{}) {
select {
case p.outgoingQueue <- outgoinMsg{msg, doneChan}:
case <-p.quit:
return
}
}
// ChannelSnapshots returns a slice of channel snapshots detailing all
// currently active channels maintained with the remote peer.
func (p *peer) ChannelSnapshots() []*channeldb.ChannelSnapshot {
resp := make(chan []*channeldb.ChannelSnapshot, 1)
p.chanSnapshotReqs <- &chanSnapshotReq{resp}
return <-resp
}
// channelManager is goroutine dedicated to handling all requests/signals
// pertaining to the opening, cooperative closing, and force closing of all
// channels maintained with the remote peer.
//
// NOTE: This method MUST be run as a goroutine.
func (p *peer) channelManager() {
out:
for {
select {
case req := <-p.chanSnapshotReqs:
p.activeChanMtx.RLock()
snapshots := make([]*channeldb.ChannelSnapshot, 0,
len(p.activeChannels))
for _, activeChan := range p.activeChannels {
snapshot := activeChan.StateSnapshot()
snapshots = append(snapshots, snapshot)
}
p.activeChanMtx.RUnlock()
req.resp <- snapshots
case newChanReq := <-p.newChannels:
chanPoint := newChanReq.channel.ChannelPoint()
chanID := lnwire.NewChanIDFromOutPoint(chanPoint)
p.activeChanMtx.Lock()
p.activeChannels[chanID] = newChanReq.channel
p.activeChanMtx.Unlock()
peerLog.Infof("New channel active ChannelPoint(%v) "+
"with peerId(%v)", chanPoint, p.id)
// Now that the channel is open, notify the Htlc
// Switch of a new active link.
// TODO(roasbeef): register needs to account for
// in-flight htlc's on restart
chanSnapShot := newChanReq.channel.StateSnapshot()
downstreamLink := make(chan *htlcPacket, 10)
plexChan := p.server.htlcSwitch.RegisterLink(p,
chanSnapShot, downstreamLink)
// With the channel registered to the HtlcSwitch spawn
// a goroutine to handle commitment updates for this
// new channel.
upstreamLink := make(chan lnwire.Message, 10)
p.htlcManMtx.Lock()
p.htlcManagers[chanID] = upstreamLink
p.htlcManMtx.Unlock()
p.wg.Add(1)
go p.htlcManager(newChanReq.channel, plexChan,
downstreamLink, upstreamLink)
close(newChanReq.done)
case req := <-p.localCloseChanReqs:
p.handleLocalClose(req)
case req := <-p.remoteCloseChanReqs:
p.handleRemoteClose(req)
case <-p.quit:
break out
}
}
p.wg.Done()
}
// executeCooperativeClose executes the initial phase of a user-executed
// cooperative channel close. The channel state machine is transitioned to the
// closing phase, then our half of the closing witness is sent over to the
// remote peer.
func (p *peer) executeCooperativeClose(channel *lnwallet.LightningChannel) (*chainhash.Hash, error) {
// Shift the channel state machine into a 'closing' state. This
// generates a signature for the closing tx, as well as a txid of the
// closing tx itself, allowing us to watch the network to determine
// when the remote node broadcasts the fully signed closing
// transaction.
sig, txid, err := channel.InitCooperativeClose()
if err != nil {
return nil, err
}
chanPoint := channel.ChannelPoint()
peerLog.Infof("Executing cooperative closure of "+
"ChanPoint(%v) with peerID(%v), txid=%v", chanPoint, p.id, txid)
// With our signature for the close tx generated, send the signature to
// the remote peer instructing it to close this particular channel
// point.
// TODO(roasbeef): remove encoding redundancy
closeSig, err := btcec.ParseSignature(sig, btcec.S256())
if err != nil {
return nil, err
}
chanID := lnwire.NewChanIDFromOutPoint(chanPoint)
closeReq := lnwire.NewCloseRequest(chanID, closeSig)
p.queueMsg(closeReq, nil)
return txid, nil
}
// handleLocalClose kicks-off the workflow to execute a cooperative or forced
// unilateral closure of the channel initiated by a local subsystem.
// TODO(roasbeef): if no more active channels with peer call Remove on connMgr
// with peerID
func (p *peer) handleLocalClose(req *closeLinkReq) {
var (
err error
closingTxid *chainhash.Hash
)
chanID := lnwire.NewChanIDFromOutPoint(req.chanPoint)
p.activeChanMtx.RLock()
channel := p.activeChannels[chanID]
p.activeChanMtx.RUnlock()
switch req.CloseType {
// A type of CloseRegular indicates that the user has opted to close
// out this channel on-chian, so we execute the cooperative channel
// closure workflow.
case CloseRegular:
closingTxid, err = p.executeCooperativeClose(channel)
peerLog.Infof("Attempting cooperative close of "+
"ChannelPoint(%v) with txid: %v", req.chanPoint,
closingTxid)
// A type of CloseBreach indicates that the counterparty has breached
// the channel therefore we need to clean up our local state.
case CloseBreach:
peerLog.Infof("ChannelPoint(%v) has been breached, wiping "+
"channel", req.chanPoint)
if err := wipeChannel(p, channel); err != nil {
peerLog.Infof("Unable to wipe channel after detected "+
"breach: %v", err)
req.err <- err
return
}
return
}
if err != nil {
req.err <- err
return
}
// Update the caller with a new event detailing the current pending
// state of this request.
req.updates <- &lnrpc.CloseStatusUpdate{
Update: &lnrpc.CloseStatusUpdate_ClosePending{
ClosePending: &lnrpc.PendingUpdate{
Txid: closingTxid[:],
},
},
}
// Finally, launch a goroutine which will request to be notified by the
// ChainNotifier once the closure transaction obtains a single
// confirmation.
go func() {
// TODO(roasbeef): add param for num needed confs
notifier := p.server.chainNotifier
confNtfn, err := notifier.RegisterConfirmationsNtfn(closingTxid, 1)
if err != nil {
req.err <- err
return
}
select {
case height, ok := <-confNtfn.Confirmed:
// In the case that the ChainNotifier is shutting down,
// all subscriber notification channels will be closed,
// generating a nil receive.
if !ok {
return
}
// The channel has been closed, remove it from any
// active indexes, and the database state.
peerLog.Infof("ChannelPoint(%v) is now closed at "+
"height %v", req.chanPoint, height.BlockHeight)
if err := wipeChannel(p, channel); err != nil {
req.err <- err
return
}
case <-p.quit:
return
}
// Respond to the local subsystem which requested the channel
// closure.
req.updates <- &lnrpc.CloseStatusUpdate{
Update: &lnrpc.CloseStatusUpdate_ChanClose{
ChanClose: &lnrpc.ChannelCloseUpdate{
ClosingTxid: closingTxid[:],
Success: true,
},
},
}
p.server.breachArbiter.settledContracts <- req.chanPoint
}()
}
// handleRemoteClose completes a request for cooperative channel closure
// initiated by the remote node.
func (p *peer) handleRemoteClose(req *lnwire.CloseRequest) {
p.activeChanMtx.RLock()
channel, ok := p.activeChannels[req.ChanID]
p.activeChanMtx.RUnlock()
if !ok {
peerLog.Errorf("unable to close channel, ChannelID(%v) is "+
"unknown", req.ChanID)
return
}
chanPoint := channel.ChannelPoint()
// Now that we have their signature for the closure transaction, we
// can assemble the final closure transaction, complete with our
// signature.
sig := req.RequesterCloseSig
closeSig := append(sig.Serialize(), byte(txscript.SigHashAll))
closeTx, err := channel.CompleteCooperativeClose(closeSig)
if err != nil {
peerLog.Errorf("unable to complete cooperative "+
"close for ChannelPoint(%v): %v",
chanPoint, err)
// TODO(roasbeef): send ErrorGeneric to other side
return
}
peerLog.Infof("Broadcasting cooperative close tx: %v",
newLogClosure(func() string {
return spew.Sdump(closeTx)
}))
// Finally, broadcast the closure transaction, to the network.
if err := p.server.lnwallet.PublishTransaction(closeTx); err != nil {
peerLog.Errorf("channel close tx from "+
"ChannelPoint(%v) rejected: %v",
chanPoint, err)
// TODO(roasbeef): send ErrorGeneric to other side
return
}
// TODO(roasbeef): also wait for confs before removing state
peerLog.Infof("ChannelPoint(%v) is now closed", chanPoint)
if err := wipeChannel(p, channel); err != nil {
peerLog.Errorf("unable to wipe channel: %v", err)
}
p.server.breachArbiter.settledContracts <- chanPoint
}
// wipeChannel removes the passed channel from all indexes associated with the
// peer, and deletes the channel from the database.
func wipeChannel(p *peer, channel *lnwallet.LightningChannel) error {
chanID := lnwire.NewChanIDFromOutPoint(channel.ChannelPoint())
p.activeChanMtx.Lock()
delete(p.activeChannels, chanID)
p.activeChanMtx.Unlock()
// Instruct the Htlc Switch to close this link as the channel is no
// longer active.
p.server.htlcSwitch.UnregisterLink(p.addr.IdentityKey, &chanID)
// Additionally, close up "down stream" link for the htlcManager which
// has been assigned to this channel. This servers the link between the
// htlcManager and the switch, signalling that the channel is no longer
// active.
p.htlcManMtx.RLock()
// If the channel can't be found in the map, then this channel has
// already been wiped.
htlcWireLink, ok := p.htlcManagers[chanID]
2016-09-13 05:04:08 +03:00
if !ok {
p.htlcManMtx.RUnlock()
2016-09-13 05:04:08 +03:00
return nil
}
close(htlcWireLink)
p.htlcManMtx.RUnlock()
2016-09-13 05:04:08 +03:00
// Next, we remove the htlcManager from our internal map as the
// goroutine should have exited gracefully due to the channel closure
// above.
p.htlcManMtx.RLock()
delete(p.htlcManagers, chanID)
p.htlcManMtx.RUnlock()
// Finally, we purge the channel's state from the database, leaving a
// small summary for historical records.
if err := channel.DeleteState(); err != nil {
peerLog.Errorf("Unable to delete ChannelPoint(%v) "+
"from db: %v", chanID, err)
return err
}
return nil
}
// pendingPayment represents a pending HTLC which has yet to be settled by the
// upstream peer. A pending payment encapsulates the initial HTLC add request
// additionally coupling the index of the HTLC within the log, and an error
// channel to signal the payment requester once the payment has been fully
// fufilled.
type pendingPayment struct {
htlc *lnwire.UpdateAddHTLC
index uint64
preImage chan [32]byte
err chan error
done chan struct{}
}
// commitmentState is the volatile+persistent state of an active channel's
// commitment update state-machine. This struct is used by htlcManager's to
// save meta-state required for proper functioning.
type commitmentState struct {
// htlcsToSettle is a list of preimages which allow us to settle one or
// many of the pending HTLCs we've received from the upstream peer.
htlcsToSettle map[uint64]*channeldb.Invoice
// htlcsToCancel is a set of HTLCs identified by their log index which
// are to be cancelled upon the next state transition.
htlcsToCancel map[uint64]lnwire.FailCode
// cancelReasons stores the reason why a particular HTLC was cancelled.
// The index of the HTLC within the log is mapped to the cancellation
// reason. This value is used to thread the proper error through to the
// htlcSwitch, or subsystem that initiated the HTLC.
cancelReasons map[uint64]lnwire.FailCode
// pendingBatch is slice of payments which have been added to the
// channel update log, but not yet committed to latest commitment.
pendingBatch []*pendingPayment
// clearedHTCLs is a map of outgoing HTLCs we've committed to in our
// chain which have not yet been settled by the upstream peer.
clearedHTCLs map[uint64]*pendingPayment
// switchChan is a channel used to send packets to the htlc switch for
// forwarding.
switchChan chan<- *htlcPacket
// sphinx is an instance of the Sphinx onion Router for this node. The
// router will be used to process all incoming Sphinx packets embedded
// within HTLC add messages.
sphinx *sphinx.Router
// pendingCircuits tracks the remote log index of the incoming HTLCs,
// mapped to the processed Sphinx packet contained within the HTLC.
// This map is used as a staging area between when an HTLC is added to
// the log, and when it's locked into the commitment state of both
// chains. Once locked in, the processed packet is sent to the switch
// along with the HTLC to forward the packet to the next hop.
pendingCircuits map[uint64]*sphinx.ProcessedPacket
channel *lnwallet.LightningChannel
chanPoint *wire.OutPoint
chanID lnwire.ChannelID
}
// htlcManager is the primary goroutine which drives a channel's commitment
// update state-machine in response to messages received via several channels.
// The htlcManager reads messages from the upstream (remote) peer, and also
// from several possible downstream channels managed by the htlcSwitch. In the
// event that an htlc needs to be forwarded, then send-only htlcPlex chan is
// used which sends htlc packets to the switch for forwarding. Additionally,
// the htlcManager handles acting upon all timeouts for any active HTLCs,
// manages the channel's revocation window, and also the htlc trickle
// queue+timer for this active channels.
func (p *peer) htlcManager(channel *lnwallet.LightningChannel,
htlcPlex chan<- *htlcPacket, downstreamLink <-chan *htlcPacket,
upstreamLink <-chan lnwire.Message) {
chanStats := channel.StateSnapshot()
peerLog.Infof("HTLC manager for ChannelPoint(%v) started, "+
"our_balance=%v, their_balance=%v, chain_height=%v",
channel.ChannelPoint(), chanStats.LocalBalance,
chanStats.RemoteBalance, chanStats.NumUpdates)
// A new session for this active channel has just started, therefore we
// need to send our initial revocation window to the remote peer.
for i := 0; i < lnwallet.InitialRevocationWindow; i++ {
rev, err := channel.ExtendRevocationWindow()
if err != nil {
peerLog.Errorf("unable to expand revocation window: %v", err)
continue
}
p.queueMsg(rev, nil)
}
chanPoint := channel.ChannelPoint()
state := &commitmentState{
channel: channel,
chanPoint: chanPoint,
chanID: lnwire.NewChanIDFromOutPoint(chanPoint),
clearedHTCLs: make(map[uint64]*pendingPayment),
htlcsToSettle: make(map[uint64]*channeldb.Invoice),
htlcsToCancel: make(map[uint64]lnwire.FailCode),
cancelReasons: make(map[uint64]lnwire.FailCode),
pendingCircuits: make(map[uint64]*sphinx.ProcessedPacket),
sphinx: p.server.sphinx,
switchChan: htlcPlex,
}
// TODO(roasbeef): check to see if able to settle any currently pending
// HTLCs
// * also need signals when new invoices are added by the
// invoiceRegistry
batchTimer := time.NewTicker(50 * time.Millisecond)
defer batchTimer.Stop()
logCommitTimer := time.NewTicker(100 * time.Millisecond)
defer logCommitTimer.Stop()
out:
for {
select {
case <-channel.UnilateralCloseSignal:
// TODO(roasbeef): need to send HTLC outputs to nursery
peerLog.Warnf("Remote peer has closed ChannelPoint(%v) on-chain",
state.chanPoint)
if err := wipeChannel(p, channel); err != nil {
peerLog.Errorf("unable to wipe channel %v", err)
}
p.server.breachArbiter.settledContracts <- state.chanPoint
break out
case <-channel.ForceCloseSignal:
// TODO(roasbeef): path never taken now that server
// force closes's directly?
peerLog.Warnf("ChannelPoint(%v) has been force "+
"closed, disconnecting from peerID(%x)",
state.chanPoint, p.id)
break out
case <-logCommitTimer.C:
// If we haven't sent or received a new commitment
// update in some time, check to see if we have any
// pending updates we need to commit due to our
// commitment chains being desynchronized.
if state.channel.FullySynced() &&
len(state.htlcsToSettle) == 0 {
continue
}
if err := p.updateCommitTx(state); err != nil {
peerLog.Errorf("unable to update commitment: %v",
err)
p.Disconnect()
break out
}
case <-batchTimer.C:
// If the current batch is empty, then we have no work
// here.
if len(state.pendingBatch) == 0 {
continue
}
// Otherwise, attempt to extend the remote commitment
// chain including all the currently pending entries.
// If the send was unsuccessful, then abandon the
// update, waiting for the revocation window to open
// up.
if err := p.updateCommitTx(state); err != nil {
peerLog.Errorf("unable to update "+
"commitment: %v", err)
p.Disconnect()
break out
}
case pkt := <-downstreamLink:
p.handleDownStreamPkt(state, pkt)
case msg, ok := <-upstreamLink:
// If the upstream message link is closed, this signals
// that the channel itself is being closed, therefore
// we exit.
if !ok {
break out
}
p.handleUpstreamMsg(state, msg)
case <-p.quit:
break out
}
}
p.wg.Done()
peerLog.Tracef("htlcManager for peer %v done", p)
}
// handleInitMsg handles the incoming init message which contains global and
// local features vectors. If feature vectors are incompatible then disconnect.
func (p *peer) handleInitMsg(msg *lnwire.Init) error {
localSharedFeatures, err := p.server.localFeatures.Compare(msg.LocalFeatures)
if err != nil {
err := errors.Errorf("can compare remote and local feature "+
"vectors: %v", err)
peerLog.Error(err)
return err
}
p.localSharedFeatures = localSharedFeatures
globalSharedFeatures, err := p.server.globalFeatures.Compare(msg.GlobalFeatures)
if err != nil {
err := errors.Errorf("can compare remote and global feature "+
"vectors: %v", err)
peerLog.Error(err)
return err
}
p.globalSharedFeatures = globalSharedFeatures
return nil
}
// sendInitMsg sends init message to remote peer which contains our currently
// supported local and global features.
func (p *peer) sendInitMsg() error {
msg := lnwire.NewInitMessage(
p.server.globalFeatures,
p.server.localFeatures,
)
return p.writeMessage(msg)
}
// handleDownStreamPkt processes an HTLC packet sent from the downstream HTLC
// Switch. Possible messages sent by the switch include requests to forward new
// HTLCs, timeout previously cleared HTLCs, and finally to settle currently
// cleared HTLCs with the upstream peer.
func (p *peer) handleDownStreamPkt(state *commitmentState, pkt *htlcPacket) {
var isSettle bool
switch htlc := pkt.msg.(type) {
case *lnwire.UpdateAddHTLC:
// A new payment has been initiated via the
// downstream channel, so we add the new HTLC
// to our local log, then update the commitment
// chains.
htlc.ChanID = state.chanID
2016-11-23 11:36:55 +03:00
index, err := state.channel.AddHTLC(htlc)
if err != nil {
// TODO: possibly perform fallback/retry logic
// depending on type of error
peerLog.Errorf("Adding HTLC rejected: %v", err)
pkt.err <- err
close(pkt.done)
// The HTLC was unable to be added to the state
// machine, as a result, we'll signal the switch to
// cancel the pending payment.
// TODO(roasbeef): need to update link as well if local
// HTLC?
state.switchChan <- &htlcPacket{
amt: htlc.Amount,
msg: &lnwire.UpdateFailHTLC{
Reason: []byte{byte(0)},
},
srcLink: state.chanID,
}
2016-11-23 11:36:55 +03:00
return
}
p.queueMsg(htlc, nil)
state.pendingBatch = append(state.pendingBatch, &pendingPayment{
htlc: htlc,
index: index,
preImage: pkt.preImage,
err: pkt.err,
done: pkt.done,
})
case *lnwire.UpdateFufillHTLC:
// An HTLC we forward to the switch has just settled somewhere
// upstream. Therefore we settle the HTLC within the our local
// state machine.
pre := htlc.PaymentPreimage
logIndex, err := state.channel.SettleHTLC(pre)
if err != nil {
// TODO(roasbeef): broadcast on-chain
peerLog.Errorf("settle for incoming HTLC rejected: %v", err)
p.Disconnect()
return
}
// With the HTLC settled, we'll need to populate the wire
// message to target the specific channel and HTLC to be
// cancelled.
htlc.ChanID = state.chanID
htlc.ID = logIndex
// Then we send the HTLC settle message to the connected peer
// so we can continue the propagation of the settle message.
p.queueMsg(htlc, nil)
isSettle = true
case *lnwire.UpdateFailHTLC:
// An HTLC cancellation has been triggered somewhere upstream,
// we'll remove then HTLC from our local state machine.
logIndex, err := state.channel.FailHTLC(pkt.payHash)
if err != nil {
peerLog.Errorf("unable to cancel HTLC: %v", err)
return
}
// With the HTLC removed, we'll need to populate the wire
// message to target the specific channel and HTLC to be
// cancelled. The "Reason" field will have already been set
// within the switch.
htlc.ChanID = state.chanID
htlc.ID = logIndex
// Finally, we send the HTLC message to the peer which
// initially created the HTLC.
p.queueMsg(htlc, nil)
isSettle = true
}
// If this newly added update exceeds the min batch size for adds, or
// this is a settle request, then initiate an update.
// TODO(roasbeef): enforce max HTLCs in flight limit
if len(state.pendingBatch) >= 10 || isSettle {
if err := p.updateCommitTx(state); err != nil {
peerLog.Errorf("unable to update "+
"commitment: %v", err)
p.Disconnect()
return
}
}
}
// handleUpstreamMsg processes wire messages related to commitment state
// updates from the upstream peer. The upstream peer is the peer whom we have a
// direct channel with, updating our respective commitment chains.
func (p *peer) handleUpstreamMsg(state *commitmentState, msg lnwire.Message) {
switch htlcPkt := msg.(type) {
// TODO(roasbeef): timeouts
// * fail if can't parse sphinx mix-header
case *lnwire.UpdateAddHTLC:
// Before adding the new HTLC to the state machine, parse the
// onion object in order to obtain the routing information.
blobReader := bytes.NewReader(htlcPkt.OnionBlob[:])
onionPkt := &sphinx.OnionPacket{}
if err := onionPkt.Decode(blobReader); err != nil {
peerLog.Errorf("unable to decode onion pkt: %v", err)
p.Disconnect()
return
}
// We just received an add request from an upstream peer, so we
// add it to our state machine, then add the HTLC to our
// "settle" list in the event that we know the preimage
index, err := state.channel.ReceiveHTLC(htlcPkt)
if err != nil {
peerLog.Errorf("Receiving HTLC rejected: %v", err)
p.Disconnect()
return
}
// TODO(roasbeef): perform sanity checks on per-hop payload
// * time-lock is sane, fee, chain, etc
// Attempt to process the Sphinx packet. We include the payment
// hash of the HTLC as it's authenticated within the Sphinx
// packet itself as associated data in order to thwart attempts
// a replay attacks. In the case of a replay, an attacker is
// *forced* to use the same payment hash twice, thereby losing
// their money entirely.
rHash := htlcPkt.PaymentHash[:]
sphinxPacket, err := state.sphinx.ProcessOnionPacket(onionPkt, rHash)
if err != nil {
// If we're unable to parse the Sphinx packet, then
// we'll cancel the HTLC after the current commitment
// transition.
peerLog.Errorf("unable to process onion pkt: %v", err)
state.htlcsToCancel[index] = lnwire.SphinxParseError
2016-11-23 11:36:55 +03:00
return
}
switch sphinxPacket.Action {
// We're the designated payment destination. Therefore we
// attempt to see if we have an invoice locally which'll allow
// us to settle this HTLC.
case sphinx.ExitNode:
rHash := htlcPkt.PaymentHash
invoice, err := p.server.invoices.LookupInvoice(rHash)
if err != nil {
// If we're the exit node, but don't recognize
// the payment hash, then we'll fail the HTLC
// on the next state transition.
peerLog.Errorf("unable to settle HTLC, "+
"payment hash (%x) unrecognized", rHash[:])
state.htlcsToCancel[index] = lnwire.UnknownPaymentHash
return
}
// If we're not currently in debug mode, and the
// extended HTLC doesn't meet the value requested, then
// we'll fail the HTLC.
if !cfg.DebugHTLC && htlcPkt.Amount < invoice.Terms.Value {
peerLog.Errorf("rejecting HTLC due to incorrect "+
"amount: expected %v, received %v",
invoice.Terms.Value, htlcPkt.Amount)
state.htlcsToCancel[index] = lnwire.IncorrectValue
} else {
// Otherwise, everything is in order and we'll
// settle the HTLC after the current state
// transition.
state.htlcsToSettle[index] = invoice
}
// There are additional hops left within this route, so we
// track the next hop according to the index of this HTLC
// within their log. When forwarding locked-in HLTC's to the
// switch, we'll attach the routing information so the switch
// can finalize the circuit.
case sphinx.MoreHops:
state.pendingCircuits[index] = sphinxPacket
default:
peerLog.Errorf("mal formed onion packet")
state.htlcsToCancel[index] = lnwire.SphinxParseError
}
case *lnwire.UpdateFufillHTLC:
pre := htlcPkt.PaymentPreimage
idx := htlcPkt.ID
if err := state.channel.ReceiveHTLCSettle(pre, idx); err != nil {
// TODO(roasbeef): broadcast on-chain
peerLog.Errorf("settle for outgoing HTLC rejected: %v", err)
p.Disconnect()
return
}
// TODO(roasbeef): add preimage to DB in order to swipe
// repeated r-values
case *lnwire.UpdateFailHTLC:
idx := htlcPkt.ID
if err := state.channel.ReceiveFailHTLC(idx); err != nil {
peerLog.Errorf("unable to recv HTLC cancel: %v", err)
p.Disconnect()
return
}
state.cancelReasons[idx] = lnwire.FailCode(htlcPkt.Reason[0])
case *lnwire.CommitSig:
// We just received a new update to our local commitment chain,
// validate this new commitment, closing the link if invalid.
// TODO(roasbeef): redundant re-serialization
sig := htlcPkt.CommitSig.Serialize()
if err := state.channel.ReceiveNewCommitment(sig); err != nil {
peerLog.Errorf("unable to accept new commitment: %v", err)
p.Disconnect()
return
}
// As we've just just accepted a new state, we'll now
// immediately send the remote peer a revocation for our prior
// state.
nextRevocation, err := state.channel.RevokeCurrentCommitment()
if err != nil {
peerLog.Errorf("unable to revoke commitment: %v", err)
return
}
p.queueMsg(nextRevocation, nil)
// If both commitment chains are fully synced from our PoV,
// then we don't need to reply with a signature as both sides
// already have a commitment with the latest accepted state.
if state.channel.FullySynced() {
return
}
// Otherwise, the remote party initiated the state transition,
// so we'll reply with a signature to provide them with their
// version of the latest commitment state.
if err := p.updateCommitTx(state); err != nil {
peerLog.Errorf("unable to update commitment: %v", err)
p.Disconnect()
return
}
case *lnwire.RevokeAndAck:
// We've received a revocation from the remote chain, if valid,
// this moves the remote chain forward, and expands our
// revocation window.
htlcsToForward, err := state.channel.ReceiveRevocation(htlcPkt)
if err != nil {
peerLog.Errorf("unable to accept revocation: %v", err)
p.Disconnect()
return
}
// If any of the HTLCs eligible for forwarding are pending
// settling or timing out previous outgoing payments, then we
2016-10-30 17:54:59 +03:00
// can them from the pending set, and signal the requester (if
// existing) that the payment has been fully fulfilled.
var bandwidthUpdate btcutil.Amount
settledPayments := make(map[lnwallet.PaymentHash]struct{})
cancelledHtlcs := make(map[uint64]struct{})
for _, htlc := range htlcsToForward {
parentIndex := htlc.ParentIndex
if p, ok := state.clearedHTCLs[parentIndex]; ok {
switch htlc.EntryType {
// If the HTLC was settled successfully, then
// we return a nil error as well as the payment
// preimage back to the possible caller.
case lnwallet.Settle:
p.preImage <- htlc.RPreimage
p.err <- nil
// Otherwise, the HTLC failed, so we propagate
// the error back to the potential caller.
case lnwallet.Fail:
errMsg := state.cancelReasons[parentIndex]
p.preImage <- [32]byte{}
p.err <- errors.New(errMsg.String())
}
close(p.done)
delete(state.clearedHTCLs, htlc.ParentIndex)
}
// TODO(roasbeef): rework log entries to a shared
// interface.
if htlc.EntryType != lnwallet.Add {
continue
}
// If we can settle this HTLC within our local state
// update log, then send the update entry to the remote
// party.
invoice, ok := state.htlcsToSettle[htlc.Index]
if ok {
preimage := invoice.Terms.PaymentPreimage
logIndex, err := state.channel.SettleHTLC(preimage)
if err != nil {
peerLog.Errorf("unable to settle htlc: %v", err)
p.Disconnect()
continue
}
settleMsg := &lnwire.UpdateFufillHTLC{
ChanID: state.chanID,
ID: logIndex,
PaymentPreimage: preimage,
}
p.queueMsg(settleMsg, nil)
delete(state.htlcsToSettle, htlc.Index)
settledPayments[htlc.RHash] = struct{}{}
bandwidthUpdate += htlc.Amount
continue
}
// Alternatively, if we marked this HTLC for
// cancellation, then immediately cancel the HTLC as
// it's now locked in within both commitment
// transactions.
reason, ok := state.htlcsToCancel[htlc.Index]
if !ok {
continue
}
logIndex, err := state.channel.FailHTLC(htlc.RHash)
if err != nil {
peerLog.Errorf("unable to cancel htlc: %v", err)
p.Disconnect()
continue
}
cancelMsg := &lnwire.UpdateFailHTLC{
ChanID: state.chanID,
ID: logIndex,
Reason: []byte{byte(reason)},
}
p.queueMsg(cancelMsg, nil)
delete(state.htlcsToCancel, htlc.Index)
cancelledHtlcs[htlc.Index] = struct{}{}
}
go func() {
for _, htlc := range htlcsToForward {
// We don't need to forward any HTLCs that we
// just settled or cancelled above.
// TODO(roasbeef): key by index instead?
if _, ok := settledPayments[htlc.RHash]; ok {
continue
}
if _, ok := cancelledHtlcs[htlc.Index]; ok {
continue
}
onionPkt := state.pendingCircuits[htlc.Index]
delete(state.pendingCircuits, htlc.Index)
reason := state.cancelReasons[htlc.ParentIndex]
delete(state.cancelReasons, htlc.ParentIndex)
// Send this fully activated HTLC to the htlc
// switch to continue the chained clear/settle.
pkt, err := logEntryToHtlcPkt(state.chanID,
htlc, onionPkt, reason)
if err != nil {
peerLog.Errorf("unable to make htlc pkt: %v",
err)
continue
}
state.switchChan <- pkt
}
}()
if len(settledPayments) == 0 && len(cancelledHtlcs) == 0 {
return
}
// Send an update to the htlc switch of our newly available
// payment bandwidth.
// TODO(roasbeef): ideally should wait for next state update.
if bandwidthUpdate != 0 {
p.server.htlcSwitch.UpdateLink(state.chanID,
bandwidthUpdate)
}
// With all the settle updates added to the local and remote
// HTLC logs, initiate a state transition by updating the
// remote commitment chain.
if err := p.updateCommitTx(state); err != nil {
peerLog.Errorf("unable to update commitment: %v", err)
p.Disconnect()
return
}
// Notify the invoiceRegistry of the invoices we just settled
// with this latest commitment update.
// TODO(roasbeef): wait until next transition?
for invoice := range settledPayments {
err := p.server.invoices.SettleInvoice(chainhash.Hash(invoice))
if err != nil {
peerLog.Errorf("unable to settle invoice: %v", err)
}
}
}
}
// updateCommitTx signs, then sends an update to the remote peer adding a new
// commitment to their commitment chain which includes all the latest updates
// we've received+processed up to this point.
func (p *peer) updateCommitTx(state *commitmentState) error {
sigTheirs, err := state.channel.SignNextCommitment()
if err == lnwallet.ErrNoWindow {
peerLog.Tracef("revocation window exhausted, unable to send %v",
len(state.pendingBatch))
return nil
} else if err != nil {
return err
}
parsedSig, err := btcec.ParseSignature(sigTheirs, btcec.S256())
if err != nil {
return fmt.Errorf("unable to parse sig: %v", err)
}
commitSig := &lnwire.CommitSig{
ChanID: state.chanID,
CommitSig: parsedSig,
}
p.queueMsg(commitSig, nil)
// As we've just cleared out a batch, move all pending updates to the
// map of cleared HTLCs, clearing out the set of pending updates.
for _, update := range state.pendingBatch {
state.clearedHTCLs[update.index] = update
}
// Finally, clear our the current batch, and flip the pendingUpdate
// bool to indicate were waiting for a commitment signature.
// TODO(roasbeef): re-slice instead to avoid GC?
state.pendingBatch = nil
return nil
}
// logEntryToHtlcPkt converts a particular Lightning Commitment Protocol (LCP)
// log entry the corresponding htlcPacket with src/dest set along with the
// proper wire message. This helper method is provided in order to aid an
// htlcManager in forwarding packets to the htlcSwitch.
func logEntryToHtlcPkt(chanID lnwire.ChannelID, pd *lnwallet.PaymentDescriptor,
onionPkt *sphinx.ProcessedPacket,
reason lnwire.FailCode) (*htlcPacket, error) {
pkt := &htlcPacket{}
// TODO(roasbeef): alter after switch to log entry interface
var msg lnwire.Message
switch pd.EntryType {
case lnwallet.Add:
// TODO(roasbeef): timeout, onion blob, etc
var b bytes.Buffer
if err := onionPkt.Packet.Encode(&b); err != nil {
return nil, err
}
htlc := &lnwire.UpdateAddHTLC{
2017-02-23 22:07:01 +03:00
Amount: pd.Amount,
PaymentHash: pd.RHash,
}
copy(htlc.OnionBlob[:], b.Bytes())
msg = htlc
case lnwallet.Settle:
msg = &lnwire.UpdateFufillHTLC{
PaymentPreimage: pd.RPreimage,
}
case lnwallet.Fail:
// For cancellation messages, we'll also need to set the rHash
// within the htlcPacket so the switch knows on which outbound
// link to forward the cancellation message
msg = &lnwire.UpdateFailHTLC{
Reason: []byte{byte(reason)},
}
pkt.payHash = pd.RHash
}
pkt.amt = pd.Amount
pkt.msg = msg
pkt.srcLink = chanID
pkt.onion = onionPkt
return pkt, nil
}
// TODO(roasbeef): make all start/stop mutexes a CAS