lnd/peer.go

1366 lines
42 KiB
Go

package main
import (
"container/list"
"fmt"
"net"
"sync"
"sync/atomic"
"time"
"github.com/davecgh/go-spew/spew"
"github.com/lightningnetwork/lnd/brontide"
"bytes"
"github.com/go-errors/errors"
"github.com/lightningnetwork/lnd/chainntnfs"
"github.com/lightningnetwork/lnd/channeldb"
"github.com/lightningnetwork/lnd/htlcswitch"
"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"
)
var (
numNodes int32
)
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
)
// 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
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.
started int32
disconnect int32
connReq *connmgr.ConnReq
conn net.Conn
addr *lnwire.NetAddress
pubKeyBytes [33]byte
inbound bool
id int32
// 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
// sendQueueSync is used as a semaphore to synchronize writes between
// the writeHandler and the queueHandler.
sendQueueSync chan struct{}
// 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
// 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 *htlcswitch.ChanClose
// shutdownChanReqs is used to send the Shutdown messages that initiate
// the cooperative close workflow.
shutdownChanReqs chan *lnwire.Shutdown
// closingSignedChanReqs is used to send signatures for proposed
// channel close transactions during the cooperative close workflow.
closingSignedChanReqs chan *lnwire.ClosingSigned
server *server
// 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
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.
func newPeer(conn net.Conn, connReq *connmgr.ConnReq, server *server,
addr *lnwire.NetAddress, inbound bool) (*peer, error) {
nodePub := addr.IdentityKey
p := &peer{
conn: conn,
addr: addr,
id: atomic.AddInt32(&numNodes, 1),
inbound: inbound,
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),
chanSnapshotReqs: make(chan *chanSnapshotReq),
newChannels: make(chan *newChannelMsg, 1),
localCloseChanReqs: make(chan *htlcswitch.ChanClose),
shutdownChanReqs: make(chan *lnwire.Shutdown),
closingSignedChanReqs: make(chan *lnwire.ClosingSigned),
localSharedFeatures: nil,
globalSharedFeatures: nil,
queueQuit: make(chan struct{}),
quit: make(chan struct{}),
}
copy(p.pubKeyBytes[:], nodePub.SerializeCompressed())
return p, 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 fmt.Errorf("unable to send init msg: %v", err)
}
// Before we launch any of the helper goroutines off the peer struct,
// we'll first ensure proper adherence to the p2p protocol. 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 fmt.Errorf("unable to read init msg: %v", err)
}
}
// Once the init message arrives, we can parse it so we can figure out
// the negotiation of features for this session.
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")
}
// Fetch and then load all the active channels we have with this remote
// peer from the database.
activeChans, err := p.server.chanDB.FetchOpenChannels(p.addr.IdentityKey)
if err != nil {
peerLog.Errorf("unable to fetch active chans "+
"for peer %v: %v", p, err)
return err
}
// Next, load all the active channels we have with this peer,
// registering them with the switch and launching the necessary
// goroutines required to operate them.
peerLog.Debugf("Loaded %v active channels from database with "+
"peerID(%v)", len(activeChans), p.id)
if err := p.loadActiveChannels(activeChans); err != nil {
return fmt.Errorf("unable to load channels: %v", err)
}
p.wg.Add(5)
go p.queueHandler()
go p.writeHandler()
go p.readHandler()
go p.channelManager()
go p.pingHandler()
return 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 the channel isn't yet open, then we don't need to process
// it any further.
if dbChan.IsPending {
continue
}
lnChan, err := lnwallet.NewLightningChannel(p.server.cc.signer,
p.server.cc.chainNotifier, p.server.cc.feeEstimator, 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.
sphinxDecoder := htlcswitch.NewSphinxDecoder(p.server.sphinx)
link := htlcswitch.NewChannelLink(
htlcswitch.ChannelLinkConfig{
Peer: p,
DecodeOnion: sphinxDecoder.Decode,
SettledContracts: p.server.breachArbiter.settledContracts,
DebugHTLC: cfg.DebugHTLC,
Registry: p.server.invoices,
Switch: p.server.htlcSwitch,
FwrdingPolicy: p.server.cc.routingPolicy,
},
lnChan,
)
if err := p.server.htlcSwitch.AddLink(link); err != nil {
return err
}
}
return nil
}
// WaitForDisconnect waits until the peer has disconnected. A peer may be
// disconnected if the local or remote side terminating the connection, or an
// irrecoverable protocol error has been encountered.
func (p *peer) WaitForDisconnect() {
<-p.quit
}
// 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)
}
// 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, error) {
noiseConn, ok := p.conn.(*brontide.Conn)
if !ok {
return nil, fmt.Errorf("brontide.Conn required to read messages")
}
// First we'll read the next _full_ message. We do this rather than
// reading incrementally from the stream as the Lightning wire protocol
// is message oriented and allows nodes to pad on additional data to
// the message stream.
rawMsg, err := noiseConn.ReadNextMessage()
atomic.AddUint64(&p.bytesReceived, uint64(len(rawMsg)))
if err != nil {
return nil, err
}
// Next, create a new io.Reader implementation from the raw message,
// and use this to decode the message directly from.
msgReader := bytes.NewReader(rawMsg)
nextMsg, err := lnwire.ReadMessage(msgReader, 0)
if err != nil {
return nil, err
}
// TODO(roasbeef): add message summaries
p.logWireMessage(nextMsg, true)
return nextMsg, 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.Shutdown:
p.shutdownChanReqs <- msg
case *lnwire.ClosingSigned:
p.closingSignedChanReqs <- msg
case *lnwire.Error:
p.server.fundingMgr.processFundingError(msg, p.addr)
// TODO(roasbeef): create ChanUpdater interface for the below
case *lnwire.UpdateAddHTLC:
isChanUpdate = true
targetChan = msg.ChanID
case *lnwire.UpdateFufillHTLC:
isChanUpdate = true
targetChan = msg.ChanID
case *lnwire.UpdateFailHTLC:
isChanUpdate = true
targetChan = msg.ChanID
case *lnwire.RevokeAndAck:
isChanUpdate = true
targetChan = msg.ChanID
case *lnwire.CommitSig:
isChanUpdate = true
targetChan = msg.ChanID
case *lnwire.ChannelUpdate,
*lnwire.ChannelAnnouncement,
*lnwire.NodeAnnouncement,
*lnwire.AnnounceSignatures:
p.server.discoverSrv.ProcessRemoteAnnouncement(msg,
p.addr.IdentityKey)
default:
peerLog.Errorf("unknown message received from peer "+
"%v", p)
}
if isChanUpdate {
sendUpdate := func() {
// Dispatch the commitment update message to the proper
// active goroutine dedicated to this channel.
link, err := p.server.htlcSwitch.GetLink(targetChan)
if err != nil {
peerLog.Errorf("recv'd update for unknown "+
"channel %v from %v", targetChan, p)
return
}
link.HandleChannelUpdate(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)
// As the Lightning wire protocol is fully message oriented, we only
// allows one wire message per outer encapsulated crypto message. So
// we'll create a temporary buffer to write the message directly to.
var msgPayload [lnwire.MaxMessagePayload]byte
b := bytes.NewBuffer(msgPayload[0:0:len(msgPayload)])
// With the temp buffer created and sliced properly (length zero, full
// capacity), we'll now encode the message directly into this buffer.
n, err := lnwire.WriteMessage(b, msg, 0)
atomic.AddUint64(&p.bytesSent, uint64(n))
// Finally, write the message itself in a single swoop.
_, err = p.conn.Write(b.Bytes())
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)
}
}
}
// 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() {
// chanShutdowns is a map of channels for which our node has initiated
// a cooperative channel close. When an lnwire.Shutdown is received,
// this allows the node to determine the next step to be taken in the
// workflow.
chanShutdowns := make(map[lnwire.ChannelID]*htlcswitch.ChanClose)
// shutdownSigs is a map of signatures maintained by the responder in a
// cooperative channel close. This map enables us to respond to
// subsequent steps in the workflow without having to recalculate our
// signature for the channel close transaction.
shutdownSigs := make(map[lnwire.ChannelID][]byte)
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)
decoder := htlcswitch.NewSphinxDecoder(p.server.sphinx)
link := htlcswitch.NewChannelLink(
htlcswitch.ChannelLinkConfig{
Peer: p,
DecodeOnion: decoder.Decode,
SettledContracts: p.server.breachArbiter.settledContracts,
DebugHTLC: cfg.DebugHTLC,
Registry: p.server.invoices,
Switch: p.server.htlcSwitch,
FwrdingPolicy: p.server.cc.routingPolicy,
},
newChanReq.channel,
)
err := p.server.htlcSwitch.AddLink(link)
if err != nil {
peerLog.Errorf("can't register new channel "+
"link(%v) with peerId(%v)", chanPoint, p.id)
}
close(newChanReq.done)
// We've just received a local quest to close an active
// channel.
case req := <-p.localCloseChanReqs:
// So we'll first transition the channel to a state of
// pending shutdown.
chanID := lnwire.NewChanIDFromOutPoint(req.ChanPoint)
// We'll only track this shutdown request if this is a
// regular close request, and not in response to a
// channel breach.
if req.CloseType == htlcswitch.CloseRegular {
chanShutdowns[chanID] = req
}
// With the state marked as shutting down, we can now
// proceed with the channel close workflow. If this is
// regular close, we'll send a shutdown. Otherwise,
// we'll simply be clearing our indexes.
p.handleLocalClose(req)
// A receipt of a message over this channel indicates that
// either a shutdown proposal has been initiated, or a prior
// one has been completed, advancing to the next state of
// channel closure.
case req := <-p.shutdownChanReqs:
// We've just received a shutdown request. First, we'll
// check in the shutdown map to see if we're the
// initiator or not. If we don't have an entry for
// this channel, then this means that we're the
// responder to the workflow.
if _, ok := chanShutdowns[req.ChannelID]; !ok {
// In this case, we'll send a shutdown message,
// and also prep our closing signature for the
// case they fees are immediately agreed upon.
closeSig := p.handleShutdownResponse(req)
if closeSig != nil {
shutdownSigs[req.ChannelID] = closeSig
}
}
// TODO(roasbeef): should also save their delivery
// address within close request after funding change.
// * modify complete to include delivery address
// A receipt of a message over this channel indicates that the
// final stage of a channel shutdown workflow has been
// completed.
case req := <-p.closingSignedChanReqs:
// First we'll check if this has an entry in the local
// shutdown map.
localCloseReq, ok := chanShutdowns[req.ChannelID]
// If it does, then this means we were the initiator of
// the channel shutdown procedure.
if ok {
// To finalize this shtudown, we'll now send a
// matching close signed message to the other
// party, and broadcast the closing transaction
// to the network.
p.handleInitClosingSigned(localCloseReq, req)
delete(chanShutdowns, req.ChannelID)
continue
}
// Otherwise, we're the responder to the channel
// shutdown procedure. In this case, we'll mark the
// channel as pending close, and watch the network for
// the ultimate confirmation of the closing
// transaction.
responderSig := append(shutdownSigs[req.ChannelID],
byte(txscript.SigHashAll))
p.handleResponseClosingSigned(req, responderSig)
delete(shutdownSigs, req.ChannelID)
case <-p.quit:
break out
}
}
p.wg.Done()
}
// 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 *htlcswitch.ChanClose) {
chanID := lnwire.NewChanIDFromOutPoint(req.ChanPoint)
p.activeChanMtx.RLock()
channel, ok := p.activeChannels[chanID]
p.activeChanMtx.RUnlock()
if !ok {
err := fmt.Errorf("unable to close channel, ChannelID(%v) is "+
"unknown", chanID)
peerLog.Errorf(err.Error())
req.Err <- err
return
}
switch req.CloseType {
// A type of CloseRegular indicates that the user has opted to close
// out this channel on-chain, so we execute the cooperative channel
// closure workflow.
case htlcswitch.CloseRegular:
err := p.sendShutdown(channel)
if err != nil {
req.Err <- err
return
}
// A type of CloseBreach indicates that the counterparty has breached
// the channel therefore we need to clean up our local state.
case htlcswitch.CloseBreach:
peerLog.Infof("ChannelPoint(%v) has been breached, wiping "+
"channel", req.ChanPoint)
if err := p.WipeChannel(channel); err != nil {
peerLog.Infof("Unable to wipe channel after detected "+
"breach: %v", err)
req.Err <- err
return
}
return
}
}
// handleShutdownResponse is called when a responder in a cooperative channel
// close workflow receives a Shutdown message. This is the second step in the
// cooperative close workflow. This function generates a close transaction with
// a proposed fee amount and sends the signed transaction to the initiator.
func (p *peer) handleShutdownResponse(msg *lnwire.Shutdown) []byte {
p.activeChanMtx.RLock()
channel, ok := p.activeChannels[msg.ChannelID]
p.activeChanMtx.RUnlock()
if !ok {
peerLog.Errorf("unable to close channel, ChannelPoint(%v) is "+
"unknown", msg.ChannelID)
return nil
}
// As we just received a shutdown message, we'll also send a shutdown
// message with our desired fee so we can start the negotiation.
if err := p.sendShutdown(channel); err != nil {
peerLog.Errorf("error while sending shutdown message: %v", err)
return nil
}
// Calculate an initial proposed fee rate for the close transaction.
feeRate := p.server.cc.feeEstimator.EstimateFeePerWeight(1) * 1000
// TODO(roasbeef): actually perform fee negotiation here, only send sig
// if we agree to fee
// Once both sides agree on a fee, we'll create a signature that closes
// the channel using the agree upon fee rate.
// TODO(roasbeef): remove encoding redundancy
closeSig, proposedFee, err := channel.CreateCloseProposal(feeRate)
if err != nil {
peerLog.Errorf("unable to create close proposal: %v", err)
return nil
}
parsedSig, err := btcec.ParseSignature(closeSig, btcec.S256())
if err != nil {
peerLog.Errorf("unable to parse signature: %v", err)
return nil
}
// With the closing signature assembled, we'll send the matching close
// signed message to the other party so they can broadcast the closing
// transaction.
closingSigned := lnwire.NewClosingSigned(msg.ChannelID, proposedFee,
parsedSig)
p.queueMsg(closingSigned, nil)
return closeSig
}
// handleInitClosingSigned is called when the initiator in a cooperative
// channel close workflow receives a ClosingSigned message from the responder.
// This method completes the channel close transaction, sends back a
// corresponding ClosingSigned message, then broadcasts the channel close
// transaction. It also performs channel cleanup and reports status back to the
// caller. This is the initiator's final step in the channel close workflow.
//
// Following the broadcast, both the initiator and responder in the channel
// closure workflow should watch the blockchain for a confirmation of the
// closing transaction before considering the channel terminated. In the case
// of an unresponsive remote party, the initiator can either choose to execute
// a force closure, or backoff for a period of time, and retry the cooperative
// closure.
func (p *peer) handleInitClosingSigned(req *htlcswitch.ChanClose, msg *lnwire.ClosingSigned) {
chanID := lnwire.NewChanIDFromOutPoint(req.ChanPoint)
p.activeChanMtx.RLock()
channel, ok := p.activeChannels[chanID]
p.activeChanMtx.RUnlock()
if !ok {
err := fmt.Errorf("unable to close channel, ChannelID(%v) is "+
"unknown", chanID)
peerLog.Errorf(err.Error())
req.Err <- err
return
}
// Calculate a fee rate that we believe to be fair and will ensure a
// timely confirmation.
//
// TODO(bvu): with a dynamic fee implementation, we will compare this
// to the fee proposed by the responder in their ClosingSigned message.
feeRate := p.server.cc.feeEstimator.EstimateFeePerWeight(1) * 1000
// We agree with the proposed channel close transaction and fee rate,
// so generate our signature.
initiatorSig, proposedFee, err := channel.CreateCloseProposal(feeRate)
if err != nil {
req.Err <- err
return
}
initSig := append(initiatorSig, byte(txscript.SigHashAll))
// Complete coop close transaction with the signatures of the close
// initiator and responder.
responderSig := msg.Signature
respSig := append(responderSig.Serialize(), byte(txscript.SigHashAll))
closeTx, err := channel.CompleteCooperativeClose(initSig, respSig,
feeRate)
if err != nil {
req.Err <- err
// TODO(roasbeef): send ErrorGeneric to other side
return
}
// As we're the initiator of this channel shutdown procedure we'll now
// create a mirrored close signed message with our completed signature.
parsedSig, err := btcec.ParseSignature(initSig, btcec.S256())
if err != nil {
req.Err <- err
return
}
closingSigned := lnwire.NewClosingSigned(chanID, proposedFee, parsedSig)
p.queueMsg(closingSigned, nil)
// Finally, broadcast the closure transaction to the network.
peerLog.Infof("Broadcasting cooperative close tx: %v",
newLogClosure(func() string {
return spew.Sdump(closeTx)
}))
if err := p.server.cc.wallet.PublishTransaction(closeTx); err != nil {
peerLog.Errorf("channel close tx from "+
"ChannelPoint(%v) rejected: %v",
req.ChanPoint, err)
// TODO(roasbeef): send ErrorGeneric to other side
return
}
// Once we've completed the cooperative channel closure, we'll wipe the
// channel so we reject any incoming forward or payment requests via
// this channel.
p.server.breachArbiter.settledContracts <- req.ChanPoint
if err := p.WipeChannel(channel); err != nil {
req.Err <- err
return
}
// TODO(roasbeef): also add closure height to summary
// Clear out the current channel state, marking the channel as being
// closed within the database.
closingTxid := closeTx.TxHash()
chanInfo := channel.StateSnapshot()
closeSummary := &channeldb.ChannelCloseSummary{
ChanPoint: *req.ChanPoint,
ClosingTXID: closingTxid,
RemotePub: &chanInfo.RemoteIdentity,
Capacity: chanInfo.Capacity,
SettledBalance: chanInfo.LocalBalance,
CloseType: channeldb.CooperativeClose,
IsPending: true,
}
if err := channel.DeleteState(closeSummary); 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[:],
},
},
}
_, bestHeight, err := p.server.cc.chainIO.GetBestBlock()
if err != nil {
req.Err <- err
return
}
// Finally, launch a goroutine which will request to be notified by the
// ChainNotifier once the closure transaction obtains a single
// confirmation.
notifier := p.server.cc.chainNotifier
go waitForChanToClose(uint32(bestHeight), notifier, req.Err,
req.ChanPoint, &closingTxid, func() {
// First, we'll mark the database as being fully closed
// so we'll no longer watch for its ultimate closure
// upon startup.
err := p.server.chanDB.MarkChanFullyClosed(req.ChanPoint)
if err != nil {
req.Err <- err
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,
},
},
}
})
}
// handleResponseClosingSigned is called when the responder in a cooperative
// close workflow receives a ClosingSigned message. This function handles the
// finalization of the cooperative close from the perspective of the responder.
func (p *peer) handleResponseClosingSigned(msg *lnwire.ClosingSigned,
respSig []byte) {
p.activeChanMtx.RLock()
channel, ok := p.activeChannels[msg.ChannelID]
p.activeChanMtx.RUnlock()
if !ok {
peerLog.Errorf("unable to close channel, ChannelID(%v) is "+
"unknown", msg.ChannelID)
return
}
// Now that we have the initiator's signature for the closure
// transaction, we can assemble the final closure transaction, complete
// with our signature.
initiatorSig := msg.Signature
initSig := append(initiatorSig.Serialize(), byte(txscript.SigHashAll))
chanPoint := channel.ChannelPoint()
// Calculate our expected fee rate.
// TODO(roasbeef): should instead use the fee within the message
feeRate := p.server.cc.feeEstimator.EstimateFeePerWeight(1) * 1000
closeTx, err := channel.CompleteCooperativeClose(respSig, initSig,
feeRate)
if err != nil {
peerLog.Errorf("unable to complete cooperative "+
"close for ChannelPoint(%v): %v",
chanPoint, err)
// TODO(roasbeef): send ErrorGeneric to other side
return
}
closeTxid := closeTx.TxHash()
_, bestHeight, err := p.server.cc.chainIO.GetBestBlock()
if err != nil {
peerLog.Errorf("unable to get best height: %v", err)
}
// Once we've completed the cooperative channel closure, we'll wipe the
// channel so we reject any incoming forward or payment requests via
// this channel.
p.server.breachArbiter.settledContracts <- chanPoint
// We've just broadcast the transaction which closes the channel, so
// we'll wipe the channel from all our local indexes and also signal to
// the switch that this channel is now closed.
peerLog.Infof("ChannelPoint(%v) is now closed", chanPoint)
if err := p.WipeChannel(channel); err != nil {
peerLog.Errorf("unable to wipe channel: %v", err)
}
// Clear out the current channel state, marking the channel as being
// closed within the database.
chanInfo := channel.StateSnapshot()
closeSummary := &channeldb.ChannelCloseSummary{
ChanPoint: *chanPoint,
ClosingTXID: closeTxid,
RemotePub: &chanInfo.RemoteIdentity,
Capacity: chanInfo.Capacity,
SettledBalance: chanInfo.LocalBalance,
CloseType: channeldb.CooperativeClose,
IsPending: true,
}
if err := channel.DeleteState(closeSummary); err != nil {
peerLog.Errorf("unable to delete channel state: %v", err)
return
}
// Finally, we'll launch a goroutine to watch the network for the
// confirmation of the closing transaction, and mark the channel as
// such within the database (once it's confirmed").
notifier := p.server.cc.chainNotifier
go waitForChanToClose(uint32(bestHeight), notifier, nil, chanPoint,
&closeTxid, func() {
// Now that the closing transaction has been confirmed,
// we'll mark the database as being fully closed so now
// that we no longer watch for its ultimate closure
// upon startup.
err := p.server.chanDB.MarkChanFullyClosed(chanPoint)
if err != nil {
peerLog.Errorf("unable to mark channel as closed: %v", err)
return
}
},
)
}
// waitForChanToClose uses the passed notifier to wait until the channel has
// been detected as closed on chain and then concludes by executing the
// following actions: the channel point will be sent over the settleChan, and
// finally the callback will be executed. If any error is encountered within
// the function, then it will be sent over the errChan.
func waitForChanToClose(bestHeight uint32, notifier chainntnfs.ChainNotifier,
errChan chan error, chanPoint *wire.OutPoint,
closingTxID *chainhash.Hash, cb func()) {
peerLog.Infof("Waiting for confirmation of cooperative close of "+
"ChannelPoint(%v) with txid: %v", chanPoint,
closingTxID)
// TODO(roasbeef): add param for num needed confs
confNtfn, err := notifier.RegisterConfirmationsNtfn(closingTxID, 1,
bestHeight)
if err != nil {
if errChan != nil {
errChan <- err
}
return
}
// In the case that the ChainNotifier is shutting down, all subscriber
// notification channels will be closed, generating a nil receive.
height, ok := <-confNtfn.Confirmed
if !ok {
return
}
// The channel has been closed, remove it from any active indexes, and
// the database state.
srvrLog.Infof("ChannelPoint(%v) is now closed at "+
"height %v", chanPoint, height.BlockHeight)
// Finally, execute the closure call back to mark the confirmation of
// the transaction closing the contract.
cb()
}
// sendShutdown handles the creation and sending of the Shutdown messages sent
// between peers to initiate the cooperative channel close workflow. In
// addition, sendShutdown also signals to the HTLC switch to stop accepting
// HTLCs for the specified channel.
func (p *peer) sendShutdown(channel *lnwallet.LightningChannel) error {
// In order to construct the shutdown message, we'll need to
// reconstruct the channelID, and the current set delivery script for
// the channel closure.
chanID := lnwire.NewChanIDFromOutPoint(channel.ChannelPoint())
addr := lnwire.DeliveryAddress(channel.LocalDeliveryScript)
// With both items constructed we'll now send the shutdown message for
// this particular channel, advertising a shutdown request to our
// desired closing script.
shutdown := lnwire.NewShutdown(chanID, addr)
p.queueMsg(shutdown, nil)
// Finally, we'll unregister the link from the switch in order to
// Prevent the HTLC switch from receiving additional HTLCs for this
// channel.
p.server.htlcSwitch.RemoveLink(chanID)
return nil
}
// WipeChannel removes the passed channel from all indexes associated with the
// peer, and deletes the channel from the database.
func (p *peer) WipeChannel(channel *lnwallet.LightningChannel) error {
channel.Stop()
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.
if err := p.server.htlcSwitch.RemoveLink(chanID); err != nil {
if err == htlcswitch.ErrChannelLinkNotFound {
peerLog.Warnf("unable remove channel link with "+
"ChannelPoint(%v): %v", chanID, err)
return nil
}
return err
}
return nil
}
// 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't 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't 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)
}
// SendMessage queues a message for sending to the target peer.
func (p *peer) SendMessage(msg lnwire.Message) error {
p.queueMsg(msg, nil)
return nil
}
// PubKey returns the pubkey of the peer in compressed serialized format.
func (p *peer) PubKey() [33]byte {
return p.pubKeyBytes
}
// TODO(roasbeef): make all start/stop mutexes a CAS