lnd.xprv/peer.go
2017-10-16 18:43:19 -07:00

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package main
import (
"container/list"
"fmt"
"net"
"strings"
"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/lightningnetwork/lnd/routing"
"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
// idleTimeout is the duration of inactivity before we time out a peer.
idleTimeout = 5 * 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
// sendQueueSync is a channel that's used to synchronize sends between
// the queueHandler and the writeHandler. At times the writeHandler may
// get blocked on sending messages. As a result we require a
// synchronization mechanism between the two otherwise the queueHandler
// would need to continually spin checking to see if the writeHandler
// is ready for an additional message.
sendQueueSync chan struct{}
// outgoingQueue is a buffered channel which allows second/third party
// objects to queue messages to be sent out on the wire.
outgoingQueue chan outgoinMsg
// 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
// 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,
sendQueue: make(chan outgoinMsg),
sendQueueSync: make(chan struct{}),
outgoingQueue: make(chan outgoinMsg),
activeChannels: make(map[lnwire.ChannelID]*lnwallet.LightningChannel),
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)
p.wg.Add(1)
go func() {
defer p.wg.Done()
msg, err := p.readNextMessage()
if err != nil {
readErr <- err
msgChan <- nil
return
}
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.FundingOutpoint
// If the channel we read form disk has a nil next revocation
// key, then we'll skip loading this channel. We must do this
// as it doesn't yet have the needed items required to initiate
// a local state transition, or one triggered by forwarding an
// HTLC.
if lnChan.RemoteNextRevocation() == nil {
peerLog.Debugf("Skipping ChannelPoint(%v), lacking "+
"next commit point", chanPoint)
continue
}
chanID := lnwire.NewChanIDFromOutPoint(chanPoint)
p.activeChanMtx.Lock()
p.activeChannels[chanID] = lnChan
p.activeChanMtx.Unlock()
peerLog.Infof("peerID(%v) loading ChannelPoint(%v)", p.id, chanPoint)
select {
case p.server.breachArbiter.newContracts <- lnChan:
case <-p.server.quit:
return fmt.Errorf("server shutting down")
case <-p.quit:
return fmt.Errorf("peer shutting down")
}
blockEpoch, err := p.server.cc.chainNotifier.RegisterBlockEpochNtfn()
if err != nil {
return err
}
_, currentHeight, err := p.server.cc.chainIO.GetBestBlock()
if err != nil {
return err
}
// Before we register this new link with the HTLC Switch, we'll
// need to fetch its current link-layer forwarding policy from
// the database.
graph := p.server.chanDB.ChannelGraph()
info, p1, p2, err := graph.FetchChannelEdgesByOutpoint(chanPoint)
if err != nil && err != channeldb.ErrEdgeNotFound {
return err
}
// We'll filter out our policy from the directional channel
// edges based whom the edge connects to. If it doesn't connect
// to us, then we know that we were the one that advertised the
// policy.
//
// TODO(roasbeef): can add helper method to get policy for
// particular channel.
var selfPolicy *channeldb.ChannelEdgePolicy
if info != nil && info.NodeKey1.IsEqual(p.server.identityPriv.PubKey()) {
selfPolicy = p1
} else {
selfPolicy = p2
}
// If we don't yet have an advertised routing policy, then
// we'll use the current default, otherwise we'll translate the
// routing policy into a forwarding policy.
var forwardingPolicy *htlcswitch.ForwardingPolicy
if selfPolicy != nil {
forwardingPolicy = &htlcswitch.ForwardingPolicy{
MinHTLC: selfPolicy.MinHTLC,
BaseFee: selfPolicy.FeeBaseMSat,
FeeRate: selfPolicy.FeeProportionalMillionths,
TimeLockDelta: uint32(selfPolicy.TimeLockDelta),
}
} else {
forwardingPolicy = &p.server.cc.routingPolicy
}
peerLog.Tracef("Using link policy of: %v", spew.Sdump(forwardingPolicy))
// 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.
linkCfg := htlcswitch.ChannelLinkConfig{
Peer: p,
DecodeHopIterator: p.server.sphinx.DecodeHopIterator,
DecodeOnionObfuscator: p.server.sphinx.ExtractErrorEncrypter,
GetLastChannelUpdate: createGetLastUpdate(p.server.chanRouter,
p.PubKey(), lnChan.ShortChanID()),
SettledContracts: p.server.breachArbiter.settledContracts,
DebugHTLC: cfg.DebugHTLC,
HodlHTLC: cfg.HodlHTLC,
Registry: p.server.invoices,
Switch: p.server.htlcSwitch,
FwrdingPolicy: *forwardingPolicy,
BlockEpochs: blockEpoch,
}
link := htlcswitch.NewChannelLink(linkCfg, lnChan,
uint32(currentHeight))
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(reason error) {
if !atomic.CompareAndSwapInt32(&p.disconnect, 0, 1) {
return
}
peerLog.Tracef("Disconnecting %s, reason: %v", p, reason)
// Ensure that the TCP connection is properly closed before continuing.
p.conn.Close()
close(p.quit)
p.wg.Wait()
}
// 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
}
// chanMsgStream implements a goroutine-safe, in-order stream of messages to be
// delivered to an active channel. These messages MUST be in order due to the
// nature of the lightning channel commitment state machine. We utilize
// additional synchronization with the fundingManager to ensure we don't
// attempt to dispatch a message to a channel before it is fully active.
type chanMsgStream struct {
fundingMgr *fundingManager
htlcSwitch *htlcswitch.Switch
cid lnwire.ChannelID
peer *peer
msgCond *sync.Cond
msgs []lnwire.Message
chanLink htlcswitch.ChannelLink
mtx sync.Mutex
wg sync.WaitGroup
quit chan struct{}
}
// newChanMsgStream creates a new instance of a chanMsgStream for a particular
// channel identified by its channel ID.
func newChanMsgStream(f *fundingManager, h *htlcswitch.Switch, p *peer,
c lnwire.ChannelID) *chanMsgStream {
stream := &chanMsgStream{
fundingMgr: f,
htlcSwitch: h,
peer: p,
cid: c,
quit: make(chan struct{}),
}
stream.msgCond = sync.NewCond(&stream.mtx)
return stream
}
// Start starts the chanMsgStream.
func (c *chanMsgStream) Start() {
c.wg.Add(1)
go c.msgConsumer()
}
// Stop stops the chanMsgStream.
func (c *chanMsgStream) Stop() {
// TODO(roasbeef): signal too?
close(c.quit)
// Wake up the msgConsumer is we've been signalled to exit.
c.msgCond.Signal()
c.wg.Wait()
}
// msgConsumer is the main goroutine that streams messages from the peer's
// readHandler directly to the target channel.
func (c *chanMsgStream) msgConsumer() {
defer c.wg.Done()
peerLog.Tracef("Update stream for ChannelID(%x) created", c.cid[:])
for {
// First, we'll check our condition. If the queue of messages
// is empty, then we'll wait until a new item is added.
c.msgCond.L.Lock()
for len(c.msgs) == 0 {
c.msgCond.Wait()
// If we were woke up in order to exit, then we'll do
// so. Otherwise, we'll check the message queue for any
// new items.
select {
case <-c.quit:
peerLog.Tracef("Update stream for "+
"ChannelID(%x) exiting", c.cid[:])
c.msgCond.L.Unlock()
return
default:
}
}
// Grab the message off the front of the queue, shifting the
// slice's reference down one in order to remove the message
// from the queue.
msg := c.msgs[0]
c.msgs[0] = nil // Set to nil to prevent GC leak.
c.msgs = c.msgs[1:]
// We'll send a message to the funding manager and wait iff an
// active funding process for this channel hasn't yet
// completed. We do this in order to account for the following
// scenario: we send the funding locked message to the other
// side, they immediately send a channel update message, but we
// haven't yet sent the channel to the channelManager.
c.fundingMgr.waitUntilChannelOpen(c.cid)
// Dispatch the commitment update message to the proper active
// goroutine dedicated to this channel.
if c.chanLink == nil {
link, err := c.htlcSwitch.GetLink(c.cid)
if err != nil {
peerLog.Errorf("recv'd update for unknown "+
"channel %v from %v", c.cid, c.peer)
continue
}
c.chanLink = link
}
c.chanLink.HandleChannelUpdate(msg)
c.msgCond.L.Unlock()
}
}
// AddMsg adds a new message to the chanMsgStream. This function is safe for
// concurrent access.
func (c *chanMsgStream) AddMsg(msg lnwire.Message) {
// First, we'll lock the condition, and add the message to the end of
// the message queue.
c.msgCond.L.Lock()
c.msgs = append(c.msgs, msg)
c.msgCond.L.Unlock()
// With the message added, we signal to the msgConsumer that there are
// additional messages to consume.
c.msgCond.Signal()
}
// 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() {
// We'll stop the timer after a new messages is received, and also
// reset it after we process the next message.
idleTimer := time.AfterFunc(idleTimeout, func() {
err := fmt.Errorf("Peer %s no answer for %s -- disconnecting",
p, idleTimeout)
p.Disconnect(err)
})
chanMsgStreams := make(map[lnwire.ChannelID]*chanMsgStream)
out:
for atomic.LoadInt32(&p.disconnect) == 0 {
nextMsg, err := p.readNextMessage()
idleTimer.Stop()
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:
idleTimer.Reset(idleTimeout)
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.OpenChannel:
p.server.fundingMgr.processFundingOpen(msg, p.addr)
case *lnwire.AcceptChannel:
p.server.fundingMgr.processFundingAccept(msg, p.addr)
case *lnwire.FundingCreated:
p.server.fundingMgr.processFundingCreated(msg, p.addr)
case *lnwire.FundingSigned:
p.server.fundingMgr.processFundingSigned(msg, p.addr)
case *lnwire.FundingLocked:
p.server.fundingMgr.processFundingLocked(msg, p.addr)
case *lnwire.Shutdown:
select {
case p.shutdownChanReqs <- msg:
case <-p.quit:
break out
}
case *lnwire.ClosingSigned:
select {
case p.closingSignedChanReqs <- msg:
case <-p.quit:
break out
}
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.UpdateFee:
isChanUpdate = true
targetChan = msg.ChanID
case *lnwire.ChannelUpdate,
*lnwire.ChannelAnnouncement,
*lnwire.NodeAnnouncement,
*lnwire.AnnounceSignatures:
p.server.authGossiper.ProcessRemoteAnnouncement(msg,
p.addr.IdentityKey)
default:
peerLog.Errorf("unknown message %v received from peer "+
"%v", uint16(msg.MsgType()), p)
}
if isChanUpdate {
// If this is a channel update, then we need to feed it
// into the channel's in-order message stream.
chanStream, ok := chanMsgStreams[targetChan]
if !ok {
// If a stream hasn't yet been created, then
// we'll do so, add it to the map, and finally
// start it.
chanStream = newChanMsgStream(p.server.fundingMgr,
p.server.htlcSwitch, p, targetChan)
chanMsgStreams[targetChan] = chanStream
chanStream.Start()
}
// With the stream obtained, add the message to the
// stream so we can continue processing message.
chanStream.AddMsg(nextMsg)
}
idleTimer.Reset(idleTimeout)
}
p.wg.Done()
p.Disconnect(errors.New("read handler closed"))
for cid, chanStream := range chanMsgStreams {
chanStream.Stop()
delete(chanMsgStreams, cid)
}
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.AcceptChannel:
m.FundingKey.Curve = nil
m.RevocationPoint.Curve = nil
m.PaymentPoint.Curve = nil
m.DelayedPaymentPoint.Curve = nil
m.FirstCommitmentPoint.Curve = nil
case *lnwire.OpenChannel:
m.FundingKey.Curve = nil
m.RevocationPoint.Curve = nil
m.PaymentPoint.Curve = nil
m.DelayedPaymentPoint.Curve = nil
m.FirstCommitmentPoint.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))
// TODO(roasbeef): add write deadline?
// 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() {
var exitErr error
out:
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 {
exitErr = errors.Errorf("unable to write message: %v", err)
break out
}
// If the queueHandler was waiting for us to complete
// the last write, then we'll send it a sginal that
// we're done and are awaiting additional messages.
select {
case p.sendQueueSync <- struct{}{}:
default:
}
case <-p.quit:
exitErr = errors.Errorf("peer exiting")
break out
}
}
p.wg.Done()
p.Disconnect(exitErr)
peerLog.Tracef("writeHandler for peer %v done", p)
}
// 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.
drain:
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:
// If the write handler is currently blocked,
// then we'll break out of this loop, to avoid
// tightly spinning waiting for a blocked write
// handler.
break drain
}
}
// 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. We'll also attempt to send
// to the writeHandler again, as if this succeeds we'll once
// again try to aggressively drain the pending message queue.
select {
case <-p.quit:
return
case msg := <-p.outgoingQueue:
pendingMsgs.PushBack(msg)
case <-p.sendQueueSync:
// Fall through so we can go back to the top of the
// drain loop.
}
}
}
// 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() {
defer p.wg.Done()
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
}
}
}
// 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 {
p.activeChanMtx.RLock()
defer p.activeChanMtx.RUnlock()
snapshots := make([]*channeldb.ChannelSnapshot, 0, len(p.activeChannels))
for _, activeChan := range p.activeChannels {
snapshot := activeChan.StateSnapshot()
snapshots = append(snapshots, snapshot)
}
return snapshots
}
// closingScripts are the set of clsoign deslivery scripts for each party. This
// intermediate state is maintained for each active close negotiation, as the
// final signatures sent must cover the specified delivery scripts for each
// party.
type closingScripts struct {
localScript []byte
remoteScript []byte
}
// 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() {
defer p.wg.Done()
// 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)
deliveryAddrs := make(map[lnwire.ChannelID]*closingScripts)
// initiator[ShutdownSigs|FeeProposals] holds the
// [signature|feeProposal] for the last ClosingSigned sent to the peer
// by the initiator. This enables us to respond to subsequent steps in
// the workflow without having to recalculate our signature for the
// channel close transaction, and track the sent fee proposals for fee
// negotiation purposes.
initiatorShutdownSigs := make(map[lnwire.ChannelID][]byte)
initiatorFeeProposals := make(map[lnwire.ChannelID]uint64)
// responder[ShutdownSigs|FeeProposals] is similar to the the maps
// above, just for the responder.
responderShutdownSigs := make(map[lnwire.ChannelID][]byte)
responderFeeProposals := make(map[lnwire.ChannelID]uint64)
// TODO(roasbeef): move to cfg closure func
genDeliveryScript := func() ([]byte, error) {
deliveryAddr, err := p.server.cc.wallet.NewAddress(
lnwallet.WitnessPubKey, false,
)
if err != nil {
return nil, err
}
peerLog.Infof("Delivery addr for channel close: %v",
deliveryAddr)
return txscript.PayToAddrScript(deliveryAddr)
}
out:
for {
select {
// A new channel has arrived which means we've just completed a
// funding workflow. We'll initialize the necessary local
// state, and notify the htlc switch of a new link.
case newChanReq := <-p.newChannels:
chanPoint := newChanReq.channel.ChannelPoint()
chanID := lnwire.NewChanIDFromOutPoint(chanPoint)
newChan := newChanReq.channel
// Make sure this channel is not already active.
p.activeChanMtx.Lock()
if _, ok := p.activeChannels[chanID]; ok {
peerLog.Infof("Already have ChannelPoint(%v), ignoring.", chanPoint)
p.activeChanMtx.Unlock()
close(newChanReq.done)
newChanReq.channel.Stop()
continue
}
// If not already active, we'll add this channel to the set of active
// channels, so we can look it up later easily
// according to its channel ID.
p.activeChannels[chanID] = newChan
p.activeChanMtx.Unlock()
peerLog.Infof("New channel active ChannelPoint(%v) "+
"with peerId(%v)", chanPoint, p.id)
// Next, we'll assemble a ChannelLink along with the
// necessary items it needs to function.
//
// TODO(roasbeef): panic on below?
blockEpoch, err := p.server.cc.chainNotifier.RegisterBlockEpochNtfn()
if err != nil {
peerLog.Errorf("unable to register for block epoch: %v", err)
continue
}
_, currentHeight, err := p.server.cc.chainIO.GetBestBlock()
if err != nil {
peerLog.Errorf("unable to get best block: %v", err)
continue
}
linkConfig := htlcswitch.ChannelLinkConfig{
Peer: p,
DecodeHopIterator: p.server.sphinx.DecodeHopIterator,
DecodeOnionObfuscator: p.server.sphinx.ExtractErrorEncrypter,
GetLastChannelUpdate: createGetLastUpdate(p.server.chanRouter,
p.PubKey(), newChanReq.channel.ShortChanID()),
SettledContracts: p.server.breachArbiter.settledContracts,
DebugHTLC: cfg.DebugHTLC,
HodlHTLC: cfg.HodlHTLC,
Registry: p.server.invoices,
Switch: p.server.htlcSwitch,
FwrdingPolicy: p.server.cc.routingPolicy,
BlockEpochs: blockEpoch,
}
link := htlcswitch.NewChannelLink(linkConfig, newChan,
uint32(currentHeight))
// With the channel link created, we'll now notify the
// htlc switch so this channel can be used to dispatch
// local payments and also passively forward payments.
if err := p.server.htlcSwitch.AddLink(link); 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.
var (
deliveryScript []byte
err error
)
if req.CloseType == htlcswitch.CloseRegular {
chanShutdowns[chanID] = req
// As we need to close out the channel and
// claim our funds on-chain, we'll request a
// new delivery address from the wallet, and
// turn that into it corresponding output
// script.
deliveryScript, err = genDeliveryScript()
if err != nil {
cErr := fmt.Errorf("Unable to generate "+
"delivery address: %v", err)
peerLog.Errorf(cErr.Error())
req.Err <- cErr
continue
}
// We'll also track this delivery script, as
// we'll need it to reconstruct the cooperative
// closure transaction during our closing fee
// negotiation ratchet.
deliveryAddrs[chanID] = &closingScripts{
localScript: deliveryScript,
}
}
// 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, deliveryScript)
// 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:
// If we don't have a channel that matches this channel
// ID, then we'll ignore this message.
chanID := req.ChannelID
p.activeChanMtx.Lock()
_, ok := p.activeChannels[chanID]
p.activeChanMtx.Unlock()
if !ok {
peerLog.Warnf("Received unsolicited shutdown msg: %v",
spew.Sdump(req))
continue
}
// First, we'll track their delivery script for when we
// ultimately create the cooperative closure
// transaction.
deliveryScripts, ok := deliveryAddrs[chanID]
if !ok {
deliveryAddrs[chanID] = &closingScripts{}
deliveryScripts = deliveryAddrs[chanID]
}
deliveryScripts.remoteScript = req.Address
// Next, 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 {
// Check responderShutdownSigs for an already
// existing shutdown signature for this channel.
// If such a signature exists, it means we
// already have sent a response to a shutdown
// message for this channel, so ignore this one.
_, exists := responderShutdownSigs[req.ChannelID]
if exists {
continue
}
// As we're the responder, we'll need to
// generate a delivery script of our own.
deliveryScript, err := genDeliveryScript()
if err != nil {
peerLog.Errorf("Unable to generate "+
"delivery address: %v", err)
continue
}
deliveryScripts.localScript = deliveryScript
// In this case, we'll send a shutdown message,
// and also prep our closing signature for the
// case the fees are immediately agreed upon.
closeSig, proposedFee := p.handleShutdownResponse(
req, deliveryScript)
if closeSig != nil {
responderShutdownSigs[req.ChannelID] = closeSig
responderFeeProposals[req.ChannelID] = proposedFee
}
}
// 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.
chanID := req.ChannelID
localCloseReq, ok := chanShutdowns[chanID]
// If it does, then this means we were the initiator of
// the channel shutdown procedure.
if ok {
shutdownSig := initiatorShutdownSigs[req.ChannelID]
initiatorSig := append(shutdownSig,
byte(txscript.SigHashAll))
// 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. If the fees are still being
// negotiated, handleClosingSigned returns the
// signature and proposed fee we sent to the
// peer. In the case fee negotiation was
// complete, and the closing tx was broadcasted,
// closeSig will be nil, and we can delete the
// state associated with this channel shutdown.
closeSig, proposedFee := p.handleClosingSigned(
localCloseReq, req,
deliveryAddrs[chanID], initiatorSig,
initiatorFeeProposals[req.ChannelID])
if closeSig != nil {
initiatorShutdownSigs[req.ChannelID] = closeSig
initiatorFeeProposals[req.ChannelID] = proposedFee
} else {
delete(initiatorShutdownSigs, req.ChannelID)
delete(initiatorFeeProposals, req.ChannelID)
delete(chanShutdowns, req.ChannelID)
delete(deliveryAddrs, req.ChannelID)
}
continue
}
shutdownSig := responderShutdownSigs[req.ChannelID]
responderSig := append(shutdownSig,
byte(txscript.SigHashAll))
// Otherwise, we're the responder to the channel
// shutdown procedure. The procedure will be the same,
// but we don't have a local request to to notify about
// updates, so just pass in nil instead.
closeSig, proposedFee := p.handleClosingSigned(nil, req,
deliveryAddrs[chanID], responderSig,
responderFeeProposals[req.ChannelID])
if closeSig != nil {
responderShutdownSigs[req.ChannelID] = closeSig
responderFeeProposals[req.ChannelID] = proposedFee
} else {
delete(responderShutdownSigs, req.ChannelID)
delete(responderFeeProposals, req.ChannelID)
delete(deliveryAddrs, chanID)
}
case <-p.quit:
break out
}
}
}
// 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, deliveryScript []byte) {
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, deliveryScript)
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:
// TODO(roasbeef): no longer need with newer beach logic?
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.
// Returns the signature used to signed the close proposal, and the proposed
// fee.
func (p *peer) handleShutdownResponse(msg *lnwire.Shutdown,
localDeliveryScript []byte) ([]byte, uint64) {
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, 0
}
// As we just received a shutdown message, we'll also send a shutdown
// message with our desired fee so we can start the negotiation.
err := p.sendShutdown(channel, localDeliveryScript)
if err != nil {
peerLog.Errorf("error while sending shutdown message: %v", err)
return nil, 0
}
// Calculate an initial proposed fee rate for the close transaction.
feeRate := p.server.cc.feeEstimator.EstimateFeePerWeight(1) * 1000
// We propose a fee and send a close proposal to the peer. This will
// start the fee negotiations. Once both sides agree on a fee, we'll
// create a signature that closes the channel using the agreed upon fee.
fee := channel.CalcFee(feeRate)
closeSig, proposedFee, err := channel.CreateCloseProposal(
fee, localDeliveryScript, msg.Address,
)
if err != nil {
peerLog.Errorf("unable to create close proposal: %v", err)
return nil, 0
}
parsedSig, err := btcec.ParseSignature(closeSig, btcec.S256())
if err != nil {
peerLog.Errorf("unable to parse signature: %v", err)
return nil, 0
}
// With the closing signature assembled, we'll send the matching close
// signed message to the other party so they can broadcast the closing
// transaction if they agree with the fee, or create a new close
// proposal if they don't.
closingSigned := lnwire.NewClosingSigned(msg.ChannelID, proposedFee,
parsedSig)
p.queueMsg(closingSigned, nil)
return closeSig, proposedFee
}
// calculateCompromiseFee performs the current fee negotiation algorithm,
// taking into consideration our ideal fee based on current fee environment,
// the fee we last proposed (if any), and the fee proposed by the peer.
func calculateCompromiseFee(ourIdealFee, lastSentFee, peerFee uint64) uint64 {
// We will accept a proposed fee in the interval
// [0.5*ourIdealFee, 2*ourIdealFee]. If the peer's fee doesn't fall in
// this range, we'll propose the average of the peer's fee and our last
// sent fee, as long as it is in this range.
// TODO(halseth): Dynamic fee to determine what we consider min/max for
// timely confirmation.
maxFee := 2 * ourIdealFee
minFee := ourIdealFee / 2
// If we didn't propose a fee before, just use our ideal fee value for
// the average calculation.
if lastSentFee == 0 {
lastSentFee = ourIdealFee
}
avgFee := (lastSentFee + peerFee) / 2
switch {
case peerFee <= maxFee && peerFee >= minFee:
// Peer fee is in the accepted range.
return peerFee
case avgFee <= maxFee && avgFee >= minFee:
// The peer's fee is not in the accepted range, but the average
// fee is.
return avgFee
case avgFee > maxFee:
// TODO(halseth): We must ensure fee is not higher than the
// current fee on the commitment transaction.
// We cannot accept the average fee, as it is more than twice
// our own estimate. Set our proposed to the maximum we can
// accept.
return maxFee
default:
// Cannot accept the average, as we consider it too low.
return minFee
}
}
// handleClosingSigned is called when the a ClosingSigned message is received
// from the peer. If we are the initiator in the shutdown procedure, localReq
// should be set to the local close request. If we are the responder, it should
// be set to nil.
//
// This method sends the necessary ClosingSigned message to continue fee
// negotiation, and in case we agreed on a fee completes the channel close
// transaction, and then broadcasts it. It also performs channel cleanup (and
// reports status back to the caller if this was a local shutdown request).
//
// It returns the signature and the proposed fee included in the ClosingSigned
// sent to the peer.
//
// 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) handleClosingSigned(localReq *htlcswitch.ChanClose,
msg *lnwire.ClosingSigned, deliveryScripts *closingScripts,
lastSig []byte, lastFee uint64) ([]byte, uint64) {
chanID := msg.ChannelID
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())
if localReq != nil {
localReq.Err <- err
}
return nil, 0
}
// We now consider the fee proposed by the peer, together with the fee
// we last proposed (if any). This method will in case more fee
// negotiation is necessary send a new ClosingSigned message to the peer
// with our new proposed fee. In case we can agree on a fee, it will
// assemble the close transaction, and we can go on to broadcasting it.
closeTx, ourSig, ourFee, err := p.negotiateFeeAndCreateCloseTx(channel,
msg, deliveryScripts, lastSig, lastFee)
if err != nil {
if localReq != nil {
localReq.Err <- err
}
return nil, 0
}
// If closeTx == nil it means that we did not agree on a fee, but we
// proposed a new fee to the peer. Return the signature used for this
// new proposal, and the fee we proposed, for use when we get a reponse.
if closeTx == nil {
return ourSig, ourFee
}
chanPoint := channel.ChannelPoint()
select {
case p.server.breachArbiter.settledContracts <- chanPoint:
case <-p.server.quit:
return nil, 0
case <-p.quit:
return nil, 0
}
// We agreed on a fee, and we can 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 {
// TODO(halseth): Add relevant error types to the
// WalletController interface as this is quite fragile.
if strings.Contains(err.Error(), "already exists") ||
strings.Contains(err.Error(), "already have") {
peerLog.Infof("channel close tx from ChannelPoint(%v) "+
" already exist, probably broadcasted by peer: %v",
chanPoint, err)
} else {
peerLog.Errorf("channel close tx from ChannelPoint(%v) "+
" rejected: %v", chanPoint, err)
// TODO(roasbeef): send ErrorGeneric to other side
return nil, 0
}
}
// 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.
select {
case p.server.breachArbiter.settledContracts <- chanPoint:
case <-p.server.quit:
return nil, 0
}
if err := p.WipeChannel(channel); err != nil {
if localReq != nil {
localReq.Err <- err
}
return nil, 0
}
// 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: *chanPoint,
ClosingTXID: closingTxid,
RemotePub: &chanInfo.RemoteIdentity,
Capacity: chanInfo.Capacity,
SettledBalance: chanInfo.LocalBalance.ToSatoshis(),
CloseType: channeldb.CooperativeClose,
IsPending: true,
}
if err := channel.DeleteState(closeSummary); err != nil {
if localReq != nil {
localReq.Err <- err
}
return nil, 0
}
// If this is a locally requested shutdown, update the caller with a new
// event detailing the current pending state of this request.
if localReq != nil {
localReq.Updates <- &lnrpc.CloseStatusUpdate{
Update: &lnrpc.CloseStatusUpdate_ClosePending{
ClosePending: &lnrpc.PendingUpdate{
Txid: closingTxid[:],
},
},
}
}
_, bestHeight, err := p.server.cc.chainIO.GetBestBlock()
if err != nil {
if localReq != nil {
localReq.Err <- err
}
return nil, 0
}
// 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
// If any error happens during waitForChanToClose, forard it to
// localReq. If this channel closure is not locally initiated, localReq
// will be nil, so just ignore the error.
errChan := make(chan error, 1)
if localReq != nil {
errChan = localReq.Err
}
go waitForChanToClose(uint32(bestHeight), notifier, errChan,
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(chanPoint)
if err != nil {
if localReq != nil {
localReq.Err <- err
}
return
}
// Respond to the local subsystem which requested the
// channel closure.
if localReq != nil {
localReq.Updates <- &lnrpc.CloseStatusUpdate{
Update: &lnrpc.CloseStatusUpdate_ChanClose{
ChanClose: &lnrpc.ChannelCloseUpdate{
ClosingTxid: closingTxid[:],
Success: true,
},
},
}
}
})
return nil, 0
}
// negotiateFeeAndCreateCloseTx takes into consideration the closing transaction
// fee proposed by the remote peer in the ClosingSigned message and our
// previously proposed fee (set to 0 if no previous), and continues the fee
// negotiation it process. In case the peer agreed on the same fee as we
// previously sent, it will assemble the close transaction and broadcast it. In
// case the peer propose a fee different from our previous proposal, but that
// can be accepted, a ClosingSigned message with the accepted fee is sent,
// before the closing transaction is broadcasted. In the case where we cannot
// accept the peer's proposed fee, a new fee proposal will be sent.
//
// TODO(halseth): In the case where we cannot accept the fee, and we cannot
// make more proposals, this method should return an error, and we should fail
// the channel.
func (p *peer) negotiateFeeAndCreateCloseTx(channel *lnwallet.LightningChannel,
msg *lnwire.ClosingSigned, deliveryScripts *closingScripts, ourSig []byte,
ourFeeProp uint64) (*wire.MsgTx, []byte, uint64, error) {
peerFeeProposal := msg.FeeSatoshis
// If the fee proposed by the peer is different from what we proposed
// before (or we did not propose anything yet), we must check if we can
// accept the proposal, or if we should negotiate.
if peerFeeProposal != ourFeeProp {
// The peer has suggested a different fee from what we proposed.
// Let's calculate if this one is tolerable.
ourIdealFeeRate := p.server.cc.feeEstimator.
EstimateFeePerWeight(1) * 1000
ourIdealFee := channel.CalcFee(ourIdealFeeRate)
fee := calculateCompromiseFee(ourIdealFee, ourFeeProp,
peerFeeProposal)
// Our new proposed fee must be strictly between what we
// proposed before and what the peer proposed.
isAcceptable := false
if fee < peerFeeProposal && fee > ourFeeProp {
isAcceptable = true
}
if fee < ourFeeProp && fee > peerFeeProposal {
isAcceptable = true
}
if !isAcceptable {
// TODO(halseth): fail channel
}
// Since the compromise fee is different from the fee we last
// proposed, we must update our proposal.
// Create a new close proposal with the compromise fee, and
// send this to the peer.
closeSig, proposedFee, err := channel.CreateCloseProposal(fee,
deliveryScripts.localScript, deliveryScripts.remoteScript)
if err != nil {
peerLog.Errorf("unable to create close proposal: %v",
err)
return nil, nil, 0, err
}
parsedSig, err := btcec.ParseSignature(closeSig, btcec.S256())
if err != nil {
peerLog.Errorf("unable to parse signature: %v", err)
return nil, nil, 0, err
}
closingSigned := lnwire.NewClosingSigned(msg.ChannelID,
proposedFee, parsedSig)
p.queueMsg(closingSigned, nil)
// If the compromise fee was different from what the peer
// proposed, then we must return and wait for an answer, if not
// we can go on to complete the close transaction.
if fee != peerFeeProposal {
return nil, closeSig, proposedFee, nil
}
// We accept the fee proposed by the peer, so prepare our
// signature to complete the close transaction.
ourSig = append(closeSig, byte(txscript.SigHashAll))
}
// We agreed on a fee, and we have the peer's signature for this fee,
// so we can assemble the close tx.
peerSig := append(msg.Signature.Serialize(), byte(txscript.SigHashAll))
chanPoint := channel.ChannelPoint()
closeTx, err := channel.CompleteCooperativeClose(ourSig, peerSig,
deliveryScripts.localScript, deliveryScripts.remoteScript,
peerFeeProposal)
if err != nil {
peerLog.Errorf("unable to complete cooperative "+
"close for ChannelPoint(%v): %v",
chanPoint, err)
// TODO(roasbeef): send ErrorGeneric to other side
return nil, nil, 0, err
}
return closeTx, nil, 0, nil
}
// 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.
peerLog.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,
deliveryScript []byte) 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())
// 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, deliveryScript)
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
// createGetLastUpdate returns the handler which serve as a source of the last
// update of the channel in a form of lnwire update message.
func createGetLastUpdate(router *routing.ChannelRouter,
pubKey [33]byte, chanID lnwire.ShortChannelID) func() (*lnwire.ChannelUpdate,
error) {
return func() (*lnwire.ChannelUpdate, error) {
info, edge1, edge2, err := router.GetChannelByID(chanID)
if err != nil {
return nil, err
}
if edge1 == nil || edge2 == nil {
return nil, errors.Errorf("unable to find "+
"channel by ShortChannelID(%v)", chanID)
}
var local *channeldb.ChannelEdgePolicy
if bytes.Compare(edge1.Node.PubKey.SerializeCompressed(),
pubKey[:]) == 0 {
local = edge2
} else {
local = edge1
}
update := &lnwire.ChannelUpdate{
Signature: local.Signature,
ChainHash: info.ChainHash,
ShortChannelID: lnwire.NewShortChanIDFromInt(local.ChannelID),
Timestamp: uint32(local.LastUpdate.Unix()),
Flags: local.Flags,
TimeLockDelta: local.TimeLockDelta,
HtlcMinimumMsat: local.MinHTLC,
BaseFee: uint32(local.FeeBaseMSat),
FeeRate: uint32(local.FeeProportionalMillionths),
}
hswcLog.Debugf("Sending latest channel_update: %v",
spew.Sdump(update))
return update, nil
}
}