// htlcManager is the primary goroutine which drives a channel's commitment
// update state-machine in response to messages received via several channels.
// The htlcManager reads messages from the upstream (remote) peer, and also
// from several possible downstream channels managed by the htlcSwitch. In the
// event that an htlc needs to be forwarded, then send-only htlcPlex chan is
// used which sends htlc packets to the switch for forwarding. Additionally,
// the htlcManager handles acting upon all timeouts for any active HTLC's,
// manages the channel's revocation window, and also the htlc trickle
// queue+timer for this active channels.
func (p *peer) htlcManager(channel *lnwallet.LightningChannel,
htlcPlex chan<- *htlcPacket, downstreamLink <-chan *htlcPacket,
upstreamLink <-chan lnwire.Message) {
chanStats := channel.StateSnapshot()
peerLog.Infof("HTLC manager for ChannelPoint(%v) started, "+
"our_balance=%v, their_balance=%v, chain_height=%v",
channel.ChannelPoint(), chanStats.LocalBalance,
chanStats.RemoteBalance, chanStats.NumUpdates)
// A new session for this active channel has just started, therefore we
// need to send our initial revocation window to the remote peer.
for i := 0; i < lnwallet.InitialRevocationWindow; i++ {
rev, err := channel.ExtendRevocationWindow()
if err != nil {
peerLog.Errorf("unable to expand revocation window: %v", err)
continue
}
p.queueMsg(rev, nil)
}
state := &commitmentState{
channel: channel,
chanPoint: channel.ChannelPoint(),
clearedHTCLs: make(map[uint32]*pendingPayment),
htlcsToSettle: make(map[uint32]*channeldb.Invoice),
pendingCircuits: make(map[uint32]*sphinx.ProcessedPacket),
sphinx: p.server.sphinx,
switchChan: htlcPlex,
}
// TODO(roasbeef): check to see if able to settle any currently pending
// HTLC's
// * also need signals when new invoices are added by the invoiceRegistry
batchTimer := time.Tick(10 * time.Millisecond)
out:
for {
select {
case <-channel.UnilateralCloseSignal:
// TODO(roasbeef): eliminate false positive via local close
peerLog.Warnf("Remote peer has closed ChannelPoint(%v) on-chain",
state.chanPoint)
if err := wipeChannel(p, channel); err != nil {
peerLog.Errorf("unable to wipe channel %v", err)
}
break out
case <-channel.ForceCloseSignal:
peerLog.Warnf("ChannelPoint(%v) has been force "+
"closed, disconnecting from peerID(%x)",
state.chanPoint, p.id)
break out
//p.Disconnect()
// TODO(roasbeef): prevent leaking ticker?
case <-state.logCommitTimer:
// If we haven't sent or received a new commitment
// update in some time, check to see if we have any
// pending updates we need to commit. If so, then send
// an update incrementing the unacked counter is
// successfully.
if !state.channel.PendingUpdates() &&
len(state.htlcsToSettle) == 0 {
continue
}
if sent, err := p.updateCommitTx(state); err != nil {
peerLog.Errorf("unable to update "+
"commitment: %v", err)
p.Disconnect()
break out
} else if sent {
state.numUnAcked += 1
}
case <-batchTimer:
// If the current batch is empty, then we have no work
// here.
if len(state.pendingBatch) == 0 {
continue
}
// Otherwise, attempt to extend the remote commitment
// chain including all the currently pending entries.
// If the send was unsuccesful, then abaondon the
// update, waiting for the revocation window to open
// up.
if sent, err := p.updateCommitTx(state); err != nil {
peerLog.Errorf("unable to update "+
"commitment: %v", err)
p.Disconnect()
break out
} else if !sent {
continue
}
state.numUnAcked += 1
case pkt := <-downstreamLink:
p.handleDownStreamPkt(state, pkt)
case msg, ok := <-upstreamLink:
// If the upstream message link is closed, this signals
// that the channel itself is being closed, therefore
// we exit.
if !ok {
break out
}
p.handleUpstreamMsg(state, msg)
case <-p.quit:
break out
}
}
p.wg.Done()
peerLog.Tracef("htlcManager for peer %v done", p)
}
