// SendCoins attemps to send amt satoshis from the internal mining node to the
// targetted lightning node.
func (n *networkHarness) SendCoins(ctx context.Context, amt btcutil.Amount,
target *lightningNode) error {
balReq := &lnrpc.WalletBalanceRequest{}
initialBalance, err := target.WalletBalance(ctx, balReq)
if err != nil {
return err
}
// First, obtain an address from the target lightning node, preferring
// to receive a p2wkh address s.t the output can immediately be used as
// an input to a funding transaction.
addrReq := &lnrpc.NewAddressRequest{
Type: lnrpc.NewAddressRequest_WITNESS_PUBKEY_HASH,
}
resp, err := target.NewAddress(ctx, addrReq)
if err != nil {
return err
}
addr, err := btcutil.DecodeAddress(resp.Address, n.netParams)
if err != nil {
return err
}
addrScript, err := txscript.PayToAddrScript(addr)
if err != nil {
return err
}
// Generate a transaction which creates an output to the target
// pkScript of the desired amount.
output := &wire.TxOut{
PkScript: addrScript,
Value: int64(amt),
}
if _, err := n.Miner.CoinbaseSpend([]*wire.TxOut{output}); err != nil {
return err
}
// Finally, generate 6 new blocks to ensure the output gains a
// sufficient number of confirmations.
if _, err := n.Miner.Node.Generate(6); err != nil {
return err
}
// Pause until the nodes current wallet balances reflects the amount
// sent to it above.
// TODO(roasbeef): factor out into helper func
for {
select {
case <-time.Tick(time.Millisecond * 50):
currentBal, err := target.WalletBalance(ctx, balReq)
if err != nil {
return err
}
if currentBal.Balance == initialBalance.Balance+amt.ToBTC() {
return nil
}
case <-time.After(time.Second * 30):
return fmt.Errorf("balances not synced after deadline")
}
}
}
// htlcForwarder is responsible for optimally forwarding (and possibly
// fragmenting) incoming/outgoing HTLC's amongst all active interfaces and
// their links. The duties of the forwarder are similar to that of a network
// switch, in that it facilitates multi-hop payments by acting as a central
// messaging bus. The switch communicates will active links to create, manage,
// and tearn down active onion routed payments.Each active channel is modeled
// as networked device with meta-data such as the available payment bandwidth,
// and total link capacity.
func (h *htlcSwitch) htlcForwarder() {
// TODO(roasbeef): track pending payments here instead of within each peer?
// Examine settles/timeouts from htlcPlex. Add src to htlcPacket, key by
// (src, htlcKey).
// TODO(roasbeef): cleared vs settled distinction
var numUpdates uint64
var satSent, satRecv btcutil.Amount
logTicker := time.NewTicker(10 * time.Second)
out:
for {
select {
case htlcPkt := <-h.outgoingPayments:
dest := htlcPkt.dest
h.interfaceMtx.RLock()
chanInterface, ok := h.interfaces[dest]
h.interfaceMtx.RUnlock()
if !ok {
err := fmt.Errorf("Unable to locate link %x",
dest[:])
hswcLog.Errorf(err.Error())
htlcPkt.err <- err
continue
}
wireMsg := htlcPkt.msg.(*lnwire.HTLCAddRequest)
amt := btcutil.Amount(wireMsg.Amount)
// Handle this send request in a distinct goroutine in
// order to avoid a possible deadlock between the htlc
// switch and channel's htlc manager.
for _, link := range chanInterface {
// TODO(roasbeef): implement HTLC fragmentation
// * avoid full channel depletion at higher
// level (here) instead of within state
// machine?
if link.availableBandwidth < int64(amt) {
continue
}
hswcLog.Tracef("Sending %v to %x", amt, dest[:])
go func() {
link.linkChan <- htlcPkt
}()
n := atomic.AddInt64(&link.availableBandwidth,
-int64(amt))
hswcLog.Tracef("Decrementing link %v bandwidth to %v",
link.chanPoint, n)
continue out
}
hswcLog.Errorf("Unable to send payment, insufficient capacity")
htlcPkt.err <- fmt.Errorf("Insufficient capacity")
case pkt := <-h.htlcPlex:
// TODO(roasbeef): properly account with cleared vs settled
numUpdates += 1
hswcLog.Tracef("plex packet: %v", newLogClosure(func() string {
return spew.Sdump(pkt)
}))
switch wireMsg := pkt.msg.(type) {
// A link has just forwarded us a new HTLC, therefore
// we initiate the payment circuit within our internal
// staate so we can properly forward the ultimate
// settle message.
case *lnwire.HTLCAddRequest:
// Create the two ends of the payment circuit
// required to ensure completion of this new
// payment.
nextHop := pkt.onion.NextHop
h.onionMtx.RLock()
clearLink, ok := h.onionIndex[nextHop]
h.onionMtx.RUnlock()
if !ok {
hswcLog.Errorf("unable to find dest end of "+
"circuit: %x", nextHop)
continue
}
h.chanIndexMtx.RLock()
settleLink := h.chanIndex[pkt.srcLink]
h.chanIndexMtx.RUnlock()
// TODO(roasbeef): examine per-hop info to decide on link?
// * check clear has enough available sat
circuit := &paymentCircuit{
clear: clearLink[0],
settle: settleLink,
}
cKey := circuitKey(wireMsg.RedemptionHashes[0])
h.paymentCircuits[cKey] = circuit
hswcLog.Debugf("Creating onion circuit for %x: %v<->%v",
cKey[:], clearLink[0].chanPoint,
settleLink.chanPoint)
// With the circuit initiated, send the htlcPkt
// to the clearing link within the circuit to
// continue propagating the HTLC accross the
// network.
circuit.clear.linkChan <- &htlcPacket{
msg: wireMsg,
err: make(chan error, 1),
}
// Reduce the available bandwidth for the link
// as it will clear the above HTLC, increasing
// the limbo balance within the channel.
n := atomic.AddInt64(&circuit.clear.availableBandwidth,
-int64(pkt.amt))
hswcLog.Tracef("Decrementing link %v bandwidth to %v",
circuit.clear.chanPoint, n)
satRecv += pkt.amt
// We've just received a settle message which means we
// can finalize the payment circuit by forwarding the
// settle msg to the link which initially created the
// circuit.
case *lnwire.HTLCSettleRequest:
rHash := fastsha256.Sum256(wireMsg.RedemptionProofs[0][:])
var cKey circuitKey
copy(cKey[:], rHash[:])
// If we initiated the payment then there won't
// be an active circuit to continue propagating
// the settle over. Therefore, we exit early.
circuit, ok := h.paymentCircuits[cKey]
if !ok {
hswcLog.Debugf("No existing circuit "+
"for %x", rHash[:])
satSent += pkt.amt
continue
}
hswcLog.Debugf("Closing completed onion "+
"circuit for %x: %v<->%v", rHash[:],
circuit.clear.chanPoint,
circuit.settle.chanPoint)
circuit.settle.linkChan <- &htlcPacket{
msg: wireMsg,
err: make(chan error, 1),
}
// Increase the available bandwidth for the
// link as it will settle the above HTLC,
// subtracting from the limbo balacne and
// incrementing its local balance.
n := atomic.AddInt64(&circuit.settle.availableBandwidth,
int64(pkt.amt))
hswcLog.Tracef("Incrementing link %v bandwidth to %v",
circuit.settle.chanPoint, n)
satSent += pkt.amt
}
case <-logTicker.C:
if numUpdates == 0 {
continue
}
hswcLog.Infof("Sent %v satoshis, received %v satoshi in "+
"the last 10 seconds (%v tx/sec)",
satSent.ToUnit(btcutil.AmountSatoshi),
satRecv.ToUnit(btcutil.AmountSatoshi),
float64(numUpdates)/10)
satSent = 0
satRecv = 0
numUpdates = 0
case <-h.quit:
break out
}
}
h.wg.Done()
}