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routing/payment_lifecycle: extract create attempt into method

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This commit is contained in:
Johan T. Halseth 2019-05-23 20:05:29 +02:00
parent e9b2182cdc
commit dd73c51a34
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1 changed files with 181 additions and 125 deletions
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306
routing/payment_lifecycle.go
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@ -6,6 +6,7 @@ import (
"github.com/davecgh/go-spew/spew"
sphinx "github.com/lightningnetwork/lightning-onion"
"github.com/lightningnetwork/lnd/channeldb"
"github.com/lightningnetwork/lnd/htlcswitch"
"github.com/lightningnetwork/lnd/lnwire"
"github.com/lightningnetwork/lnd/routing/route"
@ -20,6 +21,7 @@ type paymentLifecycle struct {
timeoutChan <-chan time.Time
currentHeight int32
finalCLTVDelta uint16
attempt *channeldb.PaymentAttemptInfo
circuit *sphinx.Circuit
lastError error
}
@ -29,122 +31,45 @@ func (p *paymentLifecycle) resumePayment() ([32]byte, *route.Route, error) {
// We'll continue until either our payment succeeds, or we encounter a
// critical error during path finding.
for {
// Before we attempt this next payment, we'll check to see if
// either we've gone past the payment attempt timeout, or the
// router is exiting. In either case, we'll stop this payment
// attempt short.
select {
case <-p.timeoutChan:
errStr := fmt.Sprintf("payment attempt not completed " +
"before timeout")
return [32]byte{}, nil, newErr(
ErrPaymentAttemptTimeout, errStr,
)
case <-p.router.quit:
// The payment will be resumed from the current state
// after restart.
return [32]byte{}, nil, ErrRouterShuttingDown
default:
// Fall through if we haven't hit our time limit, or
// are expiring.
}
// Create a new payment attempt from the given payment session.
route, err := p.paySession.RequestRoute(
p.payment, uint32(p.currentHeight), p.finalCLTVDelta,
)
if err != nil {
// If there was an error already recorded for this
// payment, we'll return that.
if p.lastError != nil {
return [32]byte{}, nil, fmt.Errorf("unable to "+
"route payment to destination: %v",
p.lastError)
}
// Terminal state, return.
return [32]byte{}, nil, err
}
// Generate a new key to be used for this attempt.
sessionKey, err := generateNewSessionKey()
if err != nil {
return [32]byte{}, nil, err
}
// Generate the raw encoded sphinx packet to be included along
// with the htlcAdd message that we send directly to the
// switch.
onionBlob, c, err := generateSphinxPacket(
route, p.payment.PaymentHash[:], sessionKey,
)
if err != nil {
return [32]byte{}, nil, err
}
// Update our cached circuit with the newly generated
// one.
p.circuit = c
// Craft an HTLC packet to send to the layer 2 switch. The
// metadata within this packet will be used to route the
// payment through the network, starting with the first-hop.
htlcAdd := &lnwire.UpdateAddHTLC{
Amount: route.TotalAmount,
Expiry: route.TotalTimeLock,
PaymentHash: p.payment.PaymentHash,
}
copy(htlcAdd.OnionBlob[:], onionBlob)
// Attempt to send this payment through the network to complete
// the payment. If this attempt fails, then we'll continue on
// to the next available route.
firstHop := lnwire.NewShortChanIDFromInt(
route.Hops[0].ChannelID,
)
// We generate a new, unique payment ID that we will use for
// this HTLC.
paymentID, err := p.router.cfg.NextPaymentID()
if err != nil {
return [32]byte{}, nil, err
}
log.Tracef("Attempting to send payment %x (pid=%v), "+
"using route: %v", p.payment.PaymentHash, paymentID,
newLogClosure(func() string {
return spew.Sdump(route)
}),
)
// Send it to the Switch. When this method returns we assume
// the Switch successfully has persisted the payment attempt,
// such that we can resume waiting for the result after a
// restart.
err = p.router.cfg.Payer.SendHTLC(
firstHop, paymentID, htlcAdd,
)
if err != nil {
log.Errorf("Failed sending attempt %d for payment "+
"%x to switch: %v", paymentID, p.payment.PaymentHash, err)
// We must inspect the error to know whether it
// was critical or not, to decide whether we
// should continue trying.
if err := p.handleSendError(route, err); err != nil {
// If this payment had no existing payment attempt, we create
// and send one now.
if p.attempt == nil {
firstHop, htlcAdd, err := p.createNewPaymentAttempt()
if err != nil {
return [32]byte{}, nil, err
}
// Error was handled successfully, make a new
// payment attempt.
continue
}
// Now that the attempt is created and checkpointed to
// the DB, we send it.
sendErr := p.sendPaymentAttempt(firstHop, htlcAdd)
if sendErr != nil {
// We must inspect the error to know whether it
// was critical or not, to decide whether we
// should continue trying.
err := p.handleSendError(sendErr)
if err != nil {
return [32]byte{}, nil, err
}
log.Debugf("Payment %x (pid=%v) successfully sent to switch",
p.payment.PaymentHash, paymentID)
// Error was handled successfully, reset the
// attempt to indicate we want to make a new
// attempt.
p.attempt = nil
continue
}
} else {
// If this was a resumed attempt, we must regenerate the
// circuit.
_, c, err := generateSphinxPacket(
&p.attempt.Route, p.payment.PaymentHash[:],
p.attempt.SessionKey,
)
if err != nil {
return [32]byte{}, nil, err
}
p.circuit = c
}
// Using the created circuit, initialize the error decrypter so we can
// parse+decode any failures incurred by this payment within the
@ -156,7 +81,7 @@ func (p *paymentLifecycle) resumePayment() ([32]byte, *route.Route, error) {
// Now ask the switch to return the result of the payment when
// available.
resultChan, err := p.router.cfg.Payer.GetPaymentResult(
paymentID, errorDecryptor,
p.attempt.PaymentID, errorDecryptor,
)
switch {
@ -166,16 +91,18 @@ func (p *paymentLifecycle) resumePayment() ([32]byte, *route.Route, error) {
// attempt, and wait for its result to be available.
case err == htlcswitch.ErrPaymentIDNotFound:
log.Debugf("Payment ID %v for hash %x not found in "+
"the Switch, retrying.", paymentID,
"the Switch, retrying.", p.attempt.PaymentID,
p.payment.PaymentHash)
// Make a new attempt.
// Reset the attempt to indicate we want to make a new
// attempt.
p.attempt = nil
continue
// A critical, unexpected error was encountered.
case err != nil:
log.Errorf("Failed getting result for paymentID %d "+
"from switch: %v", paymentID, err)
"from switch: %v", p.attempt.PaymentID, err)
return [32]byte{}, nil, err
}
@ -206,33 +133,162 @@ func (p *paymentLifecycle) resumePayment() ([32]byte, *route.Route, error) {
// We must inspect the error to know whether it was
// critical or not, to decide whether we should
// continue trying.
if err := p.handleSendError(route, result.Error); err != nil {
if err := p.handleSendError(result.Error); err != nil {
return [32]byte{}, nil, err
}
// Error was handled successfully, make a new payment
// attempt.
// Error was handled successfully, reset the attempt to
// indicate we want to make a new attempt.
p.attempt = nil
continue
}
// We successfully got a payment result back from the switch.
log.Debugf("Payment %x succeeded with pid=%v",
p.payment.PaymentHash, paymentID)
p.payment.PaymentHash, p.attempt.PaymentID)
// Terminal state, return the preimage and the route
// taken.
return result.Preimage, route, nil
return result.Preimage, &p.attempt.Route, nil
}
}
// handleSendError inspects the given error and determines whether we should
// make another payment attempt.
func (p *paymentLifecycle) handleSendError(rt *route.Route,
sendErr error) error {
// createNewPaymentAttempt creates and stores a new payment attempt to the
// database.
func (p *paymentLifecycle) createNewPaymentAttempt() (lnwire.ShortChannelID,
*lnwire.UpdateAddHTLC, error) {
// Before we attempt this next payment, we'll check to see if
// either we've gone past the payment attempt timeout, or the
// router is exiting. In either case, we'll stop this payment
// attempt short.
select {
case <-p.timeoutChan:
errStr := fmt.Sprintf("payment attempt not completed " +
"before timeout")
return lnwire.ShortChannelID{}, nil,
newErr(ErrPaymentAttemptTimeout, errStr)
case <-p.router.quit:
// The payment will be resumed from the current state
// after restart.
return lnwire.ShortChannelID{}, nil, ErrRouterShuttingDown
default:
// Fall through if we haven't hit our time limit, or
// are expiring.
}
// Create a new payment attempt from the given payment session.
route, err := p.paySession.RequestRoute(
p.payment, uint32(p.currentHeight), p.finalCLTVDelta,
)
if err != nil {
// If there was an error already recorded for this
// payment, we'll return that.
if p.lastError != nil {
return lnwire.ShortChannelID{}, nil,
fmt.Errorf("unable to route payment to "+
"destination: %v", p.lastError)
}
// Terminal state, return.
return lnwire.ShortChannelID{}, nil, err
}
// Generate a new key to be used for this attempt.
sessionKey, err := generateNewSessionKey()
if err != nil {
return lnwire.ShortChannelID{}, nil, err
}
// Generate the raw encoded sphinx packet to be included along
// with the htlcAdd message that we send directly to the
// switch.
onionBlob, c, err := generateSphinxPacket(
route, p.payment.PaymentHash[:], sessionKey,
)
if err != nil {
return lnwire.ShortChannelID{}, nil, err
}
// Update our cached circuit with the newly generated
// one.
p.circuit = c
// Craft an HTLC packet to send to the layer 2 switch. The
// metadata within this packet will be used to route the
// payment through the network, starting with the first-hop.
htlcAdd := &lnwire.UpdateAddHTLC{
Amount: route.TotalAmount,
Expiry: route.TotalTimeLock,
PaymentHash: p.payment.PaymentHash,
}
copy(htlcAdd.OnionBlob[:], onionBlob)
// Attempt to send this payment through the network to complete
// the payment. If this attempt fails, then we'll continue on
// to the next available route.
firstHop := lnwire.NewShortChanIDFromInt(
route.Hops[0].ChannelID,
)
// We generate a new, unique payment ID that we will use for
// this HTLC.
paymentID, err := p.router.cfg.NextPaymentID()
if err != nil {
return lnwire.ShortChannelID{}, nil, err
}
// We now have all the information needed to populate
// the current attempt information.
p.attempt = &channeldb.PaymentAttemptInfo{
PaymentID: paymentID,
SessionKey: sessionKey,
Route: *route,
}
return firstHop, htlcAdd, nil
}
// sendPaymentAttempt attempts to send the current attempt to the switch.
func (p *paymentLifecycle) sendPaymentAttempt(firstHop lnwire.ShortChannelID,
htlcAdd *lnwire.UpdateAddHTLC) error {
log.Tracef("Attempting to send payment %x (pid=%v), "+
"using route: %v", p.payment.PaymentHash, p.attempt.PaymentID,
newLogClosure(func() string {
return spew.Sdump(p.attempt.Route)
}),
)
// Send it to the Switch. When this method returns we assume
// the Switch successfully has persisted the payment attempt,
// such that we can resume waiting for the result after a
// restart.
err := p.router.cfg.Payer.SendHTLC(
firstHop, p.attempt.PaymentID, htlcAdd,
)
if err != nil {
log.Errorf("Failed sending attempt %d for payment "+
"%x to switch: %v", p.attempt.PaymentID,
p.payment.PaymentHash, err)
return err
}
log.Debugf("Payment %x (pid=%v) successfully sent to switch",
p.payment.PaymentHash, p.attempt.PaymentID)
return nil
}
// handleSendError inspects the given error from the Switch and determines
// whether we should make another payment attempt.
func (p *paymentLifecycle) handleSendError(sendErr error) error {
finalOutcome := p.router.processSendError(
p.paySession, rt, sendErr,
p.paySession, &p.attempt.Route, sendErr,
)
if finalOutcome {