lnd.xprv/invoices/invoiceregistry.go

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package invoices
import (
"errors"
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"fmt"
"sync"
"sync/atomic"
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"time"
"github.com/davecgh/go-spew/spew"
"github.com/lightningnetwork/lnd/channeldb"
"github.com/lightningnetwork/lnd/clock"
"github.com/lightningnetwork/lnd/lntypes"
"github.com/lightningnetwork/lnd/lnwire"
"github.com/lightningnetwork/lnd/queue"
)
var (
// ErrInvoiceExpiryTooSoon is returned when an invoice is attempted to be
// accepted or settled with not enough blocks remaining.
ErrInvoiceExpiryTooSoon = errors.New("invoice expiry too soon")
// ErrInvoiceAmountTooLow is returned when an invoice is attempted to be
// accepted or settled with an amount that is too low.
ErrInvoiceAmountTooLow = errors.New("paid amount less than invoice amount")
// ErrShuttingDown is returned when an operation failed because the
// invoice registry is shutting down.
ErrShuttingDown = errors.New("invoice registry shutting down")
)
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const (
// DefaultHtlcHoldDuration defines the default for how long mpp htlcs
// are held while waiting for the other set members to arrive.
DefaultHtlcHoldDuration = 120 * time.Second
)
// HtlcResolution describes how an htlc should be resolved. If the preimage
// field is set, the event indicates a settle event. If Preimage is nil, it is
// a cancel event.
type HtlcResolution struct {
// Preimage is the htlc preimage. Its value is nil in case of a cancel.
Preimage *lntypes.Preimage
// CircuitKey is the key of the htlc for which we have a resolution
// decision.
CircuitKey channeldb.CircuitKey
// AcceptHeight is the original height at which the htlc was accepted.
AcceptHeight int32
// Outcome indicates the outcome of the invoice registry update.
Outcome ResolutionResult
}
// NewFailureResolution returns a htlc failure resolution.
func NewFailureResolution(key channeldb.CircuitKey,
acceptHeight int32, outcome ResolutionResult) *HtlcResolution {
return &HtlcResolution{
CircuitKey: key,
AcceptHeight: acceptHeight,
Outcome: outcome,
}
}
// NewSettleResolution returns a htlc resolution which is associated with a
// settle.
func NewSettleResolution(preimage lntypes.Preimage, key channeldb.CircuitKey,
acceptHeight int32, outcome ResolutionResult) *HtlcResolution {
return &HtlcResolution{
Preimage: &preimage,
CircuitKey: key,
AcceptHeight: acceptHeight,
Outcome: outcome,
}
}
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// RegistryConfig contains the configuration parameters for invoice registry.
type RegistryConfig struct {
// FinalCltvRejectDelta defines the number of blocks before the expiry
// of the htlc where we no longer settle it as an exit hop and instead
// cancel it back. Normally this value should be lower than the cltv
// expiry of any invoice we create and the code effectuating this should
// not be hit.
FinalCltvRejectDelta int32
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// HtlcHoldDuration defines for how long mpp htlcs are held while
// waiting for the other set members to arrive.
HtlcHoldDuration time.Duration
// Clock holds the clock implementation that is used to provide
// Now() and TickAfter() and is useful to stub out the clock functions
// during testing.
Clock clock.Clock
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}
// htlcReleaseEvent describes an htlc auto-release event. It is used to release
// mpp htlcs for which the complete set didn't arrive in time.
type htlcReleaseEvent struct {
// hash is the payment hash of the htlc to release.
hash lntypes.Hash
// key is the circuit key of the htlc to release.
key channeldb.CircuitKey
// releaseTime is the time at which to release the htlc.
releaseTime time.Time
}
// Less is used to order PriorityQueueItem's by their release time such that
// items with the older release time are at the top of the queue.
//
// NOTE: Part of the queue.PriorityQueueItem interface.
func (r *htlcReleaseEvent) Less(other queue.PriorityQueueItem) bool {
return r.releaseTime.Before(other.(*htlcReleaseEvent).releaseTime)
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}
// InvoiceRegistry is a central registry of all the outstanding invoices
// created by the daemon. The registry is a thin wrapper around a map in order
// to ensure that all updates/reads are thread safe.
type InvoiceRegistry struct {
sync.RWMutex
cdb *channeldb.DB
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// cfg contains the registry's configuration parameters.
cfg *RegistryConfig
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clientMtx sync.Mutex
nextClientID uint32
notificationClients map[uint32]*InvoiceSubscription
singleNotificationClients map[uint32]*SingleInvoiceSubscription
newSubscriptions chan *InvoiceSubscription
subscriptionCancels chan uint32
// invoiceEvents is a single channel over which both invoice updates and
// new single invoice subscriptions are carried.
invoiceEvents chan interface{}
// subscriptions is a map from a circuit key to a list of subscribers.
// It is used for efficient notification of links.
hodlSubscriptions map[channeldb.CircuitKey]map[chan<- interface{}]struct{}
// reverseSubscriptions tracks circuit keys subscribed to per
// subscriber. This is used to unsubscribe from all hashes efficiently.
hodlReverseSubscriptions map[chan<- interface{}]map[channeldb.CircuitKey]struct{}
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// htlcAutoReleaseChan contains the new htlcs that need to be
// auto-released.
htlcAutoReleaseChan chan *htlcReleaseEvent
expiryWatcher *InvoiceExpiryWatcher
wg sync.WaitGroup
quit chan struct{}
}
// NewRegistry creates a new invoice registry. The invoice registry
// wraps the persistent on-disk invoice storage with an additional in-memory
// layer. The in-memory layer is in place such that debug invoices can be added
// which are volatile yet available system wide within the daemon.
func NewRegistry(cdb *channeldb.DB, expiryWatcher *InvoiceExpiryWatcher,
cfg *RegistryConfig) *InvoiceRegistry {
return &InvoiceRegistry{
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cdb: cdb,
notificationClients: make(map[uint32]*InvoiceSubscription),
singleNotificationClients: make(map[uint32]*SingleInvoiceSubscription),
newSubscriptions: make(chan *InvoiceSubscription),
subscriptionCancels: make(chan uint32),
invoiceEvents: make(chan interface{}, 100),
hodlSubscriptions: make(map[channeldb.CircuitKey]map[chan<- interface{}]struct{}),
hodlReverseSubscriptions: make(map[chan<- interface{}]map[channeldb.CircuitKey]struct{}),
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cfg: cfg,
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htlcAutoReleaseChan: make(chan *htlcReleaseEvent),
expiryWatcher: expiryWatcher,
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quit: make(chan struct{}),
}
}
// populateExpiryWatcher fetches all active invoices and their corresponding
// payment hashes from ChannelDB and adds them to the expiry watcher.
func (i *InvoiceRegistry) populateExpiryWatcher() error {
pendingOnly := true
pendingInvoices, err := i.cdb.FetchAllInvoicesWithPaymentHash(pendingOnly)
if err != nil && err != channeldb.ErrNoInvoicesCreated {
log.Errorf(
"Error while prefetching active invoices from the database: %v", err,
)
return err
}
for idx := range pendingInvoices {
i.expiryWatcher.AddInvoice(
pendingInvoices[idx].PaymentHash, &pendingInvoices[idx].Invoice,
)
}
return nil
}
// Start starts the registry and all goroutines it needs to carry out its task.
func (i *InvoiceRegistry) Start() error {
// Start InvoiceExpiryWatcher and prepopulate it with existing active
// invoices.
err := i.expiryWatcher.Start(func(paymentHash lntypes.Hash) error {
cancelIfAccepted := false
return i.cancelInvoiceImpl(paymentHash, cancelIfAccepted)
})
if err != nil {
return err
}
i.wg.Add(1)
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go i.invoiceEventLoop()
// Now prefetch all pending invoices to the expiry watcher.
err = i.populateExpiryWatcher()
if err != nil {
i.Stop()
return err
}
return nil
}
// Stop signals the registry for a graceful shutdown.
func (i *InvoiceRegistry) Stop() {
i.expiryWatcher.Stop()
close(i.quit)
i.wg.Wait()
}
// invoiceEvent represents a new event that has modified on invoice on disk.
// Only two event types are currently supported: newly created invoices, and
// instance where invoices are settled.
type invoiceEvent struct {
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hash lntypes.Hash
invoice *channeldb.Invoice
}
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// tickAt returns a channel that ticks at the specified time. If the time has
// already passed, it will tick immediately.
func (i *InvoiceRegistry) tickAt(t time.Time) <-chan time.Time {
now := i.cfg.Clock.Now()
return i.cfg.Clock.TickAfter(t.Sub(now))
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}
// invoiceEventLoop is the dedicated goroutine responsible for accepting
// new notification subscriptions, cancelling old subscriptions, and
// dispatching new invoice events.
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func (i *InvoiceRegistry) invoiceEventLoop() {
defer i.wg.Done()
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// Set up a heap for htlc auto-releases.
autoReleaseHeap := &queue.PriorityQueue{}
for {
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// If there is something to release, set up a release tick
// channel.
var nextReleaseTick <-chan time.Time
if autoReleaseHeap.Len() > 0 {
head := autoReleaseHeap.Top().(*htlcReleaseEvent)
nextReleaseTick = i.tickAt(head.releaseTime)
}
select {
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// A new invoice subscription for all invoices has just arrived!
// We'll query for any backlog notifications, then add it to the
// set of clients.
case newClient := <-i.newSubscriptions:
// Before we add the client to our set of active
// clients, we'll first attempt to deliver any backlog
// invoice events.
err := i.deliverBacklogEvents(newClient)
if err != nil {
log.Errorf("unable to deliver backlog invoice "+
"notifications: %v", err)
}
log.Infof("New invoice subscription "+
"client: id=%v", newClient.id)
// With the backlog notifications delivered (if any),
// we'll add this to our active subscriptions and
// continue.
i.notificationClients[newClient.id] = newClient
// A client no longer wishes to receive invoice notifications.
// So we'll remove them from the set of active clients.
case clientID := <-i.subscriptionCancels:
log.Infof("Cancelling invoice subscription for "+
"client=%v", clientID)
delete(i.notificationClients, clientID)
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delete(i.singleNotificationClients, clientID)
// An invoice event has come in. This can either be an update to
// an invoice or a new single invoice subscriber. Both type of
// events are passed in via the same channel, to make sure that
// subscribers get a consistent view of the event sequence.
case event := <-i.invoiceEvents:
switch e := event.(type) {
// A sub-systems has just modified the invoice state, so
// we'll dispatch notifications to all registered
// clients.
case *invoiceEvent:
// For backwards compatibility, do not notify
// all invoice subscribers of cancel and accept
// events.
state := e.invoice.State
if state != channeldb.ContractCanceled &&
state != channeldb.ContractAccepted {
i.dispatchToClients(e)
}
i.dispatchToSingleClients(e)
// A new single invoice subscription has arrived. Add it
// to the set of clients. It is important to do this in
// sequence with any other invoice events, because an
// initial invoice update has already been sent out to
// the subscriber.
case *SingleInvoiceSubscription:
log.Infof("New single invoice subscription "+
"client: id=%v, hash=%v", e.id, e.hash)
i.singleNotificationClients[e.id] = e
}
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// A new htlc came in for auto-release.
case event := <-i.htlcAutoReleaseChan:
log.Debugf("Scheduling auto-release for htlc: "+
"hash=%v, key=%v at %v",
event.hash, event.key, event.releaseTime)
// We use an independent timer for every htlc rather
// than a set timer that is reset with every htlc coming
// in. Otherwise the sender could keep resetting the
// timer until the broadcast window is entered and our
// channel is force closed.
autoReleaseHeap.Push(event)
// The htlc at the top of the heap needs to be auto-released.
case <-nextReleaseTick:
event := autoReleaseHeap.Pop().(*htlcReleaseEvent)
err := i.cancelSingleHtlc(
event.hash, event.key, ResultMppTimeout,
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)
if err != nil {
log.Errorf("HTLC timer: %v", err)
}
case <-i.quit:
return
}
}
}
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// dispatchToSingleClients passes the supplied event to all notification clients
// that subscribed to all the invoice this event applies to.
func (i *InvoiceRegistry) dispatchToSingleClients(event *invoiceEvent) {
// Dispatch to single invoice subscribers.
for _, client := range i.singleNotificationClients {
if client.hash != event.hash {
continue
}
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client.notify(event)
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}
}
// dispatchToClients passes the supplied event to all notification clients that
// subscribed to all invoices. Add and settle indices are used to make sure that
// clients don't receive duplicate or unwanted events.
func (i *InvoiceRegistry) dispatchToClients(event *invoiceEvent) {
invoice := event.invoice
for clientID, client := range i.notificationClients {
// Before we dispatch this event, we'll check
// to ensure that this client hasn't already
// received this notification in order to
// ensure we don't duplicate any events.
// TODO(joostjager): Refactor switches.
state := event.invoice.State
switch {
// If we've already sent this settle event to
// the client, then we can skip this.
case state == channeldb.ContractSettled &&
client.settleIndex >= invoice.SettleIndex:
continue
// Similarly, if we've already sent this add to
// the client then we can skip this one.
case state == channeldb.ContractOpen &&
client.addIndex >= invoice.AddIndex:
continue
// These two states should never happen, but we
// log them just in case so we can detect this
// instance.
case state == channeldb.ContractOpen &&
client.addIndex+1 != invoice.AddIndex:
log.Warnf("client=%v for invoice "+
"notifications missed an update, "+
"add_index=%v, new add event index=%v",
clientID, client.addIndex,
invoice.AddIndex)
case state == channeldb.ContractSettled &&
client.settleIndex+1 != invoice.SettleIndex:
log.Warnf("client=%v for invoice "+
"notifications missed an update, "+
"settle_index=%v, new settle event index=%v",
clientID, client.settleIndex,
invoice.SettleIndex)
}
select {
case client.ntfnQueue.ChanIn() <- &invoiceEvent{
invoice: invoice,
}:
case <-i.quit:
return
}
// Each time we send a notification to a client, we'll record
// the latest add/settle index it has. We'll use this to ensure
// we don't send a notification twice, which can happen if a new
// event is added while we're catching up a new client.
switch event.invoice.State {
case channeldb.ContractSettled:
client.settleIndex = invoice.SettleIndex
case channeldb.ContractOpen:
client.addIndex = invoice.AddIndex
default:
log.Errorf("unexpected invoice state: %v",
event.invoice.State)
}
}
}
// deliverBacklogEvents will attempts to query the invoice database for any
// notifications that the client has missed since it reconnected last.
func (i *InvoiceRegistry) deliverBacklogEvents(client *InvoiceSubscription) error {
// First, we'll query the database to see if based on the provided
// addIndex and settledIndex we need to deliver any backlog
// notifications.
addEvents, err := i.cdb.InvoicesAddedSince(client.addIndex)
if err != nil {
return err
}
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settleEvents, err := i.cdb.InvoicesSettledSince(client.settleIndex)
if err != nil {
return err
}
// If we have any to deliver, then we'll append them to the end of the
// notification queue in order to catch up the client before delivering
// any new notifications.
for _, addEvent := range addEvents {
// We re-bind the loop variable to ensure we don't hold onto
// the loop reference causing is to point to the same item.
addEvent := addEvent
select {
case client.ntfnQueue.ChanIn() <- &invoiceEvent{
invoice: &addEvent,
}:
case <-i.quit:
return ErrShuttingDown
}
}
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for _, settleEvent := range settleEvents {
// We re-bind the loop variable to ensure we don't hold onto
// the loop reference causing is to point to the same item.
settleEvent := settleEvent
select {
case client.ntfnQueue.ChanIn() <- &invoiceEvent{
invoice: &settleEvent,
}:
case <-i.quit:
return ErrShuttingDown
}
}
return nil
}
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// deliverSingleBacklogEvents will attempt to query the invoice database to
// retrieve the current invoice state and deliver this to the subscriber. Single
// invoice subscribers will always receive the current state right after
// subscribing. Only in case the invoice does not yet exist, nothing is sent
// yet.
func (i *InvoiceRegistry) deliverSingleBacklogEvents(
client *SingleInvoiceSubscription) error {
invoice, err := i.cdb.LookupInvoice(client.hash)
// It is possible that the invoice does not exist yet, but the client is
// already watching it in anticipation.
if err == channeldb.ErrInvoiceNotFound ||
err == channeldb.ErrNoInvoicesCreated {
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return nil
}
if err != nil {
return err
}
err = client.notify(&invoiceEvent{
hash: client.hash,
invoice: &invoice,
})
if err != nil {
return err
}
return nil
}
// AddInvoice adds a regular invoice for the specified amount, identified by
// the passed preimage. Additionally, any memo or receipt data provided will
// also be stored on-disk. Once this invoice is added, subsystems within the
// daemon add/forward HTLCs are able to obtain the proper preimage required for
// redemption in the case that we're the final destination. We also return the
// addIndex of the newly created invoice which monotonically increases for each
// new invoice added. A side effect of this function is that it also sets
// AddIndex on the invoice argument.
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func (i *InvoiceRegistry) AddInvoice(invoice *channeldb.Invoice,
paymentHash lntypes.Hash) (uint64, error) {
i.Lock()
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log.Debugf("Invoice(%v): added %v", paymentHash,
newLogClosure(func() string {
return spew.Sdump(invoice)
}),
)
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addIndex, err := i.cdb.AddInvoice(invoice, paymentHash)
if err != nil {
i.Unlock()
return 0, err
}
// Now that we've added the invoice, we'll send dispatch a message to
// notify the clients of this new invoice.
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i.notifyClients(paymentHash, invoice, channeldb.ContractOpen)
i.Unlock()
// InvoiceExpiryWatcher.AddInvoice must not be locked by InvoiceRegistry
// to avoid deadlock when a new invoice is added while an other is being
// canceled.
i.expiryWatcher.AddInvoice(paymentHash, invoice)
return addIndex, nil
}
// LookupInvoice looks up an invoice by its payment hash (R-Hash), if found
// then we're able to pull the funds pending within an HTLC.
//
// TODO(roasbeef): ignore if settled?
func (i *InvoiceRegistry) LookupInvoice(rHash lntypes.Hash) (channeldb.Invoice,
error) {
// We'll check the database to see if there's an existing matching
// invoice.
return i.cdb.LookupInvoice(rHash)
}
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// startHtlcTimer starts a new timer via the invoice registry main loop that
// cancels a single htlc on an invoice when the htlc hold duration has passed.
func (i *InvoiceRegistry) startHtlcTimer(hash lntypes.Hash,
key channeldb.CircuitKey, acceptTime time.Time) error {
releaseTime := acceptTime.Add(i.cfg.HtlcHoldDuration)
event := &htlcReleaseEvent{
hash: hash,
key: key,
releaseTime: releaseTime,
}
select {
case i.htlcAutoReleaseChan <- event:
return nil
case <-i.quit:
return ErrShuttingDown
}
}
// cancelSingleHtlc cancels a single accepted htlc on an invoice. It takes
// a resolution result which will be used to notify subscribed links and
// resolvers of the details of the htlc cancellation.
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func (i *InvoiceRegistry) cancelSingleHtlc(hash lntypes.Hash,
key channeldb.CircuitKey, result ResolutionResult) error {
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i.Lock()
defer i.Unlock()
updateInvoice := func(invoice *channeldb.Invoice) (
*channeldb.InvoiceUpdateDesc, error) {
// Only allow individual htlc cancelation on open invoices.
if invoice.State != channeldb.ContractOpen {
log.Debugf("cancelSingleHtlc: invoice %v no longer "+
"open", hash)
return nil, nil
}
// Lookup the current status of the htlc in the database.
htlc, ok := invoice.Htlcs[key]
if !ok {
return nil, fmt.Errorf("htlc %v not found", key)
}
// Cancelation is only possible if the htlc wasn't already
// resolved.
if htlc.State != channeldb.HtlcStateAccepted {
log.Debugf("cancelSingleHtlc: htlc %v on invoice %v "+
"is already resolved", key, hash)
return nil, nil
}
log.Debugf("cancelSingleHtlc: cancelling htlc %v on invoice %v",
key, hash)
// Return an update descriptor that cancels htlc and keeps
// invoice open.
canceledHtlcs := map[channeldb.CircuitKey]struct{}{
key: {},
}
return &channeldb.InvoiceUpdateDesc{
CancelHtlcs: canceledHtlcs,
}, nil
}
// Try to mark the specified htlc as canceled in the invoice database.
// Intercept the update descriptor to set the local updated variable. If
// no invoice update is performed, we can return early.
var updated bool
invoice, err := i.cdb.UpdateInvoice(hash,
func(invoice *channeldb.Invoice) (
*channeldb.InvoiceUpdateDesc, error) {
updateDesc, err := updateInvoice(invoice)
if err != nil {
return nil, err
}
updated = updateDesc != nil
return updateDesc, err
},
)
if err != nil {
return err
}
if !updated {
return nil
}
// The invoice has been updated. Notify subscribers of the htlc
// resolution.
htlc, ok := invoice.Htlcs[key]
if !ok {
return fmt.Errorf("htlc %v not found", key)
}
if htlc.State == channeldb.HtlcStateCanceled {
resolution := *NewFailureResolution(
key, int32(htlc.AcceptHeight), result,
)
i.notifyHodlSubscribers(resolution)
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}
return nil
}
// NotifyExitHopHtlc attempts to mark an invoice as settled. The return value
// describes how the htlc should be resolved.
//
// When the preimage of the invoice is not yet known (hodl invoice), this
// function moves the invoice to the accepted state. When SettleHoldInvoice is
// called later, a resolution message will be send back to the caller via the
// provided hodlChan. Invoice registry sends on this channel what action needs
// to be taken on the htlc (settle or cancel). The caller needs to ensure that
// the channel is either buffered or received on from another goroutine to
// prevent deadlock.
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//
// In the case that the htlc is part of a larger set of htlcs that pay to the
// same invoice (multi-path payment), the htlc is held until the set is
// complete. If the set doesn't fully arrive in time, a timer will cancel the
// held htlc.
func (i *InvoiceRegistry) NotifyExitHopHtlc(rHash lntypes.Hash,
amtPaid lnwire.MilliSatoshi, expiry uint32, currentHeight int32,
circuitKey channeldb.CircuitKey, hodlChan chan<- interface{},
payload Payload) (*HtlcResolution, error) {
i.Lock()
defer i.Unlock()
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mpp := payload.MultiPath()
debugLog := func(s string) {
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log.Debugf("Invoice(%x): %v, amt=%v, expiry=%v, circuit=%v, "+
"mpp=%v", rHash[:], s, amtPaid, expiry, circuitKey, mpp)
}
// Create the update context containing the relevant details of the
// incoming htlc.
updateCtx := invoiceUpdateCtx{
circuitKey: circuitKey,
amtPaid: amtPaid,
expiry: expiry,
currentHeight: currentHeight,
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finalCltvRejectDelta: i.cfg.FinalCltvRejectDelta,
customRecords: payload.CustomRecords(),
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mpp: mpp,
}
invoices: replay awareness Previously the invoice registry wasn't aware of replayed htlcs. This was dealt with by keeping the invoice accept/settle logic idempotent, so that a replay wouldn't have an effect. This mechanism has two limitations: 1. No accurate tracking of the total amount paid to an invoice. The total amount couldn't just be increased with every htlc received, because it could be a replay which would lead to counting the htlc amount multiple times. Therefore the total amount was set to the amount of the first htlc that was received, even though there may have been multiple htlcs paying to the invoice. 2. Impossible to check htlc expiry consistently for hodl invoices. When an htlc is new, its expiry needs to be checked against the invoice cltv delta. But for a replay, that check must be skipped. The htlc was accepted in time, the invoice was moved to the accepted state and a replay some blocks later shouldn't lead to that htlc being cancelled. Because the invoice registry couldn't recognize replays, it stopped checking htlc expiry heights when the invoice reached the accepted state. This prevents hold htlcs from being cancelled after a restart. But unfortunately this also caused additional htlcs to be accepted on an already accepted invoice without their expiry being checked. In this commit, the invoice registry starts to persistently track htlcs so that replays can be recognized. For replays, an htlc resolution action is returned early. This fixes both limitations mentioned above.
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// We'll attempt to settle an invoice matching this rHash on disk (if
// one exists). The callback will update the invoice state and/or htlcs.
var (
result ResolutionResult
updateSubscribers bool
)
invoice, err := i.cdb.UpdateInvoice(
rHash,
func(inv *channeldb.Invoice) (
*channeldb.InvoiceUpdateDesc, error) {
invoices: replay awareness Previously the invoice registry wasn't aware of replayed htlcs. This was dealt with by keeping the invoice accept/settle logic idempotent, so that a replay wouldn't have an effect. This mechanism has two limitations: 1. No accurate tracking of the total amount paid to an invoice. The total amount couldn't just be increased with every htlc received, because it could be a replay which would lead to counting the htlc amount multiple times. Therefore the total amount was set to the amount of the first htlc that was received, even though there may have been multiple htlcs paying to the invoice. 2. Impossible to check htlc expiry consistently for hodl invoices. When an htlc is new, its expiry needs to be checked against the invoice cltv delta. But for a replay, that check must be skipped. The htlc was accepted in time, the invoice was moved to the accepted state and a replay some blocks later shouldn't lead to that htlc being cancelled. Because the invoice registry couldn't recognize replays, it stopped checking htlc expiry heights when the invoice reached the accepted state. This prevents hold htlcs from being cancelled after a restart. But unfortunately this also caused additional htlcs to be accepted on an already accepted invoice without their expiry being checked. In this commit, the invoice registry starts to persistently track htlcs so that replays can be recognized. For replays, an htlc resolution action is returned early. This fixes both limitations mentioned above.
2019-08-09 16:09:57 +03:00
updateDesc, res, err := updateInvoice(&updateCtx, inv)
if err != nil {
return nil, err
invoices: replay awareness Previously the invoice registry wasn't aware of replayed htlcs. This was dealt with by keeping the invoice accept/settle logic idempotent, so that a replay wouldn't have an effect. This mechanism has two limitations: 1. No accurate tracking of the total amount paid to an invoice. The total amount couldn't just be increased with every htlc received, because it could be a replay which would lead to counting the htlc amount multiple times. Therefore the total amount was set to the amount of the first htlc that was received, even though there may have been multiple htlcs paying to the invoice. 2. Impossible to check htlc expiry consistently for hodl invoices. When an htlc is new, its expiry needs to be checked against the invoice cltv delta. But for a replay, that check must be skipped. The htlc was accepted in time, the invoice was moved to the accepted state and a replay some blocks later shouldn't lead to that htlc being cancelled. Because the invoice registry couldn't recognize replays, it stopped checking htlc expiry heights when the invoice reached the accepted state. This prevents hold htlcs from being cancelled after a restart. But unfortunately this also caused additional htlcs to be accepted on an already accepted invoice without their expiry being checked. In this commit, the invoice registry starts to persistently track htlcs so that replays can be recognized. For replays, an htlc resolution action is returned early. This fixes both limitations mentioned above.
2019-08-09 16:09:57 +03:00
}
// Only send an update if the invoice state was changed.
updateSubscribers = updateDesc != nil &&
updateDesc.State != nil
// Assign result to outer scope variable.
result = res
invoices: replay awareness Previously the invoice registry wasn't aware of replayed htlcs. This was dealt with by keeping the invoice accept/settle logic idempotent, so that a replay wouldn't have an effect. This mechanism has two limitations: 1. No accurate tracking of the total amount paid to an invoice. The total amount couldn't just be increased with every htlc received, because it could be a replay which would lead to counting the htlc amount multiple times. Therefore the total amount was set to the amount of the first htlc that was received, even though there may have been multiple htlcs paying to the invoice. 2. Impossible to check htlc expiry consistently for hodl invoices. When an htlc is new, its expiry needs to be checked against the invoice cltv delta. But for a replay, that check must be skipped. The htlc was accepted in time, the invoice was moved to the accepted state and a replay some blocks later shouldn't lead to that htlc being cancelled. Because the invoice registry couldn't recognize replays, it stopped checking htlc expiry heights when the invoice reached the accepted state. This prevents hold htlcs from being cancelled after a restart. But unfortunately this also caused additional htlcs to be accepted on an already accepted invoice without their expiry being checked. In this commit, the invoice registry starts to persistently track htlcs so that replays can be recognized. For replays, an htlc resolution action is returned early. This fixes both limitations mentioned above.
2019-08-09 16:09:57 +03:00
return updateDesc, nil
},
)
switch err {
case channeldb.ErrInvoiceNotFound:
// If the invoice was not found, return a failure resolution
// with an invoice not found result.
return NewFailureResolution(
circuitKey, currentHeight, ResultInvoiceNotFound,
), nil
case nil:
default:
debugLog(err.Error())
return nil, err
}
debugLog(result.String())
invoices: replay awareness Previously the invoice registry wasn't aware of replayed htlcs. This was dealt with by keeping the invoice accept/settle logic idempotent, so that a replay wouldn't have an effect. This mechanism has two limitations: 1. No accurate tracking of the total amount paid to an invoice. The total amount couldn't just be increased with every htlc received, because it could be a replay which would lead to counting the htlc amount multiple times. Therefore the total amount was set to the amount of the first htlc that was received, even though there may have been multiple htlcs paying to the invoice. 2. Impossible to check htlc expiry consistently for hodl invoices. When an htlc is new, its expiry needs to be checked against the invoice cltv delta. But for a replay, that check must be skipped. The htlc was accepted in time, the invoice was moved to the accepted state and a replay some blocks later shouldn't lead to that htlc being cancelled. Because the invoice registry couldn't recognize replays, it stopped checking htlc expiry heights when the invoice reached the accepted state. This prevents hold htlcs from being cancelled after a restart. But unfortunately this also caused additional htlcs to be accepted on an already accepted invoice without their expiry being checked. In this commit, the invoice registry starts to persistently track htlcs so that replays can be recognized. For replays, an htlc resolution action is returned early. This fixes both limitations mentioned above.
2019-08-09 16:09:57 +03:00
if updateSubscribers {
i.notifyClients(rHash, invoice, invoice.State)
invoices: replay awareness Previously the invoice registry wasn't aware of replayed htlcs. This was dealt with by keeping the invoice accept/settle logic idempotent, so that a replay wouldn't have an effect. This mechanism has two limitations: 1. No accurate tracking of the total amount paid to an invoice. The total amount couldn't just be increased with every htlc received, because it could be a replay which would lead to counting the htlc amount multiple times. Therefore the total amount was set to the amount of the first htlc that was received, even though there may have been multiple htlcs paying to the invoice. 2. Impossible to check htlc expiry consistently for hodl invoices. When an htlc is new, its expiry needs to be checked against the invoice cltv delta. But for a replay, that check must be skipped. The htlc was accepted in time, the invoice was moved to the accepted state and a replay some blocks later shouldn't lead to that htlc being cancelled. Because the invoice registry couldn't recognize replays, it stopped checking htlc expiry heights when the invoice reached the accepted state. This prevents hold htlcs from being cancelled after a restart. But unfortunately this also caused additional htlcs to be accepted on an already accepted invoice without their expiry being checked. In this commit, the invoice registry starts to persistently track htlcs so that replays can be recognized. For replays, an htlc resolution action is returned early. This fixes both limitations mentioned above.
2019-08-09 16:09:57 +03:00
}
// Inspect latest htlc state on the invoice.
invoiceHtlc, ok := invoice.Htlcs[circuitKey]
invoices: replay awareness Previously the invoice registry wasn't aware of replayed htlcs. This was dealt with by keeping the invoice accept/settle logic idempotent, so that a replay wouldn't have an effect. This mechanism has two limitations: 1. No accurate tracking of the total amount paid to an invoice. The total amount couldn't just be increased with every htlc received, because it could be a replay which would lead to counting the htlc amount multiple times. Therefore the total amount was set to the amount of the first htlc that was received, even though there may have been multiple htlcs paying to the invoice. 2. Impossible to check htlc expiry consistently for hodl invoices. When an htlc is new, its expiry needs to be checked against the invoice cltv delta. But for a replay, that check must be skipped. The htlc was accepted in time, the invoice was moved to the accepted state and a replay some blocks later shouldn't lead to that htlc being cancelled. Because the invoice registry couldn't recognize replays, it stopped checking htlc expiry heights when the invoice reached the accepted state. This prevents hold htlcs from being cancelled after a restart. But unfortunately this also caused additional htlcs to be accepted on an already accepted invoice without their expiry being checked. In this commit, the invoice registry starts to persistently track htlcs so that replays can be recognized. For replays, an htlc resolution action is returned early. This fixes both limitations mentioned above.
2019-08-09 16:09:57 +03:00
// If it isn't recorded, cancel htlc.
if !ok {
return NewFailureResolution(
circuitKey, currentHeight, result,
), nil
invoices: replay awareness Previously the invoice registry wasn't aware of replayed htlcs. This was dealt with by keeping the invoice accept/settle logic idempotent, so that a replay wouldn't have an effect. This mechanism has two limitations: 1. No accurate tracking of the total amount paid to an invoice. The total amount couldn't just be increased with every htlc received, because it could be a replay which would lead to counting the htlc amount multiple times. Therefore the total amount was set to the amount of the first htlc that was received, even though there may have been multiple htlcs paying to the invoice. 2. Impossible to check htlc expiry consistently for hodl invoices. When an htlc is new, its expiry needs to be checked against the invoice cltv delta. But for a replay, that check must be skipped. The htlc was accepted in time, the invoice was moved to the accepted state and a replay some blocks later shouldn't lead to that htlc being cancelled. Because the invoice registry couldn't recognize replays, it stopped checking htlc expiry heights when the invoice reached the accepted state. This prevents hold htlcs from being cancelled after a restart. But unfortunately this also caused additional htlcs to be accepted on an already accepted invoice without their expiry being checked. In this commit, the invoice registry starts to persistently track htlcs so that replays can be recognized. For replays, an htlc resolution action is returned early. This fixes both limitations mentioned above.
2019-08-09 16:09:57 +03:00
}
// Determine accepted height of this htlc. If the htlc reached the
// invoice database (possibly in a previous call to the invoice
// registry), we'll take the original accepted height as it was recorded
// in the database.
acceptHeight := int32(invoiceHtlc.AcceptHeight)
invoices: replay awareness Previously the invoice registry wasn't aware of replayed htlcs. This was dealt with by keeping the invoice accept/settle logic idempotent, so that a replay wouldn't have an effect. This mechanism has two limitations: 1. No accurate tracking of the total amount paid to an invoice. The total amount couldn't just be increased with every htlc received, because it could be a replay which would lead to counting the htlc amount multiple times. Therefore the total amount was set to the amount of the first htlc that was received, even though there may have been multiple htlcs paying to the invoice. 2. Impossible to check htlc expiry consistently for hodl invoices. When an htlc is new, its expiry needs to be checked against the invoice cltv delta. But for a replay, that check must be skipped. The htlc was accepted in time, the invoice was moved to the accepted state and a replay some blocks later shouldn't lead to that htlc being cancelled. Because the invoice registry couldn't recognize replays, it stopped checking htlc expiry heights when the invoice reached the accepted state. This prevents hold htlcs from being cancelled after a restart. But unfortunately this also caused additional htlcs to be accepted on an already accepted invoice without their expiry being checked. In this commit, the invoice registry starts to persistently track htlcs so that replays can be recognized. For replays, an htlc resolution action is returned early. This fixes both limitations mentioned above.
2019-08-09 16:09:57 +03:00
switch invoiceHtlc.State {
2019-10-03 18:22:43 +03:00
case channeldb.HtlcStateCanceled:
return NewFailureResolution(
circuitKey, acceptHeight, result,
), nil
invoices: replay awareness Previously the invoice registry wasn't aware of replayed htlcs. This was dealt with by keeping the invoice accept/settle logic idempotent, so that a replay wouldn't have an effect. This mechanism has two limitations: 1. No accurate tracking of the total amount paid to an invoice. The total amount couldn't just be increased with every htlc received, because it could be a replay which would lead to counting the htlc amount multiple times. Therefore the total amount was set to the amount of the first htlc that was received, even though there may have been multiple htlcs paying to the invoice. 2. Impossible to check htlc expiry consistently for hodl invoices. When an htlc is new, its expiry needs to be checked against the invoice cltv delta. But for a replay, that check must be skipped. The htlc was accepted in time, the invoice was moved to the accepted state and a replay some blocks later shouldn't lead to that htlc being cancelled. Because the invoice registry couldn't recognize replays, it stopped checking htlc expiry heights when the invoice reached the accepted state. This prevents hold htlcs from being cancelled after a restart. But unfortunately this also caused additional htlcs to be accepted on an already accepted invoice without their expiry being checked. In this commit, the invoice registry starts to persistently track htlcs so that replays can be recognized. For replays, an htlc resolution action is returned early. This fixes both limitations mentioned above.
2019-08-09 16:09:57 +03:00
case channeldb.HtlcStateSettled:
2019-09-03 13:23:39 +03:00
// Also settle any previously accepted htlcs. The invoice state
// is leading. If an htlc is marked as settled, we should follow
// now and settle the htlc with our peer.
for key, htlc := range invoice.Htlcs {
if htlc.State != channeldb.HtlcStateSettled {
continue
}
// Notify subscribers that the htlcs should be settled
// with our peer. Note that the outcome of the
// resolution is set based on the outcome of the single
// htlc that we just settled, so may not be accurate
// for all htlcs.
resolution := *NewSettleResolution(
invoice.Terms.PaymentPreimage, key,
acceptHeight, result,
)
i.notifyHodlSubscribers(resolution)
2019-09-03 13:23:39 +03:00
}
resolution := NewSettleResolution(
invoice.Terms.PaymentPreimage, circuitKey,
acceptHeight, result,
)
return resolution, nil
invoices: replay awareness Previously the invoice registry wasn't aware of replayed htlcs. This was dealt with by keeping the invoice accept/settle logic idempotent, so that a replay wouldn't have an effect. This mechanism has two limitations: 1. No accurate tracking of the total amount paid to an invoice. The total amount couldn't just be increased with every htlc received, because it could be a replay which would lead to counting the htlc amount multiple times. Therefore the total amount was set to the amount of the first htlc that was received, even though there may have been multiple htlcs paying to the invoice. 2. Impossible to check htlc expiry consistently for hodl invoices. When an htlc is new, its expiry needs to be checked against the invoice cltv delta. But for a replay, that check must be skipped. The htlc was accepted in time, the invoice was moved to the accepted state and a replay some blocks later shouldn't lead to that htlc being cancelled. Because the invoice registry couldn't recognize replays, it stopped checking htlc expiry heights when the invoice reached the accepted state. This prevents hold htlcs from being cancelled after a restart. But unfortunately this also caused additional htlcs to be accepted on an already accepted invoice without their expiry being checked. In this commit, the invoice registry starts to persistently track htlcs so that replays can be recognized. For replays, an htlc resolution action is returned early. This fixes both limitations mentioned above.
2019-08-09 16:09:57 +03:00
case channeldb.HtlcStateAccepted:
2019-09-03 13:23:39 +03:00
// (Re)start the htlc timer if the invoice is still open. It can
// only happen for mpp payments that there are htlcs in state
// Accepted while the invoice is Open.
if invoice.State == channeldb.ContractOpen {
err := i.startHtlcTimer(
rHash, circuitKey,
invoiceHtlc.AcceptTime,
)
if err != nil {
return nil, err
}
}
i.hodlSubscribe(hodlChan, circuitKey)
return nil, nil
default:
panic("unknown action")
}
}
// SettleHodlInvoice sets the preimage of a hodl invoice.
func (i *InvoiceRegistry) SettleHodlInvoice(preimage lntypes.Preimage) error {
i.Lock()
defer i.Unlock()
updateInvoice := func(invoice *channeldb.Invoice) (
*channeldb.InvoiceUpdateDesc, error) {
switch invoice.State {
case channeldb.ContractOpen:
return nil, channeldb.ErrInvoiceStillOpen
case channeldb.ContractCanceled:
return nil, channeldb.ErrInvoiceAlreadyCanceled
case channeldb.ContractSettled:
return nil, channeldb.ErrInvoiceAlreadySettled
}
return &channeldb.InvoiceUpdateDesc{
State: &channeldb.InvoiceStateUpdateDesc{
NewState: channeldb.ContractSettled,
Preimage: preimage,
},
}, nil
}
hash := preimage.Hash()
invoice, err := i.cdb.UpdateInvoice(hash, updateInvoice)
if err != nil {
log.Errorf("SettleHodlInvoice with preimage %v: %v",
preimage, err)
return err
}
2019-04-08 11:47:15 +03:00
log.Debugf("Invoice(%v): settled with preimage %v", hash,
invoice.Terms.PaymentPreimage)
// In the callback, we marked the invoice as settled. UpdateInvoice will
// have seen this and should have moved all htlcs that were accepted to
// the settled state. In the loop below, we go through all of these and
// notify links and resolvers that are waiting for resolution. Any htlcs
// that were already settled before, will be notified again. This isn't
// necessary but doesn't hurt either.
for key, htlc := range invoice.Htlcs {
if htlc.State != channeldb.HtlcStateSettled {
continue
}
resolution := *NewSettleResolution(
preimage, key, int32(htlc.AcceptHeight), ResultSettled,
)
i.notifyHodlSubscribers(resolution)
}
i.notifyClients(hash, invoice, invoice.State)
return nil
}
// CancelInvoice attempts to cancel the invoice corresponding to the passed
// payment hash.
func (i *InvoiceRegistry) CancelInvoice(payHash lntypes.Hash) error {
return i.cancelInvoiceImpl(payHash, true)
}
// cancelInvoice attempts to cancel the invoice corresponding to the passed
// payment hash. Accepted invoices will only be canceled if explicitly
// requested to do so. It notifies subscribing links and resolvers that
// the associated htlcs were canceled if they change state.
func (i *InvoiceRegistry) cancelInvoiceImpl(payHash lntypes.Hash,
cancelAccepted bool) error {
i.Lock()
defer i.Unlock()
2019-04-08 11:47:15 +03:00
log.Debugf("Invoice(%v): canceling invoice", payHash)
updateInvoice := func(invoice *channeldb.Invoice) (
*channeldb.InvoiceUpdateDesc, error) {
// Only cancel the invoice in ContractAccepted state if explicitly
// requested to do so.
if invoice.State == channeldb.ContractAccepted && !cancelAccepted {
return nil, nil
}
// Move invoice to the canceled state. Rely on validation in
// channeldb to return an error if the invoice is already
// settled or canceled.
return &channeldb.InvoiceUpdateDesc{
State: &channeldb.InvoiceStateUpdateDesc{
NewState: channeldb.ContractCanceled,
},
}, nil
}
invoice, err := i.cdb.UpdateInvoice(payHash, updateInvoice)
// Implement idempotency by returning success if the invoice was already
// canceled.
if err == channeldb.ErrInvoiceAlreadyCanceled {
2019-04-08 11:47:15 +03:00
log.Debugf("Invoice(%v): already canceled", payHash)
return nil
}
if err != nil {
return err
}
// Return without cancellation if the invoice state is ContractAccepted.
if invoice.State == channeldb.ContractAccepted {
log.Debugf("Invoice(%v): remains accepted as cancel wasn't"+
"explicitly requested.", payHash)
return nil
}
2019-04-08 11:47:15 +03:00
log.Debugf("Invoice(%v): canceled", payHash)
// In the callback, some htlcs may have been moved to the canceled
// state. We now go through all of these and notify links and resolvers
// that are waiting for resolution. Any htlcs that were already canceled
// before, will be notified again. This isn't necessary but doesn't hurt
// either.
for key, htlc := range invoice.Htlcs {
2019-10-03 18:22:43 +03:00
if htlc.State != channeldb.HtlcStateCanceled {
continue
}
i.notifyHodlSubscribers(
*NewFailureResolution(
key, int32(htlc.AcceptHeight), ResultCanceled,
),
)
}
i.notifyClients(payHash, invoice, channeldb.ContractCanceled)
return nil
}
2016-12-25 03:51:25 +03:00
// notifyClients notifies all currently registered invoice notification clients
// of a newly added/settled invoice.
2018-12-20 20:54:11 +03:00
func (i *InvoiceRegistry) notifyClients(hash lntypes.Hash,
invoice *channeldb.Invoice,
state channeldb.ContractState) {
event := &invoiceEvent{
invoice: invoice,
2018-12-20 20:54:11 +03:00
hash: hash,
}
select {
case i.invoiceEvents <- event:
case <-i.quit:
}
}
2018-12-20 20:54:11 +03:00
// invoiceSubscriptionKit defines that are common to both all invoice
// subscribers and single invoice subscribers.
type invoiceSubscriptionKit struct {
id uint32
inv *InvoiceRegistry
ntfnQueue *queue.ConcurrentQueue
2019-10-03 18:22:43 +03:00
canceled uint32 // To be used atomically.
2018-12-20 20:54:11 +03:00
cancelChan chan struct{}
wg sync.WaitGroup
}
// InvoiceSubscription represents an intent to receive updates for newly added
// or settled invoices. For each newly added invoice, a copy of the invoice
// will be sent over the NewInvoices channel. Similarly, for each newly settled
// invoice, a copy of the invoice will be sent over the SettledInvoices
// channel.
type InvoiceSubscription struct {
2018-12-20 20:54:11 +03:00
invoiceSubscriptionKit
// NewInvoices is a channel that we'll use to send all newly created
// invoices with an invoice index greater than the specified
// StartingInvoiceIndex field.
NewInvoices chan *channeldb.Invoice
// SettledInvoices is a channel that we'll use to send all setted
// invoices with an invoices index greater than the specified
// StartingInvoiceIndex field.
SettledInvoices chan *channeldb.Invoice
// addIndex is the highest add index the caller knows of. We'll use
// this information to send out an event backlog to the notifications
// subscriber. Any new add events with an index greater than this will
// be dispatched before any new notifications are sent out.
addIndex uint64
// settleIndex is the highest settle index the caller knows of. We'll
// use this information to send out an event backlog to the
// notifications subscriber. Any new settle events with an index
// greater than this will be dispatched before any new notifications
// are sent out.
settleIndex uint64
2018-12-20 20:54:11 +03:00
}
2018-12-20 20:54:11 +03:00
// SingleInvoiceSubscription represents an intent to receive updates for a
// specific invoice.
type SingleInvoiceSubscription struct {
invoiceSubscriptionKit
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hash lntypes.Hash
2018-12-20 20:54:11 +03:00
// Updates is a channel that we'll use to send all invoice events for
// the invoice that is subscribed to.
Updates chan *channeldb.Invoice
}
// Cancel unregisters the InvoiceSubscription, freeing any previously allocated
// resources.
2018-12-20 20:54:11 +03:00
func (i *invoiceSubscriptionKit) Cancel() {
2019-10-03 18:22:43 +03:00
if !atomic.CompareAndSwapUint32(&i.canceled, 0, 1) {
return
}
select {
case i.inv.subscriptionCancels <- i.id:
case <-i.inv.quit:
}
i.ntfnQueue.Stop()
close(i.cancelChan)
i.wg.Wait()
}
2018-12-20 20:54:11 +03:00
func (i *invoiceSubscriptionKit) notify(event *invoiceEvent) error {
select {
case i.ntfnQueue.ChanIn() <- event:
case <-i.inv.quit:
return ErrShuttingDown
2018-12-20 20:54:11 +03:00
}
return nil
}
// SubscribeNotifications returns an InvoiceSubscription which allows the
// caller to receive async notifications when any invoices are settled or
// added. The invoiceIndex parameter is a streaming "checkpoint". We'll start
// by first sending out all new events with an invoice index _greater_ than
// this value. Afterwards, we'll send out real-time notifications.
func (i *InvoiceRegistry) SubscribeNotifications(addIndex, settleIndex uint64) *InvoiceSubscription {
client := &InvoiceSubscription{
NewInvoices: make(chan *channeldb.Invoice),
SettledInvoices: make(chan *channeldb.Invoice),
addIndex: addIndex,
settleIndex: settleIndex,
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invoiceSubscriptionKit: invoiceSubscriptionKit{
inv: i,
ntfnQueue: queue.NewConcurrentQueue(20),
cancelChan: make(chan struct{}),
},
}
client.ntfnQueue.Start()
i.clientMtx.Lock()
client.id = i.nextClientID
i.nextClientID++
i.clientMtx.Unlock()
// Before we register this new invoice subscription, we'll launch a new
// goroutine that will proxy all notifications appended to the end of
// the concurrent queue to the two client-side channels the caller will
// feed off of.
i.wg.Add(1)
go func() {
defer i.wg.Done()
for {
select {
// A new invoice event has been sent by the
// invoiceRegistry! We'll figure out if this is an add
// event or a settle event, then dispatch the event to
// the client.
case ntfn := <-client.ntfnQueue.ChanOut():
invoiceEvent := ntfn.(*invoiceEvent)
var targetChan chan *channeldb.Invoice
state := invoiceEvent.invoice.State
switch state {
case channeldb.ContractOpen:
targetChan = client.NewInvoices
case channeldb.ContractSettled:
targetChan = client.SettledInvoices
default:
log.Errorf("unknown invoice "+
"state: %v", state)
continue
}
select {
case targetChan <- invoiceEvent.invoice:
case <-client.cancelChan:
return
case <-i.quit:
return
}
case <-client.cancelChan:
return
case <-i.quit:
return
}
}
}()
select {
case i.newSubscriptions <- client:
case <-i.quit:
}
return client
}
2018-12-20 20:54:11 +03:00
// SubscribeSingleInvoice returns an SingleInvoiceSubscription which allows the
// caller to receive async notifications for a specific invoice.
func (i *InvoiceRegistry) SubscribeSingleInvoice(
hash lntypes.Hash) (*SingleInvoiceSubscription, error) {
2018-12-20 20:54:11 +03:00
client := &SingleInvoiceSubscription{
Updates: make(chan *channeldb.Invoice),
invoiceSubscriptionKit: invoiceSubscriptionKit{
inv: i,
ntfnQueue: queue.NewConcurrentQueue(20),
cancelChan: make(chan struct{}),
},
hash: hash,
}
client.ntfnQueue.Start()
i.clientMtx.Lock()
client.id = i.nextClientID
i.nextClientID++
i.clientMtx.Unlock()
// Before we register this new invoice subscription, we'll launch a new
// goroutine that will proxy all notifications appended to the end of
// the concurrent queue to the two client-side channels the caller will
// feed off of.
i.wg.Add(1)
go func() {
defer i.wg.Done()
for {
select {
// A new invoice event has been sent by the
// invoiceRegistry. We will dispatch the event to the
// client.
case ntfn := <-client.ntfnQueue.ChanOut():
invoiceEvent := ntfn.(*invoiceEvent)
select {
case client.Updates <- invoiceEvent.invoice:
case <-client.cancelChan:
return
case <-i.quit:
return
}
case <-client.cancelChan:
return
case <-i.quit:
return
}
}
}()
// Within the lock, we both query the invoice state and pass the client
// subscription to the invoiceEvents channel. This is to make sure that
// the client receives a consistent stream of events.
i.Lock()
defer i.Unlock()
err := i.deliverSingleBacklogEvents(client)
if err != nil {
return nil, err
}
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select {
case i.invoiceEvents <- client:
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case <-i.quit:
return nil, ErrShuttingDown
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}
return client, nil
2018-12-20 20:54:11 +03:00
}
// notifyHodlSubscribers sends out the htlc resolution to all current
// subscribers.
func (i *InvoiceRegistry) notifyHodlSubscribers(htlcResolution HtlcResolution) {
subscribers, ok := i.hodlSubscriptions[htlcResolution.CircuitKey]
if !ok {
return
}
// Notify all interested subscribers and remove subscription from both
// maps. The subscription can be removed as there only ever will be a
// single resolution for each hash.
for subscriber := range subscribers {
select {
case subscriber <- htlcResolution:
case <-i.quit:
return
}
delete(
i.hodlReverseSubscriptions[subscriber],
htlcResolution.CircuitKey,
)
}
delete(i.hodlSubscriptions, htlcResolution.CircuitKey)
}
// hodlSubscribe adds a new invoice subscription.
func (i *InvoiceRegistry) hodlSubscribe(subscriber chan<- interface{},
circuitKey channeldb.CircuitKey) {
log.Debugf("Hodl subscribe for %v", circuitKey)
subscriptions, ok := i.hodlSubscriptions[circuitKey]
if !ok {
subscriptions = make(map[chan<- interface{}]struct{})
i.hodlSubscriptions[circuitKey] = subscriptions
}
subscriptions[subscriber] = struct{}{}
reverseSubscriptions, ok := i.hodlReverseSubscriptions[subscriber]
if !ok {
reverseSubscriptions = make(map[channeldb.CircuitKey]struct{})
i.hodlReverseSubscriptions[subscriber] = reverseSubscriptions
}
reverseSubscriptions[circuitKey] = struct{}{}
}
// HodlUnsubscribeAll cancels the subscription.
func (i *InvoiceRegistry) HodlUnsubscribeAll(subscriber chan<- interface{}) {
i.Lock()
defer i.Unlock()
hashes := i.hodlReverseSubscriptions[subscriber]
for hash := range hashes {
delete(i.hodlSubscriptions[hash], subscriber)
}
delete(i.hodlReverseSubscriptions, subscriber)
}