lnd.xprv/invoiceregistry.go

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package main
import (
"bytes"
"crypto/sha256"
"sync"
"time"
"github.com/davecgh/go-spew/spew"
"github.com/lightningnetwork/lnd/channeldb"
"github.com/roasbeef/btcd/chaincfg/chainhash"
"github.com/roasbeef/btcutil"
)
var (
// debugPre is the default debug preimage which is inserted into the
// invoice registry if the --debughtlc flag is activated on start up.
// All nodes initialized with the flag active will immediately settle
// any incoming HTLC whose rHash corresponds with the debug
// preimage.
debugPre, _ = chainhash.NewHash(bytes.Repeat([]byte{1}, 32))
debugHash = chainhash.Hash(sha256.Sum256(debugPre[:]))
)
// 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
clientMtx sync.Mutex
nextClientID uint32
notificationClients map[uint32]*invoiceSubscription
// debugInvoices is a map which stores special "debug" invoices which
// should be only created/used when manual tests require an invoice
// that *all* nodes are able to fully settle.
debugInvoices map[chainhash.Hash]*channeldb.Invoice
}
// newInvoiceRegistry 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 newInvoiceRegistry(cdb *channeldb.DB) *invoiceRegistry {
return &invoiceRegistry{
cdb: cdb,
debugInvoices: make(map[chainhash.Hash]*channeldb.Invoice),
notificationClients: make(map[uint32]*invoiceSubscription),
}
}
// addDebugInvoice adds a debug invoice for the specified amount, identified
// by the passed preimage. 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.
func (i *invoiceRegistry) AddDebugInvoice(amt btcutil.Amount, preimage chainhash.Hash) {
paymentHash := chainhash.Hash(sha256.Sum256(preimage[:]))
invoice := &channeldb.Invoice{
CreationDate: time.Now(),
Terms: channeldb.ContractTerm{
Value: amt,
PaymentPreimage: preimage,
},
}
i.Lock()
i.debugInvoices[paymentHash] = invoice
i.Unlock()
ltndLog.Debugf("Adding debug invoice %v", newLogClosure(func() string {
return spew.Sdump(invoice)
}))
}
// 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.
func (i *invoiceRegistry) AddInvoice(invoice *channeldb.Invoice) error {
ltndLog.Debugf("Adding invoice %v", newLogClosure(func() string {
return spew.Sdump(invoice)
}))
// TODO(roasbeef): also check in memory for quick lookups/settles?
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return i.cdb.AddInvoice(invoice)
// TODO(roasbeef): re-enable?
//go i.notifyClients(invoice, false)
}
// 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 chainhash.Hash) (*channeldb.Invoice, error) {
// First check the in-memory debug invoice index to see if this is an
// existing invoice added for debugging.
i.RLock()
invoice, ok := i.debugInvoices[rHash]
i.RUnlock()
// If found, then simply return the invoice directly.
if ok {
return invoice, nil
}
// Otherwise, we'll check the database to see if there's an existing
// matching invoice.
return i.cdb.LookupInvoice(rHash)
}
// SettleInvoice attempts to mark an invoice as settled. If the invoice is a
// debug invoice, then this method is a noop as debug invoices are never fully
// settled.
func (i *invoiceRegistry) SettleInvoice(rHash chainhash.Hash) error {
ltndLog.Debugf("Settling invoice %x", rHash[:])
// First check the in-memory debug invoice index to see if this is an
// existing invoice added for debugging.
i.RLock()
if _, ok := i.debugInvoices[rHash]; ok {
// Debug invoices are never fully settled, so we simply return
// immediately in this case.
i.RUnlock()
return nil
}
i.RUnlock()
// If this isn't a debug invoice, then we'll attempt to settle an
// invoice matching this rHash on disk (if one exists).
if err := i.cdb.SettleInvoice(rHash); err != nil {
return err
}
// Launch a new goroutine to notify any/all registered invoice
// notification clients.
go func() {
invoice, err := i.cdb.LookupInvoice(rHash)
if err != nil {
ltndLog.Errorf("unable to find invoice: %v", err)
return
}
ltndLog.Infof("Payment received: %v", spew.Sdump(invoice))
i.notifyClients(invoice, true)
}()
return nil
}
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// notifyClients notifies all currently registered invoice notification clients
// of a newly added/settled invoice.
func (i *invoiceRegistry) notifyClients(invoice *channeldb.Invoice, settle bool) {
i.clientMtx.Lock()
defer i.clientMtx.Unlock()
for _, client := range i.notificationClients {
var eventChan chan *channeldb.Invoice
if settle {
eventChan = client.SettledInvoices
} else {
eventChan = client.NewInvoices
}
go func() {
eventChan <- invoice
}()
}
}
// 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 {
NewInvoices chan *channeldb.Invoice
SettledInvoices chan *channeldb.Invoice
inv *invoiceRegistry
id uint32
}
// Cancel unregisters the invoiceSubscription, freeing any previously allocated
// resources.
func (i *invoiceSubscription) Cancel() {
i.inv.clientMtx.Lock()
delete(i.inv.notificationClients, i.id)
i.inv.clientMtx.Unlock()
}
// SubscribeNotifications returns an invoiceSubscription which allows the
// caller to receive async notifications when any invoices are settled or
// added.
func (i *invoiceRegistry) SubscribeNotifications() *invoiceSubscription {
client := &invoiceSubscription{
NewInvoices: make(chan *channeldb.Invoice),
SettledInvoices: make(chan *channeldb.Invoice),
inv: i,
}
i.clientMtx.Lock()
i.notificationClients[i.nextClientID] = client
client.id = i.nextClientID
i.nextClientID++
i.clientMtx.Unlock()
return client
}