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? 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 } // 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 }