9915780197

Committed 13 Jul 2024 12:30AM UTC coverage: 49.268% (-9.1%) from 58.413%

Build # 9915780197

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push

github

Committed by

web-flow

Commit Message

Merge pull request #8653 from ProofOfKeags/fn-prim

DynComms [0/n]: `fn` package additions

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84.08

/htlcswitch/payment_result.go

package htlcswitch

import (
        "bytes"
        "encoding/binary"
        "errors"
        "io"
        "sync"

        "github.com/lightningnetwork/lnd/channeldb"
        "github.com/lightningnetwork/lnd/kvdb"
        "github.com/lightningnetwork/lnd/lnwire"
        "github.com/lightningnetwork/lnd/multimutex"
)

var (

        // networkResultStoreBucketKey is used for the root level bucket that
        // stores the network result for each payment ID.
        networkResultStoreBucketKey = []byte("network-result-store-bucket")

        // ErrPaymentIDNotFound is an error returned if the given paymentID is
        // not found.
        ErrPaymentIDNotFound = errors.New("paymentID not found")

        // ErrPaymentIDAlreadyExists is returned if we try to write a pending
        // payment whose paymentID already exists.
        ErrPaymentIDAlreadyExists = errors.New("paymentID already exists")
)

// PaymentResult wraps a decoded result received from the network after a
// payment attempt was made. This is what is eventually handed to the router
// for processing.
type PaymentResult struct {
        // Preimage is set by the switch in case a sent HTLC was settled.
        Preimage [32]byte

        // Error is non-nil in case a HTLC send failed, and the HTLC is now
        // irrevocably canceled. If the payment failed during forwarding, this
        // error will be a *ForwardingError.
        Error error
}

// networkResult is the raw result received from the network after a payment
// attempt has been made. Since the switch doesn't always have the necessary
// data to decode the raw message, we store it together with some meta data,
// and decode it when the router query for the final result.
type networkResult struct {
        // msg is the received result. This should be of type UpdateFulfillHTLC
        // or UpdateFailHTLC.
        msg lnwire.Message

        // unencrypted indicates whether the failure encoded in the message is
        // unencrypted, and hence doesn't need to be decrypted.
        unencrypted bool

        // isResolution indicates whether this is a resolution message, in
        // which the failure reason might not be included.
        isResolution bool
}

// serializeNetworkResult serializes the networkResult.
func serializeNetworkResult(w io.Writer, n *networkResult) error {
        return channeldb.WriteElements(w, n.msg, n.unencrypted, n.isResolution)
}

// deserializeNetworkResult deserializes the networkResult.
func deserializeNetworkResult(r io.Reader) (*networkResult, error) {
        n := &networkResult{}

        if err := channeldb.ReadElements(r,
                &n.msg, &n.unencrypted, &n.isResolution,
        ); err != nil {
                return nil, err
        }

        return n, nil
}

// networkResultStore is a persistent store that stores any results of HTLCs in
// flight on the network. Since payment results are inherently asynchronous, it
// is used as a common access point for senders of HTLCs, to know when a result
// is back. The Switch will checkpoint any received result to the store, and
// the store will keep results and notify the callers about them.
type networkResultStore struct {
        backend kvdb.Backend

        // results is a map from paymentIDs to channels where subscribers to
        // payment results will be notified.
        results    map[uint64][]chan *networkResult
        resultsMtx sync.Mutex

        // paymentIDMtx is a multimutex used to make sure the database and
        // result subscribers map is consistent for each payment ID in case of
        // concurrent callers.
        paymentIDMtx *multimutex.Mutex[uint64]
}

func newNetworkResultStore(db kvdb.Backend) *networkResultStore {
        return &networkResultStore{
                backend:      db,
                results:      make(map[uint64][]chan *networkResult),
                paymentIDMtx: multimutex.NewMutex[uint64](),
        }
}

// storeResult stores the networkResult for the given paymentID, and
// notifies any subscribers.
func (store *networkResultStore) storeResult(paymentID uint64,
        result *networkResult) error {

        // We get a mutex for this payment ID. This is needed to ensure
        // consistency between the database state and the subscribers in case
        // of concurrent calls.
        store.paymentIDMtx.Lock(paymentID)
        defer store.paymentIDMtx.Unlock(paymentID)

        log.Debugf("Storing result for paymentID=%v", paymentID)

        // Serialize the payment result.
        var b bytes.Buffer
        if err := serializeNetworkResult(&b, result); err != nil {
                return err
        }

        var paymentIDBytes [8]byte
        binary.BigEndian.PutUint64(paymentIDBytes[:], paymentID)

        err := kvdb.Batch(store.backend, func(tx kvdb.RwTx) error {
                networkResults, err := tx.CreateTopLevelBucket(
                        networkResultStoreBucketKey,
                )
                if err != nil {
                        return err
                }

                return networkResults.Put(paymentIDBytes[:], b.Bytes())
        })
        if err != nil {
                return err
        }

        // Now that the result is stored in the database, we can notify any
        // active subscribers.
        store.resultsMtx.Lock()
        for _, res := range store.results[paymentID] {
                res <- result
        }
        delete(store.results, paymentID)
        store.resultsMtx.Unlock()

        return nil
}

// subscribeResult is used to get the payment result for the given
// payment ID. It returns a channel on which the result will be delivered when
// ready.
func (store *networkResultStore) subscribeResult(paymentID uint64) (
        <-chan *networkResult, error) {

        // We get a mutex for this payment ID. This is needed to ensure
        // consistency between the database state and the subscribers in case
        // of concurrent calls.
        store.paymentIDMtx.Lock(paymentID)
        defer store.paymentIDMtx.Unlock(paymentID)

        log.Debugf("Subscribing to result for paymentID=%v", paymentID)

        var (
                result     *networkResult
                resultChan = make(chan *networkResult, 1)
        )

        err := kvdb.View(store.backend, func(tx kvdb.RTx) error {
                var err error
                result, err = fetchResult(tx, paymentID)
                switch {

                // Result not yet available, we will notify once a result is
                // available.
                case err == ErrPaymentIDNotFound:
                        return nil

                case err != nil:
                        return err

                // The result was found, and will be returned immediately.
                default:
                        return nil
                }
        }, func() {
                result = nil
        })
        if err != nil {
                return nil, err
        }

        // If the result was found, we can send it on the result channel
        // imemdiately.
        if result != nil {
                resultChan <- result
                return resultChan, nil
        }

        // Otherwise we store the result channel for when the result is
        // available.
        store.resultsMtx.Lock()
        store.results[paymentID] = append(
                store.results[paymentID], resultChan,
        )
        store.resultsMtx.Unlock()

        return resultChan, nil
}

// getResult attempts to immediately fetch the result for the given pid from
// the store. If no result is available, ErrPaymentIDNotFound is returned.
func (store *networkResultStore) getResult(pid uint64) (
        *networkResult, error) {

        var result *networkResult
        err := kvdb.View(store.backend, func(tx kvdb.RTx) error {
                var err error
                result, err = fetchResult(tx, pid)
                return err
        }, func() {
                result = nil
        })
        if err != nil {
                return nil, err
        }

        return result, nil
}

func fetchResult(tx kvdb.RTx, pid uint64) (*networkResult, error) {
        var paymentIDBytes [8]byte
        binary.BigEndian.PutUint64(paymentIDBytes[:], pid)

        networkResults := tx.ReadBucket(networkResultStoreBucketKey)
        if networkResults == nil {
                return nil, ErrPaymentIDNotFound
        }

        // Check whether a result is already available.
        resultBytes := networkResults.Get(paymentIDBytes[:])
        if resultBytes == nil {
                return nil, ErrPaymentIDNotFound
        }

        // Decode the result we found.
        r := bytes.NewReader(resultBytes)

        return deserializeNetworkResult(r)
}

// cleanStore removes all entries from the store, except the payment IDs given.
// NOTE: Since every result not listed in the keep map will be deleted, care
// should be taken to ensure no new payment attempts are being made
// concurrently while this process is ongoing, as its result might end up being
// deleted.
func (store *networkResultStore) cleanStore(keep map[uint64]struct{}) error {
        return kvdb.Update(store.backend, func(tx kvdb.RwTx) error {
                networkResults, err := tx.CreateTopLevelBucket(
                        networkResultStoreBucketKey,
                )
                if err != nil {
                        return err
                }

                // Iterate through the bucket, deleting all items not in the
                // keep map.
                var toClean [][]byte
                if err := networkResults.ForEach(func(k, _ []byte) error {
                        pid := binary.BigEndian.Uint64(k)
                        if _, ok := keep[pid]; ok {
                                return nil
                        }

                        toClean = append(toClean, k)
                        return nil
                }); err != nil {
                        return err
                }

                for _, k := range toClean {
                        err := networkResults.Delete(k)
                        if err != nil {
                                return err
                        }
                }

                if len(toClean) > 0 {
                        log.Infof("Removed %d stale entries from network "+
                                "result store", len(toClean))
                }

                return nil
        }, func() {})
}

1	package htlcswitch
2
3	import (
4	"bytes"
5	"encoding/binary"
6	"errors"
7	"io"
8	"sync"
9
10	"github.com/lightningnetwork/lnd/channeldb"
11	"github.com/lightningnetwork/lnd/kvdb"
12	"github.com/lightningnetwork/lnd/lnwire"
13	"github.com/lightningnetwork/lnd/multimutex"
14	)
15
16	var (
17
18	// networkResultStoreBucketKey is used for the root level bucket that
19	// stores the network result for each payment ID.
20	networkResultStoreBucketKey = []byte("network-result-store-bucket")
21
22	// ErrPaymentIDNotFound is an error returned if the given paymentID is
23	// not found.
24	ErrPaymentIDNotFound = errors.New("paymentID not found")
25
26	// ErrPaymentIDAlreadyExists is returned if we try to write a pending
27	// payment whose paymentID already exists.
28	ErrPaymentIDAlreadyExists = errors.New("paymentID already exists")
29	)
30
31	// PaymentResult wraps a decoded result received from the network after a
32	// payment attempt was made. This is what is eventually handed to the router
33	// for processing.
34	type PaymentResult struct {
35	// Preimage is set by the switch in case a sent HTLC was settled.
36	Preimage [32]byte
37
38	// Error is non-nil in case a HTLC send failed, and the HTLC is now
39	// irrevocably canceled. If the payment failed during forwarding, this
40	// error will be a *ForwardingError.
41	Error error
42	}
43
44	// networkResult is the raw result received from the network after a payment
45	// attempt has been made. Since the switch doesn't always have the necessary
46	// data to decode the raw message, we store it together with some meta data,
47	// and decode it when the router query for the final result.
48	type networkResult struct {
49	// msg is the received result. This should be of type UpdateFulfillHTLC
50	// or UpdateFailHTLC.
51	msg lnwire.Message
52
53	// unencrypted indicates whether the failure encoded in the message is
54	// unencrypted, and hence doesn't need to be decrypted.
55	unencrypted bool
56
57	// isResolution indicates whether this is a resolution message, in
58	// which the failure reason might not be included.
59	isResolution bool
60	}
61
62	// serializeNetworkResult serializes the networkResult.
63	func serializeNetworkResult(w io.Writer, n *networkResult) error {	3✔
64	return channeldb.WriteElements(w, n.msg, n.unencrypted, n.isResolution)	3✔
65	}	3✔
66
67	// deserializeNetworkResult deserializes the networkResult.
68	func deserializeNetworkResult(r io.Reader) (*networkResult, error) {	3✔
69	n := &networkResult{}	3✔
70		3✔
71	if err := channeldb.ReadElements(r,	3✔
72	&n.msg, &n.unencrypted, &n.isResolution,	3✔
73	); err != nil {	3✔
74	return nil, err	×
75	}	×
76
77	return n, nil	3✔
78	}
79
80	// networkResultStore is a persistent store that stores any results of HTLCs in
81	// flight on the network. Since payment results are inherently asynchronous, it
82	// is used as a common access point for senders of HTLCs, to know when a result
83	// is back. The Switch will checkpoint any received result to the store, and
84	// the store will keep results and notify the callers about them.
85	type networkResultStore struct {
86	backend kvdb.Backend
87
88	// results is a map from paymentIDs to channels where subscribers to
89	// payment results will be notified.
90	results map[uint64][]chan *networkResult
91	resultsMtx sync.Mutex
92
93	// paymentIDMtx is a multimutex used to make sure the database and
94	// result subscribers map is consistent for each payment ID in case of
95	// concurrent callers.
96	paymentIDMtx *multimutex.Mutex[uint64]
97	}
98
99	func newNetworkResultStore(db kvdb.Backend) *networkResultStore {	3✔
100	return &networkResultStore{	3✔
101	backend: db,	3✔
102	results: make(map[uint64][]chan *networkResult),	3✔
103	paymentIDMtx: multimutex.NewMutex[uint64](),	3✔
104	}	3✔
105	}	3✔
106
107	// storeResult stores the networkResult for the given paymentID, and
108	// notifies any subscribers.
109	func (store *networkResultStore) storeResult(paymentID uint64,
110	result *networkResult) error {	3✔
111		3✔
112	// We get a mutex for this payment ID. This is needed to ensure	3✔
113	// consistency between the database state and the subscribers in case	3✔
114	// of concurrent calls.	3✔
115	store.paymentIDMtx.Lock(paymentID)	3✔
116	defer store.paymentIDMtx.Unlock(paymentID)	3✔
117		3✔
118	log.Debugf("Storing result for paymentID=%v", paymentID)	3✔
119		3✔
120	// Serialize the payment result.	3✔
121	var b bytes.Buffer	3✔
122	if err := serializeNetworkResult(&b, result); err != nil {	3✔
123	return err	×
124	}	×
125
126	var paymentIDBytes [8]byte	3✔
127	binary.BigEndian.PutUint64(paymentIDBytes[:], paymentID)	3✔
128		3✔
129	err := kvdb.Batch(store.backend, func(tx kvdb.RwTx) error {	6✔
130	networkResults, err := tx.CreateTopLevelBucket(	3✔
131	networkResultStoreBucketKey,	3✔
132	)	3✔
133	if err != nil {	3✔
134	return err	×
135	}	×
136
137	return networkResults.Put(paymentIDBytes[:], b.Bytes())	3✔
138	})
139	if err != nil {	3✔
140	return err	×
141	}	×
142
143	// Now that the result is stored in the database, we can notify any
144	// active subscribers.
145	store.resultsMtx.Lock()	3✔
146	for _, res := range store.results[paymentID] {	6✔
147	res <- result	3✔
148	}	3✔
149	delete(store.results, paymentID)	3✔
150	store.resultsMtx.Unlock()	3✔
151		3✔
152	return nil	3✔
153	}
154
155	// subscribeResult is used to get the payment result for the given
156	// payment ID. It returns a channel on which the result will be delivered when
157	// ready.
158	func (store *networkResultStore) subscribeResult(paymentID uint64) (
159	<-chan *networkResult, error) {	3✔
160		3✔
161	// We get a mutex for this payment ID. This is needed to ensure	3✔
162	// consistency between the database state and the subscribers in case	3✔
163	// of concurrent calls.	3✔
164	store.paymentIDMtx.Lock(paymentID)	3✔
165	defer store.paymentIDMtx.Unlock(paymentID)	3✔
166		3✔
167	log.Debugf("Subscribing to result for paymentID=%v", paymentID)	3✔
168		3✔
169	var (	3✔
170	result *networkResult	3✔
171	resultChan = make(chan *networkResult, 1)	3✔
172	)	3✔
173		3✔
174	err := kvdb.View(store.backend, func(tx kvdb.RTx) error {	6✔
175	var err error	3✔
176	result, err = fetchResult(tx, paymentID)	3✔
177	switch {	3✔
178
179	// Result not yet available, we will notify once a result is
180	// available.
181	case err == ErrPaymentIDNotFound:	3✔
182	return nil	3✔
183
184	case err != nil:	×
185	return err	×
186
187	// The result was found, and will be returned immediately.
188	default:	3✔
189	return nil	3✔
190	}
191	}, func() {	3✔
192	result = nil	3✔
193	})	3✔
194	if err != nil {	3✔
195	return nil, err	×
196	}	×
197
198	// If the result was found, we can send it on the result channel
199	// imemdiately.
200	if result != nil {	6✔
201	resultChan <- result	3✔
202	return resultChan, nil	3✔
203	}	3✔
204
205	// Otherwise we store the result channel for when the result is
206	// available.
207	store.resultsMtx.Lock()	3✔
208	store.results[paymentID] = append(	3✔
209	store.results[paymentID], resultChan,	3✔
210	)	3✔
211	store.resultsMtx.Unlock()	3✔
212		3✔
213	return resultChan, nil	3✔
214	}
215
216	// getResult attempts to immediately fetch the result for the given pid from
217	// the store. If no result is available, ErrPaymentIDNotFound is returned.
218	func (store *networkResultStore) getResult(pid uint64) (
219	*networkResult, error) {	2✔
220		2✔
221	var result *networkResult	2✔
222	err := kvdb.View(store.backend, func(tx kvdb.RTx) error {	4✔
223	var err error	2✔
224	result, err = fetchResult(tx, pid)	2✔
225	return err	2✔
226	}, func() {	4✔
227	result = nil	2✔
228	})	2✔
229	if err != nil {	2✔
230	return nil, err	×
231	}	×
232
233	return result, nil	2✔
234	}
235
236	func fetchResult(tx kvdb.RTx, pid uint64) (*networkResult, error) {	3✔
237	var paymentIDBytes [8]byte	3✔
238	binary.BigEndian.PutUint64(paymentIDBytes[:], pid)	3✔
239		3✔
240	networkResults := tx.ReadBucket(networkResultStoreBucketKey)	3✔
241	if networkResults == nil {	3✔
242	return nil, ErrPaymentIDNotFound	×
243	}	×
244
245	// Check whether a result is already available.
246	resultBytes := networkResults.Get(paymentIDBytes[:])	3✔
247	if resultBytes == nil {	6✔
248	return nil, ErrPaymentIDNotFound	3✔
249	}	3✔
250
251	// Decode the result we found.
252	r := bytes.NewReader(resultBytes)	3✔
253		3✔
254	return deserializeNetworkResult(r)	3✔
255	}
256
257	// cleanStore removes all entries from the store, except the payment IDs given.
258	// NOTE: Since every result not listed in the keep map will be deleted, care
259	// should be taken to ensure no new payment attempts are being made
260	// concurrently while this process is ongoing, as its result might end up being
261	// deleted.
262	func (store *networkResultStore) cleanStore(keep map[uint64]struct{}) error {	3✔
263	return kvdb.Update(store.backend, func(tx kvdb.RwTx) error {	6✔
264	networkResults, err := tx.CreateTopLevelBucket(	3✔
265	networkResultStoreBucketKey,	3✔
266	)	3✔
267	if err != nil {	3✔
268	return err	×
269	}	×
270
271	// Iterate through the bucket, deleting all items not in the
272	// keep map.
273	var toClean [][]byte	3✔
274	if err := networkResults.ForEach(func(k, _ []byte) error {	6✔
275	pid := binary.BigEndian.Uint64(k)	3✔
276	if _, ok := keep[pid]; ok {	3✔
277	return nil	×
278	}	×
279
280	toClean = append(toClean, k)	3✔
281	return nil	3✔
282	}); err != nil {	×
283	return err	×
284	}	×
285
286	for _, k := range toClean {	6✔
287	err := networkResults.Delete(k)	3✔
288	if err != nil {	3✔
289	return err	×
290	}	×
291	}
292
293	if len(toClean) > 0 {	6✔
294	log.Infof("Removed %d stale entries from network "+	3✔
295	"result store", len(toClean))	3✔
296	}	3✔
297
298	return nil	3✔
299	}, func() {})	3✔
300	}

lightningnetwork / lnd / 9915780197

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