12199391122

Committed 06 Dec 2024 01:10PM UTC coverage: 49.807% (-9.1%) from 58.933%

Build # 12199391122

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push

github

Committed by

web-flow

Commit Message

Merge pull request #9337 from Guayaba221/patch-1

chore: fix typo in ruby.md

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85.35

/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

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

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

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

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

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

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

        var attemptIDBytes [8]byte
        binary.BigEndian.PutUint64(attemptIDBytes[:], attemptID)

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

                return networkResults.Put(attemptIDBytes[:], 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[attemptID] {
                res <- result
        }
        delete(store.results, attemptID)
        store.resultsMtx.Unlock()

        return nil
}

// subscribeResult is used to get the HTLC attempt result for the given attempt
// ID.  It returns a channel on which the result will be delivered when ready.
func (store *networkResultStore) subscribeResult(attemptID 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.attemptIDMtx.Lock(attemptID)
        defer store.attemptIDMtx.Unlock(attemptID)

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

        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, attemptID)
                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[attemptID] = append(
                store.results[attemptID], 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 attemptIDBytes [8]byte
        binary.BigEndian.PutUint64(attemptIDBytes[:], pid)

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

        // Check whether a result is already available.
        resultBytes := networkResults.Get(attemptIDBytes[:])
        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 {	4✔
64	return channeldb.WriteElements(w, n.msg, n.unencrypted, n.isResolution)	4✔
65	}	4✔
66
67	// deserializeNetworkResult deserializes the networkResult.
68	func deserializeNetworkResult(r io.Reader) (*networkResult, error) {	4✔
69	n := &networkResult{}	4✔
70		4✔
71	if err := channeldb.ReadElements(r,	4✔
72	&n.msg, &n.unencrypted, &n.isResolution,	4✔
73	); err != nil {	4✔
74	return nil, err	×
75	}	×
76
77	return n, nil	4✔
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	// attemptIDMtx is a multimutex used to make sure the database and
94	// result subscribers map is consistent for each attempt ID in case of
95	// concurrent callers.
96	attemptIDMtx *multimutex.Mutex[uint64]
97	}
98
99	func newNetworkResultStore(db kvdb.Backend) *networkResultStore {	4✔
100	return &networkResultStore{	4✔
101	backend: db,	4✔
102	results: make(map[uint64][]chan *networkResult),	4✔
103	attemptIDMtx: multimutex.NewMutex[uint64](),	4✔
104	}	4✔
105	}	4✔
106
107	// storeResult stores the networkResult for the given attemptID, and notifies
108	// any subscribers.
109	func (store *networkResultStore) storeResult(attemptID uint64,
110	result *networkResult) error {	4✔
111		4✔
112	// We get a mutex for this attempt ID. This is needed to ensure	4✔
113	// consistency between the database state and the subscribers in case	4✔
114	// of concurrent calls.	4✔
115	store.attemptIDMtx.Lock(attemptID)	4✔
116	defer store.attemptIDMtx.Unlock(attemptID)	4✔
117		4✔
118	log.Debugf("Storing result for attemptID=%v", attemptID)	4✔
119		4✔
120	// Serialize the payment result.	4✔
121	var b bytes.Buffer	4✔
122	if err := serializeNetworkResult(&b, result); err != nil {	4✔
123	return err	×
124	}	×
125
126	var attemptIDBytes [8]byte	4✔
127	binary.BigEndian.PutUint64(attemptIDBytes[:], attemptID)	4✔
128		4✔
129	err := kvdb.Batch(store.backend, func(tx kvdb.RwTx) error {	8✔
130	networkResults, err := tx.CreateTopLevelBucket(	4✔
131	networkResultStoreBucketKey,	4✔
132	)	4✔
133	if err != nil {	4✔
134	return err	×
135	}	×
136
137	return networkResults.Put(attemptIDBytes[:], b.Bytes())	4✔
138	})
139	if err != nil {	4✔
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()	4✔
146	for _, res := range store.results[attemptID] {	8✔
147	res <- result	4✔
148	}	4✔
149	delete(store.results, attemptID)	4✔
150	store.resultsMtx.Unlock()	4✔
151		4✔
152	return nil	4✔
153	}
154
155	// subscribeResult is used to get the HTLC attempt result for the given attempt
156	// ID. It returns a channel on which the result will be delivered when ready.
157	func (store *networkResultStore) subscribeResult(attemptID uint64) (
158	<-chan *networkResult, error) {	4✔
159		4✔
160	// We get a mutex for this payment ID. This is needed to ensure	4✔
161	// consistency between the database state and the subscribers in case	4✔
162	// of concurrent calls.	4✔
163	store.attemptIDMtx.Lock(attemptID)	4✔
164	defer store.attemptIDMtx.Unlock(attemptID)	4✔
165		4✔
166	log.Debugf("Subscribing to result for attemptID=%v", attemptID)	4✔
167		4✔
168	var (	4✔
169	result *networkResult	4✔
170	resultChan = make(chan *networkResult, 1)	4✔
171	)	4✔
172		4✔
173	err := kvdb.View(store.backend, func(tx kvdb.RTx) error {	8✔
174	var err error	4✔
175	result, err = fetchResult(tx, attemptID)	4✔
176	switch {	4✔
177
178	// Result not yet available, we will notify once a result is
179	// available.
180	case err == ErrPaymentIDNotFound:	4✔
181	return nil	4✔
182
183	case err != nil:	×
184	return err	×
185
186	// The result was found, and will be returned immediately.
187	default:	4✔
188	return nil	4✔
189	}
190	}, func() {	4✔
191	result = nil	4✔
192	})	4✔
193	if err != nil {	4✔
194	return nil, err	×
195	}	×
196
197	// If the result was found, we can send it on the result channel
198	// imemdiately.
199	if result != nil {	8✔
200	resultChan <- result	4✔
201	return resultChan, nil	4✔
202	}	4✔
203
204	// Otherwise we store the result channel for when the result is
205	// available.
206	store.resultsMtx.Lock()	4✔
207	store.results[attemptID] = append(	4✔
208	store.results[attemptID], resultChan,	4✔
209	)	4✔
210	store.resultsMtx.Unlock()	4✔
211		4✔
212	return resultChan, nil	4✔
213	}
214
215	// getResult attempts to immediately fetch the result for the given pid from
216	// the store. If no result is available, ErrPaymentIDNotFound is returned.
217	func (store *networkResultStore) getResult(pid uint64) (
218	*networkResult, error) {	4✔
219		4✔
220	var result *networkResult	4✔
221	err := kvdb.View(store.backend, func(tx kvdb.RTx) error {	8✔
222	var err error	4✔
223	result, err = fetchResult(tx, pid)	4✔
224	return err	4✔
225	}, func() {	8✔
226	result = nil	4✔
227	})	4✔
228	if err != nil {	8✔
229	return nil, err	4✔
230	}	4✔
231
232	return result, nil	4✔
233	}
234
235	func fetchResult(tx kvdb.RTx, pid uint64) (*networkResult, error) {	4✔
236	var attemptIDBytes [8]byte	4✔
237	binary.BigEndian.PutUint64(attemptIDBytes[:], pid)	4✔
238		4✔
239	networkResults := tx.ReadBucket(networkResultStoreBucketKey)	4✔
240	if networkResults == nil {	4✔
241	return nil, ErrPaymentIDNotFound	×
242	}	×
243
244	// Check whether a result is already available.
245	resultBytes := networkResults.Get(attemptIDBytes[:])	4✔
246	if resultBytes == nil {	8✔
247	return nil, ErrPaymentIDNotFound	4✔
248	}	4✔
249
250	// Decode the result we found.
251	r := bytes.NewReader(resultBytes)	4✔
252		4✔
253	return deserializeNetworkResult(r)	4✔
254	}
255
256	// cleanStore removes all entries from the store, except the payment IDs given.
257	// NOTE: Since every result not listed in the keep map will be deleted, care
258	// should be taken to ensure no new payment attempts are being made
259	// concurrently while this process is ongoing, as its result might end up being
260	// deleted.
261	func (store *networkResultStore) cleanStore(keep map[uint64]struct{}) error {	4✔
262	return kvdb.Update(store.backend, func(tx kvdb.RwTx) error {	8✔
263	networkResults, err := tx.CreateTopLevelBucket(	4✔
264	networkResultStoreBucketKey,	4✔
265	)	4✔
266	if err != nil {	4✔
267	return err	×
268	}	×
269
270	// Iterate through the bucket, deleting all items not in the
271	// keep map.
272	var toClean [][]byte	4✔
273	if err := networkResults.ForEach(func(k, _ []byte) error {	8✔
274	pid := binary.BigEndian.Uint64(k)	4✔
275	if _, ok := keep[pid]; ok {	4✔
276	return nil	×
277	}	×
278
279	toClean = append(toClean, k)	4✔
280	return nil	4✔
281	}); err != nil {	×
282	return err	×
283	}	×
284
285	for _, k := range toClean {	8✔
286	err := networkResults.Delete(k)	4✔
287	if err != nil {	4✔
288	return err	×
289	}	×
290	}
291
292	if len(toClean) > 0 {	8✔
293	log.Infof("Removed %d stale entries from network "+	4✔
294	"result store", len(toClean))	4✔
295	}	4✔
296
297	return nil	4✔
298	}, func() {})	4✔
299	}

lightningnetwork / lnd / 12199391122

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