9915780197

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

Build # 9915780197

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Merge pull request #8653 from ProofOfKeags/fn-prim

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

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73.52

/routing/chainview/bitcoind.go

package chainview

import (
        "bytes"
        "encoding/hex"
        "fmt"
        "sync"
        "sync/atomic"

        "github.com/btcsuite/btcd/btcjson"
        "github.com/btcsuite/btcd/chaincfg/chainhash"
        "github.com/btcsuite/btcd/wire"
        "github.com/btcsuite/btcwallet/chain"
        "github.com/btcsuite/btcwallet/wtxmgr"
        "github.com/lightningnetwork/lnd/blockcache"
        "github.com/lightningnetwork/lnd/channeldb"
)

// BitcoindFilteredChainView is an implementation of the FilteredChainView
// interface which is backed by bitcoind.
type BitcoindFilteredChainView struct {
        started int32 // To be used atomically.
        stopped int32 // To be used atomically.

        // bestHeight is the height of the latest block added to the
        // blockQueue from the onFilteredConnectedMethod. It is used to
        // determine up to what height we would need to rescan in case
        // of a filter update.
        bestHeightMtx sync.Mutex
        bestHeight    uint32

        // TODO: Factor out common logic between bitcoind and btcd into a
        // NodeFilteredView interface.
        chainClient *chain.BitcoindClient

        // blockEventQueue is the ordered queue used to keep the order
        // of connected and disconnected blocks sent to the reader of the
        // chainView.
        blockQueue *blockEventQueue

        // blockCache is an LRU block cache.
        blockCache *blockcache.BlockCache

        // filterUpdates is a channel in which updates to the utxo filter
        // attached to this instance are sent over.
        filterUpdates chan filterUpdate

        // chainFilter is the set of utox's that we're currently watching
        // spends for within the chain.
        filterMtx   sync.RWMutex
        chainFilter map[wire.OutPoint]struct{}

        // filterBlockReqs is a channel in which requests to filter select
        // blocks will be sent over.
        filterBlockReqs chan *filterBlockReq

        quit chan struct{}
        wg   sync.WaitGroup
}

// A compile time check to ensure BitcoindFilteredChainView implements the
// chainview.FilteredChainView.
var _ FilteredChainView = (*BitcoindFilteredChainView)(nil)

// NewBitcoindFilteredChainView creates a new instance of a FilteredChainView
// from RPC credentials and a ZMQ socket address for a bitcoind instance.
func NewBitcoindFilteredChainView(
        chainConn *chain.BitcoindConn,
        blockCache *blockcache.BlockCache) *BitcoindFilteredChainView {

        chainView := &BitcoindFilteredChainView{
                chainFilter:     make(map[wire.OutPoint]struct{}),
                filterUpdates:   make(chan filterUpdate),
                filterBlockReqs: make(chan *filterBlockReq),
                blockCache:      blockCache,
                quit:            make(chan struct{}),
        }

        chainView.chainClient = chainConn.NewBitcoindClient()
        chainView.blockQueue = newBlockEventQueue()

        return chainView
}

// Start starts all goroutines necessary for normal operation.
//
// NOTE: This is part of the FilteredChainView interface.
func (b *BitcoindFilteredChainView) Start() error {
        // Already started?
        if atomic.AddInt32(&b.started, 1) != 1 {
                return nil
        }

        log.Infof("FilteredChainView starting")

        err := b.chainClient.Start()
        if err != nil {
                return err
        }

        err = b.chainClient.NotifyBlocks()
        if err != nil {
                return err
        }

        _, bestHeight, err := b.chainClient.GetBestBlock()
        if err != nil {
                return err
        }

        b.bestHeightMtx.Lock()
        b.bestHeight = uint32(bestHeight)
        b.bestHeightMtx.Unlock()

        b.blockQueue.Start()

        b.wg.Add(1)
        go b.chainFilterer()

        return nil
}

// Stop stops all goroutines which we launched by the prior call to the Start
// method.
//
// NOTE: This is part of the FilteredChainView interface.
func (b *BitcoindFilteredChainView) Stop() error {
        // Already shutting down?
        if atomic.AddInt32(&b.stopped, 1) != 1 {
                return nil
        }

        // Shutdown the rpc client, this gracefully disconnects from bitcoind's
        // zmq socket, and cleans up all related resources.
        b.chainClient.Stop()

        b.blockQueue.Stop()

        log.Infof("FilteredChainView stopping")

        close(b.quit)
        b.wg.Wait()

        return nil
}

// onFilteredBlockConnected is called for each block that's connected to the
// end of the main chain. Based on our current chain filter, the block may or
// may not include any relevant transactions.
func (b *BitcoindFilteredChainView) onFilteredBlockConnected(height int32,
        hash chainhash.Hash, txns []*wtxmgr.TxRecord) {

        mtxs := make([]*wire.MsgTx, len(txns))
        b.filterMtx.Lock()
        for i, tx := range txns {
                mtxs[i] = &tx.MsgTx

                for _, txIn := range mtxs[i].TxIn {
                        // We can delete this outpoint from the chainFilter, as
                        // we just received a block where it was spent. In case
                        // of a reorg, this outpoint might get "un-spent", but
                        // that's okay since it would never be wise to consider
                        // the channel open again (since a spending transaction
                        // exists on the network).
                        delete(b.chainFilter, txIn.PreviousOutPoint)
                }

        }
        b.filterMtx.Unlock()

        // We record the height of the last connected block added to the
        // blockQueue such that we can scan up to this height in case of
        // a rescan. It must be protected by a mutex since a filter update
        // might be trying to read it concurrently.
        b.bestHeightMtx.Lock()
        b.bestHeight = uint32(height)
        b.bestHeightMtx.Unlock()

        block := &FilteredBlock{
                Hash:         hash,
                Height:       uint32(height),
                Transactions: mtxs,
        }

        b.blockQueue.Add(&blockEvent{
                eventType: connected,
                block:     block,
        })
}

// onFilteredBlockDisconnected is a callback which is executed once a block is
// disconnected from the end of the main chain.
func (b *BitcoindFilteredChainView) onFilteredBlockDisconnected(height int32,
        hash chainhash.Hash) {

        log.Debugf("got disconnected block at height %d: %v", height,
                hash)

        filteredBlock := &FilteredBlock{
                Hash:   hash,
                Height: uint32(height),
        }

        b.blockQueue.Add(&blockEvent{
                eventType: disconnected,
                block:     filteredBlock,
        })
}

// FilterBlock takes a block hash, and returns a FilteredBlocks which is the
// result of applying the current registered UTXO sub-set on the block
// corresponding to that block hash. If any watched UTOX's are spent by the
// selected lock, then the internal chainFilter will also be updated.
//
// NOTE: This is part of the FilteredChainView interface.
func (b *BitcoindFilteredChainView) FilterBlock(blockHash *chainhash.Hash) (*FilteredBlock, error) {
        req := &filterBlockReq{
                blockHash: blockHash,
                resp:      make(chan *FilteredBlock, 1),
                err:       make(chan error, 1),
        }

        select {
        case b.filterBlockReqs <- req:
        case <-b.quit:
                return nil, fmt.Errorf("FilteredChainView shutting down")
        }

        return <-req.resp, <-req.err
}

// chainFilterer is the primary goroutine which: listens for new blocks coming
// and dispatches the relevant FilteredBlock notifications, updates the filter
// due to requests by callers, and finally is able to perform targeted block
// filtration.
//
// TODO(roasbeef): change to use loadfilter RPC's
func (b *BitcoindFilteredChainView) chainFilterer() {
        defer b.wg.Done()

        // filterBlock is a helper function that scans the given block, and
        // notes which transactions spend outputs which are currently being
        // watched. Additionally, the chain filter will also be updated by
        // removing any spent outputs.
        filterBlock := func(blk *wire.MsgBlock) []*wire.MsgTx {
                b.filterMtx.Lock()
                defer b.filterMtx.Unlock()

                var filteredTxns []*wire.MsgTx
                for _, tx := range blk.Transactions {
                        var txAlreadyFiltered bool
                        for _, txIn := range tx.TxIn {
                                prevOp := txIn.PreviousOutPoint
                                if _, ok := b.chainFilter[prevOp]; !ok {
                                        continue
                                }

                                delete(b.chainFilter, prevOp)

                                // Only add this txn to our list of filtered
                                // txns if it is the first previous outpoint to
                                // cause a match.
                                if txAlreadyFiltered {
                                        continue
                                }

                                filteredTxns = append(filteredTxns, tx.Copy())
                                txAlreadyFiltered = true
                        }
                }

                return filteredTxns
        }

        decodeJSONBlock := func(block *btcjson.RescannedBlock,
                height uint32) (*FilteredBlock, error) {
                hash, err := chainhash.NewHashFromStr(block.Hash)
                if err != nil {
                        return nil, err

                }
                txs := make([]*wire.MsgTx, 0, len(block.Transactions))
                for _, str := range block.Transactions {
                        b, err := hex.DecodeString(str)
                        if err != nil {
                                return nil, err
                        }
                        tx := &wire.MsgTx{}
                        err = tx.Deserialize(bytes.NewReader(b))
                        if err != nil {
                                return nil, err
                        }
                        txs = append(txs, tx)
                }
                return &FilteredBlock{
                        Hash:         *hash,
                        Height:       height,
                        Transactions: txs,
                }, nil
        }

        for {
                select {
                // The caller has just sent an update to the current chain
                // filter, so we'll apply the update, possibly rewinding our
                // state partially.
                case update := <-b.filterUpdates:
                        // First, we'll add all the new UTXO's to the set of
                        // watched UTXO's, eliminating any duplicates in the
                        // process.
                        log.Tracef("Updating chain filter with new UTXO's: %v",
                                update.newUtxos)

                        b.filterMtx.Lock()
                        for _, newOp := range update.newUtxos {
                                b.chainFilter[newOp] = struct{}{}
                        }
                        b.filterMtx.Unlock()

                        // Apply the new TX filter to the chain client, which
                        // will cause all following notifications from and
                        // calls to it return blocks filtered with the new
                        // filter.
                        err := b.chainClient.LoadTxFilter(false, update.newUtxos)
                        if err != nil {
                                log.Errorf("Unable to update filter: %v", err)
                                continue
                        }

                        // All blocks gotten after we loaded the filter will
                        // have the filter applied, but we will need to rescan
                        // the blocks up to the height of the block we last
                        // added to the blockQueue.
                        b.bestHeightMtx.Lock()
                        bestHeight := b.bestHeight
                        b.bestHeightMtx.Unlock()

                        // If the update height matches our best known height,
                        // then we don't need to do any rewinding.
                        if update.updateHeight == bestHeight {
                                continue
                        }

                        // Otherwise, we'll rewind the state to ensure the
                        // caller doesn't miss any relevant notifications.
                        // Starting from the height _after_ the update height,
                        // we'll walk forwards, rescanning one block at a time
                        // with the chain client applying the newly loaded
                        // filter to each block.
                        for i := update.updateHeight + 1; i < bestHeight+1; i++ {
                                blockHash, err := b.chainClient.GetBlockHash(int64(i))
                                if err != nil {
                                        log.Warnf("Unable to get block hash "+
                                                "for block at height %d: %v",
                                                i, err)
                                        continue
                                }

                                // To avoid dealing with the case where a reorg
                                // is happening while we rescan, we scan one
                                // block at a time, skipping blocks that might
                                // have gone missing.
                                rescanned, err := b.chainClient.RescanBlocks(
                                        []chainhash.Hash{*blockHash},
                                )
                                if err != nil {
                                        log.Warnf("Unable to rescan block "+
                                                "with hash %v at height %d: %v",
                                                blockHash, i, err)
                                        continue
                                }

                                // If no block was returned from the rescan, it
                                // means no matching transactions were found.
                                if len(rescanned) != 1 {
                                        log.Tracef("rescan of block %v at "+
                                                "height=%d yielded no "+
                                                "transactions", blockHash, i)
                                        continue
                                }
                                decoded, err := decodeJSONBlock(
                                        &rescanned[0], i,
                                )
                                if err != nil {
                                        log.Errorf("Unable to decode block: %v",
                                                err)
                                        continue
                                }
                                b.blockQueue.Add(&blockEvent{
                                        eventType: connected,
                                        block:     decoded,
                                })
                        }

                // We've received a new request to manually filter a block.
                case req := <-b.filterBlockReqs:
                        // First we'll fetch the block itself as well as some
                        // additional information including its height.
                        block, err := b.GetBlock(req.blockHash)
                        if err != nil {
                                req.err <- err
                                req.resp <- nil
                                continue
                        }
                        header, err := b.chainClient.GetBlockHeaderVerbose(
                                req.blockHash)
                        if err != nil {
                                req.err <- err
                                req.resp <- nil
                                continue
                        }

                        // Once we have this info, we can directly filter the
                        // block and dispatch the proper notification.
                        req.resp <- &FilteredBlock{
                                Hash:         *req.blockHash,
                                Height:       uint32(header.Height),
                                Transactions: filterBlock(block),
                        }
                        req.err <- err

                // We've received a new event from the chain client.
                case event := <-b.chainClient.Notifications():
                        switch e := event.(type) {

                        case chain.FilteredBlockConnected:
                                b.onFilteredBlockConnected(
                                        e.Block.Height, e.Block.Hash, e.RelevantTxs,
                                )

                        case chain.BlockDisconnected:
                                b.onFilteredBlockDisconnected(e.Height, e.Hash)
                        }

                case <-b.quit:
                        return
                }
        }
}

// UpdateFilter updates the UTXO filter which is to be consulted when creating
// FilteredBlocks to be sent to subscribed clients. This method is cumulative
// meaning repeated calls to this method should _expand_ the size of the UTXO
// sub-set currently being watched.  If the set updateHeight is _lower_ than
// the best known height of the implementation, then the state should be
// rewound to ensure all relevant notifications are dispatched.
//
// NOTE: This is part of the FilteredChainView interface.
func (b *BitcoindFilteredChainView) UpdateFilter(ops []channeldb.EdgePoint,
        updateHeight uint32) error {

        newUtxos := make([]wire.OutPoint, len(ops))
        for i, op := range ops {
                newUtxos[i] = op.OutPoint
        }

        select {

        case b.filterUpdates <- filterUpdate{
                newUtxos:     newUtxos,
                updateHeight: updateHeight,
        }:
                return nil

        case <-b.quit:
                return fmt.Errorf("chain filter shutting down")
        }
}

// FilteredBlocks returns the channel that filtered blocks are to be sent over.
// Each time a block is connected to the end of a main chain, and appropriate
// FilteredBlock which contains the transactions which mutate our watched UTXO
// set is to be returned.
//
// NOTE: This is part of the FilteredChainView interface.
func (b *BitcoindFilteredChainView) FilteredBlocks() <-chan *FilteredBlock {
        return b.blockQueue.newBlocks
}

// DisconnectedBlocks returns a receive only channel which will be sent upon
// with the empty filtered blocks of blocks which are disconnected from the
// main chain in the case of a re-org.
//
// NOTE: This is part of the FilteredChainView interface.
func (b *BitcoindFilteredChainView) DisconnectedBlocks() <-chan *FilteredBlock {
        return b.blockQueue.staleBlocks
}

// GetBlock is used to retrieve the block with the given hash. This function
// wraps the blockCache's GetBlock function.
func (b *BitcoindFilteredChainView) GetBlock(hash *chainhash.Hash) (
        *wire.MsgBlock, error) {

        return b.blockCache.GetBlock(hash, b.chainClient.GetBlock)
}

1	package chainview
2
3	import (
4	"bytes"
5	"encoding/hex"
6	"fmt"
7	"sync"
8	"sync/atomic"
9
10	"github.com/btcsuite/btcd/btcjson"
11	"github.com/btcsuite/btcd/chaincfg/chainhash"
12	"github.com/btcsuite/btcd/wire"
13	"github.com/btcsuite/btcwallet/chain"
14	"github.com/btcsuite/btcwallet/wtxmgr"
15	"github.com/lightningnetwork/lnd/blockcache"
16	"github.com/lightningnetwork/lnd/channeldb"
17	)
18
19	// BitcoindFilteredChainView is an implementation of the FilteredChainView
20	// interface which is backed by bitcoind.
21	type BitcoindFilteredChainView struct {
22	started int32 // To be used atomically.
23	stopped int32 // To be used atomically.
24
25	// bestHeight is the height of the latest block added to the
26	// blockQueue from the onFilteredConnectedMethod. It is used to
27	// determine up to what height we would need to rescan in case
28	// of a filter update.
29	bestHeightMtx sync.Mutex
30	bestHeight uint32
31
32	// TODO: Factor out common logic between bitcoind and btcd into a
33	// NodeFilteredView interface.
34	chainClient *chain.BitcoindClient
35
36	// blockEventQueue is the ordered queue used to keep the order
37	// of connected and disconnected blocks sent to the reader of the
38	// chainView.
39	blockQueue *blockEventQueue
40
41	// blockCache is an LRU block cache.
42	blockCache *blockcache.BlockCache
43
44	// filterUpdates is a channel in which updates to the utxo filter
45	// attached to this instance are sent over.
46	filterUpdates chan filterUpdate
47
48	// chainFilter is the set of utox's that we're currently watching
49	// spends for within the chain.
50	filterMtx sync.RWMutex
51	chainFilter map[wire.OutPoint]struct{}
52
53	// filterBlockReqs is a channel in which requests to filter select
54	// blocks will be sent over.
55	filterBlockReqs chan *filterBlockReq
56
57	quit chan struct{}
58	wg sync.WaitGroup
59	}
60
61	// A compile time check to ensure BitcoindFilteredChainView implements the
62	// chainview.FilteredChainView.
63	var _ FilteredChainView = (*BitcoindFilteredChainView)(nil)
64
65	// NewBitcoindFilteredChainView creates a new instance of a FilteredChainView
66	// from RPC credentials and a ZMQ socket address for a bitcoind instance.
67	func NewBitcoindFilteredChainView(
68	chainConn *chain.BitcoindConn,
69	blockCache blockcache.BlockCache) BitcoindFilteredChainView {	2✔
70		2✔
71	chainView := &BitcoindFilteredChainView{	2✔
72	chainFilter: make(map[wire.OutPoint]struct{}),	2✔
73	filterUpdates: make(chan filterUpdate),	2✔
74	filterBlockReqs: make(chan *filterBlockReq),	2✔
75	blockCache: blockCache,	2✔
76	quit: make(chan struct{}),	2✔
77	}	2✔
78		2✔
79	chainView.chainClient = chainConn.NewBitcoindClient()	2✔
80	chainView.blockQueue = newBlockEventQueue()	2✔
81		2✔
82	return chainView	2✔
83	}	2✔
84
85	// Start starts all goroutines necessary for normal operation.
86	//
87	// NOTE: This is part of the FilteredChainView interface.
88	func (b *BitcoindFilteredChainView) Start() error {	2✔
89	// Already started?	2✔
90	if atomic.AddInt32(&b.started, 1) != 1 {	2✔
91	return nil	×
92	}	×
93
94	log.Infof("FilteredChainView starting")	2✔
95		2✔
96	err := b.chainClient.Start()	2✔
97	if err != nil {	2✔
98	return err	×
99	}	×
100
101	err = b.chainClient.NotifyBlocks()	2✔
102	if err != nil {	2✔
103	return err	×
104	}	×
105
106	_, bestHeight, err := b.chainClient.GetBestBlock()	2✔
107	if err != nil {	2✔
108	return err	×
109	}	×
110
111	b.bestHeightMtx.Lock()	2✔
112	b.bestHeight = uint32(bestHeight)	2✔
113	b.bestHeightMtx.Unlock()	2✔
114		2✔
115	b.blockQueue.Start()	2✔
116		2✔
117	b.wg.Add(1)	2✔
118	go b.chainFilterer()	2✔
119		2✔
120	return nil	2✔
121	}
122
123	// Stop stops all goroutines which we launched by the prior call to the Start
124	// method.
125	//
126	// NOTE: This is part of the FilteredChainView interface.
127	func (b *BitcoindFilteredChainView) Stop() error {	2✔
128	// Already shutting down?	2✔
129	if atomic.AddInt32(&b.stopped, 1) != 1 {	2✔
130	return nil	×
131	}	×
132
133	// Shutdown the rpc client, this gracefully disconnects from bitcoind's
134	// zmq socket, and cleans up all related resources.
135	b.chainClient.Stop()	2✔
136		2✔
137	b.blockQueue.Stop()	2✔
138		2✔
139	log.Infof("FilteredChainView stopping")	2✔
140		2✔
141	close(b.quit)	2✔
142	b.wg.Wait()	2✔
143		2✔
144	return nil	2✔
145	}
146
147	// onFilteredBlockConnected is called for each block that's connected to the
148	// end of the main chain. Based on our current chain filter, the block may or
149	// may not include any relevant transactions.
150	func (b *BitcoindFilteredChainView) onFilteredBlockConnected(height int32,
151	hash chainhash.Hash, txns []*wtxmgr.TxRecord) {	2✔
152		2✔
153	mtxs := make([]*wire.MsgTx, len(txns))	2✔
154	b.filterMtx.Lock()	2✔
155	for i, tx := range txns {	4✔
156	mtxs[i] = &tx.MsgTx	2✔
157		2✔
158	for _, txIn := range mtxs[i].TxIn {	4✔
159	// We can delete this outpoint from the chainFilter, as	2✔
160	// we just received a block where it was spent. In case	2✔
161	// of a reorg, this outpoint might get "un-spent", but	2✔
162	// that's okay since it would never be wise to consider	2✔
163	// the channel open again (since a spending transaction	2✔
164	// exists on the network).	2✔
165	delete(b.chainFilter, txIn.PreviousOutPoint)	2✔
166	}	2✔
167
168	}
169	b.filterMtx.Unlock()	2✔
170		2✔
171	// We record the height of the last connected block added to the	2✔
172	// blockQueue such that we can scan up to this height in case of	2✔
173	// a rescan. It must be protected by a mutex since a filter update	2✔
174	// might be trying to read it concurrently.	2✔
175	b.bestHeightMtx.Lock()	2✔
176	b.bestHeight = uint32(height)	2✔
177	b.bestHeightMtx.Unlock()	2✔
178		2✔
179	block := &FilteredBlock{	2✔
180	Hash: hash,	2✔
181	Height: uint32(height),	2✔
182	Transactions: mtxs,	2✔
183	}	2✔
184		2✔
185	b.blockQueue.Add(&blockEvent{	2✔
186	eventType: connected,	2✔
187	block: block,	2✔
188	})	2✔
189	}
190
191	// onFilteredBlockDisconnected is a callback which is executed once a block is
192	// disconnected from the end of the main chain.
193	func (b *BitcoindFilteredChainView) onFilteredBlockDisconnected(height int32,
194	hash chainhash.Hash) {	2✔
195		2✔
196	log.Debugf("got disconnected block at height %d: %v", height,	2✔
197	hash)	2✔
198		2✔
199	filteredBlock := &FilteredBlock{	2✔
200	Hash: hash,	2✔
201	Height: uint32(height),	2✔
202	}	2✔
203		2✔
204	b.blockQueue.Add(&blockEvent{	2✔
205	eventType: disconnected,	2✔
206	block: filteredBlock,	2✔
207	})	2✔
208	}	2✔
209
210	// FilterBlock takes a block hash, and returns a FilteredBlocks which is the
211	// result of applying the current registered UTXO sub-set on the block
212	// corresponding to that block hash. If any watched UTOX's are spent by the
213	// selected lock, then the internal chainFilter will also be updated.
214	//
215	// NOTE: This is part of the FilteredChainView interface.
216	func (b BitcoindFilteredChainView) FilterBlock(blockHash chainhash.Hash) (*FilteredBlock, error) {	2✔
217	req := &filterBlockReq{	2✔
218	blockHash: blockHash,	2✔
219	resp: make(chan *FilteredBlock, 1),	2✔
220	err: make(chan error, 1),	2✔
221	}	2✔
222		2✔
223	select {	2✔
224	case b.filterBlockReqs <- req:	2✔
225	case <-b.quit:	×
226	return nil, fmt.Errorf("FilteredChainView shutting down")	×
227	}
228
229	return <-req.resp, <-req.err	2✔
230	}
231
232	// chainFilterer is the primary goroutine which: listens for new blocks coming
233	// and dispatches the relevant FilteredBlock notifications, updates the filter
234	// due to requests by callers, and finally is able to perform targeted block
235	// filtration.
236	//
237	// TODO(roasbeef): change to use loadfilter RPC's
238	func (b *BitcoindFilteredChainView) chainFilterer() {	2✔
239	defer b.wg.Done()	2✔
240		2✔
241	// filterBlock is a helper function that scans the given block, and	2✔
242	// notes which transactions spend outputs which are currently being	2✔
243	// watched. Additionally, the chain filter will also be updated by	2✔
244	// removing any spent outputs.	2✔
245	filterBlock := func(blk wire.MsgBlock) []wire.MsgTx {	4✔
246	b.filterMtx.Lock()	2✔
247	defer b.filterMtx.Unlock()	2✔
248		2✔
249	var filteredTxns []*wire.MsgTx	2✔
250	for _, tx := range blk.Transactions {	4✔
251	var txAlreadyFiltered bool	2✔
252	for _, txIn := range tx.TxIn {	4✔
253	prevOp := txIn.PreviousOutPoint	2✔
254	if _, ok := b.chainFilter[prevOp]; !ok {	4✔
255	continue	2✔
256	}
257
258	delete(b.chainFilter, prevOp)	2✔
259		2✔
260	// Only add this txn to our list of filtered	2✔
261	// txns if it is the first previous outpoint to	2✔
262	// cause a match.	2✔
263	if txAlreadyFiltered {	2✔
264	continue	×
265	}
266
267	filteredTxns = append(filteredTxns, tx.Copy())	2✔
268	txAlreadyFiltered = true	2✔
269	}
270	}
271
272	return filteredTxns	2✔
273	}
274
275	decodeJSONBlock := func(block *btcjson.RescannedBlock,	2✔
276	height uint32) (*FilteredBlock, error) {	2✔
277	hash, err := chainhash.NewHashFromStr(block.Hash)	×
278	if err != nil {	×
279	return nil, err	×
280		×
281	}	×
282	txs := make([]*wire.MsgTx, 0, len(block.Transactions))	×
283	for _, str := range block.Transactions {	×
284	b, err := hex.DecodeString(str)	×
285	if err != nil {	×
286	return nil, err	×
287	}	×
288	tx := &wire.MsgTx{}	×
289	err = tx.Deserialize(bytes.NewReader(b))	×
290	if err != nil {	×
291	return nil, err	×
292	}	×
293	txs = append(txs, tx)	×
294	}
295	return &FilteredBlock{	×
296	Hash: *hash,	×
297	Height: height,	×
298	Transactions: txs,	×
299	}, nil	×
300	}
301
302	for {	4✔
303	select {	2✔
304	// The caller has just sent an update to the current chain
305	// filter, so we'll apply the update, possibly rewinding our
306	// state partially.
307	case update := <-b.filterUpdates:	2✔
308	// First, we'll add all the new UTXO's to the set of	2✔
309	// watched UTXO's, eliminating any duplicates in the	2✔
310	// process.	2✔
311	log.Tracef("Updating chain filter with new UTXO's: %v",	2✔
312	update.newUtxos)	2✔
313		2✔
314	b.filterMtx.Lock()	2✔
315	for _, newOp := range update.newUtxos {	4✔
316	b.chainFilter[newOp] = struct{}{}	2✔
317	}	2✔
318	b.filterMtx.Unlock()	2✔
319		2✔
320	// Apply the new TX filter to the chain client, which	2✔
321	// will cause all following notifications from and	2✔
322	// calls to it return blocks filtered with the new	2✔
323	// filter.	2✔
324	err := b.chainClient.LoadTxFilter(false, update.newUtxos)	2✔
325	if err != nil {	2✔
326	log.Errorf("Unable to update filter: %v", err)	×
327	continue	×
328	}
329
330	// All blocks gotten after we loaded the filter will
331	// have the filter applied, but we will need to rescan
332	// the blocks up to the height of the block we last
333	// added to the blockQueue.
334	b.bestHeightMtx.Lock()	2✔
335	bestHeight := b.bestHeight	2✔
336	b.bestHeightMtx.Unlock()	2✔
337		2✔
338	// If the update height matches our best known height,	2✔
339	// then we don't need to do any rewinding.	2✔
340	if update.updateHeight == bestHeight {	4✔
341	continue	2✔
342	}
343
344	// Otherwise, we'll rewind the state to ensure the
345	// caller doesn't miss any relevant notifications.
346	// Starting from the height _after_ the update height,
347	// we'll walk forwards, rescanning one block at a time
348	// with the chain client applying the newly loaded
349	// filter to each block.
350	for i := update.updateHeight + 1; i < bestHeight+1; i++ {	×
351	blockHash, err := b.chainClient.GetBlockHash(int64(i))	×
352	if err != nil {	×
353	log.Warnf("Unable to get block hash "+	×
354	"for block at height %d: %v",	×
355	i, err)	×
356	continue	×
357	}
358
359	// To avoid dealing with the case where a reorg
360	// is happening while we rescan, we scan one
361	// block at a time, skipping blocks that might
362	// have gone missing.
363	rescanned, err := b.chainClient.RescanBlocks(	×
364	[]chainhash.Hash{*blockHash},	×
365	)	×
366	if err != nil {	×
367	log.Warnf("Unable to rescan block "+	×
368	"with hash %v at height %d: %v",	×
369	blockHash, i, err)	×
370	continue	×
371	}
372
373	// If no block was returned from the rescan, it
374	// means no matching transactions were found.
375	if len(rescanned) != 1 {	×
376	log.Tracef("rescan of block %v at "+	×
377	"height=%d yielded no "+	×
378	"transactions", blockHash, i)	×
379	continue	×
380	}
381	decoded, err := decodeJSONBlock(	×
382	&rescanned[0], i,	×
383	)	×
384	if err != nil {	×
385	log.Errorf("Unable to decode block: %v",	×
386	err)	×
387	continue	×
388	}
389	b.blockQueue.Add(&blockEvent{	×
390	eventType: connected,	×
391	block: decoded,	×
392	})	×
393	}
394
395	// We've received a new request to manually filter a block.
396	case req := <-b.filterBlockReqs:	2✔
397	// First we'll fetch the block itself as well as some	2✔
398	// additional information including its height.	2✔
399	block, err := b.GetBlock(req.blockHash)	2✔
400	if err != nil {	2✔
401	req.err <- err	×
402	req.resp <- nil	×
403	continue	×
404	}
405	header, err := b.chainClient.GetBlockHeaderVerbose(	2✔
406	req.blockHash)	2✔
407	if err != nil {	2✔
408	req.err <- err	×
409	req.resp <- nil	×
410	continue	×
411	}
412
413	// Once we have this info, we can directly filter the
414	// block and dispatch the proper notification.
415	req.resp <- &FilteredBlock{	2✔
416	Hash: *req.blockHash,	2✔
417	Height: uint32(header.Height),	2✔
418	Transactions: filterBlock(block),	2✔
419	}	2✔
420	req.err <- err	2✔
421
422	// We've received a new event from the chain client.
423	case event := <-b.chainClient.Notifications():	2✔
424	switch e := event.(type) {	2✔
425
426	case chain.FilteredBlockConnected:	2✔
427	b.onFilteredBlockConnected(	2✔
428	e.Block.Height, e.Block.Hash, e.RelevantTxs,	2✔
429	)	2✔
430
431	case chain.BlockDisconnected:	2✔
432	b.onFilteredBlockDisconnected(e.Height, e.Hash)	2✔
433	}
434
435	case <-b.quit:	2✔
436	return	2✔
437	}
438	}
439	}
440
441	// UpdateFilter updates the UTXO filter which is to be consulted when creating
442	// FilteredBlocks to be sent to subscribed clients. This method is cumulative
443	// meaning repeated calls to this method should _expand_ the size of the UTXO
444	// sub-set currently being watched. If the set updateHeight is _lower_ than
445	// the best known height of the implementation, then the state should be
446	// rewound to ensure all relevant notifications are dispatched.
447	//
448	// NOTE: This is part of the FilteredChainView interface.
449	func (b *BitcoindFilteredChainView) UpdateFilter(ops []channeldb.EdgePoint,
450	updateHeight uint32) error {	2✔
451		2✔
452	newUtxos := make([]wire.OutPoint, len(ops))	2✔
453	for i, op := range ops {	4✔
454	newUtxos[i] = op.OutPoint	2✔
455	}	2✔
456
457	select {	2✔
458
459	case b.filterUpdates <- filterUpdate{
460	newUtxos: newUtxos,
461	updateHeight: updateHeight,
462	}:	2✔
463	return nil	2✔
464
465	case <-b.quit:	×
466	return fmt.Errorf("chain filter shutting down")	×
467	}
468	}
469
470	// FilteredBlocks returns the channel that filtered blocks are to be sent over.
471	// Each time a block is connected to the end of a main chain, and appropriate
472	// FilteredBlock which contains the transactions which mutate our watched UTXO
473	// set is to be returned.
474	//
475	// NOTE: This is part of the FilteredChainView interface.
476	func (b BitcoindFilteredChainView) FilteredBlocks() <-chan FilteredBlock {	2✔
477	return b.blockQueue.newBlocks	2✔
478	}	2✔
479
480	// DisconnectedBlocks returns a receive only channel which will be sent upon
481	// with the empty filtered blocks of blocks which are disconnected from the
482	// main chain in the case of a re-org.
483	//
484	// NOTE: This is part of the FilteredChainView interface.
485	func (b BitcoindFilteredChainView) DisconnectedBlocks() <-chan FilteredBlock {	2✔
486	return b.blockQueue.staleBlocks	2✔
487	}	2✔
488
489	// GetBlock is used to retrieve the block with the given hash. This function
490	// wraps the blockCache's GetBlock function.
491	func (b BitcoindFilteredChainView) GetBlock(hash chainhash.Hash) (
492	*wire.MsgBlock, error) {	2✔
493		2✔
494	return b.blockCache.GetBlock(hash, b.chainClient.GetBlock)	2✔
495	}	2✔

lightningnetwork / lnd / 9915780197

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