14880107727

Committed 07 May 2025 09:35AM UTC coverage: 58.446% (-10.5%) from 68.992%

Build # 14880107727

Build Type

Pull #9789

github

Committed by

web-flow

Commit Message

Merge ed3471042 into 67a40c90a

Pull Request Pull Request #9789: multi: use updated TLV SizeFunc signature

Run Details

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0.0

/channeldb/migration30/revocation_log.go

package migration30

import (
        "bytes"
        "errors"
        "io"
        "math"

        "github.com/btcsuite/btcd/btcutil"
        lnwire "github.com/lightningnetwork/lnd/channeldb/migration/lnwire21"
        mig24 "github.com/lightningnetwork/lnd/channeldb/migration24"
        mig25 "github.com/lightningnetwork/lnd/channeldb/migration25"
        mig26 "github.com/lightningnetwork/lnd/channeldb/migration26"
        mig "github.com/lightningnetwork/lnd/channeldb/migration_01_to_11"
        "github.com/lightningnetwork/lnd/kvdb"
        "github.com/lightningnetwork/lnd/lntypes"
        "github.com/lightningnetwork/lnd/tlv"
)

const (
        // OutputIndexEmpty is used when the output index doesn't exist.
        OutputIndexEmpty = math.MaxUint16

        // A set of tlv type definitions used to serialize the body of
        // revocation logs to the database.
        //
        // NOTE: A migration should be added whenever this list changes.
        revLogOurOutputIndexType   tlv.Type = 0
        revLogTheirOutputIndexType tlv.Type = 1
        revLogCommitTxHashType     tlv.Type = 2
        revLogOurBalanceType       tlv.Type = 3
        revLogTheirBalanceType     tlv.Type = 4
)

var (
        // revocationLogBucketDeprecated is dedicated for storing the necessary
        // delta state between channel updates required to re-construct a past
        // state in order to punish a counterparty attempting a non-cooperative
        // channel closure. This key should be accessed from within the
        // sub-bucket of a target channel, identified by its channel point.
        //
        // Deprecated: This bucket is kept for read-only in case the user
        // choose not to migrate the old data.
        revocationLogBucketDeprecated = []byte("revocation-log-key")

        // revocationLogBucket is a sub-bucket under openChannelBucket. This
        // sub-bucket is dedicated for storing the minimal info required to
        // re-construct a past state in order to punish a counterparty
        // attempting a non-cooperative channel closure.
        revocationLogBucket = []byte("revocation-log")

        // revocationStateKey stores their current revocation hash, our
        // preimage producer and their preimage store.
        revocationStateKey = []byte("revocation-state-key")

        // ErrNoRevocationsFound is returned when revocation state for a
        // particular channel cannot be found.
        ErrNoRevocationsFound = errors.New("no revocations found")

        // ErrLogEntryNotFound is returned when we cannot find a log entry at
        // the height requested in the revocation log.
        ErrLogEntryNotFound = errors.New("log entry not found")

        // ErrOutputIndexTooBig is returned when the output index is greater
        // than uint16.
        ErrOutputIndexTooBig = errors.New("output index is over uint16")
)

// HTLCEntry specifies the minimal info needed to be stored on disk for ALL the
// historical HTLCs, which is useful for constructing RevocationLog when a
// breach is detected.
// The actual size of each HTLCEntry varies based on its RHash and Amt(sat),
// summarized as follows,
//
//        | RHash empty | Amt<=252 | Amt<=65,535 | Amt<=4,294,967,295 | otherwise |
//        |:-----------:|:--------:|:-----------:|:------------------:|:---------:|
//        |     true    |    19    |      21     |         23         |     26    |
//        |     false   |    51    |      53     |         55         |     58    |
//
// So the size varies from 19 bytes to 58 bytes, where most likely to be 23 or
// 55 bytes.
//
// NOTE: all the fields saved to disk use the primitive go types so they can be
// made into tlv records without further conversion.
type HTLCEntry struct {
        // RHash is the payment hash of the HTLC.
        RHash [32]byte

        // RefundTimeout is the absolute timeout on the HTLC that the sender
        // must wait before reclaiming the funds in limbo.
        RefundTimeout uint32

        // OutputIndex is the output index for this particular HTLC output
        // within the commitment transaction.
        //
        // NOTE: we use uint16 instead of int32 here to save us 2 bytes, which
        // gives us a max number of HTLCs of 65K.
        OutputIndex uint16

        // Incoming denotes whether we're the receiver or the sender of this
        // HTLC.
        //
        // NOTE: this field is the memory representation of the field
        // incomingUint.
        Incoming bool

        // Amt is the amount of satoshis this HTLC escrows.
        //
        // NOTE: this field is the memory representation of the field amtUint.
        Amt btcutil.Amount

        // amtTlv is the uint64 format of Amt. This field is created so we can
        // easily make it into a tlv record and save it to disk.
        //
        // NOTE: we keep this field for accounting purpose only. If the disk
        // space becomes an issue, we could delete this field to save us extra
        // 8 bytes.
        amtTlv uint64

        // incomingTlv is the uint8 format of Incoming. This field is created
        // so we can easily make it into a tlv record and save it to disk.
        incomingTlv uint8
}

// RHashLen is used by MakeDynamicRecord to return the size of the RHash.
//
// NOTE: for zero hash, we return a length 0.
func (h *HTLCEntry) RHashLen() uint64 {
        if h.RHash == lntypes.ZeroHash {
                return 0
        }
        return 32
}

// RHashEncoder is the customized encoder which skips encoding the empty hash.
func RHashEncoder(w io.Writer, val interface{}, buf *[8]byte) error {
        v, ok := val.(*[32]byte)
        if !ok {
                return tlv.NewTypeForEncodingErr(val, "RHash")
        }

        // If the value is an empty hash, we will skip encoding it.
        if *v == lntypes.ZeroHash {
                return nil
        }

        return tlv.EBytes32(w, v, buf)
}

// RHashDecoder is the customized decoder which skips decoding the empty hash.
func RHashDecoder(r io.Reader, val interface{}, buf *[8]byte, l uint64) error {
        v, ok := val.(*[32]byte)
        if !ok {
                return tlv.NewTypeForEncodingErr(val, "RHash")
        }

        // If the length is zero, we will skip encoding the empty hash.
        if l == 0 {
                return nil
        }

        return tlv.DBytes32(r, v, buf, 32)
}

// toTlvStream converts an HTLCEntry record into a tlv representation.
func (h *HTLCEntry) toTlvStream() (*tlv.Stream, error) {
        const (
                // A set of tlv type definitions used to serialize htlc entries
                // to the database. We define it here instead of the head of
                // the file to avoid naming conflicts.
                //
                // NOTE: A migration should be added whenever this list
                // changes.
                rHashType         tlv.Type = 0
                refundTimeoutType tlv.Type = 1
                outputIndexType   tlv.Type = 2
                incomingType      tlv.Type = 3
                amtType           tlv.Type = 4
        )

        return tlv.NewStream(
                tlv.MakeDynamicRecord(
                        rHashType, &h.RHash, func() (uint64, error) {
                                return h.RHashLen(), nil
                        },
                        RHashEncoder, RHashDecoder,
                ),
                tlv.MakePrimitiveRecord(
                        refundTimeoutType, &h.RefundTimeout,
                ),
                tlv.MakePrimitiveRecord(
                        outputIndexType, &h.OutputIndex,
                ),
                tlv.MakePrimitiveRecord(incomingType, &h.incomingTlv),
                // We will save 3 bytes if the amount is less or equal to
                // 4,294,967,295 msat, or roughly 0.043 bitcoin.
                tlv.MakeBigSizeRecord(amtType, &h.amtTlv),
        )
}

// RevocationLog stores the info needed to construct a breach retribution. Its
// fields can be viewed as a subset of a ChannelCommitment's. In the database,
// all historical versions of the RevocationLog are saved using the
// CommitHeight as the key.
type RevocationLog struct {
        // OurOutputIndex specifies our output index in this commitment. In a
        // remote commitment transaction, this is the to remote output index.
        OurOutputIndex uint16

        // TheirOutputIndex specifies their output index in this commitment. In
        // a remote commitment transaction, this is the to local output index.
        TheirOutputIndex uint16

        // CommitTxHash is the hash of the latest version of the commitment
        // state, broadcast able by us.
        CommitTxHash [32]byte

        // HTLCEntries is the set of HTLCEntry's that are pending at this
        // particular commitment height.
        HTLCEntries []*HTLCEntry

        // OurBalance is the current available balance within the channel
        // directly spendable by us. In other words, it is the value of the
        // to_remote output on the remote parties' commitment transaction.
        //
        // NOTE: this is a pointer so that it is clear if the value is zero or
        // nil. Since migration 30 of the channeldb initially did not include
        // this field, it could be the case that the field is not present for
        // all revocation logs.
        OurBalance *lnwire.MilliSatoshi

        // TheirBalance is the current available balance within the channel
        // directly spendable by the remote node. In other words, it is the
        // value of the to_local output on the remote parties' commitment.
        //
        // NOTE: this is a pointer so that it is clear if the value is zero or
        // nil. Since migration 30 of the channeldb initially did not include
        // this field, it could be the case that the field is not present for
        // all revocation logs.
        TheirBalance *lnwire.MilliSatoshi
}

// putRevocationLog uses the fields `CommitTx` and `Htlcs` from a
// ChannelCommitment to construct a revocation log entry and saves them to
// disk. It also saves our output index and their output index, which are
// useful when creating breach retribution.
func putRevocationLog(bucket kvdb.RwBucket, commit *mig.ChannelCommitment,
        ourOutputIndex, theirOutputIndex uint32, noAmtData bool) error {

        // Sanity check that the output indexes can be safely converted.
        if ourOutputIndex > math.MaxUint16 {
                return ErrOutputIndexTooBig
        }
        if theirOutputIndex > math.MaxUint16 {
                return ErrOutputIndexTooBig
        }

        rl := &RevocationLog{
                OurOutputIndex:   uint16(ourOutputIndex),
                TheirOutputIndex: uint16(theirOutputIndex),
                CommitTxHash:     commit.CommitTx.TxHash(),
                HTLCEntries:      make([]*HTLCEntry, 0, len(commit.Htlcs)),
        }

        if !noAmtData {
                rl.OurBalance = &commit.LocalBalance
                rl.TheirBalance = &commit.RemoteBalance
        }

        for _, htlc := range commit.Htlcs {
                // Skip dust HTLCs.
                if htlc.OutputIndex < 0 {
                        continue
                }

                // Sanity check that the output indexes can be safely
                // converted.
                if htlc.OutputIndex > math.MaxUint16 {
                        return ErrOutputIndexTooBig
                }

                entry := &HTLCEntry{
                        RHash:         htlc.RHash,
                        RefundTimeout: htlc.RefundTimeout,
                        Incoming:      htlc.Incoming,
                        OutputIndex:   uint16(htlc.OutputIndex),
                        Amt:           htlc.Amt.ToSatoshis(),
                }
                rl.HTLCEntries = append(rl.HTLCEntries, entry)
        }

        var b bytes.Buffer
        err := serializeRevocationLog(&b, rl)
        if err != nil {
                return err
        }

        logEntrykey := mig24.MakeLogKey(commit.CommitHeight)
        return bucket.Put(logEntrykey[:], b.Bytes())
}

// fetchRevocationLog queries the revocation log bucket to find an log entry.
// Return an error if not found.
func fetchRevocationLog(log kvdb.RBucket,
        updateNum uint64) (RevocationLog, error) {

        logEntrykey := mig24.MakeLogKey(updateNum)
        commitBytes := log.Get(logEntrykey[:])
        if commitBytes == nil {
                return RevocationLog{}, ErrLogEntryNotFound
        }

        commitReader := bytes.NewReader(commitBytes)

        return deserializeRevocationLog(commitReader)
}

// serializeRevocationLog serializes a RevocationLog record based on tlv
// format.
func serializeRevocationLog(w io.Writer, rl *RevocationLog) error {
        // Add the tlv records for all non-optional fields.
        records := []tlv.Record{
                tlv.MakePrimitiveRecord(
                        revLogOurOutputIndexType, &rl.OurOutputIndex,
                ),
                tlv.MakePrimitiveRecord(
                        revLogTheirOutputIndexType, &rl.TheirOutputIndex,
                ),
                tlv.MakePrimitiveRecord(
                        revLogCommitTxHashType, &rl.CommitTxHash,
                ),
        }

        // Now we add any optional fields that are non-nil.
        if rl.OurBalance != nil {
                lb := uint64(*rl.OurBalance)
                records = append(records, tlv.MakeBigSizeRecord(
                        revLogOurBalanceType, &lb,
                ))
        }

        if rl.TheirBalance != nil {
                rb := uint64(*rl.TheirBalance)
                records = append(records, tlv.MakeBigSizeRecord(
                        revLogTheirBalanceType, &rb,
                ))
        }

        // Create the tlv stream.
        tlvStream, err := tlv.NewStream(records...)
        if err != nil {
                return err
        }

        // Write the tlv stream.
        if err := writeTlvStream(w, tlvStream); err != nil {
                return err
        }

        // Write the HTLCs.
        return serializeHTLCEntries(w, rl.HTLCEntries)
}

// serializeHTLCEntries serializes a list of HTLCEntry records based on tlv
// format.
func serializeHTLCEntries(w io.Writer, htlcs []*HTLCEntry) error {
        for _, htlc := range htlcs {
                // Patch the incomingTlv field.
                if htlc.Incoming {
                        htlc.incomingTlv = 1
                }

                // Patch the amtTlv field.
                htlc.amtTlv = uint64(htlc.Amt)

                // Create the tlv stream.
                tlvStream, err := htlc.toTlvStream()
                if err != nil {
                        return err
                }

                // Write the tlv stream.
                if err := writeTlvStream(w, tlvStream); err != nil {
                        return err
                }
        }

        return nil
}

// deserializeRevocationLog deserializes a RevocationLog based on tlv format.
func deserializeRevocationLog(r io.Reader) (RevocationLog, error) {
        var (
                rl            RevocationLog
                localBalance  uint64
                remoteBalance uint64
        )

        // Create the tlv stream.
        tlvStream, err := tlv.NewStream(
                tlv.MakePrimitiveRecord(
                        revLogOurOutputIndexType, &rl.OurOutputIndex,
                ),
                tlv.MakePrimitiveRecord(
                        revLogTheirOutputIndexType, &rl.TheirOutputIndex,
                ),
                tlv.MakePrimitiveRecord(
                        revLogCommitTxHashType, &rl.CommitTxHash,
                ),
                tlv.MakeBigSizeRecord(revLogOurBalanceType, &localBalance),
                tlv.MakeBigSizeRecord(
                        revLogTheirBalanceType, &remoteBalance,
                ),
        )
        if err != nil {
                return rl, err
        }

        // Read the tlv stream.
        parsedTypes, err := readTlvStream(r, tlvStream)
        if err != nil {
                return rl, err
        }

        if t, ok := parsedTypes[revLogOurBalanceType]; ok && t == nil {
                lb := lnwire.MilliSatoshi(localBalance)
                rl.OurBalance = &lb
        }

        if t, ok := parsedTypes[revLogTheirBalanceType]; ok && t == nil {
                rb := lnwire.MilliSatoshi(remoteBalance)
                rl.TheirBalance = &rb
        }

        // Read the HTLC entries.
        rl.HTLCEntries, err = deserializeHTLCEntries(r)

        return rl, err
}

// deserializeHTLCEntries deserializes a list of HTLC entries based on tlv
// format.
func deserializeHTLCEntries(r io.Reader) ([]*HTLCEntry, error) {
        var htlcs []*HTLCEntry

        for {
                var htlc HTLCEntry

                // Create the tlv stream.
                tlvStream, err := htlc.toTlvStream()
                if err != nil {
                        return nil, err
                }

                // Read the HTLC entry.
                if _, err := readTlvStream(r, tlvStream); err != nil {
                        // We've reached the end when hitting an EOF.
                        if err == io.ErrUnexpectedEOF {
                                break
                        }
                        return nil, err
                }

                // Patch the Incoming field.
                if htlc.incomingTlv == 1 {
                        htlc.Incoming = true
                }

                // Patch the Amt field.
                htlc.Amt = btcutil.Amount(htlc.amtTlv)

                // Append the entry.
                htlcs = append(htlcs, &htlc)
        }

        return htlcs, nil
}

// writeTlvStream is a helper function that encodes the tlv stream into the
// writer.
func writeTlvStream(w io.Writer, s *tlv.Stream) error {
        var b bytes.Buffer
        if err := s.Encode(&b); err != nil {
                return err
        }
        // Write the stream's length as a varint.
        err := tlv.WriteVarInt(w, uint64(b.Len()), &[8]byte{})
        if err != nil {
                return err
        }

        if _, err = w.Write(b.Bytes()); err != nil {
                return err
        }

        return nil
}

// readTlvStream is a helper function that decodes the tlv stream from the
// reader.
func readTlvStream(r io.Reader, s *tlv.Stream) (tlv.TypeMap, error) {
        var bodyLen uint64

        // Read the stream's length.
        bodyLen, err := tlv.ReadVarInt(r, &[8]byte{})
        switch {
        // We'll convert any EOFs to ErrUnexpectedEOF, since this results in an
        // invalid record.
        case err == io.EOF:
                return nil, io.ErrUnexpectedEOF

        // Other unexpected errors.
        case err != nil:
                return nil, err
        }

        // TODO(yy): add overflow check.
        lr := io.LimitReader(r, int64(bodyLen))

        return s.DecodeWithParsedTypes(lr)
}

// fetchLogBucket returns a read bucket by visiting both the new and the old
// bucket.
func fetchLogBucket(chanBucket kvdb.RBucket) (kvdb.RBucket, error) {
        logBucket := chanBucket.NestedReadBucket(revocationLogBucket)
        if logBucket == nil {
                logBucket = chanBucket.NestedReadBucket(
                        revocationLogBucketDeprecated,
                )
                if logBucket == nil {
                        return nil, mig25.ErrNoPastDeltas
                }
        }

        return logBucket, nil
}

// putOldRevocationLog saves a revocation log using the old format.
func putOldRevocationLog(log kvdb.RwBucket,
        commit *mig.ChannelCommitment) error {

        var b bytes.Buffer
        if err := mig.SerializeChanCommit(&b, commit); err != nil {
                return err
        }

        logEntrykey := mig24.MakeLogKey(commit.CommitHeight)
        return log.Put(logEntrykey[:], b.Bytes())
}

func putChanRevocationState(chanBucket kvdb.RwBucket,
        channel *mig26.OpenChannel) error {

        var b bytes.Buffer
        err := mig.WriteElements(
                &b, channel.RemoteCurrentRevocation, channel.RevocationProducer,
                channel.RevocationStore,
        )
        if err != nil {
                return err
        }

        // TODO(roasbeef): don't keep producer on disk

        // If the next revocation is present, which is only the case after the
        // FundingLocked message has been sent, then we'll write it to disk.
        if channel.RemoteNextRevocation != nil {
                err = mig.WriteElements(&b, channel.RemoteNextRevocation)
                if err != nil {
                        return err
                }
        }

        return chanBucket.Put(revocationStateKey, b.Bytes())
}

func fetchChanRevocationState(chanBucket kvdb.RBucket,
        c *mig26.OpenChannel) error {

        revBytes := chanBucket.Get(revocationStateKey)
        if revBytes == nil {
                return ErrNoRevocationsFound
        }
        r := bytes.NewReader(revBytes)

        err := mig.ReadElements(
                r, &c.RemoteCurrentRevocation, &c.RevocationProducer,
                &c.RevocationStore,
        )
        if err != nil {
                return err
        }

        // If there aren't any bytes left in the buffer, then we don't yet have
        // the next remote revocation, so we can exit early here.
        if r.Len() == 0 {
                return nil
        }

        // Otherwise we'll read the next revocation for the remote party which
        // is always the last item within the buffer.
        return mig.ReadElements(r, &c.RemoteNextRevocation)
}

func findOutputIndexes(chanState *mig26.OpenChannel,
        oldLog *mig.ChannelCommitment) (uint32, uint32, error) {

        // With the state number broadcast known, we can now derive/restore the
        // proper revocation preimage necessary to sweep the remote party's
        // output.
        revocationPreimage, err := chanState.RevocationStore.LookUp(
                oldLog.CommitHeight,
        )
        if err != nil {
                return 0, 0, err
        }

        return findOutputIndexesFromRemote(
                revocationPreimage, chanState, oldLog,
        )
}

lightningnetwork / lnd / 14880107727

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