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channeldb: additionally store static channel information in CloseChannelSummary

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In this commit, we extend the CloseChannelSummary by also storing: the
current unrevoked revocation for the remote party, the next pending
unused revocation, and also the local channel config. We move to store
these as the provide an extra level of defense against bugs as we'll
always store information required to derive keys for any current and
prior states.
This commit is contained in:
Olaoluwa Osuntokun 2018-04-29 15:26:37 -07:00
parent d50247304b
commit 1ec5dc3c2d
No known key found for this signature in database
GPG Key ID: 964EA263DD637C21
1 changed files with 115 additions and 24 deletions
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139
channeldb/channel.go
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@ -1578,9 +1578,9 @@ const (
)
// ChannelCloseSummary contains the final state of a channel at the point it
// was closed. Once a channel is closed, all the information pertaining to
// that channel within the openChannelBucket is deleted, and a compact
// summary is put in place instead.
// was closed. Once a channel is closed, all the information pertaining to that
// channel within the openChannelBucket is deleted, and a compact summary is
// put in place instead.
type ChannelCloseSummary struct {
// ChanPoint is the outpoint for this channel's funding transaction,
// and is used as a unique identifier for the channel.
@ -1606,7 +1606,8 @@ type ChannelCloseSummary struct {
// Capacity was the total capacity of the channel.
Capacity btcutil.Amount
// CloseHeight is the height at which the funding transaction was spent.
// CloseHeight is the height at which the funding transaction was
// spent.
CloseHeight uint32
// SettledBalance is our total balance settled balance at the time of
@ -1636,6 +1637,21 @@ type ChannelCloseSummary struct {
// closed, they'll stay marked as "pending" until _all_ the pending
// funds have been swept.
IsPending bool
// RemoteCurrentRevocation is the current revocation for their
// commitment transaction. However, since this the derived public key,
// we don't yet have the private key so we aren't yet able to verify
// that it's actually in the hash chain.
RemoteCurrentRevocation *btcec.PublicKey
// RemoteNextRevocation is the revocation key to be used for the *next*
// commitment transaction we create for the local node. Within the
// specification, this value is referred to as the
// per-commitment-point.
RemoteNextRevocation *btcec.PublicKey
// LocalChanCfg is the channel configuration for the local node.
LocalChanConfig ChannelConfig
}
// CloseChannel closes a previously active Lightning channel. Closing a channel
@ -1675,6 +1691,16 @@ func (c *OpenChannel) CloseChannel(summary *ChannelCloseSummary) error {
return ErrNoActiveChannels
}
// Before we delete the channel state, we'll read out the full
// details, as we'll also store portions of this information
// for record keeping.
chanState, err := fetchOpenChannel(
chanBucket, &c.FundingOutpoint,
)
if err != nil {
return err
}
// Now that the index to this channel has been deleted, purge
// the remaining channel metadata from the database.
err = deleteOpenChannel(chanBucket, chanPointBuf.Bytes())
@ -1703,7 +1729,9 @@ func (c *OpenChannel) CloseChannel(summary *ChannelCloseSummary) error {
// Finally, create a summary of this channel in the closed
// channel bucket for this node.
return putChannelCloseSummary(tx, chanPointBuf.Bytes(), summary)
return putChannelCloseSummary(
tx, chanPointBuf.Bytes(), summary, chanState,
)
})
}
@ -1818,13 +1846,17 @@ func (c *OpenChannel) RemoteRevocationStore() (shachain.Store, error) {
}
func putChannelCloseSummary(tx *bolt.Tx, chanID []byte,
summary *ChannelCloseSummary) error {
summary *ChannelCloseSummary, lastChanState *OpenChannel) error {
closedChanBucket, err := tx.CreateBucketIfNotExists(closedChannelBucket)
if err != nil {
return err
}
summary.RemoteCurrentRevocation = lastChanState.RemoteCurrentRevocation
summary.RemoteNextRevocation = lastChanState.RemoteNextRevocation
summary.LocalChanConfig = lastChanState.LocalChanCfg
var b bytes.Buffer
if err := serializeChannelCloseSummary(&b, summary); err != nil {
return err
@ -1834,11 +1866,37 @@ func putChannelCloseSummary(tx *bolt.Tx, chanID []byte,
}
func serializeChannelCloseSummary(w io.Writer, cs *ChannelCloseSummary) error {
return writeElements(w,
err := writeElements(w,
cs.ChanPoint, cs.ShortChanID, cs.ChainHash, cs.ClosingTXID,
cs.CloseHeight, cs.RemotePub, cs.Capacity, cs.SettledBalance,
cs.TimeLockedBalance, cs.CloseType, cs.IsPending,
)
if err != nil {
return err
}
// If this is a close channel summary created before the addition of
// the new fields, then we can exit here.
if cs.RemoteCurrentRevocation == nil {
return nil
}
if err := writeElements(w, cs.RemoteCurrentRevocation); err != nil {
return err
}
if err := writeChanConfig(w, &cs.LocalChanConfig); err != nil {
return err
}
// We'll write this field last, as it's possible for a channel to be
// closed before we learn of the next unrevoked revocation point for
// the remote party.
if cs.RemoteNextRevocation == nil {
return nil
}
return writeElements(w, cs.RemoteNextRevocation)
}
func fetchChannelCloseSummary(tx *bolt.Tx,
@ -1870,9 +1928,49 @@ func deserializeCloseChannelSummary(r io.Reader) (*ChannelCloseSummary, error) {
return nil, err
}
// We'll now check to see if the channel close summary was encoded with
// any of the additional optional fields.
err = readElements(r, &c.RemoteCurrentRevocation)
switch {
case err == io.EOF:
return c, nil
// If we got a non-eof error, then we know there's an actually issue.
// Otherwise, it may have been the case that this summary didn't have
// the set of optional fields.
case err != nil:
return nil, err
}
if err := readChanConfig(r, &c.LocalChanConfig); err != nil {
return nil, err
}
// Finally, we'll attempt to read the next unrevoked commitment point
// for the remote party. If we closed the channel before receiving a
// funding locked message, then this can be nil. As a result, we'll use
// the same technique to read the field, only if there's still data
// left in the buffer.
err = readElements(r, &c.RemoteNextRevocation)
if err != nil && err != io.EOF {
// If we got a non-eof error, then we know there's an actually
// issue. Otherwise, it may have been the case that this
// summary didn't have the set of optional fields.
return nil, err
}
return c, nil
}
func writeChanConfig(b io.Writer, c *ChannelConfig) error {
return writeElements(b,
c.DustLimit, c.MaxPendingAmount, c.ChanReserve, c.MinHTLC,
c.MaxAcceptedHtlcs, c.CsvDelay, c.MultiSigKey,
c.RevocationBasePoint, c.PaymentBasePoint, c.DelayBasePoint,
c.HtlcBasePoint,
)
}
func putChanInfo(chanBucket *bolt.Bucket, channel *OpenChannel) error {
var w bytes.Buffer
if err := writeElements(&w,
@ -1893,14 +1991,6 @@ func putChanInfo(chanBucket *bolt.Bucket, channel *OpenChannel) error {
}
}
writeChanConfig := func(b io.Writer, c *ChannelConfig) error {
return writeElements(b,
c.DustLimit, c.MaxPendingAmount, c.ChanReserve, c.MinHTLC,
c.MaxAcceptedHtlcs, c.CsvDelay, c.MultiSigKey,
c.RevocationBasePoint, c.PaymentBasePoint, c.DelayBasePoint,
c.HtlcBasePoint,
)
}
if err := writeChanConfig(&w, &channel.LocalChanCfg); err != nil {
return err
}
@ -1976,6 +2066,16 @@ func putChanRevocationState(chanBucket *bolt.Bucket, channel *OpenChannel) error
return chanBucket.Put(revocationStateKey, b.Bytes())
}
func readChanConfig(b io.Reader, c *ChannelConfig) error {
return readElements(b,
&c.DustLimit, &c.MaxPendingAmount, &c.ChanReserve,
&c.MinHTLC, &c.MaxAcceptedHtlcs, &c.CsvDelay,
&c.MultiSigKey, &c.RevocationBasePoint,
&c.PaymentBasePoint, &c.DelayBasePoint,
&c.HtlcBasePoint,
)
}
func fetchChanInfo(chanBucket *bolt.Bucket, channel *OpenChannel) error {
infoBytes := chanBucket.Get(chanInfoKey)
if infoBytes == nil {
@ -2001,15 +2101,6 @@ func fetchChanInfo(chanBucket *bolt.Bucket, channel *OpenChannel) error {
}
}
readChanConfig := func(b io.Reader, c *ChannelConfig) error {
return readElements(b,
&c.DustLimit, &c.MaxPendingAmount, &c.ChanReserve,
&c.MinHTLC, &c.MaxAcceptedHtlcs, &c.CsvDelay,
&c.MultiSigKey, &c.RevocationBasePoint,
&c.PaymentBasePoint, &c.DelayBasePoint,
&c.HtlcBasePoint,
)
}
if err := readChanConfig(r, &channel.LocalChanCfg); err != nil {
return err
}