package channeldb
import (
"bytes"
"crypto/sha256"
"encoding/binary"
"errors"
"fmt"
"io"
"net"
"strconv"
"strings"
"sync"
"github.com/btcsuite/btcd/btcec"
"github.com/btcsuite/btcd/chaincfg/chainhash"
"github.com/btcsuite/btcd/wire"
"github.com/btcsuite/btcutil"
"github.com/lightningnetwork/lnd/channeldb/kvdb"
"github.com/lightningnetwork/lnd/input"
"github.com/lightningnetwork/lnd/keychain"
"github.com/lightningnetwork/lnd/lnwire"
"github.com/lightningnetwork/lnd/shachain"
"github.com/lightningnetwork/lnd/tlv"
)
const (
// AbsoluteThawHeightThreshold is the threshold at which a thaw height
// begins to be interpreted as an absolute block height, rather than a
// relative one.
AbsoluteThawHeightThreshold uint32 = 500000
)
var (
// closedChannelBucket stores summarization information concerning
// previously open, but now closed channels.
closedChannelBucket = []byte("closed-chan-bucket")
// openChanBucket stores all the currently open channels. This bucket
// has a second, nested bucket which is keyed by a node's ID. Within
// that node ID bucket, all attributes required to track, update, and
// close a channel are stored.
//
// openChan -> nodeID -> chanPoint
//
// TODO(roasbeef): flesh out comment
openChannelBucket = []byte("open-chan-bucket")
// outpointBucket stores all of our channel outpoints and a tlv
// stream containing channel data.
//
// outpoint -> tlv stream
//
outpointBucket = []byte("outpoint-bucket")
// historicalChannelBucket stores all channels that have seen their
// commitment tx confirm. All information from their previous open state
// is retained.
historicalChannelBucket = []byte("historical-chan-bucket")
// chanInfoKey can be accessed within the bucket for a channel
// (identified by its chanPoint). This key stores all the static
// information for a channel which is decided at the end of the
// funding flow.
chanInfoKey = []byte("chan-info-key")
// localUpfrontShutdownKey can be accessed within the bucket for a channel
// (identified by its chanPoint). This key stores an optional upfront
// shutdown script for the local peer.
localUpfrontShutdownKey = []byte("local-upfront-shutdown-key")
// remoteUpfrontShutdownKey can be accessed within the bucket for a channel
// (identified by its chanPoint). This key stores an optional upfront
// shutdown script for the remote peer.
remoteUpfrontShutdownKey = []byte("remote-upfront-shutdown-key")
// chanCommitmentKey can be accessed within the sub-bucket for a
// particular channel. This key stores the up to date commitment state
// for a particular channel party. Appending a 0 to the end of this key
// indicates it's the commitment for the local party, and appending a 1
// to the end of this key indicates it's the commitment for the remote
// party.
chanCommitmentKey = []byte("chan-commitment-key")
// unsignedAckedUpdatesKey is an entry in the channel bucket that
// contains the remote updates that we have acked, but not yet signed
// for in one of our remote commits.
unsignedAckedUpdatesKey = []byte("unsigned-acked-updates-key")
// remoteUnsignedLocalUpdatesKey is an entry in the channel bucket that
// contains the local updates that the remote party has acked, but
// has not yet signed for in one of their local commits.
remoteUnsignedLocalUpdatesKey = []byte("remote-unsigned-local-updates-key")
// revocationStateKey stores their current revocation hash, our
// preimage producer and their preimage store.
revocationStateKey = []byte("revocation-state-key")
// dataLossCommitPointKey stores the commitment point received from the
// remote peer during a channel sync in case we have lost channel state.
dataLossCommitPointKey = []byte("data-loss-commit-point-key")
// forceCloseTxKey points to a the unilateral closing tx that we
// broadcasted when moving the channel to state CommitBroadcasted.
forceCloseTxKey = []byte("closing-tx-key")
// coopCloseTxKey points to a the cooperative closing tx that we
// broadcasted when moving the channel to state CoopBroadcasted.
coopCloseTxKey = []byte("coop-closing-tx-key")
// commitDiffKey stores the current pending commitment state we've
// extended to the remote party (if any). Each time we propose a new
// state, we store the information necessary to reconstruct this state
// from the prior commitment. This allows us to resync the remote party
// to their expected state in the case of message loss.
//
// TODO(roasbeef): rename to commit chain?
commitDiffKey = []byte("commit-diff-key")
// revocationLogBucket 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.
revocationLogBucket = []byte("revocation-log-key")
// frozenChanKey is the key where we store the information for any
// active "frozen" channels. This key is present only in the leaf
// bucket for a given channel.
frozenChanKey = []byte("frozen-chans")
)
var (
// ErrNoCommitmentsFound is returned when a channel has not set
// commitment states.
ErrNoCommitmentsFound = fmt.Errorf("no commitments found")
// ErrNoChanInfoFound is returned when a particular channel does not
// have any channels state.
ErrNoChanInfoFound = fmt.Errorf("no chan info found")
// ErrNoRevocationsFound is returned when revocation state for a
// particular channel cannot be found.
ErrNoRevocationsFound = fmt.Errorf("no revocations found")
// ErrNoPendingCommit is returned when there is not a pending
// commitment for a remote party. A new commitment is written to disk
// each time we write a new state in order to be properly fault
// tolerant.
ErrNoPendingCommit = fmt.Errorf("no pending commits found")
// ErrInvalidCircuitKeyLen signals that a circuit key could not be
// decoded because the byte slice is of an invalid length.
ErrInvalidCircuitKeyLen = fmt.Errorf(
"length of serialized circuit key must be 16 bytes")
// ErrNoCommitPoint is returned when no data loss commit point is found
// in the database.
ErrNoCommitPoint = fmt.Errorf("no commit point found")
// ErrNoCloseTx is returned when no closing tx is found for a channel
// in the state CommitBroadcasted.
ErrNoCloseTx = fmt.Errorf("no closing tx found")
// ErrNoRestoredChannelMutation is returned when a caller attempts to
// mutate a channel that's been recovered.
ErrNoRestoredChannelMutation = fmt.Errorf("cannot mutate restored " +
"channel state")
// ErrChanBorked is returned when a caller attempts to mutate a borked
// channel.
ErrChanBorked = fmt.Errorf("cannot mutate borked channel")
// ErrLogEntryNotFound is returned when we cannot find a log entry at
// the height requested in the revocation log.
ErrLogEntryNotFound = fmt.Errorf("log entry not found")
// ErrMissingIndexEntry is returned when a caller attempts to close a
// channel and the outpoint is missing from the index.
ErrMissingIndexEntry = fmt.Errorf("missing outpoint from index")
// errHeightNotFound is returned when a query for channel balances at
// a height that we have not reached yet is made.
errHeightNotReached = fmt.Errorf("height requested greater than " +
"current commit height")
)
const (
// A tlv type definition used to serialize an outpoint's indexStatus
// for use in the outpoint index.
indexStatusType tlv.Type = 0
)
// indexStatus is an enum-like type that describes what state the
// outpoint is in. Currently only two possible values.
type indexStatus uint8
const (
// outpointOpen represents an outpoint that is open in the outpoint index.
outpointOpen indexStatus = 0
// outpointClosed represents an outpoint that is closed in the outpoint
// index.
outpointClosed indexStatus = 1
)
// ChannelType is an enum-like type that describes one of several possible
// channel types. Each open channel is associated with a particular type as the
// channel type may determine how higher level operations are conducted such as
// fee negotiation, channel closing, the format of HTLCs, etc. Structure-wise,
// a ChannelType is a bit field, with each bit denoting a modification from the
// base channel type of single funder.
type ChannelType uint8
const (
// NOTE: iota isn't used here for this enum needs to be stable
// long-term as it will be persisted to the database.
// SingleFunderBit represents a channel wherein one party solely funds
// the entire capacity of the channel.
SingleFunderBit ChannelType = 0
// DualFunderBit represents a channel wherein both parties contribute
// funds towards the total capacity of the channel. The channel may be
// funded symmetrically or asymmetrically.
DualFunderBit ChannelType = 1 << 0
// SingleFunderTweakless is similar to the basic SingleFunder channel
// type, but it omits the tweak for one's key in the commitment
// transaction of the remote party.
SingleFunderTweaklessBit ChannelType = 1 << 1
// NoFundingTxBit denotes if we have the funding transaction locally on
// disk. This bit may be on if the funding transaction was crafted by a
// wallet external to the primary daemon.
NoFundingTxBit ChannelType = 1 << 2
// AnchorOutputsBit indicates that the channel makes use of anchor
// outputs to bump the commitment transaction's effective feerate. This
// channel type also uses a delayed to_remote output script.
AnchorOutputsBit ChannelType = 1 << 3
// FrozenBit indicates that the channel is a frozen channel, meaning
// that only the responder can decide to cooperatively close the
// channel.
FrozenBit ChannelType = 1 << 4
// ZeroHtlcTxFeeBit indicates that the channel should use zero-fee
// second-level HTLC transactions.
ZeroHtlcTxFeeBit ChannelType = 1 << 5
)
// IsSingleFunder returns true if the channel type if one of the known single
// funder variants.
func (c ChannelType) IsSingleFunder() bool {
return c&DualFunderBit == 0
}
// IsDualFunder returns true if the ChannelType has the DualFunderBit set.
func (c ChannelType) IsDualFunder() bool {
return c&DualFunderBit == DualFunderBit
}
// IsTweakless returns true if the target channel uses a commitment that
// doesn't tweak the key for the remote party.
func (c ChannelType) IsTweakless() bool {
return c&SingleFunderTweaklessBit == SingleFunderTweaklessBit
}
// HasFundingTx returns true if this channel type is one that has a funding
// transaction stored locally.
func (c ChannelType) HasFundingTx() bool {
return c&NoFundingTxBit == 0
}
// HasAnchors returns true if this channel type has anchor ouputs on its
// commitment.
func (c ChannelType) HasAnchors() bool {
return c&AnchorOutputsBit == AnchorOutputsBit
}
// ZeroHtlcTxFee returns true if this channel type uses second-level HTLC
// transactions signed with zero-fee.
func (c ChannelType) ZeroHtlcTxFee() bool {
return c&ZeroHtlcTxFeeBit == ZeroHtlcTxFeeBit
}
// IsFrozen returns true if the channel is considered to be "frozen". A frozen
// channel means that only the responder can initiate a cooperative channel
// closure.
func (c ChannelType) IsFrozen() bool {
return c&FrozenBit == FrozenBit
}
// ChannelConstraints represents a set of constraints meant to allow a node to
// limit their exposure, enact flow control and ensure that all HTLCs are
// economically relevant. This struct will be mirrored for both sides of the
// channel, as each side will enforce various constraints that MUST be adhered
// to for the life time of the channel. The parameters for each of these
// constraints are static for the duration of the channel, meaning the channel
// must be torn down for them to change.
type ChannelConstraints struct {
// DustLimit is the threshold (in satoshis) below which any outputs
// should be trimmed. When an output is trimmed, it isn't materialized
// as an actual output, but is instead burned to miner's fees.
DustLimit btcutil.Amount
// ChanReserve is an absolute reservation on the channel for the
// owner of this set of constraints. This means that the current
// settled balance for this node CANNOT dip below the reservation
// amount. This acts as a defense against costless attacks when
// either side no longer has any skin in the game.
ChanReserve btcutil.Amount
// MaxPendingAmount is the maximum pending HTLC value that the
// owner of these constraints can offer the remote node at a
// particular time.
MaxPendingAmount lnwire.MilliSatoshi
// MinHTLC is the minimum HTLC value that the owner of these
// constraints can offer the remote node. If any HTLCs below this
// amount are offered, then the HTLC will be rejected. This, in
// tandem with the dust limit allows a node to regulate the
// smallest HTLC that it deems economically relevant.
MinHTLC lnwire.MilliSatoshi
// MaxAcceptedHtlcs is the maximum number of HTLCs that the owner of
// this set of constraints can offer the remote node. This allows each
// node to limit their over all exposure to HTLCs that may need to be
// acted upon in the case of a unilateral channel closure or a contract
// breach.
MaxAcceptedHtlcs uint16
// CsvDelay is the relative time lock delay expressed in blocks. Any
// settled outputs that pay to the owner of this channel configuration
// MUST ensure that the delay branch uses this value as the relative
// time lock. Similarly, any HTLC's offered by this node should use
// this value as well.
CsvDelay uint16
}
// ChannelConfig is a struct that houses the various configuration opens for
// channels. Each side maintains an instance of this configuration file as it
// governs: how the funding and commitment transaction to be created, the
// nature of HTLC's allotted, the keys to be used for delivery, and relative
// time lock parameters.
type ChannelConfig struct {
// ChannelConstraints is the set of constraints that must be upheld for
// the duration of the channel for the owner of this channel
// configuration. Constraints govern a number of flow control related
// parameters, also including the smallest HTLC that will be accepted
// by a participant.
ChannelConstraints
// MultiSigKey is the key to be used within the 2-of-2 output script
// for the owner of this channel config.
MultiSigKey keychain.KeyDescriptor
// RevocationBasePoint is the base public key to be used when deriving
// revocation keys for the remote node's commitment transaction. This
// will be combined along with a per commitment secret to derive a
// unique revocation key for each state.
RevocationBasePoint keychain.KeyDescriptor
// PaymentBasePoint is the base public key to be used when deriving
// the key used within the non-delayed pay-to-self output on the
// commitment transaction for a node. This will be combined with a
// tweak derived from the per-commitment point to ensure unique keys
// for each commitment transaction.
PaymentBasePoint keychain.KeyDescriptor
// DelayBasePoint is the base public key to be used when deriving the
// key used within the delayed pay-to-self output on the commitment
// transaction for a node. This will be combined with a tweak derived
// from the per-commitment point to ensure unique keys for each
// commitment transaction.
DelayBasePoint keychain.KeyDescriptor
// HtlcBasePoint is the base public key to be used when deriving the
// local HTLC key. The derived key (combined with the tweak derived
// from the per-commitment point) is used within the "to self" clause
// within any HTLC output scripts.
HtlcBasePoint keychain.KeyDescriptor
}
// ChannelCommitment is a snapshot of the commitment state at a particular
// point in the commitment chain. With each state transition, a snapshot of the
// current state along with all non-settled HTLCs are recorded. These snapshots
// detail the state of the _remote_ party's commitment at a particular state
// number. For ourselves (the local node) we ONLY store our most recent
// (unrevoked) state for safety purposes.
type ChannelCommitment struct {
// CommitHeight is the update number that this ChannelDelta represents
// the total number of commitment updates to this point. This can be
// viewed as sort of a "commitment height" as this number is
// monotonically increasing.
CommitHeight uint64
// LocalLogIndex is the cumulative log index index of the local node at
// this point in the commitment chain. This value will be incremented
// for each _update_ added to the local update log.
LocalLogIndex uint64
// LocalHtlcIndex is the current local running HTLC index. This value
// will be incremented for each outgoing HTLC the local node offers.
LocalHtlcIndex uint64
// RemoteLogIndex is the cumulative log index index of the remote node
// at this point in the commitment chain. This value will be
// incremented for each _update_ added to the remote update log.
RemoteLogIndex uint64
// RemoteHtlcIndex is the current remote running HTLC index. This value
// will be incremented for each outgoing HTLC the remote node offers.
RemoteHtlcIndex uint64
// LocalBalance is the current available settled balance within the
// channel directly spendable by us.
//
// NOTE: This is the balance *after* subtracting any commitment fee,
// AND anchor output values.
LocalBalance lnwire.MilliSatoshi
// RemoteBalance is the current available settled balance within the
// channel directly spendable by the remote node.
//
// NOTE: This is the balance *after* subtracting any commitment fee,
// AND anchor output values.
RemoteBalance lnwire.MilliSatoshi
// CommitFee is the amount calculated to be paid in fees for the
// current set of commitment transactions. The fee amount is persisted
// with the channel in order to allow the fee amount to be removed and
// recalculated with each channel state update, including updates that
// happen after a system restart.
CommitFee btcutil.Amount
// FeePerKw is the min satoshis/kilo-weight that should be paid within
// the commitment transaction for the entire duration of the channel's
// lifetime. This field may be updated during normal operation of the
// channel as on-chain conditions change.
//
// TODO(halseth): make this SatPerKWeight. Cannot be done atm because
// this will cause the import cycle lnwallet<->channeldb. Fee
// estimation stuff should be in its own package.
FeePerKw btcutil.Amount
// CommitTx is the latest version of the commitment state, broadcast
// able by us.
CommitTx *wire.MsgTx
// CommitSig is one half of the signature required to fully complete
// the script for the commitment transaction above. This is the
// signature signed by the remote party for our version of the
// commitment transactions.
CommitSig []byte
// Htlcs is the set of HTLC's that are pending at this particular
// commitment height.
Htlcs []HTLC
// TODO(roasbeef): pending commit pointer?
// * lets just walk through
}
// ChannelStatus is a bit vector used to indicate whether an OpenChannel is in
// the default usable state, or a state where it shouldn't be used.
type ChannelStatus uint8
var (
// ChanStatusDefault is the normal state of an open channel.
ChanStatusDefault ChannelStatus
// ChanStatusBorked indicates that the channel has entered an
// irreconcilable state, triggered by a state desynchronization or
// channel breach. Channels in this state should never be added to the
// htlc switch.
ChanStatusBorked ChannelStatus = 1
// ChanStatusCommitBroadcasted indicates that a commitment for this
// channel has been broadcasted.
ChanStatusCommitBroadcasted ChannelStatus = 1 << 1
// ChanStatusLocalDataLoss indicates that we have lost channel state
// for this channel, and broadcasting our latest commitment might be
// considered a breach.
//
// TODO(halseh): actually enforce that we are not force closing such a
// channel.
ChanStatusLocalDataLoss ChannelStatus = 1 << 2
// ChanStatusRestored is a status flag that signals that the channel
// has been restored, and doesn't have all the fields a typical channel
// will have.
ChanStatusRestored ChannelStatus = 1 << 3
// ChanStatusCoopBroadcasted indicates that a cooperative close for
// this channel has been broadcasted. Older cooperatively closed
// channels will only have this status set. Newer ones will also have
// close initiator information stored using the local/remote initiator
// status. This status is set in conjunction with the initiator status
// so that we do not need to check multiple channel statues for
// cooperative closes.
ChanStatusCoopBroadcasted ChannelStatus = 1 << 4
// ChanStatusLocalCloseInitiator indicates that we initiated closing
// the channel.
ChanStatusLocalCloseInitiator ChannelStatus = 1 << 5
// ChanStatusRemoteCloseInitiator indicates that the remote node
// initiated closing the channel.
ChanStatusRemoteCloseInitiator ChannelStatus = 1 << 6
)
// chanStatusStrings maps a ChannelStatus to a human friendly string that
// describes that status.
var chanStatusStrings = map[ChannelStatus]string{
ChanStatusDefault: "ChanStatusDefault",
ChanStatusBorked: "ChanStatusBorked",
ChanStatusCommitBroadcasted: "ChanStatusCommitBroadcasted",
ChanStatusLocalDataLoss: "ChanStatusLocalDataLoss",
ChanStatusRestored: "ChanStatusRestored",
ChanStatusCoopBroadcasted: "ChanStatusCoopBroadcasted",
ChanStatusLocalCloseInitiator: "ChanStatusLocalCloseInitiator",
ChanStatusRemoteCloseInitiator: "ChanStatusRemoteCloseInitiator",
}
// orderedChanStatusFlags is an in-order list of all that channel status flags.
var orderedChanStatusFlags = []ChannelStatus{
ChanStatusBorked,
ChanStatusCommitBroadcasted,
ChanStatusLocalDataLoss,
ChanStatusRestored,
ChanStatusCoopBroadcasted,
ChanStatusLocalCloseInitiator,
ChanStatusRemoteCloseInitiator,
}
// String returns a human-readable representation of the ChannelStatus.
func (c ChannelStatus) String() string {
// If no flags are set, then this is the default case.
if c == ChanStatusDefault {
return chanStatusStrings[ChanStatusDefault]
}
// Add individual bit flags.
statusStr := ""
for _, flag := range orderedChanStatusFlags {
if c&flag == flag {
statusStr += chanStatusStrings[flag] + "|"
c -= flag
}
}
// Remove anything to the right of the final bar, including it as well.
statusStr = strings.TrimRight(statusStr, "|")
// Add any remaining flags which aren't accounted for as hex.
if c != 0 {
statusStr += "|0x" + strconv.FormatUint(uint64(c), 16)
}
// If this was purely an unknown flag, then remove the extra bar at the
// start of the string.
statusStr = strings.TrimLeft(statusStr, "|")
return statusStr
}
// OpenChannel encapsulates the persistent and dynamic state of an open channel
// with a remote node. An open channel supports several options for on-disk
// serialization depending on the exact context. Full (upon channel creation)
// state commitments, and partial (due to a commitment update) writes are
// supported. Each partial write due to a state update appends the new update
// to an on-disk log, which can then subsequently be queried in order to
// "time-travel" to a prior state.
type OpenChannel struct {
// ChanType denotes which type of channel this is.
ChanType ChannelType
// ChainHash is a hash which represents the blockchain that this
// channel will be opened within. This value is typically the genesis
// hash. In the case that the original chain went through a contentious
// hard-fork, then this value will be tweaked using the unique fork
// point on each branch.
ChainHash chainhash.Hash
// FundingOutpoint is the outpoint of the final funding transaction.
// This value uniquely and globally identifies the channel within the
// target blockchain as specified by the chain hash parameter.
FundingOutpoint wire.OutPoint
// ShortChannelID encodes the exact location in the chain in which the
// channel was initially confirmed. This includes: the block height,
// transaction index, and the output within the target transaction.
ShortChannelID lnwire.ShortChannelID
// IsPending indicates whether a channel's funding transaction has been
// confirmed.
IsPending bool
// IsInitiator is a bool which indicates if we were the original
// initiator for the channel. This value may affect how higher levels
// negotiate fees, or close the channel.
IsInitiator bool
// chanStatus is the current status of this channel. If it is not in
// the state Default, it should not be used for forwarding payments.
chanStatus ChannelStatus
// FundingBroadcastHeight is the height in which the funding
// transaction was broadcast. This value can be used by higher level
// sub-systems to determine if a channel is stale and/or should have
// been confirmed before a certain height.
FundingBroadcastHeight uint32
// NumConfsRequired is the number of confirmations a channel's funding
// transaction must have received in order to be considered available
// for normal transactional use.
NumConfsRequired uint16
// ChannelFlags holds the flags that were sent as part of the
// open_channel message.
ChannelFlags lnwire.FundingFlag
// IdentityPub is the identity public key of the remote node this
// channel has been established with.
IdentityPub *btcec.PublicKey
// Capacity is the total capacity of this channel.
Capacity btcutil.Amount
// TotalMSatSent is the total number of milli-satoshis we've sent
// within this channel.
TotalMSatSent lnwire.MilliSatoshi
// TotalMSatReceived is the total number of milli-satoshis we've
// received within this channel.
TotalMSatReceived lnwire.MilliSatoshi
// LocalChanCfg is the channel configuration for the local node.
LocalChanCfg ChannelConfig
// RemoteChanCfg is the channel configuration for the remote node.
RemoteChanCfg ChannelConfig
// LocalCommitment is the current local commitment state for the local
// party. This is stored distinct from the state of the remote party
// as there are certain asymmetric parameters which affect the
// structure of each commitment.
LocalCommitment ChannelCommitment
// RemoteCommitment is the current remote commitment state for the
// remote party. This is stored distinct from the state of the local
// party as there are certain asymmetric parameters which affect the
// structure of each commitment.
RemoteCommitment ChannelCommitment
// 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
// RevocationProducer is used to generate the revocation in such a way
// that remote side might store it efficiently and have the ability to
// restore the revocation by index if needed. Current implementation of
// secret producer is shachain producer.
RevocationProducer shachain.Producer
// RevocationStore is used to efficiently store the revocations for
// previous channels states sent to us by remote side. Current
// implementation of secret store is shachain store.
RevocationStore shachain.Store
// Packager is used to create and update forwarding packages for this
// channel, which encodes all necessary information to recover from
// failures and reforward HTLCs that were not fully processed.
Packager FwdPackager
// FundingTxn is the transaction containing this channel's funding
// outpoint. Upon restarts, this txn will be rebroadcast if the channel
// is found to be pending.
//
// NOTE: This value will only be populated for single-funder channels
// for which we are the initiator, and that we also have the funding
// transaction for. One can check this by using the HasFundingTx()
// method on the ChanType field.
FundingTxn *wire.MsgTx
// LocalShutdownScript is set to a pre-set script if the channel was opened
// by the local node with option_upfront_shutdown_script set. If the option
// was not set, the field is empty.
LocalShutdownScript lnwire.DeliveryAddress
// RemoteShutdownScript is set to a pre-set script if the channel was opened
// by the remote node with option_upfront_shutdown_script set. If the option
// was not set, the field is empty.
RemoteShutdownScript lnwire.DeliveryAddress
// ThawHeight is the height when a frozen channel once again becomes a
// normal channel. If this is zero, then there're no restrictions on
// this channel. If the value is lower than 500,000, then it's
// interpreted as a relative height, or an absolute height otherwise.
ThawHeight uint32
// TODO(roasbeef): eww
Db *DB
// TODO(roasbeef): just need to store local and remote HTLC's?
sync.RWMutex
}
// ShortChanID returns the current ShortChannelID of this channel.
func (c *OpenChannel) ShortChanID() lnwire.ShortChannelID {
c.RLock()
defer c.RUnlock()
return c.ShortChannelID
}
// ChanStatus returns the current ChannelStatus of this channel.
func (c *OpenChannel) ChanStatus() ChannelStatus {
c.RLock()
defer c.RUnlock()
return c.chanStatus
}
// ApplyChanStatus allows the caller to modify the internal channel state in a
// thead-safe manner.
func (c *OpenChannel) ApplyChanStatus(status ChannelStatus) error {
c.Lock()
defer c.Unlock()
return c.putChanStatus(status)
}
// ClearChanStatus allows the caller to clear a particular channel status from
// the primary channel status bit field. After this method returns, a call to
// HasChanStatus(status) should return false.
func (c *OpenChannel) ClearChanStatus(status ChannelStatus) error {
c.Lock()
defer c.Unlock()
return c.clearChanStatus(status)
}
// HasChanStatus returns true if the internal bitfield channel status of the
// target channel has the specified status bit set.
func (c *OpenChannel) HasChanStatus(status ChannelStatus) bool {
c.RLock()
defer c.RUnlock()
return c.hasChanStatus(status)
}
func (c *OpenChannel) hasChanStatus(status ChannelStatus) bool {
// Special case ChanStatusDefualt since it isn't actually flag, but a
// particular combination (or lack-there-of) of flags.
if status == ChanStatusDefault {
return c.chanStatus == ChanStatusDefault
}
return c.chanStatus&status == status
}
// RefreshShortChanID updates the in-memory channel state using the latest
// value observed on disk.
//
// TODO: the name of this function should be changed to reflect the fact that
// it is not only refreshing the short channel id but all the channel state.
// maybe Refresh/Reload?
func (c *OpenChannel) RefreshShortChanID() error {
c.Lock()
defer c.Unlock()
err := kvdb.View(c.Db, func(tx kvdb.RTx) error {
chanBucket, err := fetchChanBucket(
tx, c.IdentityPub, &c.FundingOutpoint, c.ChainHash,
)
if err != nil {
return err
}
// We'll re-populating the in-memory channel with the info
// fetched from disk.
if err := fetchChanInfo(chanBucket, c); err != nil {
return fmt.Errorf("unable to fetch chan info: %v", err)
}
return nil
}, func() {})
if err != nil {
return err
}
return nil
}
// fetchChanBucket is a helper function that returns the bucket where a
// channel's data resides in given: the public key for the node, the outpoint,
// and the chainhash that the channel resides on.
func fetchChanBucket(tx kvdb.RTx, nodeKey *btcec.PublicKey,
outPoint *wire.OutPoint, chainHash chainhash.Hash) (kvdb.RBucket, error) {
// First fetch the top level bucket which stores all data related to
// current, active channels.
openChanBucket := tx.ReadBucket(openChannelBucket)
if openChanBucket == nil {
return nil, ErrNoChanDBExists
}
// TODO(roasbeef): CreateTopLevelBucket on the interface isn't like
// CreateIfNotExists, will return error
// Within this top level bucket, fetch the bucket dedicated to storing
// open channel data specific to the remote node.
nodePub := nodeKey.SerializeCompressed()
nodeChanBucket := openChanBucket.NestedReadBucket(nodePub)
if nodeChanBucket == nil {
return nil, ErrNoActiveChannels
}
// We'll then recurse down an additional layer in order to fetch the
// bucket for this particular chain.
chainBucket := nodeChanBucket.NestedReadBucket(chainHash[:])
if chainBucket == nil {
return nil, ErrNoActiveChannels
}
// With the bucket for the node and chain fetched, we can now go down
// another level, for this channel itself.
var chanPointBuf bytes.Buffer
if err := writeOutpoint(&chanPointBuf, outPoint); err != nil {
return nil, err
}
chanBucket := chainBucket.NestedReadBucket(chanPointBuf.Bytes())
if chanBucket == nil {
return nil, ErrChannelNotFound
}
return chanBucket, nil
}
// fetchChanBucketRw is a helper function that returns the bucket where a
// channel's data resides in given: the public key for the node, the outpoint,
// and the chainhash that the channel resides on. This differs from
// fetchChanBucket in that it returns a writeable bucket.
func fetchChanBucketRw(tx kvdb.RwTx, nodeKey *btcec.PublicKey, // nolint:interfacer
outPoint *wire.OutPoint, chainHash chainhash.Hash) (kvdb.RwBucket, error) {
readBucket, err := fetchChanBucket(tx, nodeKey, outPoint, chainHash)
if err != nil {
return nil, err
}
return readBucket.(kvdb.RwBucket), nil
}
// fullSync syncs the contents of an OpenChannel while re-using an existing
// database transaction.
func (c *OpenChannel) fullSync(tx kvdb.RwTx) error {
// Fetch the outpoint bucket and check if the outpoint already exists.
opBucket := tx.ReadWriteBucket(outpointBucket)
var chanPointBuf bytes.Buffer
if err := writeOutpoint(&chanPointBuf, &c.FundingOutpoint); err != nil {
return err
}
// Now, check if the outpoint exists in our index.
if opBucket.Get(chanPointBuf.Bytes()) != nil {
return ErrChanAlreadyExists
}
status := uint8(outpointOpen)
// Write the status of this outpoint as the first entry in a tlv
// stream.
statusRecord := tlv.MakePrimitiveRecord(indexStatusType, &status)
opStream, err := tlv.NewStream(statusRecord)
if err != nil {
return err
}
var b bytes.Buffer
if err := opStream.Encode(&b); err != nil {
return err
}
// Add the outpoint to our outpoint index with the tlv stream.
if err := opBucket.Put(chanPointBuf.Bytes(), b.Bytes()); err != nil {
return err
}
// First fetch the top level bucket which stores all data related to
// current, active channels.
openChanBucket, err := tx.CreateTopLevelBucket(openChannelBucket)
if err != nil {
return err
}
// Within this top level bucket, fetch the bucket dedicated to storing
// open channel data specific to the remote node.
nodePub := c.IdentityPub.SerializeCompressed()
nodeChanBucket, err := openChanBucket.CreateBucketIfNotExists(nodePub)
if err != nil {
return err
}
// We'll then recurse down an additional layer in order to fetch the
// bucket for this particular chain.
chainBucket, err := nodeChanBucket.CreateBucketIfNotExists(c.ChainHash[:])
if err != nil {
return err
}
// With the bucket for the node fetched, we can now go down another
// level, creating the bucket for this channel itself.
chanBucket, err := chainBucket.CreateBucket(
chanPointBuf.Bytes(),
)
switch {
case err == kvdb.ErrBucketExists:
// If this channel already exists, then in order to avoid
// overriding it, we'll return an error back up to the caller.
return ErrChanAlreadyExists
case err != nil:
return err
}
return putOpenChannel(chanBucket, c)
}
// MarkAsOpen marks a channel as fully open given a locator that uniquely
// describes its location within the chain.
func (c *OpenChannel) MarkAsOpen(openLoc lnwire.ShortChannelID) error {
c.Lock()
defer c.Unlock()
if err := kvdb.Update(c.Db, func(tx kvdb.RwTx) error {
chanBucket, err := fetchChanBucket(
tx, c.IdentityPub, &c.FundingOutpoint, c.ChainHash,
)
if err != nil {
return err
}
channel, err := fetchOpenChannel(chanBucket, &c.FundingOutpoint)
if err != nil {
return err
}
channel.IsPending = false
channel.ShortChannelID = openLoc
return putOpenChannel(chanBucket.(kvdb.RwBucket), channel)
}, func() {}); err != nil {
return err
}
c.IsPending = false
c.ShortChannelID = openLoc
c.Packager = NewChannelPackager(openLoc)
return nil
}
// MarkDataLoss marks sets the channel status to LocalDataLoss and stores the
// passed commitPoint for use to retrieve funds in case the remote force closes
// the channel.
func (c *OpenChannel) MarkDataLoss(commitPoint *btcec.PublicKey) error {
c.Lock()
defer c.Unlock()
var b bytes.Buffer
if err := WriteElement(&b, commitPoint); err != nil {
return err
}
putCommitPoint := func(chanBucket kvdb.RwBucket) error {
return chanBucket.Put(dataLossCommitPointKey, b.Bytes())
}
return c.putChanStatus(ChanStatusLocalDataLoss, putCommitPoint)
}
// DataLossCommitPoint retrieves the stored commit point set during
// MarkDataLoss. If not found ErrNoCommitPoint is returned.
func (c *OpenChannel) DataLossCommitPoint() (*btcec.PublicKey, error) {
var commitPoint *btcec.PublicKey
err := kvdb.View(c.Db, func(tx kvdb.RTx) error {
chanBucket, err := fetchChanBucket(
tx, c.IdentityPub, &c.FundingOutpoint, c.ChainHash,
)
switch err {
case nil:
case ErrNoChanDBExists, ErrNoActiveChannels, ErrChannelNotFound:
return ErrNoCommitPoint
default:
return err
}
bs := chanBucket.Get(dataLossCommitPointKey)
if bs == nil {
return ErrNoCommitPoint
}
r := bytes.NewReader(bs)
if err := ReadElements(r, &commitPoint); err != nil {
return err
}
return nil
}, func() {
commitPoint = nil
})
if err != nil {
return nil, err
}
return commitPoint, nil
}
// MarkBorked marks the event when the channel as reached an irreconcilable
// state, such as a channel breach or state desynchronization. Borked channels
// should never be added to the switch.
func (c *OpenChannel) MarkBorked() error {
c.Lock()
defer c.Unlock()
return c.putChanStatus(ChanStatusBorked)
}
// ChanSyncMsg returns the ChannelReestablish message that should be sent upon
// reconnection with the remote peer that we're maintaining this channel with.
// The information contained within this message is necessary to re-sync our
// commitment chains in the case of a last or only partially processed message.
// When the remote party receiver this message one of three things may happen:
//
// 1. We're fully synced and no messages need to be sent.
// 2. We didn't get the last CommitSig message they sent, to they'll re-send
// it.
// 3. We didn't get the last RevokeAndAck message they sent, so they'll
// re-send it.
//
// If this is a restored channel, having status ChanStatusRestored, then we'll
// modify our typical chan sync message to ensure they force close even if
// we're on the very first state.
func (c *OpenChannel) ChanSyncMsg() (*lnwire.ChannelReestablish, error) {
c.Lock()
defer c.Unlock()
// The remote commitment height that we'll send in the
// ChannelReestablish message is our current commitment height plus
// one. If the receiver thinks that our commitment height is actually
// *equal* to this value, then they'll re-send the last commitment that
// they sent but we never fully processed.
localHeight := c.LocalCommitment.CommitHeight
nextLocalCommitHeight := localHeight + 1
// The second value we'll send is the height of the remote commitment
// from our PoV. If the receiver thinks that their height is actually
// *one plus* this value, then they'll re-send their last revocation.
remoteChainTipHeight := c.RemoteCommitment.CommitHeight
// If this channel has undergone a commitment update, then in order to
// prove to the remote party our knowledge of their prior commitment
// state, we'll also send over the last commitment secret that the
// remote party sent.
var lastCommitSecret [32]byte
if remoteChainTipHeight != 0 {
remoteSecret, err := c.RevocationStore.LookUp(
remoteChainTipHeight - 1,
)
if err != nil {
return nil, err
}
lastCommitSecret = [32]byte(*remoteSecret)
}
// Additionally, we'll send over the current unrevoked commitment on
// our local commitment transaction.
currentCommitSecret, err := c.RevocationProducer.AtIndex(
localHeight,
)
if err != nil {
return nil, err
}
// If we've restored this channel, then we'll purposefully give them an
// invalid LocalUnrevokedCommitPoint so they'll force close the channel
// allowing us to sweep our funds.
if c.hasChanStatus(ChanStatusRestored) {
currentCommitSecret[0] ^= 1
// If this is a tweakless channel, then we'll purposefully send
// a next local height taht's invalid to trigger a force close
// on their end. We do this as tweakless channels don't require
// that the commitment point is valid, only that it's present.
if c.ChanType.IsTweakless() {
nextLocalCommitHeight = 0
}
}
return &lnwire.ChannelReestablish{
ChanID: lnwire.NewChanIDFromOutPoint(
&c.FundingOutpoint,
),
NextLocalCommitHeight: nextLocalCommitHeight,
RemoteCommitTailHeight: remoteChainTipHeight,
LastRemoteCommitSecret: lastCommitSecret,
LocalUnrevokedCommitPoint: input.ComputeCommitmentPoint(
currentCommitSecret[:],
),
}, nil
}
// isBorked returns true if the channel has been marked as borked in the
// database. This requires an existing database transaction to already be
// active.
//
// NOTE: The primary mutex should already be held before this method is called.
func (c *OpenChannel) isBorked(chanBucket kvdb.RBucket) (bool, error) {
channel, err := fetchOpenChannel(chanBucket, &c.FundingOutpoint)
if err != nil {
return false, err
}
return channel.chanStatus != ChanStatusDefault, nil
}
// MarkCommitmentBroadcasted marks the channel as a commitment transaction has
// been broadcast, either our own or the remote, and we should watch the chain
// for it to confirm before taking any further action. It takes as argument the
// closing tx _we believe_ will appear in the chain. This is only used to
// republish this tx at startup to ensure propagation, and we should still
// handle the case where a different tx actually hits the chain.
func (c *OpenChannel) MarkCommitmentBroadcasted(closeTx *wire.MsgTx,
locallyInitiated bool) error {
return c.markBroadcasted(
ChanStatusCommitBroadcasted, forceCloseTxKey, closeTx,
locallyInitiated,
)
}
// MarkCoopBroadcasted marks the channel to indicate that a cooperative close
// transaction has been broadcast, either our own or the remote, and that we
// should watch the chain for it to confirm before taking further action. It
// takes as argument a cooperative close tx that could appear on chain, and
// should be rebroadcast upon startup. This is only used to republish and
// ensure propagation, and we should still handle the case where a different tx
// actually hits the chain.
func (c *OpenChannel) MarkCoopBroadcasted(closeTx *wire.MsgTx,
locallyInitiated bool) error {
return c.markBroadcasted(
ChanStatusCoopBroadcasted, coopCloseTxKey, closeTx,
locallyInitiated,
)
}
// markBroadcasted is a helper function which modifies the channel status of the
// receiving channel and inserts a close transaction under the requested key,
// which should specify either a coop or force close. It adds a status which
// indicates the party that initiated the channel close.
func (c *OpenChannel) markBroadcasted(status ChannelStatus, key []byte,
closeTx *wire.MsgTx, locallyInitiated bool) error {
c.Lock()
defer c.Unlock()
// If a closing tx is provided, we'll generate a closure to write the
// transaction in the appropriate bucket under the given key.
var putClosingTx func(kvdb.RwBucket) error
if closeTx != nil {
var b bytes.Buffer
if err := WriteElement(&b, closeTx); err != nil {
return err
}
putClosingTx = func(chanBucket kvdb.RwBucket) error {
return chanBucket.Put(key, b.Bytes())
}
}
// Add the initiator status to the status provided. These statuses are
// set in addition to the broadcast status so that we do not need to
// migrate the original logic which does not store initiator.
if locallyInitiated {
status |= ChanStatusLocalCloseInitiator
} else {
status |= ChanStatusRemoteCloseInitiator
}
return c.putChanStatus(status, putClosingTx)
}
// BroadcastedCommitment retrieves the stored unilateral closing tx set during
// MarkCommitmentBroadcasted. If not found ErrNoCloseTx is returned.
func (c *OpenChannel) BroadcastedCommitment() (*wire.MsgTx, error) {
return c.getClosingTx(forceCloseTxKey)
}
// BroadcastedCooperative retrieves the stored cooperative closing tx set during
// MarkCoopBroadcasted. If not found ErrNoCloseTx is returned.
func (c *OpenChannel) BroadcastedCooperative() (*wire.MsgTx, error) {
return c.getClosingTx(coopCloseTxKey)
}
// getClosingTx is a helper method which returns the stored closing transaction
// for key. The caller should use either the force or coop closing keys.
func (c *OpenChannel) getClosingTx(key []byte) (*wire.MsgTx, error) {
var closeTx *wire.MsgTx
err := kvdb.View(c.Db, func(tx kvdb.RTx) error {
chanBucket, err := fetchChanBucket(
tx, c.IdentityPub, &c.FundingOutpoint, c.ChainHash,
)
switch err {
case nil:
case ErrNoChanDBExists, ErrNoActiveChannels, ErrChannelNotFound:
return ErrNoCloseTx
default:
return err
}
bs := chanBucket.Get(key)
if bs == nil {
return ErrNoCloseTx
}
r := bytes.NewReader(bs)
return ReadElement(r, &closeTx)
}, func() {
closeTx = nil
})
if err != nil {
return nil, err
}
return closeTx, nil
}
// putChanStatus appends the given status to the channel. fs is an optional
// list of closures that are given the chanBucket in order to atomically add
// extra information together with the new status.
func (c *OpenChannel) putChanStatus(status ChannelStatus,
fs ...func(kvdb.RwBucket) error) error {
if err := kvdb.Update(c.Db, func(tx kvdb.RwTx) error {
chanBucket, err := fetchChanBucketRw(
tx, c.IdentityPub, &c.FundingOutpoint, c.ChainHash,
)
if err != nil {
return err
}
channel, err := fetchOpenChannel(chanBucket, &c.FundingOutpoint)
if err != nil {
return err
}
// Add this status to the existing bitvector found in the DB.
status = channel.chanStatus | status
channel.chanStatus = status
if err := putOpenChannel(chanBucket, channel); err != nil {
return err
}
for _, f := range fs {
// Skip execution of nil closures.
if f == nil {
continue
}
if err := f(chanBucket); err != nil {
return err
}
}
return nil
}, func() {}); err != nil {
return err
}
// Update the in-memory representation to keep it in sync with the DB.
c.chanStatus = status
return nil
}
func (c *OpenChannel) clearChanStatus(status ChannelStatus) error {
if err := kvdb.Update(c.Db, func(tx kvdb.RwTx) error {
chanBucket, err := fetchChanBucketRw(
tx, c.IdentityPub, &c.FundingOutpoint, c.ChainHash,
)
if err != nil {
return err
}
channel, err := fetchOpenChannel(chanBucket, &c.FundingOutpoint)
if err != nil {
return err
}
// Unset this bit in the bitvector on disk.
status = channel.chanStatus & ^status
channel.chanStatus = status
return putOpenChannel(chanBucket, channel)
}, func() {}); err != nil {
return err
}
// Update the in-memory representation to keep it in sync with the DB.
c.chanStatus = status
return nil
}
// putOpenChannel serializes, and stores the current state of the channel in its
// entirety.
func putOpenChannel(chanBucket kvdb.RwBucket, channel *OpenChannel) error {
// First, we'll write out all the relatively static fields, that are
// decided upon initial channel creation.
if err := putChanInfo(chanBucket, channel); err != nil {
return fmt.Errorf("unable to store chan info: %v", err)
}
// With the static channel info written out, we'll now write out the
// current commitment state for both parties.
if err := putChanCommitments(chanBucket, channel); err != nil {
return fmt.Errorf("unable to store chan commitments: %v", err)
}
// Next, if this is a frozen channel, we'll add in the axillary
// information we need to store.
if channel.ChanType.IsFrozen() {
err := storeThawHeight(
chanBucket, channel.ThawHeight,
)
if err != nil {
return fmt.Errorf("unable to store thaw height: %v", err)
}
}
// Finally, we'll write out the revocation state for both parties
// within a distinct key space.
if err := putChanRevocationState(chanBucket, channel); err != nil {
return fmt.Errorf("unable to store chan revocations: %v", err)
}
return nil
}
// fetchOpenChannel retrieves, and deserializes (including decrypting
// sensitive) the complete channel currently active with the passed nodeID.
func fetchOpenChannel(chanBucket kvdb.RBucket,
chanPoint *wire.OutPoint) (*OpenChannel, error) {
channel := &OpenChannel{
FundingOutpoint: *chanPoint,
}
// First, we'll read all the static information that changes less
// frequently from disk.
if err := fetchChanInfo(chanBucket, channel); err != nil {
return nil, fmt.Errorf("unable to fetch chan info: %v", err)
}
// With the static information read, we'll now read the current
// commitment state for both sides of the channel.
if err := fetchChanCommitments(chanBucket, channel); err != nil {
return nil, fmt.Errorf("unable to fetch chan commitments: %v", err)
}
// Next, if this is a frozen channel, we'll add in the axillary
// information we need to store.
if channel.ChanType.IsFrozen() {
thawHeight, err := fetchThawHeight(chanBucket)
if err != nil {
return nil, fmt.Errorf("unable to store thaw "+
"height: %v", err)
}
channel.ThawHeight = thawHeight
}
// Finally, we'll retrieve the current revocation state so we can
// properly
if err := fetchChanRevocationState(chanBucket, channel); err != nil {
return nil, fmt.Errorf("unable to fetch chan revocations: %v", err)
}
channel.Packager = NewChannelPackager(channel.ShortChannelID)
return channel, nil
}
// SyncPending writes the contents of the channel to the database while it's in
// the pending (waiting for funding confirmation) state. The IsPending flag
// will be set to true. When the channel's funding transaction is confirmed,
// the channel should be marked as "open" and the IsPending flag set to false.
// Note that this function also creates a LinkNode relationship between this
// newly created channel and a new LinkNode instance. This allows listing all
// channels in the database globally, or according to the LinkNode they were
// created with.
//
// TODO(roasbeef): addr param should eventually be an lnwire.NetAddress type
// that includes service bits.
func (c *OpenChannel) SyncPending(addr net.Addr, pendingHeight uint32) error {
c.Lock()
defer c.Unlock()
c.FundingBroadcastHeight = pendingHeight
return kvdb.Update(c.Db, func(tx kvdb.RwTx) error {
return syncNewChannel(tx, c, []net.Addr{addr})
}, func() {})
}
// syncNewChannel will write the passed channel to disk, and also create a
// LinkNode (if needed) for the channel peer.
func syncNewChannel(tx kvdb.RwTx, c *OpenChannel, addrs []net.Addr) error {
// First, sync all the persistent channel state to disk.
if err := c.fullSync(tx); err != nil {
return err
}
nodeInfoBucket, err := tx.CreateTopLevelBucket(nodeInfoBucket)
if err != nil {
return err
}
// If a LinkNode for this identity public key already exists,
// then we can exit early.
nodePub := c.IdentityPub.SerializeCompressed()
if nodeInfoBucket.Get(nodePub) != nil {
return nil
}
// Next, we need to establish a (possibly) new LinkNode relationship
// for this channel. The LinkNode metadata contains reachability,
// up-time, and service bits related information.
linkNode := c.Db.NewLinkNode(wire.MainNet, c.IdentityPub, addrs...)
// TODO(roasbeef): do away with link node all together?
return putLinkNode(nodeInfoBucket, linkNode)
}
// UpdateCommitment updates the local commitment state. It locks in the pending
// local updates that were received by us from the remote party. The commitment
// state completely describes the balance state at this point in the commitment
// chain. In addition to that, it persists all the remote log updates that we
// have acked, but not signed a remote commitment for yet. These need to be
// persisted to be able to produce a valid commit signature if a restart would
// occur. This method its to be called when we revoke our prior commitment
// state.
func (c *OpenChannel) UpdateCommitment(newCommitment *ChannelCommitment,
unsignedAckedUpdates []LogUpdate) error {
c.Lock()
defer c.Unlock()
// If this is a restored channel, then we want to avoid mutating the
// state as all, as it's impossible to do so in a protocol compliant
// manner.
if c.hasChanStatus(ChanStatusRestored) {
return ErrNoRestoredChannelMutation
}
err := kvdb.Update(c.Db, func(tx kvdb.RwTx) error {
chanBucket, err := fetchChanBucketRw(
tx, c.IdentityPub, &c.FundingOutpoint, c.ChainHash,
)
if err != nil {
return err
}
// If the channel is marked as borked, then for safety reasons,
// we shouldn't attempt any further updates.
isBorked, err := c.isBorked(chanBucket)
if err != nil {
return err
}
if isBorked {
return ErrChanBorked
}
if err = putChanInfo(chanBucket, c); err != nil {
return fmt.Errorf("unable to store chan info: %v", err)
}
// With the proper bucket fetched, we'll now write the latest
// commitment state to disk for the target party.
err = putChanCommitment(
chanBucket, newCommitment, true,
)
if err != nil {
return fmt.Errorf("unable to store chan "+
"revocations: %v", err)
}
// Persist unsigned but acked remote updates that need to be
// restored after a restart.
var b bytes.Buffer
err = serializeLogUpdates(&b, unsignedAckedUpdates)
if err != nil {
return err
}
err = chanBucket.Put(unsignedAckedUpdatesKey, b.Bytes())
if err != nil {
return fmt.Errorf("unable to store dangline remote "+
"updates: %v", err)
}
// Persist the remote unsigned local updates that are not included
// in our new commitment.
updateBytes := chanBucket.Get(remoteUnsignedLocalUpdatesKey)
if updateBytes == nil {
return nil
}
r := bytes.NewReader(updateBytes)
updates, err := deserializeLogUpdates(r)
if err != nil {
return err
}
var validUpdates []LogUpdate
for _, upd := range updates {
// Filter for updates that are not on our local
// commitment.
if upd.LogIndex >= newCommitment.LocalLogIndex {
validUpdates = append(validUpdates, upd)
}
}
var b2 bytes.Buffer
err = serializeLogUpdates(&b2, validUpdates)
if err != nil {
return fmt.Errorf("unable to serialize log updates: %v", err)
}
err = chanBucket.Put(remoteUnsignedLocalUpdatesKey, b2.Bytes())
if err != nil {
return fmt.Errorf("unable to restore chanbucket: %v", err)
}
return nil
}, func() {})
if err != nil {
return err
}
c.LocalCommitment = *newCommitment
return nil
}
// BalancesAtHeight returns the local and remote balances on our commitment
// transactions as of a given height.
//
// NOTE: these are our balances *after* subtracting the commitment fee and
// anchor outputs.
func (c *OpenChannel) BalancesAtHeight(height uint64) (lnwire.MilliSatoshi,
lnwire.MilliSatoshi, error) {
if height > c.LocalCommitment.CommitHeight &&
height > c.RemoteCommitment.CommitHeight {
return 0, 0, errHeightNotReached
}
// If our current commit is as the desired height, we can return our
// current balances.
if c.LocalCommitment.CommitHeight == height {
return c.LocalCommitment.LocalBalance,
c.LocalCommitment.RemoteBalance, nil
}
// If our current remote commit is at the desired height, we can return
// the current balances.
if c.RemoteCommitment.CommitHeight == height {
return c.RemoteCommitment.LocalBalance,
c.RemoteCommitment.RemoteBalance, nil
}
// If we are not currently on the height requested, we need to look up
// the previous height to obtain our balances at the given height.
commit, err := c.FindPreviousState(height)
if err != nil {
return 0, 0, err
}
return commit.LocalBalance, commit.RemoteBalance, nil
}
// ActiveHtlcs returns a slice of HTLC's which are currently active on *both*
// commitment transactions.
func (c *OpenChannel) ActiveHtlcs() []HTLC {
c.RLock()
defer c.RUnlock()
// We'll only return HTLC's that are locked into *both* commitment
// transactions. So we'll iterate through their set of HTLC's to note
// which ones are present on their commitment.
remoteHtlcs := make(map[[32]byte]struct{})
for _, htlc := range c.RemoteCommitment.Htlcs {
onionHash := sha256.Sum256(htlc.OnionBlob)
remoteHtlcs[onionHash] = struct{}{}
}
// Now that we know which HTLC's they have, we'll only mark the HTLC's
// as active if *we* know them as well.
activeHtlcs := make([]HTLC, 0, len(remoteHtlcs))
for _, htlc := range c.LocalCommitment.Htlcs {
onionHash := sha256.Sum256(htlc.OnionBlob)
if _, ok := remoteHtlcs[onionHash]; !ok {
continue
}
activeHtlcs = append(activeHtlcs, htlc)
}
return activeHtlcs
}
// HTLC is the on-disk representation of a hash time-locked contract. HTLCs are
// contained within ChannelDeltas which encode the current state of the
// commitment between state updates.
//
// TODO(roasbeef): save space by using smaller ints at tail end?
type HTLC struct {
// Signature is the signature for the second level covenant transaction
// for this HTLC. The second level transaction is a timeout tx in the
// case that this is an outgoing HTLC, and a success tx in the case
// that this is an incoming HTLC.
//
// TODO(roasbeef): make [64]byte instead?
Signature []byte
// RHash is the payment hash of the HTLC.
RHash [32]byte
// Amt is the amount of milli-satoshis this HTLC escrows.
Amt lnwire.MilliSatoshi
// 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.
OutputIndex int32
// Incoming denotes whether we're the receiver or the sender of this
// HTLC.
Incoming bool
// OnionBlob is an opaque blob which is used to complete multi-hop
// routing.
OnionBlob []byte
// HtlcIndex is the HTLC counter index of this active, outstanding
// HTLC. This differs from the LogIndex, as the HtlcIndex is only
// incremented for each offered HTLC, while they LogIndex is
// incremented for each update (includes settle+fail).
HtlcIndex uint64
// LogIndex is the cumulative log index of this HTLC. This differs
// from the HtlcIndex as this will be incremented for each new log
// update added.
LogIndex uint64
}
// SerializeHtlcs writes out the passed set of HTLC's into the passed writer
// using the current default on-disk serialization format.
//
// NOTE: This API is NOT stable, the on-disk format will likely change in the
// future.
func SerializeHtlcs(b io.Writer, htlcs ...HTLC) error {
numHtlcs := uint16(len(htlcs))
if err := WriteElement(b, numHtlcs); err != nil {
return err
}
for _, htlc := range htlcs {
if err := WriteElements(b,
htlc.Signature, htlc.RHash, htlc.Amt, htlc.RefundTimeout,
htlc.OutputIndex, htlc.Incoming, htlc.OnionBlob[:],
htlc.HtlcIndex, htlc.LogIndex,
); err != nil {
return err
}
}
return nil
}
// DeserializeHtlcs attempts to read out a slice of HTLC's from the passed
// io.Reader. The bytes within the passed reader MUST have been previously
// written to using the SerializeHtlcs function.
//
// NOTE: This API is NOT stable, the on-disk format will likely change in the
// future.
func DeserializeHtlcs(r io.Reader) ([]HTLC, error) {
var numHtlcs uint16
if err := ReadElement(r, &numHtlcs); err != nil {
return nil, err
}
var htlcs []HTLC
if numHtlcs == 0 {
return htlcs, nil
}
htlcs = make([]HTLC, numHtlcs)
for i := uint16(0); i < numHtlcs; i++ {
if err := ReadElements(r,
&htlcs[i].Signature, &htlcs[i].RHash, &htlcs[i].Amt,
&htlcs[i].RefundTimeout, &htlcs[i].OutputIndex,
&htlcs[i].Incoming, &htlcs[i].OnionBlob,
&htlcs[i].HtlcIndex, &htlcs[i].LogIndex,
); err != nil {
return htlcs, err
}
}
return htlcs, nil
}
// Copy returns a full copy of the target HTLC.
func (h *HTLC) Copy() HTLC {
clone := HTLC{
Incoming: h.Incoming,
Amt: h.Amt,
RefundTimeout: h.RefundTimeout,
OutputIndex: h.OutputIndex,
}
copy(clone.Signature[:], h.Signature)
copy(clone.RHash[:], h.RHash[:])
return clone
}
// LogUpdate represents a pending update to the remote commitment chain. The
// log update may be an add, fail, or settle entry. We maintain this data in
// order to be able to properly retransmit our proposed
// state if necessary.
type LogUpdate struct {
// LogIndex is the log index of this proposed commitment update entry.
LogIndex uint64
// UpdateMsg is the update message that was included within the our
// local update log. The LogIndex value denotes the log index of this
// update which will be used when restoring our local update log if
// we're left with a dangling update on restart.
UpdateMsg lnwire.Message
}
// Encode writes a log update to the provided io.Writer.
func (l *LogUpdate) Encode(w io.Writer) error {
return WriteElements(w, l.LogIndex, l.UpdateMsg)
}
// Decode reads a log update from the provided io.Reader.
func (l *LogUpdate) Decode(r io.Reader) error {
return ReadElements(r, &l.LogIndex, &l.UpdateMsg)
}
// CircuitKey is used by a channel to uniquely identify the HTLCs it receives
// from the switch, and is used to purge our in-memory state of HTLCs that have
// already been processed by a link. Two list of CircuitKeys are included in
// each CommitDiff to allow a link to determine which in-memory htlcs directed
// the opening and closing of circuits in the switch's circuit map.
type CircuitKey struct {
// ChanID is the short chanid indicating the HTLC's origin.
//
// NOTE: It is fine for this value to be blank, as this indicates a
// locally-sourced payment.
ChanID lnwire.ShortChannelID
// HtlcID is the unique htlc index predominately assigned by links,
// though can also be assigned by switch in the case of locally-sourced
// payments.
HtlcID uint64
}
// SetBytes deserializes the given bytes into this CircuitKey.
func (k *CircuitKey) SetBytes(bs []byte) error {
if len(bs) != 16 {
return ErrInvalidCircuitKeyLen
}
k.ChanID = lnwire.NewShortChanIDFromInt(
binary.BigEndian.Uint64(bs[:8]))
k.HtlcID = binary.BigEndian.Uint64(bs[8:])
return nil
}
// Bytes returns the serialized bytes for this circuit key.
func (k CircuitKey) Bytes() []byte {
var bs = make([]byte, 16)
binary.BigEndian.PutUint64(bs[:8], k.ChanID.ToUint64())
binary.BigEndian.PutUint64(bs[8:], k.HtlcID)
return bs
}
// Encode writes a CircuitKey to the provided io.Writer.
func (k *CircuitKey) Encode(w io.Writer) error {
var scratch [16]byte
binary.BigEndian.PutUint64(scratch[:8], k.ChanID.ToUint64())
binary.BigEndian.PutUint64(scratch[8:], k.HtlcID)
_, err := w.Write(scratch[:])
return err
}
// Decode reads a CircuitKey from the provided io.Reader.
func (k *CircuitKey) Decode(r io.Reader) error {
var scratch [16]byte
if _, err := io.ReadFull(r, scratch[:]); err != nil {
return err
}
k.ChanID = lnwire.NewShortChanIDFromInt(
binary.BigEndian.Uint64(scratch[:8]))
k.HtlcID = binary.BigEndian.Uint64(scratch[8:])
return nil
}
// String returns a string representation of the CircuitKey.
func (k CircuitKey) String() string {
return fmt.Sprintf("(Chan ID=%s, HTLC ID=%d)", k.ChanID, k.HtlcID)
}
// CommitDiff represents the delta needed to apply the state transition between
// two subsequent commitment states. Given state N and state N+1, one is able
// to apply the set of messages contained within the CommitDiff to N to arrive
// at state N+1. Each time a new commitment is extended, we'll write a new
// commitment (along with the full commitment state) to disk so we can
// re-transmit the state in the case of a connection loss or message drop.
type CommitDiff struct {
// ChannelCommitment is the full commitment state that one would arrive
// at by applying the set of messages contained in the UpdateDiff to
// the prior accepted commitment.
Commitment ChannelCommitment
// LogUpdates is the set of messages sent prior to the commitment state
// transition in question. Upon reconnection, if we detect that they
// don't have the commitment, then we re-send this along with the
// proper signature.
LogUpdates []LogUpdate
// CommitSig is the exact CommitSig message that should be sent after
// the set of LogUpdates above has been retransmitted. The signatures
// within this message should properly cover the new commitment state
// and also the HTLC's within the new commitment state.
CommitSig *lnwire.CommitSig
// OpenedCircuitKeys is a set of unique identifiers for any downstream
// Add packets included in this commitment txn. After a restart, this
// set of htlcs is acked from the link's incoming mailbox to ensure
// there isn't an attempt to re-add them to this commitment txn.
OpenedCircuitKeys []CircuitKey
// ClosedCircuitKeys records the unique identifiers for any settle/fail
// packets that were resolved by this commitment txn. After a restart,
// this is used to ensure those circuits are removed from the circuit
// map, and the downstream packets in the link's mailbox are removed.
ClosedCircuitKeys []CircuitKey
// AddAcks specifies the locations (commit height, pkg index) of any
// Adds that were failed/settled in this commit diff. This will ack
// entries in *this* channel's forwarding packages.
//
// NOTE: This value is not serialized, it is used to atomically mark the
// resolution of adds, such that they will not be reprocessed after a
// restart.
AddAcks []AddRef
// SettleFailAcks specifies the locations (chan id, commit height, pkg
// index) of any Settles or Fails that were locked into this commit
// diff, and originate from *another* channel, i.e. the outgoing link.
//
// NOTE: This value is not serialized, it is used to atomically acks
// settles and fails from the forwarding packages of other channels,
// such that they will not be reforwarded internally after a restart.
SettleFailAcks []SettleFailRef
}
// serializeLogUpdates serializes provided list of updates to a stream.
func serializeLogUpdates(w io.Writer, logUpdates []LogUpdate) error {
numUpdates := uint16(len(logUpdates))
if err := binary.Write(w, byteOrder, numUpdates); err != nil {
return err
}
for _, diff := range logUpdates {
err := WriteElements(w, diff.LogIndex, diff.UpdateMsg)
if err != nil {
return err
}
}
return nil
}
// deserializeLogUpdates deserializes a list of updates from a stream.
func deserializeLogUpdates(r io.Reader) ([]LogUpdate, error) {
var numUpdates uint16
if err := binary.Read(r, byteOrder, &numUpdates); err != nil {
return nil, err
}
logUpdates := make([]LogUpdate, numUpdates)
for i := 0; i < int(numUpdates); i++ {
err := ReadElements(r,
&logUpdates[i].LogIndex, &logUpdates[i].UpdateMsg,
)
if err != nil {
return nil, err
}
}
return logUpdates, nil
}
func serializeCommitDiff(w io.Writer, diff *CommitDiff) error {
if err := serializeChanCommit(w, &diff.Commitment); err != nil {
return err
}
if err := diff.CommitSig.Encode(w, 0); err != nil {
return err
}
if err := serializeLogUpdates(w, diff.LogUpdates); err != nil {
return err
}
numOpenRefs := uint16(len(diff.OpenedCircuitKeys))
if err := binary.Write(w, byteOrder, numOpenRefs); err != nil {
return err
}
for _, openRef := range diff.OpenedCircuitKeys {
err := WriteElements(w, openRef.ChanID, openRef.HtlcID)
if err != nil {
return err
}
}
numClosedRefs := uint16(len(diff.ClosedCircuitKeys))
if err := binary.Write(w, byteOrder, numClosedRefs); err != nil {
return err
}
for _, closedRef := range diff.ClosedCircuitKeys {
err := WriteElements(w, closedRef.ChanID, closedRef.HtlcID)
if err != nil {
return err
}
}
return nil
}
func deserializeCommitDiff(r io.Reader) (*CommitDiff, error) {
var (
d CommitDiff
err error
)
d.Commitment, err = deserializeChanCommit(r)
if err != nil {
return nil, err
}
d.CommitSig = &lnwire.CommitSig{}
if err := d.CommitSig.Decode(r, 0); err != nil {
return nil, err
}
d.LogUpdates, err = deserializeLogUpdates(r)
if err != nil {
return nil, err
}
var numOpenRefs uint16
if err := binary.Read(r, byteOrder, &numOpenRefs); err != nil {
return nil, err
}
d.OpenedCircuitKeys = make([]CircuitKey, numOpenRefs)
for i := 0; i < int(numOpenRefs); i++ {
err := ReadElements(r,
&d.OpenedCircuitKeys[i].ChanID,
&d.OpenedCircuitKeys[i].HtlcID)
if err != nil {
return nil, err
}
}
var numClosedRefs uint16
if err := binary.Read(r, byteOrder, &numClosedRefs); err != nil {
return nil, err
}
d.ClosedCircuitKeys = make([]CircuitKey, numClosedRefs)
for i := 0; i < int(numClosedRefs); i++ {
err := ReadElements(r,
&d.ClosedCircuitKeys[i].ChanID,
&d.ClosedCircuitKeys[i].HtlcID)
if err != nil {
return nil, err
}
}
return &d, nil
}
// AppendRemoteCommitChain appends a new CommitDiff to the end of the
// commitment chain for the remote party. This method is to be used once we
// have prepared a new commitment state for the remote party, but before we
// transmit it to the remote party. The contents of the argument should be
// sufficient to retransmit the updates and signature needed to reconstruct the
// state in full, in the case that we need to retransmit.
func (c *OpenChannel) AppendRemoteCommitChain(diff *CommitDiff) error {
c.Lock()
defer c.Unlock()
// If this is a restored channel, then we want to avoid mutating the
// state at all, as it's impossible to do so in a protocol compliant
// manner.
if c.hasChanStatus(ChanStatusRestored) {
return ErrNoRestoredChannelMutation
}
return kvdb.Update(c.Db, func(tx kvdb.RwTx) error {
// First, we'll grab the writable bucket where this channel's
// data resides.
chanBucket, err := fetchChanBucketRw(
tx, c.IdentityPub, &c.FundingOutpoint, c.ChainHash,
)
if err != nil {
return err
}
// If the channel is marked as borked, then for safety reasons,
// we shouldn't attempt any further updates.
isBorked, err := c.isBorked(chanBucket)
if err != nil {
return err
}
if isBorked {
return ErrChanBorked
}
// Any outgoing settles and fails necessarily have a
// corresponding adds in this channel's forwarding packages.
// Mark all of these as being fully processed in our forwarding
// package, which prevents us from reprocessing them after
// startup.
err = c.Packager.AckAddHtlcs(tx, diff.AddAcks...)
if err != nil {
return err
}
// Additionally, we ack from any fails or settles that are
// persisted in another channel's forwarding package. This
// prevents the same fails and settles from being retransmitted
// after restarts. The actual fail or settle we need to
// propagate to the remote party is now in the commit diff.
err = c.Packager.AckSettleFails(tx, diff.SettleFailAcks...)
if err != nil {
return err
}
// TODO(roasbeef): use seqno to derive key for later LCP
// With the bucket retrieved, we'll now serialize the commit
// diff itself, and write it to disk.
var b bytes.Buffer
if err := serializeCommitDiff(&b, diff); err != nil {
return err
}
return chanBucket.Put(commitDiffKey, b.Bytes())
}, func() {})
}
// RemoteCommitChainTip returns the "tip" of the current remote commitment
// chain. This value will be non-nil iff, we've created a new commitment for
// the remote party that they haven't yet ACK'd. In this case, their commitment
// chain will have a length of two: their current unrevoked commitment, and
// this new pending commitment. Once they revoked their prior state, we'll swap
// these pointers, causing the tip and the tail to point to the same entry.
func (c *OpenChannel) RemoteCommitChainTip() (*CommitDiff, error) {
var cd *CommitDiff
err := kvdb.View(c.Db, func(tx kvdb.RTx) error {
chanBucket, err := fetchChanBucket(
tx, c.IdentityPub, &c.FundingOutpoint, c.ChainHash,
)
switch err {
case nil:
case ErrNoChanDBExists, ErrNoActiveChannels, ErrChannelNotFound:
return ErrNoPendingCommit
default:
return err
}
tipBytes := chanBucket.Get(commitDiffKey)
if tipBytes == nil {
return ErrNoPendingCommit
}
tipReader := bytes.NewReader(tipBytes)
dcd, err := deserializeCommitDiff(tipReader)
if err != nil {
return err
}
cd = dcd
return nil
}, func() {
cd = nil
})
if err != nil {
return nil, err
}
return cd, err
}
// UnsignedAckedUpdates retrieves the persisted unsigned acked remote log
// updates that still need to be signed for.
func (c *OpenChannel) UnsignedAckedUpdates() ([]LogUpdate, error) {
var updates []LogUpdate
err := kvdb.View(c.Db, func(tx kvdb.RTx) error {
chanBucket, err := fetchChanBucket(
tx, c.IdentityPub, &c.FundingOutpoint, c.ChainHash,
)
switch err {
case nil:
case ErrNoChanDBExists, ErrNoActiveChannels, ErrChannelNotFound:
return nil
default:
return err
}
updateBytes := chanBucket.Get(unsignedAckedUpdatesKey)
if updateBytes == nil {
return nil
}
r := bytes.NewReader(updateBytes)
updates, err = deserializeLogUpdates(r)
return err
}, func() {
updates = nil
})
if err != nil {
return nil, err
}
return updates, nil
}
// RemoteUnsignedLocalUpdates retrieves the persisted, unsigned local log
// updates that the remote still needs to sign for.
func (c *OpenChannel) RemoteUnsignedLocalUpdates() ([]LogUpdate, error) {
var updates []LogUpdate
err := kvdb.View(c.Db, func(tx kvdb.RTx) error {
chanBucket, err := fetchChanBucket(
tx, c.IdentityPub, &c.FundingOutpoint, c.ChainHash,
)
switch err {
case nil:
break
case ErrNoChanDBExists, ErrNoActiveChannels, ErrChannelNotFound:
return nil
default:
return err
}
updateBytes := chanBucket.Get(remoteUnsignedLocalUpdatesKey)
if updateBytes == nil {
return nil
}
r := bytes.NewReader(updateBytes)
updates, err = deserializeLogUpdates(r)
return err
}, func() {
updates = nil
})
if err != nil {
return nil, err
}
return updates, nil
}
// InsertNextRevocation inserts the _next_ commitment point (revocation) into
// the database, and also modifies the internal RemoteNextRevocation attribute
// to point to the passed key. This method is to be using during final channel
// set up, _after_ the channel has been fully confirmed.
//
// NOTE: If this method isn't called, then the target channel won't be able to
// propose new states for the commitment state of the remote party.
func (c *OpenChannel) InsertNextRevocation(revKey *btcec.PublicKey) error {
c.Lock()
defer c.Unlock()
c.RemoteNextRevocation = revKey
err := kvdb.Update(c.Db, func(tx kvdb.RwTx) error {
chanBucket, err := fetchChanBucketRw(
tx, c.IdentityPub, &c.FundingOutpoint, c.ChainHash,
)
if err != nil {
return err
}
return putChanRevocationState(chanBucket, c)
}, func() {})
if err != nil {
return err
}
return nil
}
// AdvanceCommitChainTail records the new state transition within an on-disk
// append-only log which records all state transitions by the remote peer. In
// the case of an uncooperative broadcast of a prior state by the remote peer,
// this log can be consulted in order to reconstruct the state needed to
// rectify the situation. This method will add the current commitment for the
// remote party to the revocation log, and promote the current pending
// commitment to the current remote commitment. The updates parameter is the
// set of local updates that the peer still needs to send us a signature for.
// We store this set of updates in case we go down.
func (c *OpenChannel) AdvanceCommitChainTail(fwdPkg *FwdPkg,
updates []LogUpdate) error {
c.Lock()
defer c.Unlock()
// If this is a restored channel, then we want to avoid mutating the
// state at all, as it's impossible to do so in a protocol compliant
// manner.
if c.hasChanStatus(ChanStatusRestored) {
return ErrNoRestoredChannelMutation
}
var newRemoteCommit *ChannelCommitment
err := kvdb.Update(c.Db, func(tx kvdb.RwTx) error {
chanBucket, err := fetchChanBucketRw(
tx, c.IdentityPub, &c.FundingOutpoint, c.ChainHash,
)
if err != nil {
return err
}
// If the channel is marked as borked, then for safety reasons,
// we shouldn't attempt any further updates.
isBorked, err := c.isBorked(chanBucket)
if err != nil {
return err
}
if isBorked {
return ErrChanBorked
}
// Persist the latest preimage state to disk as the remote peer
// has just added to our local preimage store, and given us a
// new pending revocation key.
if err := putChanRevocationState(chanBucket, c); err != nil {
return err
}
// With the current preimage producer/store state updated,
// append a new log entry recording this the delta of this
// state transition.
//
// TODO(roasbeef): could make the deltas relative, would save
// space, but then tradeoff for more disk-seeks to recover the
// full state.
logKey := revocationLogBucket
logBucket, err := chanBucket.CreateBucketIfNotExists(logKey)
if err != nil {
return err
}
// Before we append this revoked state to the revocation log,
// we'll swap out what's currently the tail of the commit tip,
// with the current locked-in commitment for the remote party.
tipBytes := chanBucket.Get(commitDiffKey)
tipReader := bytes.NewReader(tipBytes)
newCommit, err := deserializeCommitDiff(tipReader)
if err != nil {
return err
}
err = putChanCommitment(
chanBucket, &newCommit.Commitment, false,
)
if err != nil {
return err
}
if err := chanBucket.Delete(commitDiffKey); err != nil {
return err
}
// With the commitment pointer swapped, we can now add the
// revoked (prior) state to the revocation log.
//
// TODO(roasbeef): store less
err = appendChannelLogEntry(logBucket, &c.RemoteCommitment)
if err != nil {
return err
}
// Lastly, we write the forwarding package to disk so that we
// can properly recover from failures and reforward HTLCs that
// have not received a corresponding settle/fail.
if err := c.Packager.AddFwdPkg(tx, fwdPkg); err != nil {
return err
}
// Persist the unsigned acked updates that are not included
// in their new commitment.
updateBytes := chanBucket.Get(unsignedAckedUpdatesKey)
if updateBytes == nil {
// If there are no updates to sign, we don't need to
// filter out any updates.
newRemoteCommit = &newCommit.Commitment
return nil
}
r := bytes.NewReader(updateBytes)
unsignedUpdates, err := deserializeLogUpdates(r)
if err != nil {
return err
}
var validUpdates []LogUpdate
for _, upd := range unsignedUpdates {
lIdx := upd.LogIndex
// Filter for updates that are not on the remote
// commitment.
if lIdx >= newCommit.Commitment.RemoteLogIndex {
validUpdates = append(validUpdates, upd)
}
}
var b bytes.Buffer
err = serializeLogUpdates(&b, validUpdates)
if err != nil {
return fmt.Errorf("unable to serialize log updates: %v", err)
}
err = chanBucket.Put(unsignedAckedUpdatesKey, b.Bytes())
if err != nil {
return fmt.Errorf("unable to store under unsignedAckedUpdatesKey: %v", err)
}
// Persist the local updates the peer hasn't yet signed so they
// can be restored after restart.
var b2 bytes.Buffer
err = serializeLogUpdates(&b2, updates)
if err != nil {
return err
}
err = chanBucket.Put(remoteUnsignedLocalUpdatesKey, b2.Bytes())
if err != nil {
return fmt.Errorf("unable to restore remote unsigned "+
"local updates: %v", err)
}
newRemoteCommit = &newCommit.Commitment
return nil
}, func() {
newRemoteCommit = nil
})
if err != nil {
return err
}
// With the db transaction complete, we'll swap over the in-memory
// pointer of the new remote commitment, which was previously the tip
// of the commit chain.
c.RemoteCommitment = *newRemoteCommit
return nil
}
// NextLocalHtlcIndex returns the next unallocated local htlc index. To ensure
// this always returns the next index that has been not been allocated, this
// will first try to examine any pending commitments, before falling back to the
// last locked-in remote commitment.
func (c *OpenChannel) NextLocalHtlcIndex() (uint64, error) {
// First, load the most recent commit diff that we initiated for the
// remote party. If no pending commit is found, this is not treated as
// a critical error, since we can always fall back.
pendingRemoteCommit, err := c.RemoteCommitChainTip()
if err != nil && err != ErrNoPendingCommit {
return 0, err
}
// If a pending commit was found, its local htlc index will be at least
// as large as the one on our local commitment.
if pendingRemoteCommit != nil {
return pendingRemoteCommit.Commitment.LocalHtlcIndex, nil
}
// Otherwise, fallback to using the local htlc index of their commitment.
return c.RemoteCommitment.LocalHtlcIndex, nil
}
// LoadFwdPkgs scans the forwarding log for any packages that haven't been
// processed, and returns their deserialized log updates in map indexed by the
// remote commitment height at which the updates were locked in.
func (c *OpenChannel) LoadFwdPkgs() ([]*FwdPkg, error) {
c.RLock()
defer c.RUnlock()
var fwdPkgs []*FwdPkg
if err := kvdb.View(c.Db, func(tx kvdb.RTx) error {
var err error
fwdPkgs, err = c.Packager.LoadFwdPkgs(tx)
return err
}, func() {
fwdPkgs = nil
}); err != nil {
return nil, err
}
return fwdPkgs, nil
}
// AckAddHtlcs updates the AckAddFilter containing any of the provided AddRefs
// indicating that a response to this Add has been committed to the remote party.
// Doing so will prevent these Add HTLCs from being reforwarded internally.
func (c *OpenChannel) AckAddHtlcs(addRefs ...AddRef) error {
c.Lock()
defer c.Unlock()
return kvdb.Update(c.Db, func(tx kvdb.RwTx) error {
return c.Packager.AckAddHtlcs(tx, addRefs...)
}, func() {})
}
// AckSettleFails updates the SettleFailFilter containing any of the provided
// SettleFailRefs, indicating that the response has been delivered to the
// incoming link, corresponding to a particular AddRef. Doing so will prevent
// the responses from being retransmitted internally.
func (c *OpenChannel) AckSettleFails(settleFailRefs ...SettleFailRef) error {
c.Lock()
defer c.Unlock()
return kvdb.Update(c.Db, func(tx kvdb.RwTx) error {
return c.Packager.AckSettleFails(tx, settleFailRefs...)
}, func() {})
}
// SetFwdFilter atomically sets the forwarding filter for the forwarding package
// identified by `height`.
func (c *OpenChannel) SetFwdFilter(height uint64, fwdFilter *PkgFilter) error {
c.Lock()
defer c.Unlock()
return kvdb.Update(c.Db, func(tx kvdb.RwTx) error {
return c.Packager.SetFwdFilter(tx, height, fwdFilter)
}, func() {})
}
// RemoveFwdPkgs atomically removes forwarding packages specified by the remote
// commitment heights. If one of the intermediate RemovePkg calls fails, then the
// later packages won't be removed.
//
// NOTE: This method should only be called on packages marked FwdStateCompleted.
func (c *OpenChannel) RemoveFwdPkgs(heights ...uint64) error {
c.Lock()
defer c.Unlock()
return kvdb.Update(c.Db, func(tx kvdb.RwTx) error {
for _, height := range heights {
err := c.Packager.RemovePkg(tx, height)
if err != nil {
return err
}
}
return nil
}, func() {})
}
// RevocationLogTail returns the "tail", or the end of the current revocation
// log. This entry represents the last previous state for the remote node's
// commitment chain. The ChannelDelta returned by this method will always lag
// one state behind the most current (unrevoked) state of the remote node's
// commitment chain.
func (c *OpenChannel) RevocationLogTail() (*ChannelCommitment, error) {
c.RLock()
defer c.RUnlock()
// If we haven't created any state updates yet, then we'll exit early as
// there's nothing to be found on disk in the revocation bucket.
if c.RemoteCommitment.CommitHeight == 0 {
return nil, nil
}
var commit ChannelCommitment
if err := kvdb.View(c.Db, func(tx kvdb.RTx) error {
chanBucket, err := fetchChanBucket(
tx, c.IdentityPub, &c.FundingOutpoint, c.ChainHash,
)
if err != nil {
return err
}
logBucket := chanBucket.NestedReadBucket(revocationLogBucket)
if logBucket == nil {
return ErrNoPastDeltas
}
// Once we have the bucket that stores the revocation log from
// this channel, we'll jump to the _last_ key in bucket. As we
// store the update number on disk in a big-endian format,
// this will retrieve the latest entry.
cursor := logBucket.ReadCursor()
_, tailLogEntry := cursor.Last()
logEntryReader := bytes.NewReader(tailLogEntry)
// Once we have the entry, we'll decode it into the channel
// delta pointer we created above.
var dbErr error
commit, dbErr = deserializeChanCommit(logEntryReader)
if dbErr != nil {
return dbErr
}
return nil
}, func() {}); err != nil {
return nil, err
}
return &commit, nil
}
// CommitmentHeight returns the current commitment height. The commitment
// height represents the number of updates to the commitment state to date.
// This value is always monotonically increasing. This method is provided in
// order to allow multiple instances of a particular open channel to obtain a
// consistent view of the number of channel updates to date.
func (c *OpenChannel) CommitmentHeight() (uint64, error) {
c.RLock()
defer c.RUnlock()
var height uint64
err := kvdb.View(c.Db, func(tx kvdb.RTx) error {
// Get the bucket dedicated to storing the metadata for open
// channels.
chanBucket, err := fetchChanBucket(
tx, c.IdentityPub, &c.FundingOutpoint, c.ChainHash,
)
if err != nil {
return err
}
commit, err := fetchChanCommitment(chanBucket, true)
if err != nil {
return err
}
height = commit.CommitHeight
return nil
}, func() {
height = 0
})
if err != nil {
return 0, err
}
return height, nil
}
// FindPreviousState scans through the append-only log in an attempt to recover
// the previous channel state indicated by the update number. This method is
// intended to be used for obtaining the relevant data needed to claim all
// funds rightfully spendable in the case of an on-chain broadcast of the
// commitment transaction.
func (c *OpenChannel) FindPreviousState(updateNum uint64) (*ChannelCommitment, error) {
c.RLock()
defer c.RUnlock()
var commit ChannelCommitment
err := kvdb.View(c.Db, func(tx kvdb.RTx) error {
chanBucket, err := fetchChanBucket(
tx, c.IdentityPub, &c.FundingOutpoint, c.ChainHash,
)
if err != nil {
return err
}
logBucket := chanBucket.NestedReadBucket(revocationLogBucket)
if logBucket == nil {
return ErrNoPastDeltas
}
c, err := fetchChannelLogEntry(logBucket, updateNum)
if err != nil {
return err
}
commit = c
return nil
}, func() {})
if err != nil {
return nil, err
}
return &commit, nil
}
// ClosureType is an enum like structure that details exactly _how_ a channel
// was closed. Three closure types are currently possible: none, cooperative,
// local force close, remote force close, and (remote) breach.
type ClosureType uint8
const (
// CooperativeClose indicates that a channel has been closed
// cooperatively. This means that both channel peers were online and
// signed a new transaction paying out the settled balance of the
// contract.
CooperativeClose ClosureType = 0
// LocalForceClose indicates that we have unilaterally broadcast our
// current commitment state on-chain.
LocalForceClose ClosureType = 1
// RemoteForceClose indicates that the remote peer has unilaterally
// broadcast their current commitment state on-chain.
RemoteForceClose ClosureType = 4
// BreachClose indicates that the remote peer attempted to broadcast a
// prior _revoked_ channel state.
BreachClose ClosureType = 2
// FundingCanceled indicates that the channel never was fully opened
// before it was marked as closed in the database. This can happen if
// we or the remote fail at some point during the opening workflow, or
// we timeout waiting for the funding transaction to be confirmed.
FundingCanceled ClosureType = 3
// Abandoned indicates that the channel state was removed without
// any further actions. This is intended to clean up unusable
// channels during development.
Abandoned ClosureType = 5
)
// 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.
type ChannelCloseSummary struct {
// ChanPoint is the outpoint for this channel's funding transaction,
// and is used as a unique identifier for the channel.
ChanPoint wire.OutPoint
// ShortChanID encodes the exact location in the chain in which the
// channel was initially confirmed. This includes: the block height,
// transaction index, and the output within the target transaction.
ShortChanID lnwire.ShortChannelID
// ChainHash is the hash of the genesis block that this channel resides
// within.
ChainHash chainhash.Hash
// ClosingTXID is the txid of the transaction which ultimately closed
// this channel.
ClosingTXID chainhash.Hash
// RemotePub is the public key of the remote peer that we formerly had
// a channel with.
RemotePub *btcec.PublicKey
// Capacity was the total capacity of the channel.
Capacity btcutil.Amount
// CloseHeight is the height at which the funding transaction was
// spent.
CloseHeight uint32
// SettledBalance is our total balance settled balance at the time of
// channel closure. This _does not_ include the sum of any outputs that
// have been time-locked as a result of the unilateral channel closure.
SettledBalance btcutil.Amount
// TimeLockedBalance is the sum of all the time-locked outputs at the
// time of channel closure. If we triggered the force closure of this
// channel, then this value will be non-zero if our settled output is
// above the dust limit. If we were on the receiving side of a channel
// force closure, then this value will be non-zero if we had any
// outstanding outgoing HTLC's at the time of channel closure.
TimeLockedBalance btcutil.Amount
// CloseType details exactly _how_ the channel was closed. Five closure
// types are possible: cooperative, local force, remote force, breach
// and funding canceled.
CloseType ClosureType
// IsPending indicates whether this channel is in the 'pending close'
// state, which means the channel closing transaction has been
// confirmed, but not yet been fully resolved. In the case of a channel
// that has been cooperatively closed, it will go straight into the
// fully resolved state as soon as the closing transaction has been
// confirmed. However, for channels that have been force 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 is 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
// LastChanSyncMsg is the ChannelReestablish message for this channel
// for the state at the point where it was closed.
LastChanSyncMsg *lnwire.ChannelReestablish
}
// CloseChannel closes a previously active Lightning channel. Closing a channel
// entails deleting all saved state within the database concerning this
// channel. This method also takes a struct that summarizes the state of the
// channel at closing, this compact representation will be the only component
// of a channel left over after a full closing. It takes an optional set of
// channel statuses which will be written to the historical channel bucket.
// These statuses are used to record close initiators.
func (c *OpenChannel) CloseChannel(summary *ChannelCloseSummary,
statuses ...ChannelStatus) error {
c.Lock()
defer c.Unlock()
return kvdb.Update(c.Db, func(tx kvdb.RwTx) error {
openChanBucket := tx.ReadWriteBucket(openChannelBucket)
if openChanBucket == nil {
return ErrNoChanDBExists
}
nodePub := c.IdentityPub.SerializeCompressed()
nodeChanBucket := openChanBucket.NestedReadWriteBucket(nodePub)
if nodeChanBucket == nil {
return ErrNoActiveChannels
}
chainBucket := nodeChanBucket.NestedReadWriteBucket(c.ChainHash[:])
if chainBucket == nil {
return ErrNoActiveChannels
}
var chanPointBuf bytes.Buffer
err := writeOutpoint(&chanPointBuf, &c.FundingOutpoint)
if err != nil {
return err
}
chanKey := chanPointBuf.Bytes()
chanBucket := chainBucket.NestedReadWriteBucket(
chanKey,
)
if chanBucket == nil {
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)
if err != nil {
return err
}
// We'll also remove the channel from the frozen channel bucket
// if we need to.
if c.ChanType.IsFrozen() {
err := deleteThawHeight(chanBucket)
if err != nil {
return err
}
}
// With the base channel data deleted, attempt to delete the
// information stored within the revocation log.
logBucket := chanBucket.NestedReadWriteBucket(revocationLogBucket)
if logBucket != nil {
err = chanBucket.DeleteNestedBucket(revocationLogBucket)
if err != nil {
return err
}
}
err = chainBucket.DeleteNestedBucket(chanPointBuf.Bytes())
if err != nil {
return err
}
// Fetch the outpoint bucket to see if the outpoint exists or
// not.
opBucket := tx.ReadWriteBucket(outpointBucket)
// Add the closed outpoint to our outpoint index. This should
// replace an open outpoint in the index.
if opBucket.Get(chanPointBuf.Bytes()) == nil {
return ErrMissingIndexEntry
}
status := uint8(outpointClosed)
// Write the IndexStatus of this outpoint as the first entry in a tlv
// stream.
statusRecord := tlv.MakePrimitiveRecord(indexStatusType, &status)
opStream, err := tlv.NewStream(statusRecord)
if err != nil {
return err
}
var b bytes.Buffer
if err := opStream.Encode(&b); err != nil {
return err
}
// Finally add the closed outpoint and tlv stream to the index.
if err := opBucket.Put(chanPointBuf.Bytes(), b.Bytes()); err != nil {
return err
}
// Add channel state to the historical channel bucket.
historicalBucket, err := tx.CreateTopLevelBucket(
historicalChannelBucket,
)
if err != nil {
return err
}
historicalChanBucket, err :=
historicalBucket.CreateBucketIfNotExists(chanKey)
if err != nil {
return err
}
// Apply any additional statuses to the channel state.
for _, status := range statuses {
chanState.chanStatus |= status
}
err = putOpenChannel(historicalChanBucket, chanState)
if err != nil {
return err
}
// Finally, create a summary of this channel in the closed
// channel bucket for this node.
return putChannelCloseSummary(
tx, chanPointBuf.Bytes(), summary, chanState,
)
}, func() {})
}
// ChannelSnapshot is a frozen snapshot of the current channel state. A
// snapshot is detached from the original channel that generated it, providing
// read-only access to the current or prior state of an active channel.
//
// TODO(roasbeef): remove all together? pretty much just commitment
type ChannelSnapshot struct {
// RemoteIdentity is the identity public key of the remote node that we
// are maintaining the open channel with.
RemoteIdentity btcec.PublicKey
// ChanPoint is the outpoint that created the channel. This output is
// found within the funding transaction and uniquely identified the
// channel on the resident chain.
ChannelPoint wire.OutPoint
// ChainHash is the genesis hash of the chain that the channel resides
// within.
ChainHash chainhash.Hash
// Capacity is the total capacity of the channel.
Capacity btcutil.Amount
// TotalMSatSent is the total number of milli-satoshis we've sent
// within this channel.
TotalMSatSent lnwire.MilliSatoshi
// TotalMSatReceived is the total number of milli-satoshis we've
// received within this channel.
TotalMSatReceived lnwire.MilliSatoshi
// ChannelCommitment is the current up-to-date commitment for the
// target channel.
ChannelCommitment
}
// Snapshot returns a read-only snapshot of the current channel state. This
// snapshot includes information concerning the current settled balance within
// the channel, metadata detailing total flows, and any outstanding HTLCs.
func (c *OpenChannel) Snapshot() *ChannelSnapshot {
c.RLock()
defer c.RUnlock()
localCommit := c.LocalCommitment
snapshot := &ChannelSnapshot{
RemoteIdentity: *c.IdentityPub,
ChannelPoint: c.FundingOutpoint,
Capacity: c.Capacity,
TotalMSatSent: c.TotalMSatSent,
TotalMSatReceived: c.TotalMSatReceived,
ChainHash: c.ChainHash,
ChannelCommitment: ChannelCommitment{
LocalBalance: localCommit.LocalBalance,
RemoteBalance: localCommit.RemoteBalance,
CommitHeight: localCommit.CommitHeight,
CommitFee: localCommit.CommitFee,
},
}
// Copy over the current set of HTLCs to ensure the caller can't mutate
// our internal state.
snapshot.Htlcs = make([]HTLC, len(localCommit.Htlcs))
for i, h := range localCommit.Htlcs {
snapshot.Htlcs[i] = h.Copy()
}
return snapshot
}
// LatestCommitments returns the two latest commitments for both the local and
// remote party. These commitments are read from disk to ensure that only the
// latest fully committed state is returned. The first commitment returned is
// the local commitment, and the second returned is the remote commitment.
func (c *OpenChannel) LatestCommitments() (*ChannelCommitment, *ChannelCommitment, error) {
err := kvdb.View(c.Db, func(tx kvdb.RTx) error {
chanBucket, err := fetchChanBucket(
tx, c.IdentityPub, &c.FundingOutpoint, c.ChainHash,
)
if err != nil {
return err
}
return fetchChanCommitments(chanBucket, c)
}, func() {})
if err != nil {
return nil, nil, err
}
return &c.LocalCommitment, &c.RemoteCommitment, nil
}
// RemoteRevocationStore returns the most up to date commitment version of the
// revocation storage tree for the remote party. This method can be used when
// acting on a possible contract breach to ensure, that the caller has the most
// up to date information required to deliver justice.
func (c *OpenChannel) RemoteRevocationStore() (shachain.Store, error) {
err := kvdb.View(c.Db, func(tx kvdb.RTx) error {
chanBucket, err := fetchChanBucket(
tx, c.IdentityPub, &c.FundingOutpoint, c.ChainHash,
)
if err != nil {
return err
}
return fetchChanRevocationState(chanBucket, c)
}, func() {})
if err != nil {
return nil, err
}
return c.RevocationStore, nil
}
// AbsoluteThawHeight determines a frozen channel's absolute thaw height. If the
// channel is not frozen, then 0 is returned.
func (c *OpenChannel) AbsoluteThawHeight() (uint32, error) {
// Only frozen channels have a thaw height.
if !c.ChanType.IsFrozen() {
return 0, nil
}
// If the channel's thaw height is below the absolute threshold, then
// it's interpreted as a relative height to the chain's current height.
if c.ThawHeight < AbsoluteThawHeightThreshold {
// We'll only known of the channel's short ID once it's
// confirmed.
if c.IsPending {
return 0, errors.New("cannot use relative thaw " +
"height for unconfirmed channel")
}
return c.ShortChannelID.BlockHeight + c.ThawHeight, nil
}
return c.ThawHeight, nil
}
func putChannelCloseSummary(tx kvdb.RwTx, chanID []byte,
summary *ChannelCloseSummary, lastChanState *OpenChannel) error {
closedChanBucket, err := tx.CreateTopLevelBucket(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
}
return closedChanBucket.Put(chanID, b.Bytes())
}
func serializeChannelCloseSummary(w io.Writer, cs *ChannelCloseSummary) error {
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 WriteElements(w, false)
}
// If fields are present, write boolean to indicate this, and continue.
if err := WriteElements(w, true); err != nil {
return err
}
if err := WriteElements(w, cs.RemoteCurrentRevocation); err != nil {
return err
}
if err := writeChanConfig(w, &cs.LocalChanConfig); err != nil {
return err
}
// The RemoteNextRevocation field is optional, as it's possible for a
// channel to be closed before we learn of the next unrevoked
// revocation point for the remote party. Write a boolen indicating
// whether this field is present or not.
if err := WriteElements(w, cs.RemoteNextRevocation != nil); err != nil {
return err
}
// Write the field, if present.
if cs.RemoteNextRevocation != nil {
if err = WriteElements(w, cs.RemoteNextRevocation); err != nil {
return err
}
}
// Write whether the channel sync message is present.
if err := WriteElements(w, cs.LastChanSyncMsg != nil); err != nil {
return err
}
// Write the channel sync message, if present.
if cs.LastChanSyncMsg != nil {
if err := WriteElements(w, cs.LastChanSyncMsg); err != nil {
return err
}
}
return nil
}
func deserializeCloseChannelSummary(r io.Reader) (*ChannelCloseSummary, error) {
c := &ChannelCloseSummary{}
err := ReadElements(r,
&c.ChanPoint, &c.ShortChanID, &c.ChainHash, &c.ClosingTXID,
&c.CloseHeight, &c.RemotePub, &c.Capacity, &c.SettledBalance,
&c.TimeLockedBalance, &c.CloseType, &c.IsPending,
)
if err != nil {
return nil, err
}
// We'll now check to see if the channel close summary was encoded with
// any of the additional optional fields.
var hasNewFields bool
err = ReadElements(r, &hasNewFields)
if err != nil {
return nil, err
}
// If fields are not present, we can return.
if !hasNewFields {
return c, nil
}
// Otherwise read the new fields.
if err := ReadElements(r, &c.RemoteCurrentRevocation); 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 might not be present. A boolean
// indicating whether the field is present will come first.
var hasRemoteNextRevocation bool
err = ReadElements(r, &hasRemoteNextRevocation)
if err != nil {
return nil, err
}
// If this field was written, read it.
if hasRemoteNextRevocation {
err = ReadElements(r, &c.RemoteNextRevocation)
if err != nil {
return nil, err
}
}
// Check if we have a channel sync message to read.
var hasChanSyncMsg bool
err = ReadElements(r, &hasChanSyncMsg)
if err == io.EOF {
return c, nil
} else if err != nil {
return nil, err
}
// If a chan sync message is present, read it.
if hasChanSyncMsg {
// We must pass in reference to a lnwire.Message for the codec
// to support it.
var msg lnwire.Message
if err := ReadElements(r, &msg); err != nil {
return nil, err
}
chanSync, ok := msg.(*lnwire.ChannelReestablish)
if !ok {
return nil, errors.New("unable cast db Message to " +
"ChannelReestablish")
}
c.LastChanSyncMsg = chanSync
}
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,
)
}
// fundingTxPresent returns true if expect the funding transcation to be found
// on disk or already populated within the passed oen chanel struct.
func fundingTxPresent(channel *OpenChannel) bool {
chanType := channel.ChanType
return chanType.IsSingleFunder() && chanType.HasFundingTx() &&
channel.IsInitiator &&
!channel.hasChanStatus(ChanStatusRestored)
}
func putChanInfo(chanBucket kvdb.RwBucket, channel *OpenChannel) error {
var w bytes.Buffer
if err := WriteElements(&w,
channel.ChanType, channel.ChainHash, channel.FundingOutpoint,
channel.ShortChannelID, channel.IsPending, channel.IsInitiator,
channel.chanStatus, channel.FundingBroadcastHeight,
channel.NumConfsRequired, channel.ChannelFlags,
channel.IdentityPub, channel.Capacity, channel.TotalMSatSent,
channel.TotalMSatReceived,
); err != nil {
return err
}
// For single funder channels that we initiated, and we have the
// funding transaction, then write the funding txn.
if fundingTxPresent(channel) {
if err := WriteElement(&w, channel.FundingTxn); err != nil {
return err
}
}
if err := writeChanConfig(&w, &channel.LocalChanCfg); err != nil {
return err
}
if err := writeChanConfig(&w, &channel.RemoteChanCfg); err != nil {
return err
}
if err := chanBucket.Put(chanInfoKey, w.Bytes()); err != nil {
return err
}
// Finally, add optional shutdown scripts for the local and remote peer if
// they are present.
if err := putOptionalUpfrontShutdownScript(
chanBucket, localUpfrontShutdownKey, channel.LocalShutdownScript,
); err != nil {
return err
}
return putOptionalUpfrontShutdownScript(
chanBucket, remoteUpfrontShutdownKey, channel.RemoteShutdownScript,
)
}
// putOptionalUpfrontShutdownScript adds a shutdown script under the key
// provided if it has a non-zero length.
func putOptionalUpfrontShutdownScript(chanBucket kvdb.RwBucket, key []byte,
script []byte) error {
// If the script is empty, we do not need to add anything.
if len(script) == 0 {
return nil
}
var w bytes.Buffer
if err := WriteElement(&w, script); err != nil {
return err
}
return chanBucket.Put(key, w.Bytes())
}
// getOptionalUpfrontShutdownScript reads the shutdown script stored under the
// key provided if it is present. Upfront shutdown scripts are optional, so the
// function returns with no error if the key is not present.
func getOptionalUpfrontShutdownScript(chanBucket kvdb.RBucket, key []byte,
script *lnwire.DeliveryAddress) error {
// Return early if the bucket does not exit, a shutdown script was not set.
bs := chanBucket.Get(key)
if bs == nil {
return nil
}
var tempScript []byte
r := bytes.NewReader(bs)
if err := ReadElement(r, &tempScript); err != nil {
return err
}
*script = tempScript
return nil
}
func serializeChanCommit(w io.Writer, c *ChannelCommitment) error {
if err := WriteElements(w,
c.CommitHeight, c.LocalLogIndex, c.LocalHtlcIndex,
c.RemoteLogIndex, c.RemoteHtlcIndex, c.LocalBalance,
c.RemoteBalance, c.CommitFee, c.FeePerKw, c.CommitTx,
c.CommitSig,
); err != nil {
return err
}
return SerializeHtlcs(w, c.Htlcs...)
}
func putChanCommitment(chanBucket kvdb.RwBucket, c *ChannelCommitment,
local bool) error {
var commitKey []byte
if local {
commitKey = append(chanCommitmentKey, byte(0x00))
} else {
commitKey = append(chanCommitmentKey, byte(0x01))
}
var b bytes.Buffer
if err := serializeChanCommit(&b, c); err != nil {
return err
}
return chanBucket.Put(commitKey, b.Bytes())
}
func putChanCommitments(chanBucket kvdb.RwBucket, channel *OpenChannel) error {
// If this is a restored channel, then we don't have any commitments to
// write.
if channel.hasChanStatus(ChanStatusRestored) {
return nil
}
err := putChanCommitment(
chanBucket, &channel.LocalCommitment, true,
)
if err != nil {
return err
}
return putChanCommitment(
chanBucket, &channel.RemoteCommitment, false,
)
}
func putChanRevocationState(chanBucket kvdb.RwBucket, channel *OpenChannel) error {
var b bytes.Buffer
err := 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 = WriteElements(&b, channel.RemoteNextRevocation)
if err != nil {
return err
}
}
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 kvdb.RBucket, channel *OpenChannel) error {
infoBytes := chanBucket.Get(chanInfoKey)
if infoBytes == nil {
return ErrNoChanInfoFound
}
r := bytes.NewReader(infoBytes)
if err := ReadElements(r,
&channel.ChanType, &channel.ChainHash, &channel.FundingOutpoint,
&channel.ShortChannelID, &channel.IsPending, &channel.IsInitiator,
&channel.chanStatus, &channel.FundingBroadcastHeight,
&channel.NumConfsRequired, &channel.ChannelFlags,
&channel.IdentityPub, &channel.Capacity, &channel.TotalMSatSent,
&channel.TotalMSatReceived,
); err != nil {
return err
}
// For single funder channels that we initiated and have the funding
// transaction to, read the funding txn.
if fundingTxPresent(channel) {
if err := ReadElement(r, &channel.FundingTxn); err != nil {
return err
}
}
if err := readChanConfig(r, &channel.LocalChanCfg); err != nil {
return err
}
if err := readChanConfig(r, &channel.RemoteChanCfg); err != nil {
return err
}
channel.Packager = NewChannelPackager(channel.ShortChannelID)
// Finally, read the optional shutdown scripts.
if err := getOptionalUpfrontShutdownScript(
chanBucket, localUpfrontShutdownKey, &channel.LocalShutdownScript,
); err != nil {
return err
}
return getOptionalUpfrontShutdownScript(
chanBucket, remoteUpfrontShutdownKey, &channel.RemoteShutdownScript,
)
}
func deserializeChanCommit(r io.Reader) (ChannelCommitment, error) {
var c ChannelCommitment
err := ReadElements(r,
&c.CommitHeight, &c.LocalLogIndex, &c.LocalHtlcIndex, &c.RemoteLogIndex,
&c.RemoteHtlcIndex, &c.LocalBalance, &c.RemoteBalance,
&c.CommitFee, &c.FeePerKw, &c.CommitTx, &c.CommitSig,
)
if err != nil {
return c, err
}
c.Htlcs, err = DeserializeHtlcs(r)
if err != nil {
return c, err
}
return c, nil
}
func fetchChanCommitment(chanBucket kvdb.RBucket, local bool) (ChannelCommitment, error) {
var commitKey []byte
if local {
commitKey = append(chanCommitmentKey, byte(0x00))
} else {
commitKey = append(chanCommitmentKey, byte(0x01))
}
commitBytes := chanBucket.Get(commitKey)
if commitBytes == nil {
return ChannelCommitment{}, ErrNoCommitmentsFound
}
r := bytes.NewReader(commitBytes)
return deserializeChanCommit(r)
}
func fetchChanCommitments(chanBucket kvdb.RBucket, channel *OpenChannel) error {
var err error
// If this is a restored channel, then we don't have any commitments to
// read.
if channel.hasChanStatus(ChanStatusRestored) {
return nil
}
channel.LocalCommitment, err = fetchChanCommitment(chanBucket, true)
if err != nil {
return err
}
channel.RemoteCommitment, err = fetchChanCommitment(chanBucket, false)
if err != nil {
return err
}
return nil
}
func fetchChanRevocationState(chanBucket kvdb.RBucket, channel *OpenChannel) error {
revBytes := chanBucket.Get(revocationStateKey)
if revBytes == nil {
return ErrNoRevocationsFound
}
r := bytes.NewReader(revBytes)
err := ReadElements(
r, &channel.RemoteCurrentRevocation, &channel.RevocationProducer,
&channel.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 ReadElements(r, &channel.RemoteNextRevocation)
}
func deleteOpenChannel(chanBucket kvdb.RwBucket) error {
if err := chanBucket.Delete(chanInfoKey); err != nil {
return err
}
err := chanBucket.Delete(append(chanCommitmentKey, byte(0x00)))
if err != nil {
return err
}
err = chanBucket.Delete(append(chanCommitmentKey, byte(0x01)))
if err != nil {
return err
}
if err := chanBucket.Delete(revocationStateKey); err != nil {
return err
}
if diff := chanBucket.Get(commitDiffKey); diff != nil {
return chanBucket.Delete(commitDiffKey)
}
return nil
}
// makeLogKey converts a uint64 into an 8 byte array.
func makeLogKey(updateNum uint64) [8]byte {
var key [8]byte
byteOrder.PutUint64(key[:], updateNum)
return key
}
func appendChannelLogEntry(log kvdb.RwBucket,
commit *ChannelCommitment) error {
var b bytes.Buffer
if err := serializeChanCommit(&b, commit); err != nil {
return err
}
logEntrykey := makeLogKey(commit.CommitHeight)
return log.Put(logEntrykey[:], b.Bytes())
}
func fetchChannelLogEntry(log kvdb.RBucket,
updateNum uint64) (ChannelCommitment, error) {
logEntrykey := makeLogKey(updateNum)
commitBytes := log.Get(logEntrykey[:])
if commitBytes == nil {
return ChannelCommitment{}, ErrLogEntryNotFound
}
commitReader := bytes.NewReader(commitBytes)
return deserializeChanCommit(commitReader)
}
func fetchThawHeight(chanBucket kvdb.RBucket) (uint32, error) {
var height uint32
heightBytes := chanBucket.Get(frozenChanKey)
heightReader := bytes.NewReader(heightBytes)
if err := ReadElements(heightReader, &height); err != nil {
return 0, err
}
return height, nil
}
func storeThawHeight(chanBucket kvdb.RwBucket, height uint32) error {
var heightBuf bytes.Buffer
if err := WriteElements(&heightBuf, height); err != nil {
return err
}
return chanBucket.Put(frozenChanKey, heightBuf.Bytes())
}
func deleteThawHeight(chanBucket kvdb.RwBucket) error {
return chanBucket.Delete(frozenChanKey)
}