lightningnetwork / lnd / 11292787765

package lnwallet

import (

        "crypto/sha256"

        "github.com/lightningnetwork/lnd/channeldb"

        "github.com/lightningnetwork/lnd/channeldb/models"

        "github.com/lightningnetwork/lnd/input"

        "github.com/lightningnetwork/lnd/lnwire"

)

// updateType is the exact type of an entry within the shared HTLC log.

type updateType uint8

const (

        // Add is an update type that adds a new HTLC entry into the log.

        // Either side can add a new pending HTLC by adding a new Add entry

        // into their update log.

        Add updateType = iota

        // Fail is an update type which removes a prior HTLC entry from the

        // log. Adding a Fail entry to one's log will modify the _remote_

        // party's update log once a new commitment view has been evaluated

        // which contains the Fail entry.

        Fail

        // MalformedFail is an update type which removes a prior HTLC entry

        // from the log. Adding a MalformedFail entry to one's log will modify

        // the _remote_ party's update log once a new commitment view has been

        // evaluated which contains the MalformedFail entry. The difference

        // from Fail type lie in the different data we have to store.

        MalformedFail

        // Settle is an update type which settles a prior HTLC crediting the

        // balance of the receiving node. Adding a Settle entry to a log will

        // result in the settle entry being removed on the log as well as the

        // original add entry from the remote party's log after the next state

        // transition.

        Settle

        // FeeUpdate is an update type sent by the channel initiator that

        // updates the fee rate used when signing the commitment transaction.

        FeeUpdate

)

// String returns a human readable string that uniquely identifies the target

// update type.

        }

}

// paymentDescriptor represents a commitment state update which either adds,

// settles, or removes an HTLC. paymentDescriptors encapsulate all necessary

// metadata w.r.t to an HTLC, and additional data pairing a settle message to

// the original added HTLC.

//

// TODO(roasbeef): LogEntry interface??

//   - need to separate attrs for cancel/add/settle/feeupdate

type paymentDescriptor struct {

        // ChanID is the ChannelID of the LightningChannel that this

        // paymentDescriptor belongs to. We track this here so we can

        // reconstruct the Messages that this paymentDescriptor is built from.

        ChanID lnwire.ChannelID

        // RHash is the payment hash for this HTLC. The HTLC can be settled iff

        // the preimage to this hash is presented.

        RHash PaymentHash

        // RPreimage is the preimage that settles the HTLC pointed to within the

        // log by the ParentIndex.

        RPreimage PaymentHash

        // Timeout is the absolute timeout in blocks, after which this HTLC

        // expires.

        Timeout uint32

        // Amount is the HTLC amount in milli-satoshis.

        Amount lnwire.MilliSatoshi

        // LogIndex is the log entry number that his HTLC update has within the

        // log. Depending on if IsIncoming is true, this is either an entry the

        // remote party added, or one that we added locally.

        LogIndex uint64

        // HtlcIndex is the index within the main update log for this HTLC.

        // Entries within the log of type Add will have this field populated,

        // as other entries will point to the entry via this counter.

        //

        // NOTE: This field will only be populate if EntryType is Add.

        HtlcIndex uint64

        // ParentIndex is the HTLC index of the entry that this update settles

        // or times out.

        //

        // NOTE: This field will only be populate if EntryType is Fail or

        // Settle.

        ParentIndex uint64

        // SourceRef points to an Add update in a forwarding package owned by

        // this channel.

        //

        // NOTE: This field will only be populated if EntryType is Fail or

        // Settle.

        SourceRef *channeldb.AddRef

        // DestRef points to a Fail/Settle update in another link's forwarding

        // package.

        //

        // NOTE: This field will only be populated if EntryType is Fail or

        // Settle, and the forwarded Add successfully included in an outgoing

        // link's commitment txn.

        DestRef *channeldb.SettleFailRef

        // OpenCircuitKey references the incoming Chan/HTLC ID of an Add HTLC

        // packet delivered by the switch.

        //

        // NOTE: This field is only populated for payment descriptors in the

        // *local* update log, and if the Add packet was delivered by the

        // switch.

        OpenCircuitKey *models.CircuitKey

        // ClosedCircuitKey references the incoming Chan/HTLC ID of the Add HTLC

        // that opened the circuit.

        //

        // NOTE: This field is only populated for payment descriptors in the

        // *local* update log, and if settle/fails have a committed circuit in

        // the circuit map.

        ClosedCircuitKey *models.CircuitKey

        // localOutputIndex is the output index of this HTLc output in the

        // commitment transaction of the local node.

        //

        // NOTE: If the output is dust from the PoV of the local commitment

        // chain, then this value will be -1.

        localOutputIndex int32

        // remoteOutputIndex is the output index of this HTLC output in the

        // commitment transaction of the remote node.

        //

        // NOTE: If the output is dust from the PoV of the remote commitment

        // chain, then this value will be -1.

        remoteOutputIndex int32

        // sig is the signature for the second-level HTLC transaction that

        // spends the version of this HTLC on the commitment transaction of the

        // local node. This signature is generated by the remote node and

        // stored by the local node in the case that local node needs to

        // broadcast their commitment transaction.

        sig input.Signature

        // addCommitHeight[Remote|Local] encodes the height of the commitment

        // which included this HTLC on either the remote or local commitment

        // chain. This value is used to determine when an HTLC is fully

        // "locked-in".

        addCommitHeightRemote uint64

        addCommitHeightLocal  uint64

        // removeCommitHeight[Remote|Local] encodes the height of the

        // commitment which removed the parent pointer of this

        // paymentDescriptor either due to a timeout or a settle. Once both

        // these heights are below the tail of both chains, the log entries can

        // safely be removed.

        removeCommitHeightRemote uint64

        removeCommitHeightLocal  uint64

        // OnionBlob is an opaque blob which is used to complete multi-hop

        // routing.

        //

        // NOTE: Populated only on add payment descriptor entry types.

        OnionBlob [lnwire.OnionPacketSize]byte

        // ShaOnionBlob is a sha of the onion blob.

        //

        // NOTE: Populated only in payment descriptor with MalformedFail type.

        ShaOnionBlob [sha256.Size]byte

        // FailReason stores the reason why a particular payment was canceled.

        //

        // NOTE: Populate only in fail payment descriptor entry types.

        FailReason []byte

        // FailCode stores the code why a particular payment was canceled.

        //

        // NOTE: Populated only in payment descriptor with MalformedFail type.

        FailCode lnwire.FailCode

        // [our|their|]PkScript are the raw public key scripts that encodes the

        // redemption rules for this particular HTLC. These fields will only be

        // populated iff the EntryType of this paymentDescriptor is Add.

        // ourPkScript is the ourPkScript from the context of our local

        // commitment chain. theirPkScript is the latest pkScript from the

        // context of the remote commitment chain.

        //

        // NOTE: These values may change within the logs themselves, however,

        // they'll stay consistent within the commitment chain entries

        // themselves.

        ourPkScript        []byte

        ourWitnessScript   []byte

        theirPkScript      []byte

        theirWitnessScript []byte

        // EntryType denotes the exact type of the paymentDescriptor. In the

        // case of a Timeout, or Settle type, then the Parent field will point

        // into the log to the HTLC being modified.

        EntryType updateType

        // isForwarded denotes if an incoming HTLC has been forwarded to any

        // possible upstream peers in the route.

        isForwarded bool

        // BlindingPoint is an optional ephemeral key used in route blinding.

        // This value is set for nodes that are relaying payments inside of a

        // blinded route (ie, not the introduction node) from update_add_htlc's

        // TLVs.

        BlindingPoint lnwire.BlindingPointRecord

        // CustomRecords also stores the set of optional custom records that

        // may have been attached to a sent HTLC.

        CustomRecords lnwire.CustomRecords

}

// toLogUpdate recovers the underlying LogUpdate from the paymentDescriptor.

// This operation is lossy and will forget some extra information tracked by the

// paymentDescriptor but the function is total in that all paymentDescriptors

// can be converted back to LogUpdates.

        }

}