Documentation
¶
Index ¶
- Constants
- Variables
- type Hop
- type Route
- func (r *Route) Copy() *Route
- func (r *Route) FinalHop() *Hop
- func (r *Route) HopFee(hopIndex int) lnwire.MilliSatoshi
- func (r *Route) ReceiverAmt() lnwire.MilliSatoshi
- func (r *Route) String() string
- func (r *Route) ToSphinxPath() (*sphinx.PaymentPath, error)
- func (r *Route) TotalFees() lnwire.MilliSatoshi
- type Vertex
Constants ¶
const VertexSize = 33
VertexSize is the size of the array to store a vertex.
Variables ¶
var ( // ErrNoRouteHopsProvided is returned when a caller attempts to // construct a new sphinx packet, but provides an empty set of hops for // each route. ErrNoRouteHopsProvided = fmt.Errorf("empty route hops provided") // ErrMaxRouteHopsExceeded is returned when a caller attempts to // construct a new sphinx packet, but provides too many hops. ErrMaxRouteHopsExceeded = fmt.Errorf("route has too many hops") // ErrIntermediateMPPHop is returned when a hop tries to deliver an MPP // record to an intermediate hop, only final hops can receive MPP // records. ErrIntermediateMPPHop = errors.New("cannot send MPP to intermediate") // ErrAMPMissingMPP is returned when the caller tries to attach an AMP // record but no MPP record is presented for the final hop. ErrAMPMissingMPP = errors.New("cannot send AMP without MPP record") // ErrMissingField is returned if a required TLV is missing. ErrMissingField = errors.New("required tlv missing") // ErrUnexpectedField is returned if a tlv field is included when it // should not be. ErrUnexpectedField = errors.New("unexpected tlv included") )
Functions ¶
This section is empty.
Types ¶
type Hop ¶
type Hop struct {
// PubKeyBytes is the raw bytes of the public key of the target node.
PubKeyBytes Vertex
// ChannelID is the unique channel ID for the channel. The first 3
// bytes are the block height, the next 3 the index within the block,
// and the last 2 bytes are the output index for the channel.
ChannelID uint64
// OutgoingTimeLock is the timelock value that should be used when
// crafting the _outgoing_ HTLC from this hop.
OutgoingTimeLock uint32
// AmtToForward is the amount that this hop will forward to the next
// hop. This value is less than the value that the incoming HTLC
// carries as a fee will be subtracted by the hop.
AmtToForward lnwire.MilliSatoshi
// MPP encapsulates the data required for option_mpp. This field should
// only be set for the final hop.
MPP *record.MPP
// AMP encapsulates the data required for option_amp. This field should
// only be set for the final hop.
AMP *record.AMP
// CustomRecords if non-nil are a set of additional TLV records that
// should be included in the forwarding instructions for this node.
CustomRecords record.CustomSet
// LegacyPayload if true, then this signals that this node doesn't
// understand the new TLV payload, so we must instead use the legacy
// payload.
//
// NOTE: we should no longer ever create a Hop with Legacy set to true.
// The only reason we are keeping this member is that it could be the
// case that we have serialised hops persisted to disk where
// LegacyPayload is true.
LegacyPayload bool
// Metadata is additional data that is sent along with the payment to
// the payee.
Metadata []byte
// EncryptedData is an encrypted data blob includes for hops that are
// part of a blinded route.
EncryptedData []byte
// BlindingPoint is an ephemeral public key used by introduction nodes
// in blinded routes to unblind their portion of the route and pass on
// the next ephemeral key to the next blinded node to do the same.
BlindingPoint *btcec.PublicKey
// TotalAmtMsat is the total amount for a blinded payment, potentially
// spread over more than one HTLC. This field should only be set for
// the final hop in a blinded path.
TotalAmtMsat lnwire.MilliSatoshi
}
Hop represents an intermediate or final node of the route. This naming is in line with the definition given in BOLT #4: Onion Routing Protocol. The struct houses the channel along which this hop can be reached and the values necessary to create the HTLC that needs to be sent to the next hop. It is also used to encode the per-hop payload included within the Sphinx packet.
func (*Hop) PackHopPayload ¶
PackHopPayload writes to the passed io.Writer, the series of byes that can be placed directly into the per-hop payload (EOB) for this hop. This will include the required routing fields, as well as serializing any of the passed optional TLVRecords. nextChanID is the unique channel ID that references the _outgoing_ channel ID that follows this hop. The lastHop bool is used to signal whether this hop is the final hop in a route. Previously, a zero nextChanID would be used for this purpose, but with the addition of blinded routes which allow zero nextChanID values for intermediate hops we add an explicit signal.
func (*Hop) PayloadSize ¶
PayloadSize returns the total size this hop's payload would take up in the onion packet.
type Route ¶
type Route struct {
// TotalTimeLock is the cumulative (final) time lock across the entire
// route. This is the CLTV value that should be extended to the first
// hop in the route. All other hops will decrement the time-lock as
// advertised, leaving enough time for all hops to wait for or present
// the payment preimage to complete the payment.
TotalTimeLock uint32
// TotalAmount is the total amount of funds required to complete a
// payment over this route. This value includes the cumulative fees at
// each hop. As a result, the HTLC extended to the first-hop in the
// route will need to have at least this many satoshis, otherwise the
// route will fail at an intermediate node due to an insufficient
// amount of fees.
TotalAmount lnwire.MilliSatoshi
// SourcePubKey is the pubkey of the node where this route originates
// from.
SourcePubKey Vertex
// Hops contains details concerning the specific forwarding details at
// each hop.
Hops []*Hop
}
Route represents a path through the channel graph which runs over one or more channels in succession. This struct carries all the information required to craft the Sphinx onion packet, and send the payment along the first hop in the path. A route is only selected as valid if all the channels have sufficient capacity to carry the initial payment amount after fees are accounted for.
func NewRouteFromHops ¶
func NewRouteFromHops(amtToSend lnwire.MilliSatoshi, timeLock uint32, sourceVertex Vertex, hops []*Hop) (*Route, error)
NewRouteFromHops creates a new Route structure from the minimally required information to perform the payment. It infers fee amounts and populates the node, chan and prev/next hop maps.
func (*Route) HopFee ¶
func (r *Route) HopFee(hopIndex int) lnwire.MilliSatoshi
HopFee returns the fee charged by the route hop indicated by hopIndex.
This calculation takes into account the possibility that the route contains some blinded hops, that will not have the amount to forward set. We take note of various points in the blinded route.
Given the following route where Carol is the introduction node and B2 is the recipient, Carol and B1's hops will not have an amount to forward set: Alice --- Bob ---- Carol (introduction) ----- B1 ----- B2
We locate ourselves in the route as follows: * Regular Hop (eg Alice - Bob):
incomingAmt !=0 outgoingAmt !=0 -> Fee = incomingAmt - outgoingAmt
* Introduction Hop (eg Bob - Carol):
incomingAmt !=0 outgoingAmt = 0 -> Fee = incomingAmt - receiverAmt
This has the impact of attributing the full fees for the blinded route to the introduction node.
* Blinded Intermediate Hop (eg Carol - B1):
incomingAmt = 0 outgoingAmt = 0 -> Fee = 0
* Final Blinded Hop (B1 - B2):
incomingAmt = 0 outgoingAmt !=0 -> Fee = 0
func (*Route) ReceiverAmt ¶
func (r *Route) ReceiverAmt() lnwire.MilliSatoshi
ReceiverAmt is the amount received by the final hop of this route.
func (*Route) ToSphinxPath ¶
func (r *Route) ToSphinxPath() (*sphinx.PaymentPath, error)
ToSphinxPath converts a complete route into a sphinx PaymentPath that contains the per-hop payloads used to encoding the HTLC routing data for each hop in the route. This method also accepts an optional EOB payload for the final hop.
func (*Route) TotalFees ¶
func (r *Route) TotalFees() lnwire.MilliSatoshi
TotalFees is the sum of the fees paid at each hop within the final route. In the case of a one-hop payment, this value will be zero as we don't need to pay a fee to ourself.
type Vertex ¶
type Vertex [VertexSize]byte
Vertex is a simple alias for the serialization of a compressed Bitcoin public key.
func NewVertex ¶
func NewVertex(pub *btcec.PublicKey) Vertex
NewVertex returns a new Vertex given a public key.
func NewVertexFromBytes ¶
NewVertexFromBytes returns a new Vertex based on a serialized pubkey in a byte slice.
func NewVertexFromStr ¶
NewVertexFromStr returns a new Vertex given its hex-encoded string format.
Source Files