331 lines
10 KiB
Go
331 lines
10 KiB
Go
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package migration_01_to_11
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import (
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"bytes"
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"encoding/binary"
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"encoding/hex"
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"fmt"
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"io"
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"strconv"
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"strings"
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"github.com/btcsuite/btcd/btcec"
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sphinx "github.com/lightningnetwork/lightning-onion"
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"github.com/lightningnetwork/lnd/lnwire"
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"github.com/lightningnetwork/lnd/record"
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"github.com/lightningnetwork/lnd/tlv"
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)
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// VertexSize is the size of the array to store a vertex.
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const VertexSize = 33
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// ErrNoRouteHopsProvided is returned when a caller attempts to construct a new
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// sphinx packet, but provides an empty set of hops for each route.
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var ErrNoRouteHopsProvided = fmt.Errorf("empty route hops provided")
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// Vertex is a simple alias for the serialization of a compressed Bitcoin
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// public key.
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type Vertex [VertexSize]byte
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// NewVertex returns a new Vertex given a public key.
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func NewVertex(pub *btcec.PublicKey) Vertex {
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var v Vertex
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copy(v[:], pub.SerializeCompressed())
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return v
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}
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// NewVertexFromBytes returns a new Vertex based on a serialized pubkey in a
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// byte slice.
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func NewVertexFromBytes(b []byte) (Vertex, error) {
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vertexLen := len(b)
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if vertexLen != VertexSize {
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return Vertex{}, fmt.Errorf("invalid vertex length of %v, "+
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"want %v", vertexLen, VertexSize)
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}
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var v Vertex
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copy(v[:], b)
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return v, nil
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}
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// NewVertexFromStr returns a new Vertex given its hex-encoded string format.
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func NewVertexFromStr(v string) (Vertex, error) {
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// Return error if hex string is of incorrect length.
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if len(v) != VertexSize*2 {
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return Vertex{}, fmt.Errorf("invalid vertex string length of "+
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"%v, want %v", len(v), VertexSize*2)
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}
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vertex, err := hex.DecodeString(v)
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if err != nil {
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return Vertex{}, err
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}
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return NewVertexFromBytes(vertex)
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}
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// String returns a human readable version of the Vertex which is the
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// hex-encoding of the serialized compressed public key.
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func (v Vertex) String() string {
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return fmt.Sprintf("%x", v[:])
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}
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// Hop represents an intermediate or final node of the route. This naming
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// is in line with the definition given in BOLT #4: Onion Routing Protocol.
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// The struct houses the channel along which this hop can be reached and
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// the values necessary to create the HTLC that needs to be sent to the
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// next hop. It is also used to encode the per-hop payload included within
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// the Sphinx packet.
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type Hop struct {
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// PubKeyBytes is the raw bytes of the public key of the target node.
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PubKeyBytes Vertex
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// ChannelID is the unique channel ID for the channel. The first 3
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// bytes are the block height, the next 3 the index within the block,
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// and the last 2 bytes are the output index for the channel.
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ChannelID uint64
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// OutgoingTimeLock is the timelock value that should be used when
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// crafting the _outgoing_ HTLC from this hop.
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OutgoingTimeLock uint32
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// AmtToForward is the amount that this hop will forward to the next
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// hop. This value is less than the value that the incoming HTLC
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// carries as a fee will be subtracted by the hop.
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AmtToForward lnwire.MilliSatoshi
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// TLVRecords if non-nil are a set of additional TLV records that
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// should be included in the forwarding instructions for this node.
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TLVRecords []tlv.Record
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// LegacyPayload if true, then this signals that this node doesn't
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// understand the new TLV payload, so we must instead use the legacy
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// payload.
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LegacyPayload bool
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}
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// PackHopPayload writes to the passed io.Writer, the series of byes that can
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// be placed directly into the per-hop payload (EOB) for this hop. This will
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// include the required routing fields, as well as serializing any of the
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// passed optional TLVRecords. nextChanID is the unique channel ID that
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// references the _outgoing_ channel ID that follows this hop. This field
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// follows the same semantics as the NextAddress field in the onion: it should
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// be set to zero to indicate the terminal hop.
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func (h *Hop) PackHopPayload(w io.Writer, nextChanID uint64) error {
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// If this is a legacy payload, then we'll exit here as this method
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// shouldn't be called.
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if h.LegacyPayload == true {
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return fmt.Errorf("cannot pack hop payloads for legacy " +
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"payloads")
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}
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// Otherwise, we'll need to make a new stream that includes our
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// required routing fields, as well as these optional values.
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var records []tlv.Record
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// Every hop must have an amount to forward and CLTV expiry.
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amt := uint64(h.AmtToForward)
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records = append(records,
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record.NewAmtToFwdRecord(&amt),
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record.NewLockTimeRecord(&h.OutgoingTimeLock),
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)
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// BOLT 04 says the next_hop_id should be omitted for the final hop,
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// but present for all others.
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//
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// TODO(conner): test using hop.Exit once available
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if nextChanID != 0 {
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records = append(records,
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record.NewNextHopIDRecord(&nextChanID),
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)
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}
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// Append any custom types destined for this hop.
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records = append(records, h.TLVRecords...)
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// To ensure we produce a canonical stream, we'll sort the records
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// before encoding them as a stream in the hop payload.
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tlv.SortRecords(records)
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tlvStream, err := tlv.NewStream(records...)
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if err != nil {
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return err
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}
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return tlvStream.Encode(w)
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}
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// Route represents a path through the channel graph which runs over one or
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// more channels in succession. This struct carries all the information
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// required to craft the Sphinx onion packet, and send the payment along the
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// first hop in the path. A route is only selected as valid if all the channels
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// have sufficient capacity to carry the initial payment amount after fees are
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// accounted for.
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type Route struct {
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// TotalTimeLock is the cumulative (final) time lock across the entire
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// route. This is the CLTV value that should be extended to the first
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// hop in the route. All other hops will decrement the time-lock as
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// advertised, leaving enough time for all hops to wait for or present
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// the payment preimage to complete the payment.
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TotalTimeLock uint32
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// TotalAmount is the total amount of funds required to complete a
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// payment over this route. This value includes the cumulative fees at
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// each hop. As a result, the HTLC extended to the first-hop in the
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// route will need to have at least this many satoshis, otherwise the
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// route will fail at an intermediate node due to an insufficient
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// amount of fees.
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TotalAmount lnwire.MilliSatoshi
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// SourcePubKey is the pubkey of the node where this route originates
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// from.
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SourcePubKey Vertex
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// Hops contains details concerning the specific forwarding details at
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// each hop.
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Hops []*Hop
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}
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// HopFee returns the fee charged by the route hop indicated by hopIndex.
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func (r *Route) HopFee(hopIndex int) lnwire.MilliSatoshi {
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var incomingAmt lnwire.MilliSatoshi
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if hopIndex == 0 {
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incomingAmt = r.TotalAmount
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} else {
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incomingAmt = r.Hops[hopIndex-1].AmtToForward
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}
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// Fee is calculated as difference between incoming and outgoing amount.
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return incomingAmt - r.Hops[hopIndex].AmtToForward
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}
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// TotalFees is the sum of the fees paid at each hop within the final route. In
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// the case of a one-hop payment, this value will be zero as we don't need to
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// pay a fee to ourself.
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func (r *Route) TotalFees() lnwire.MilliSatoshi {
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if len(r.Hops) == 0 {
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return 0
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}
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return r.TotalAmount - r.Hops[len(r.Hops)-1].AmtToForward
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}
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// NewRouteFromHops creates a new Route structure from the minimally required
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// information to perform the payment. It infers fee amounts and populates the
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// node, chan and prev/next hop maps.
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func NewRouteFromHops(amtToSend lnwire.MilliSatoshi, timeLock uint32,
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sourceVertex Vertex, hops []*Hop) (*Route, error) {
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if len(hops) == 0 {
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return nil, ErrNoRouteHopsProvided
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}
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// First, we'll create a route struct and populate it with the fields
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// for which the values are provided as arguments of this function.
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// TotalFees is determined based on the difference between the amount
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// that is send from the source and the final amount that is received
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// by the destination.
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route := &Route{
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SourcePubKey: sourceVertex,
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Hops: hops,
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TotalTimeLock: timeLock,
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TotalAmount: amtToSend,
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}
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return route, nil
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}
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// ToSphinxPath converts a complete route into a sphinx PaymentPath that
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// contains the per-hop paylods used to encoding the HTLC routing data for each
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// hop in the route. This method also accepts an optional EOB payload for the
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// final hop.
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func (r *Route) ToSphinxPath() (*sphinx.PaymentPath, error) {
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var path sphinx.PaymentPath
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// For each hop encoded within the route, we'll convert the hop struct
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// to an OnionHop with matching per-hop payload within the path as used
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// by the sphinx package.
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for i, hop := range r.Hops {
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pub, err := btcec.ParsePubKey(
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hop.PubKeyBytes[:], btcec.S256(),
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)
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if err != nil {
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return nil, err
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}
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// As a base case, the next hop is set to all zeroes in order
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// to indicate that the "last hop" as no further hops after it.
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nextHop := uint64(0)
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// If we aren't on the last hop, then we set the "next address"
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// field to be the channel that directly follows it.
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if i != len(r.Hops)-1 {
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nextHop = r.Hops[i+1].ChannelID
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}
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var payload sphinx.HopPayload
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// If this is the legacy payload, then we can just include the
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// hop data as normal.
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if hop.LegacyPayload {
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// Before we encode this value, we'll pack the next hop
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// into the NextAddress field of the hop info to ensure
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// we point to the right now.
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hopData := sphinx.HopData{
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ForwardAmount: uint64(hop.AmtToForward),
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OutgoingCltv: hop.OutgoingTimeLock,
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}
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binary.BigEndian.PutUint64(
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hopData.NextAddress[:], nextHop,
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)
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payload, err = sphinx.NewHopPayload(&hopData, nil)
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if err != nil {
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return nil, err
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}
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} else {
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// For non-legacy payloads, we'll need to pack the
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// routing information, along with any extra TLV
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// information into the new per-hop payload format.
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// We'll also pass in the chan ID of the hop this
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// channel should be forwarded to so we can construct a
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// valid payload.
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var b bytes.Buffer
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err := hop.PackHopPayload(&b, nextHop)
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if err != nil {
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return nil, err
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}
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// TODO(roasbeef): make better API for NewHopPayload?
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payload, err = sphinx.NewHopPayload(nil, b.Bytes())
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if err != nil {
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return nil, err
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}
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}
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path[i] = sphinx.OnionHop{
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NodePub: *pub,
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HopPayload: payload,
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}
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}
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return &path, nil
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}
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// String returns a human readable representation of the route.
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func (r *Route) String() string {
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var b strings.Builder
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for i, hop := range r.Hops {
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if i > 0 {
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b.WriteString(",")
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}
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b.WriteString(strconv.FormatUint(hop.ChannelID, 10))
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}
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return fmt.Sprintf("amt=%v, fees=%v, tl=%v, chans=%v",
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r.TotalAmount-r.TotalFees(), r.TotalFees(), r.TotalTimeLock,
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b.String(),
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)
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}
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