324 lines
9.4 KiB
Go
324 lines
9.4 KiB
Go
package routerrpc
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import (
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"encoding/hex"
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"errors"
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"fmt"
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"github.com/btcsuite/btcutil"
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"github.com/lightningnetwork/lnd/lnrpc"
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"github.com/lightningnetwork/lnd/lnwire"
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"github.com/lightningnetwork/lnd/routing"
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"github.com/lightningnetwork/lnd/routing/route"
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context "golang.org/x/net/context"
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)
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// RouterBackend contains the backend implementation of the router rpc sub
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// server calls.
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type RouterBackend struct {
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// MaxPaymentMSat is the largest payment permitted by the backend.
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MaxPaymentMSat lnwire.MilliSatoshi
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// SelfNode is the vertex of the node sending the payment.
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SelfNode route.Vertex
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// FetchChannelCapacity is a closure that we'll use the fetch the total
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// capacity of a channel to populate in responses.
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FetchChannelCapacity func(chanID uint64) (btcutil.Amount, error)
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// FetchChannelEndpoints returns the pubkeys of both endpoints of the
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// given channel id.
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FetchChannelEndpoints func(chanID uint64) (route.Vertex,
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route.Vertex, error)
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// FindRoutes is a closure that abstracts away how we locate/query for
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// routes.
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FindRoute func(source, target route.Vertex,
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amt lnwire.MilliSatoshi, restrictions *routing.RestrictParams,
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finalExpiry ...uint16) (*route.Route, error)
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}
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// QueryRoutes attempts to query the daemons' Channel Router for a possible
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// route to a target destination capable of carrying a specific amount of
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// satoshis within the route's flow. The retuned route contains the full
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// details required to craft and send an HTLC, also including the necessary
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// information that should be present within the Sphinx packet encapsulated
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// within the HTLC.
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//
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// TODO(roasbeef): should return a slice of routes in reality * create separate
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// PR to send based on well formatted route
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func (r *RouterBackend) QueryRoutes(ctx context.Context,
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in *lnrpc.QueryRoutesRequest) (*lnrpc.QueryRoutesResponse, error) {
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parsePubKey := func(key string) (route.Vertex, error) {
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pubKeyBytes, err := hex.DecodeString(key)
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if err != nil {
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return route.Vertex{}, err
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}
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if len(pubKeyBytes) != 33 {
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return route.Vertex{},
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errors.New("invalid key length")
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}
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var v route.Vertex
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copy(v[:], pubKeyBytes)
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return v, nil
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}
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// Parse the hex-encoded source and target public keys into full public
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// key objects we can properly manipulate.
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targetPubKey, err := parsePubKey(in.PubKey)
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if err != nil {
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return nil, err
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}
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var sourcePubKey route.Vertex
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if in.SourcePubKey != "" {
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var err error
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sourcePubKey, err = parsePubKey(in.SourcePubKey)
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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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// If no source is specified, use self.
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sourcePubKey = r.SelfNode
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}
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// Currently, within the bootstrap phase of the network, we limit the
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// largest payment size allotted to (2^32) - 1 mSAT or 4.29 million
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// satoshis.
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amt := btcutil.Amount(in.Amt)
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amtMSat := lnwire.NewMSatFromSatoshis(amt)
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if amtMSat > r.MaxPaymentMSat {
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return nil, fmt.Errorf("payment of %v is too large, max payment "+
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"allowed is %v", amt, r.MaxPaymentMSat.ToSatoshis())
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}
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// Unmarshall restrictions from request.
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feeLimit := calculateFeeLimit(in.FeeLimit, amtMSat)
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ignoredNodes := make(map[route.Vertex]struct{})
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for _, ignorePubKey := range in.IgnoredNodes {
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if len(ignorePubKey) != 33 {
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return nil, fmt.Errorf("invalid ignore node pubkey")
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}
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var ignoreVertex route.Vertex
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copy(ignoreVertex[:], ignorePubKey)
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ignoredNodes[ignoreVertex] = struct{}{}
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}
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ignoredEdges := make(map[routing.EdgeLocator]struct{})
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for _, ignoredEdge := range in.IgnoredEdges {
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locator := routing.EdgeLocator{
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ChannelID: ignoredEdge.ChannelId,
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}
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if ignoredEdge.DirectionReverse {
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locator.Direction = 1
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}
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ignoredEdges[locator] = struct{}{}
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}
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restrictions := &routing.RestrictParams{
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FeeLimit: feeLimit,
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IgnoredNodes: ignoredNodes,
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IgnoredEdges: ignoredEdges,
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}
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// Query the channel router for a possible path to the destination that
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// can carry `in.Amt` satoshis _including_ the total fee required on
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// the route.
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var (
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route *route.Route
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findErr error
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)
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if in.FinalCltvDelta == 0 {
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route, findErr = r.FindRoute(
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sourcePubKey, targetPubKey, amtMSat, restrictions,
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)
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} else {
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route, findErr = r.FindRoute(
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sourcePubKey, targetPubKey, amtMSat, restrictions,
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uint16(in.FinalCltvDelta),
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)
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}
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if findErr != nil {
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return nil, findErr
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}
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// For each valid route, we'll convert the result into the format
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// required by the RPC system.
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rpcRoute := r.MarshallRoute(route)
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routeResp := &lnrpc.QueryRoutesResponse{
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Routes: []*lnrpc.Route{rpcRoute},
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}
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return routeResp, nil
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}
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// calculateFeeLimit returns the fee limit in millisatoshis. If a percentage
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// based fee limit has been requested, we'll factor in the ratio provided with
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// the amount of the payment.
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func calculateFeeLimit(feeLimit *lnrpc.FeeLimit,
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amount lnwire.MilliSatoshi) lnwire.MilliSatoshi {
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switch feeLimit.GetLimit().(type) {
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case *lnrpc.FeeLimit_Fixed:
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return lnwire.NewMSatFromSatoshis(
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btcutil.Amount(feeLimit.GetFixed()),
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)
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case *lnrpc.FeeLimit_Percent:
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return amount * lnwire.MilliSatoshi(feeLimit.GetPercent()) / 100
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default:
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// If a fee limit was not specified, we'll use the payment's
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// amount as an upper bound in order to avoid payment attempts
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// from incurring fees higher than the payment amount itself.
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return amount
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}
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}
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// MarshallRoute marshalls an internal route to an rpc route struct.
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func (r *RouterBackend) MarshallRoute(route *route.Route) *lnrpc.Route {
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resp := &lnrpc.Route{
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TotalTimeLock: route.TotalTimeLock,
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TotalFees: int64(route.TotalFees().ToSatoshis()),
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TotalFeesMsat: int64(route.TotalFees()),
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TotalAmt: int64(route.TotalAmount.ToSatoshis()),
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TotalAmtMsat: int64(route.TotalAmount),
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Hops: make([]*lnrpc.Hop, len(route.Hops)),
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}
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incomingAmt := route.TotalAmount
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for i, hop := range route.Hops {
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fee := route.HopFee(i)
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// Channel capacity is not a defining property of a route. For
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// backwards RPC compatibility, we retrieve it here from the
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// graph.
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chanCapacity, err := r.FetchChannelCapacity(hop.ChannelID)
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if err != nil {
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// If capacity cannot be retrieved, this may be a
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// not-yet-received or private channel. Then report
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// amount that is sent through the channel as capacity.
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chanCapacity = incomingAmt.ToSatoshis()
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}
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resp.Hops[i] = &lnrpc.Hop{
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ChanId: hop.ChannelID,
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ChanCapacity: int64(chanCapacity),
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AmtToForward: int64(hop.AmtToForward.ToSatoshis()),
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AmtToForwardMsat: int64(hop.AmtToForward),
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Fee: int64(fee.ToSatoshis()),
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FeeMsat: int64(fee),
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Expiry: uint32(hop.OutgoingTimeLock),
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PubKey: hex.EncodeToString(
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hop.PubKeyBytes[:],
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),
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}
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incomingAmt = hop.AmtToForward
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}
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return resp
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}
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// UnmarshallHopByChannelLookup unmarshalls an rpc hop for which the pub key is
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// not known. This function will query the channel graph with channel id to
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// retrieve both endpoints and determine the hop pubkey using the previous hop
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// pubkey. If the channel is unknown, an error is returned.
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func (r *RouterBackend) UnmarshallHopByChannelLookup(hop *lnrpc.Hop,
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prevPubKeyBytes [33]byte) (*route.Hop, error) {
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// Discard edge policies, because they may be nil.
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node1, node2, err := r.FetchChannelEndpoints(hop.ChanId)
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if err != nil {
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return nil, err
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}
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var pubKeyBytes [33]byte
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switch {
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case prevPubKeyBytes == node1:
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pubKeyBytes = node2
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case prevPubKeyBytes == node2:
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pubKeyBytes = node1
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default:
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return nil, fmt.Errorf("channel edge does not match expected node")
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}
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return &route.Hop{
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OutgoingTimeLock: hop.Expiry,
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AmtToForward: lnwire.MilliSatoshi(hop.AmtToForwardMsat),
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PubKeyBytes: pubKeyBytes,
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ChannelID: hop.ChanId,
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}, nil
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}
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// UnmarshallKnownPubkeyHop unmarshalls an rpc hop that contains the hop pubkey.
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// The channel graph doesn't need to be queried because all information required
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// for sending the payment is present.
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func UnmarshallKnownPubkeyHop(hop *lnrpc.Hop) (*route.Hop, error) {
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pubKey, err := hex.DecodeString(hop.PubKey)
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if err != nil {
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return nil, fmt.Errorf("cannot decode pubkey %s", hop.PubKey)
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}
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var pubKeyBytes [33]byte
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copy(pubKeyBytes[:], pubKey)
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return &route.Hop{
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OutgoingTimeLock: hop.Expiry,
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AmtToForward: lnwire.MilliSatoshi(hop.AmtToForwardMsat),
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PubKeyBytes: pubKeyBytes,
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ChannelID: hop.ChanId,
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}, nil
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}
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// UnmarshallHop unmarshalls an rpc hop that may or may not contain a node
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// pubkey.
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func (r *RouterBackend) UnmarshallHop(hop *lnrpc.Hop,
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prevNodePubKey [33]byte) (*route.Hop, error) {
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if hop.PubKey == "" {
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// If no pub key is given of the hop, the local channel
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// graph needs to be queried to complete the information
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// necessary for routing.
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return r.UnmarshallHopByChannelLookup(hop, prevNodePubKey)
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}
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return UnmarshallKnownPubkeyHop(hop)
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}
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// UnmarshallRoute unmarshalls an rpc route. For hops that don't specify a
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// pubkey, the channel graph is queried.
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func (r *RouterBackend) UnmarshallRoute(rpcroute *lnrpc.Route) (
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*route.Route, error) {
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prevNodePubKey := r.SelfNode
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hops := make([]*route.Hop, len(rpcroute.Hops))
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for i, hop := range rpcroute.Hops {
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routeHop, err := r.UnmarshallHop(hop, prevNodePubKey)
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if err != nil {
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return nil, err
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}
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hops[i] = routeHop
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prevNodePubKey = routeHop.PubKeyBytes
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}
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route, err := route.NewRouteFromHops(
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lnwire.MilliSatoshi(rpcroute.TotalAmtMsat),
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rpcroute.TotalTimeLock,
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r.SelfNode,
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hops,
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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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return route, nil
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}
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