lnd.xprv/lnrpc/routerrpc/router_backend.go
Joost Jager 7133f37bb8
routing: global probability based mission control
Previously every payment had its own local mission control state which
was in effect only for that payment. In this commit most of the local
state is removed and payments all tap into the global mission control
probability estimator.

Furthermore the decay time of pruned edges and nodes is extended, so
that observations about the network can better benefit future payment
processes.

Last, the probability function is transformed from a binary output to a
gradual curve, allowing for a better trade off between candidate routes.
2019-06-04 10:00:25 +02:00

339 lines
9.6 KiB
Go

package routerrpc
import (
"encoding/hex"
"errors"
"fmt"
"github.com/btcsuite/btcutil"
"github.com/lightningnetwork/lnd/lnrpc"
"github.com/lightningnetwork/lnd/lnwire"
"github.com/lightningnetwork/lnd/routing"
"github.com/lightningnetwork/lnd/routing/route"
context "golang.org/x/net/context"
)
// RouterBackend contains the backend implementation of the router rpc sub
// server calls.
type RouterBackend struct {
// MaxPaymentMSat is the largest payment permitted by the backend.
MaxPaymentMSat lnwire.MilliSatoshi
// SelfNode is the vertex of the node sending the payment.
SelfNode route.Vertex
// FetchChannelCapacity is a closure that we'll use the fetch the total
// capacity of a channel to populate in responses.
FetchChannelCapacity func(chanID uint64) (btcutil.Amount, error)
// FetchChannelEndpoints returns the pubkeys of both endpoints of the
// given channel id.
FetchChannelEndpoints func(chanID uint64) (route.Vertex,
route.Vertex, error)
// FindRoutes is a closure that abstracts away how we locate/query for
// routes.
FindRoute func(source, target route.Vertex,
amt lnwire.MilliSatoshi, restrictions *routing.RestrictParams,
finalExpiry ...uint16) (*route.Route, error)
MissionControl *routing.MissionControl
}
// QueryRoutes attempts to query the daemons' Channel Router for a possible
// route to a target destination capable of carrying a specific amount of
// satoshis within the route's flow. The retuned route contains the full
// details required to craft and send an HTLC, also including the necessary
// information that should be present within the Sphinx packet encapsulated
// within the HTLC.
//
// TODO(roasbeef): should return a slice of routes in reality * create separate
// PR to send based on well formatted route
func (r *RouterBackend) QueryRoutes(ctx context.Context,
in *lnrpc.QueryRoutesRequest) (*lnrpc.QueryRoutesResponse, error) {
parsePubKey := func(key string) (route.Vertex, error) {
pubKeyBytes, err := hex.DecodeString(key)
if err != nil {
return route.Vertex{}, err
}
if len(pubKeyBytes) != 33 {
return route.Vertex{},
errors.New("invalid key length")
}
var v route.Vertex
copy(v[:], pubKeyBytes)
return v, nil
}
// Parse the hex-encoded source and target public keys into full public
// key objects we can properly manipulate.
targetPubKey, err := parsePubKey(in.PubKey)
if err != nil {
return nil, err
}
var sourcePubKey route.Vertex
if in.SourcePubKey != "" {
var err error
sourcePubKey, err = parsePubKey(in.SourcePubKey)
if err != nil {
return nil, err
}
} else {
// If no source is specified, use self.
sourcePubKey = r.SelfNode
}
// Currently, within the bootstrap phase of the network, we limit the
// largest payment size allotted to (2^32) - 1 mSAT or 4.29 million
// satoshis.
amt := btcutil.Amount(in.Amt)
amtMSat := lnwire.NewMSatFromSatoshis(amt)
if amtMSat > r.MaxPaymentMSat {
return nil, fmt.Errorf("payment of %v is too large, max payment "+
"allowed is %v", amt, r.MaxPaymentMSat.ToSatoshis())
}
// Unmarshall restrictions from request.
feeLimit := calculateFeeLimit(in.FeeLimit, amtMSat)
ignoredNodes := make(map[route.Vertex]struct{})
for _, ignorePubKey := range in.IgnoredNodes {
if len(ignorePubKey) != 33 {
return nil, fmt.Errorf("invalid ignore node pubkey")
}
var ignoreVertex route.Vertex
copy(ignoreVertex[:], ignorePubKey)
ignoredNodes[ignoreVertex] = struct{}{}
}
ignoredEdges := make(map[routing.EdgeLocator]struct{})
for _, ignoredEdge := range in.IgnoredEdges {
locator := routing.EdgeLocator{
ChannelID: ignoredEdge.ChannelId,
}
if ignoredEdge.DirectionReverse {
locator.Direction = 1
}
ignoredEdges[locator] = struct{}{}
}
restrictions := &routing.RestrictParams{
FeeLimit: feeLimit,
ProbabilitySource: func(node route.Vertex,
edge routing.EdgeLocator,
amt lnwire.MilliSatoshi) float64 {
if _, ok := ignoredNodes[node]; ok {
return 0
}
if _, ok := ignoredEdges[edge]; ok {
return 0
}
return 1
},
PaymentAttemptPenalty: routing.DefaultPaymentAttemptPenalty,
}
// Query the channel router for a possible path to the destination that
// can carry `in.Amt` satoshis _including_ the total fee required on
// the route.
var (
route *route.Route
findErr error
)
if in.FinalCltvDelta == 0 {
route, findErr = r.FindRoute(
sourcePubKey, targetPubKey, amtMSat, restrictions,
)
} else {
route, findErr = r.FindRoute(
sourcePubKey, targetPubKey, amtMSat, restrictions,
uint16(in.FinalCltvDelta),
)
}
if findErr != nil {
return nil, findErr
}
// For each valid route, we'll convert the result into the format
// required by the RPC system.
rpcRoute := r.MarshallRoute(route)
routeResp := &lnrpc.QueryRoutesResponse{
Routes: []*lnrpc.Route{rpcRoute},
}
return routeResp, nil
}
// calculateFeeLimit returns the fee limit in millisatoshis. If a percentage
// based fee limit has been requested, we'll factor in the ratio provided with
// the amount of the payment.
func calculateFeeLimit(feeLimit *lnrpc.FeeLimit,
amount lnwire.MilliSatoshi) lnwire.MilliSatoshi {
switch feeLimit.GetLimit().(type) {
case *lnrpc.FeeLimit_Fixed:
return lnwire.NewMSatFromSatoshis(
btcutil.Amount(feeLimit.GetFixed()),
)
case *lnrpc.FeeLimit_Percent:
return amount * lnwire.MilliSatoshi(feeLimit.GetPercent()) / 100
default:
// If a fee limit was not specified, we'll use the payment's
// amount as an upper bound in order to avoid payment attempts
// from incurring fees higher than the payment amount itself.
return amount
}
}
// MarshallRoute marshalls an internal route to an rpc route struct.
func (r *RouterBackend) MarshallRoute(route *route.Route) *lnrpc.Route {
resp := &lnrpc.Route{
TotalTimeLock: route.TotalTimeLock,
TotalFees: int64(route.TotalFees().ToSatoshis()),
TotalFeesMsat: int64(route.TotalFees()),
TotalAmt: int64(route.TotalAmount.ToSatoshis()),
TotalAmtMsat: int64(route.TotalAmount),
Hops: make([]*lnrpc.Hop, len(route.Hops)),
}
incomingAmt := route.TotalAmount
for i, hop := range route.Hops {
fee := route.HopFee(i)
// Channel capacity is not a defining property of a route. For
// backwards RPC compatibility, we retrieve it here from the
// graph.
chanCapacity, err := r.FetchChannelCapacity(hop.ChannelID)
if err != nil {
// If capacity cannot be retrieved, this may be a
// not-yet-received or private channel. Then report
// amount that is sent through the channel as capacity.
chanCapacity = incomingAmt.ToSatoshis()
}
resp.Hops[i] = &lnrpc.Hop{
ChanId: hop.ChannelID,
ChanCapacity: int64(chanCapacity),
AmtToForward: int64(hop.AmtToForward.ToSatoshis()),
AmtToForwardMsat: int64(hop.AmtToForward),
Fee: int64(fee.ToSatoshis()),
FeeMsat: int64(fee),
Expiry: uint32(hop.OutgoingTimeLock),
PubKey: hex.EncodeToString(
hop.PubKeyBytes[:],
),
}
incomingAmt = hop.AmtToForward
}
return resp
}
// UnmarshallHopByChannelLookup unmarshalls an rpc hop for which the pub key is
// not known. This function will query the channel graph with channel id to
// retrieve both endpoints and determine the hop pubkey using the previous hop
// pubkey. If the channel is unknown, an error is returned.
func (r *RouterBackend) UnmarshallHopByChannelLookup(hop *lnrpc.Hop,
prevPubKeyBytes [33]byte) (*route.Hop, error) {
// Discard edge policies, because they may be nil.
node1, node2, err := r.FetchChannelEndpoints(hop.ChanId)
if err != nil {
return nil, err
}
var pubKeyBytes [33]byte
switch {
case prevPubKeyBytes == node1:
pubKeyBytes = node2
case prevPubKeyBytes == node2:
pubKeyBytes = node1
default:
return nil, fmt.Errorf("channel edge does not match expected node")
}
return &route.Hop{
OutgoingTimeLock: hop.Expiry,
AmtToForward: lnwire.MilliSatoshi(hop.AmtToForwardMsat),
PubKeyBytes: pubKeyBytes,
ChannelID: hop.ChanId,
}, nil
}
// UnmarshallKnownPubkeyHop unmarshalls an rpc hop that contains the hop pubkey.
// The channel graph doesn't need to be queried because all information required
// for sending the payment is present.
func UnmarshallKnownPubkeyHop(hop *lnrpc.Hop) (*route.Hop, error) {
pubKey, err := hex.DecodeString(hop.PubKey)
if err != nil {
return nil, fmt.Errorf("cannot decode pubkey %s", hop.PubKey)
}
var pubKeyBytes [33]byte
copy(pubKeyBytes[:], pubKey)
return &route.Hop{
OutgoingTimeLock: hop.Expiry,
AmtToForward: lnwire.MilliSatoshi(hop.AmtToForwardMsat),
PubKeyBytes: pubKeyBytes,
ChannelID: hop.ChanId,
}, nil
}
// UnmarshallHop unmarshalls an rpc hop that may or may not contain a node
// pubkey.
func (r *RouterBackend) UnmarshallHop(hop *lnrpc.Hop,
prevNodePubKey [33]byte) (*route.Hop, error) {
if hop.PubKey == "" {
// If no pub key is given of the hop, the local channel
// graph needs to be queried to complete the information
// necessary for routing.
return r.UnmarshallHopByChannelLookup(hop, prevNodePubKey)
}
return UnmarshallKnownPubkeyHop(hop)
}
// UnmarshallRoute unmarshalls an rpc route. For hops that don't specify a
// pubkey, the channel graph is queried.
func (r *RouterBackend) UnmarshallRoute(rpcroute *lnrpc.Route) (
*route.Route, error) {
prevNodePubKey := r.SelfNode
hops := make([]*route.Hop, len(rpcroute.Hops))
for i, hop := range rpcroute.Hops {
routeHop, err := r.UnmarshallHop(hop, prevNodePubKey)
if err != nil {
return nil, err
}
hops[i] = routeHop
prevNodePubKey = routeHop.PubKeyBytes
}
route, err := route.NewRouteFromHops(
lnwire.MilliSatoshi(rpcroute.TotalAmtMsat),
rpcroute.TotalTimeLock,
r.SelfNode,
hops,
)
if err != nil {
return nil, err
}
return route, nil
}