lnd.xprv/lnrpc/routerrpc/router_server.go

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// +build routerrpc
package routerrpc
import (
"context"
"errors"
"fmt"
"io/ioutil"
"os"
"path/filepath"
"github.com/btcsuite/btcutil"
"github.com/lightningnetwork/lnd/channeldb"
"github.com/lightningnetwork/lnd/htlcswitch"
"github.com/lightningnetwork/lnd/lnrpc"
"github.com/lightningnetwork/lnd/lntypes"
"github.com/lightningnetwork/lnd/lnwire"
"github.com/lightningnetwork/lnd/routing"
"github.com/lightningnetwork/lnd/routing/route"
"google.golang.org/grpc"
"google.golang.org/grpc/codes"
"google.golang.org/grpc/status"
"gopkg.in/macaroon-bakery.v2/bakery"
)
const (
// subServerName is the name of the sub rpc server. We'll use this name
// to register ourselves, and we also require that the main
// SubServerConfigDispatcher instance recognize as the name of our
subServerName = "RouterRPC"
)
var (
// macaroonOps are the set of capabilities that our minted macaroon (if
// it doesn't already exist) will have.
macaroonOps = []bakery.Op{
{
Entity: "offchain",
Action: "read",
},
{
Entity: "offchain",
Action: "write",
},
}
// macPermissions maps RPC calls to the permissions they require.
macPermissions = map[string][]bakery.Op{
"/routerrpc.Router/SendPayment": {{
Entity: "offchain",
Action: "write",
}},
"/routerrpc.Router/SendToRoute": {{
Entity: "offchain",
Action: "write",
}},
"/routerrpc.Router/TrackPayment": {{
Entity: "offchain",
Action: "read",
}},
"/routerrpc.Router/EstimateRouteFee": {{
Entity: "offchain",
Action: "read",
}},
"/routerrpc.Router/QueryMissionControl": {{
Entity: "offchain",
Action: "read",
}},
"/routerrpc.Router/QueryProbability": {{
Entity: "offchain",
Action: "read",
}},
"/routerrpc.Router/ResetMissionControl": {{
Entity: "offchain",
Action: "write",
}},
"/routerrpc.Router/BuildRoute": {{
Entity: "offchain",
Action: "read",
}},
}
// DefaultRouterMacFilename is the default name of the router macaroon
// that we expect to find via a file handle within the main
// configuration file in this package.
DefaultRouterMacFilename = "router.macaroon"
)
// Server is a stand alone sub RPC server which exposes functionality that
// allows clients to route arbitrary payment through the Lightning Network.
type Server struct {
cfg *Config
}
// A compile time check to ensure that Server fully implements the RouterServer
// gRPC service.
var _ RouterServer = (*Server)(nil)
// fileExists reports whether the named file or directory exists.
func fileExists(name string) bool {
if _, err := os.Stat(name); err != nil {
if os.IsNotExist(err) {
return false
}
}
return true
}
// New creates a new instance of the RouterServer given a configuration struct
// that contains all external dependencies. If the target macaroon exists, and
// we're unable to create it, then an error will be returned. We also return
// the set of permissions that we require as a server. At the time of writing
// of this documentation, this is the same macaroon as as the admin macaroon.
func New(cfg *Config) (*Server, lnrpc.MacaroonPerms, error) {
// If the path of the router macaroon wasn't generated, then we'll
// assume that it's found at the default network directory.
if cfg.RouterMacPath == "" {
cfg.RouterMacPath = filepath.Join(
cfg.NetworkDir, DefaultRouterMacFilename,
)
}
// Now that we know the full path of the router macaroon, we can check
// to see if we need to create it or not.
macFilePath := cfg.RouterMacPath
if !fileExists(macFilePath) && cfg.MacService != nil {
log.Infof("Making macaroons for Router RPC Server at: %v",
macFilePath)
// At this point, we know that the router macaroon doesn't yet,
// exist, so we need to create it with the help of the main
// macaroon service.
routerMac, err := cfg.MacService.Oven.NewMacaroon(
context.Background(), bakery.LatestVersion, nil,
macaroonOps...,
)
if err != nil {
return nil, nil, err
}
routerMacBytes, err := routerMac.M().MarshalBinary()
if err != nil {
return nil, nil, err
}
err = ioutil.WriteFile(macFilePath, routerMacBytes, 0644)
if err != nil {
os.Remove(macFilePath)
return nil, nil, err
}
}
routerServer := &Server{
cfg: cfg,
}
return routerServer, macPermissions, nil
}
// Start launches any helper goroutines required for the rpcServer to function.
//
// NOTE: This is part of the lnrpc.SubServer interface.
func (s *Server) Start() error {
return nil
}
// Stop signals any active goroutines for a graceful closure.
//
// NOTE: This is part of the lnrpc.SubServer interface.
func (s *Server) Stop() error {
return nil
}
// Name returns a unique string representation of the sub-server. This can be
// used to identify the sub-server and also de-duplicate them.
//
// NOTE: This is part of the lnrpc.SubServer interface.
func (s *Server) Name() string {
return subServerName
}
// RegisterWithRootServer will be called by the root gRPC server to direct a
// sub RPC server to register itself with the main gRPC root server. Until this
// is called, each sub-server won't be able to have requests routed towards it.
//
// NOTE: This is part of the lnrpc.SubServer interface.
func (s *Server) RegisterWithRootServer(grpcServer *grpc.Server) error {
// We make sure that we register it with the main gRPC server to ensure
// all our methods are routed properly.
RegisterRouterServer(grpcServer, s)
log.Debugf("Router RPC server successfully register with root gRPC " +
"server")
return nil
}
// SendPayment attempts to route a payment described by the passed
// PaymentRequest to the final destination. If we are unable to route the
// payment, or cannot find a route that satisfies the constraints in the
// PaymentRequest, then an error will be returned. Otherwise, the payment
// pre-image, along with the final route will be returned.
func (s *Server) SendPayment(req *SendPaymentRequest,
stream Router_SendPaymentServer) error {
payment, err := s.cfg.RouterBackend.extractIntentFromSendRequest(req)
if err != nil {
return err
}
err = s.cfg.Router.SendPaymentAsync(payment)
if err != nil {
// Transform user errors to grpc code.
if err == channeldb.ErrPaymentInFlight ||
err == channeldb.ErrAlreadyPaid {
log.Debugf("SendPayment async result for hash %x: %v",
payment.PaymentHash, err)
return status.Error(
codes.AlreadyExists, err.Error(),
)
}
log.Errorf("SendPayment async error for hash %x: %v",
payment.PaymentHash, err)
return err
}
return s.trackPayment(payment.PaymentHash, stream)
}
// EstimateRouteFee allows callers to obtain a lower bound w.r.t how much it
// may cost to send an HTLC to the target end destination.
func (s *Server) EstimateRouteFee(ctx context.Context,
req *RouteFeeRequest) (*RouteFeeResponse, error) {
if len(req.Dest) != 33 {
return nil, errors.New("invalid length destination key")
}
var destNode route.Vertex
copy(destNode[:], req.Dest)
// Next, we'll convert the amount in satoshis to mSAT, which are the
// native unit of LN.
amtMsat := lnwire.NewMSatFromSatoshis(btcutil.Amount(req.AmtSat))
// Pick a fee limit
//
// TODO: Change this into behaviour that makes more sense.
feeLimit := lnwire.NewMSatFromSatoshis(btcutil.SatoshiPerBitcoin)
// Finally, we'll query for a route to the destination that can carry
// that target amount, we'll only request a single route. Set a
// restriction for the default CLTV limit, otherwise we can find a route
// that exceeds it and is useless to us.
route, err := s.cfg.Router.FindRoute(
s.cfg.RouterBackend.SelfNode, destNode, amtMsat,
&routing.RestrictParams{
FeeLimit: feeLimit,
CltvLimit: s.cfg.RouterBackend.MaxTotalTimelock,
}, nil,
)
if err != nil {
return nil, err
}
return &RouteFeeResponse{
RoutingFeeMsat: int64(route.TotalFees()),
TimeLockDelay: int64(route.TotalTimeLock),
}, nil
}
// SendToRoute sends a payment through a predefined route. The response of this
// call contains structured error information.
func (s *Server) SendToRoute(ctx context.Context,
req *SendToRouteRequest) (*SendToRouteResponse, error) {
if req.Route == nil {
return nil, fmt.Errorf("unable to send, no routes provided")
}
route, err := s.cfg.RouterBackend.UnmarshallRoute(req.Route)
if err != nil {
return nil, err
}
hash, err := lntypes.MakeHash(req.PaymentHash)
if err != nil {
return nil, err
}
preimage, err := s.cfg.Router.SendToRoute(hash, route)
// In the success case, return the preimage.
if err == nil {
return &SendToRouteResponse{
Preimage: preimage[:],
}, nil
}
// In the failure case, marshall the failure message to the rpc format
// before returning it to the caller.
rpcErr, err := marshallError(err)
if err != nil {
return nil, err
}
return &SendToRouteResponse{
Failure: rpcErr,
}, nil
}
// marshallError marshall an error as received from the switch to rpc structs
// suitable for returning to the caller of an rpc method.
//
// Because of difficulties with using protobuf oneof constructs in some
// languages, the decision was made here to use a single message format for all
// failure messages with some fields left empty depending on the failure type.
func marshallError(sendError error) (*Failure, error) {
response := &Failure{}
if sendError == htlcswitch.ErrUnreadableFailureMessage {
response.Code = Failure_UNREADABLE_FAILURE
return response, nil
}
rtErr, ok := sendError.(htlcswitch.ClearTextError)
if !ok {
return nil, sendError
}
switch onionErr := rtErr.WireMessage().(type) {
case *lnwire.FailIncorrectDetails:
response.Code = Failure_INCORRECT_OR_UNKNOWN_PAYMENT_DETAILS
response.Height = onionErr.Height()
case *lnwire.FailIncorrectPaymentAmount:
response.Code = Failure_INCORRECT_PAYMENT_AMOUNT
case *lnwire.FailFinalIncorrectCltvExpiry:
response.Code = Failure_FINAL_INCORRECT_CLTV_EXPIRY
response.CltvExpiry = onionErr.CltvExpiry
case *lnwire.FailFinalIncorrectHtlcAmount:
response.Code = Failure_FINAL_INCORRECT_HTLC_AMOUNT
response.HtlcMsat = uint64(onionErr.IncomingHTLCAmount)
case *lnwire.FailFinalExpiryTooSoon:
response.Code = Failure_FINAL_EXPIRY_TOO_SOON
case *lnwire.FailInvalidRealm:
response.Code = Failure_INVALID_REALM
case *lnwire.FailExpiryTooSoon:
response.Code = Failure_EXPIRY_TOO_SOON
response.ChannelUpdate = marshallChannelUpdate(&onionErr.Update)
case *lnwire.FailExpiryTooFar:
response.Code = Failure_EXPIRY_TOO_FAR
case *lnwire.FailInvalidOnionVersion:
response.Code = Failure_INVALID_ONION_VERSION
response.OnionSha_256 = onionErr.OnionSHA256[:]
case *lnwire.FailInvalidOnionHmac:
response.Code = Failure_INVALID_ONION_HMAC
response.OnionSha_256 = onionErr.OnionSHA256[:]
case *lnwire.FailInvalidOnionKey:
response.Code = Failure_INVALID_ONION_KEY
response.OnionSha_256 = onionErr.OnionSHA256[:]
case *lnwire.FailAmountBelowMinimum:
response.Code = Failure_AMOUNT_BELOW_MINIMUM
response.ChannelUpdate = marshallChannelUpdate(&onionErr.Update)
response.HtlcMsat = uint64(onionErr.HtlcMsat)
case *lnwire.FailFeeInsufficient:
response.Code = Failure_FEE_INSUFFICIENT
response.ChannelUpdate = marshallChannelUpdate(&onionErr.Update)
response.HtlcMsat = uint64(onionErr.HtlcMsat)
case *lnwire.FailIncorrectCltvExpiry:
response.Code = Failure_INCORRECT_CLTV_EXPIRY
response.ChannelUpdate = marshallChannelUpdate(&onionErr.Update)
response.CltvExpiry = onionErr.CltvExpiry
case *lnwire.FailChannelDisabled:
response.Code = Failure_CHANNEL_DISABLED
response.ChannelUpdate = marshallChannelUpdate(&onionErr.Update)
response.Flags = uint32(onionErr.Flags)
case *lnwire.FailTemporaryChannelFailure:
response.Code = Failure_TEMPORARY_CHANNEL_FAILURE
response.ChannelUpdate = marshallChannelUpdate(onionErr.Update)
case *lnwire.FailRequiredNodeFeatureMissing:
response.Code = Failure_REQUIRED_NODE_FEATURE_MISSING
case *lnwire.FailRequiredChannelFeatureMissing:
response.Code = Failure_REQUIRED_CHANNEL_FEATURE_MISSING
case *lnwire.FailUnknownNextPeer:
response.Code = Failure_UNKNOWN_NEXT_PEER
case *lnwire.FailTemporaryNodeFailure:
response.Code = Failure_TEMPORARY_NODE_FAILURE
case *lnwire.FailPermanentNodeFailure:
response.Code = Failure_PERMANENT_NODE_FAILURE
case *lnwire.FailPermanentChannelFailure:
response.Code = Failure_PERMANENT_CHANNEL_FAILURE
case *lnwire.FailMPPTimeout:
response.Code = Failure_MPP_TIMEOUT
case nil:
response.Code = Failure_UNKNOWN_FAILURE
default:
return nil, fmt.Errorf("cannot marshall failure %T", onionErr)
}
// If the ClearTextError received is a ForwardingError, the error
// originated from a node along the route, not locally on our outgoing
// link. We set failureSourceIdx to the index of the node where the
// failure occurred. If the error is not a ForwardingError, the failure
// occurred at our node, so we leave the index as 0 to indicate that
// we failed locally.
fErr, ok := rtErr.(*htlcswitch.ForwardingError)
if ok {
response.FailureSourceIndex = uint32(fErr.FailureSourceIdx)
}
return response, nil
}
// marshallChannelUpdate marshalls a channel update as received over the wire to
// the router rpc format.
func marshallChannelUpdate(update *lnwire.ChannelUpdate) *ChannelUpdate {
if update == nil {
return nil
}
return &ChannelUpdate{
Signature: update.Signature[:],
ChainHash: update.ChainHash[:],
ChanId: update.ShortChannelID.ToUint64(),
Timestamp: update.Timestamp,
MessageFlags: uint32(update.MessageFlags),
ChannelFlags: uint32(update.ChannelFlags),
TimeLockDelta: uint32(update.TimeLockDelta),
HtlcMinimumMsat: uint64(update.HtlcMinimumMsat),
BaseFee: update.BaseFee,
FeeRate: update.FeeRate,
HtlcMaximumMsat: uint64(update.HtlcMaximumMsat),
ExtraOpaqueData: update.ExtraOpaqueData,
}
}
// ResetMissionControl clears all mission control state and starts with a clean
// slate.
func (s *Server) ResetMissionControl(ctx context.Context,
req *ResetMissionControlRequest) (*ResetMissionControlResponse, error) {
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err := s.cfg.RouterBackend.MissionControl.ResetHistory()
if err != nil {
return nil, err
}
return &ResetMissionControlResponse{}, nil
}
// QueryMissionControl exposes the internal mission control state to callers. It
// is a development feature.
func (s *Server) QueryMissionControl(ctx context.Context,
req *QueryMissionControlRequest) (*QueryMissionControlResponse, error) {
snapshot := s.cfg.RouterBackend.MissionControl.GetHistorySnapshot()
rpcPairs := make([]*PairHistory, 0, len(snapshot.Pairs))
for _, p := range snapshot.Pairs {
// Prevent binding to loop variable.
pair := p
rpcPair := PairHistory{
NodeFrom: pair.Pair.From[:],
NodeTo: pair.Pair.To[:],
History: toRPCPairData(&pair.TimedPairResult),
}
rpcPairs = append(rpcPairs, &rpcPair)
}
response := QueryMissionControlResponse{
Pairs: rpcPairs,
}
return &response, nil
}
// toRPCPairData marshalls mission control pair data to the rpc struct.
func toRPCPairData(data *routing.TimedPairResult) *PairData {
rpcData := PairData{
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FailAmtSat: int64(data.FailAmt.ToSatoshis()),
FailAmtMsat: int64(data.FailAmt),
SuccessAmtSat: int64(data.SuccessAmt.ToSatoshis()),
SuccessAmtMsat: int64(data.SuccessAmt),
}
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if !data.FailTime.IsZero() {
rpcData.FailTime = data.FailTime.Unix()
}
if !data.SuccessTime.IsZero() {
rpcData.SuccessTime = data.SuccessTime.Unix()
}
return &rpcData
}
// QueryProbability returns the current success probability estimate for a
// given node pair and amount.
func (s *Server) QueryProbability(ctx context.Context,
req *QueryProbabilityRequest) (*QueryProbabilityResponse, error) {
fromNode, err := route.NewVertexFromBytes(req.FromNode)
if err != nil {
return nil, err
}
toNode, err := route.NewVertexFromBytes(req.ToNode)
if err != nil {
return nil, err
}
amt := lnwire.MilliSatoshi(req.AmtMsat)
mc := s.cfg.RouterBackend.MissionControl
prob := mc.GetProbability(fromNode, toNode, amt)
history := mc.GetPairHistorySnapshot(fromNode, toNode)
return &QueryProbabilityResponse{
Probability: prob,
History: toRPCPairData(&history),
}, nil
}
// TrackPayment returns a stream of payment state updates. The stream is
// closed when the payment completes.
func (s *Server) TrackPayment(request *TrackPaymentRequest,
stream Router_TrackPaymentServer) error {
paymentHash, err := lntypes.MakeHash(request.PaymentHash)
if err != nil {
return err
}
log.Debugf("TrackPayment called for payment %v", paymentHash)
return s.trackPayment(paymentHash, stream)
}
// trackPayment writes payment status updates to the provided stream.
func (s *Server) trackPayment(paymentHash lntypes.Hash,
stream Router_TrackPaymentServer) error {
router := s.cfg.RouterBackend
// Subscribe to the outcome of this payment.
inFlight, resultChan, err := router.Tower.SubscribePayment(
paymentHash,
)
switch {
case err == channeldb.ErrPaymentNotInitiated:
return status.Error(codes.NotFound, err.Error())
case err != nil:
return err
}
// If it is in flight, send a state update to the client. Payment status
// update streams are expected to always send the current payment state
// immediately.
if inFlight {
err = stream.Send(&PaymentStatus{
State: PaymentState_IN_FLIGHT,
})
if err != nil {
return err
}
}
// Wait for the outcome of the payment. For payments that have
// completed, the result should already be waiting on the channel.
select {
case result := <-resultChan:
// Marshall result to rpc type.
var status PaymentStatus
if result.Success {
log.Debugf("Payment %v successfully completed",
paymentHash)
status.State = PaymentState_SUCCEEDED
status.Preimage = result.Preimage[:]
} else {
state, err := marshallFailureReason(
result.FailureReason,
)
if err != nil {
return err
}
status.State = state
}
// Extract the last route from the given list of HTLCs. This
// will populate the legacy route field for backwards
// compatibility.
//
// NOTE: For now there will be at most one HTLC, this code
// should be revisted or the field removed when multiple HTLCs
// are permitted.
var legacyRoute *route.Route
for _, htlc := range result.HTLCs {
switch {
case htlc.Settle != nil:
legacyRoute = &htlc.Route
// Only display the route for failed payments if we got
// an incorrect payment details error, so that it can be
// used for probing or fee estimation.
case htlc.Failure != nil && result.FailureReason ==
channeldb.FailureReasonPaymentDetails:
legacyRoute = &htlc.Route
}
}
if legacyRoute != nil {
status.Route, err = router.MarshallRoute(legacyRoute)
if err != nil {
return err
}
}
// Marshal our list of HTLCs that have been tried for this
// payment.
htlcs := make([]*lnrpc.HTLCAttempt, 0, len(result.HTLCs))
for _, dbHtlc := range result.HTLCs {
htlc, err := router.MarshalHTLCAttempt(dbHtlc)
if err != nil {
return err
}
htlcs = append(htlcs, htlc)
}
status.Htlcs = htlcs
// Send event to the client.
err = stream.Send(&status)
if err != nil {
return err
}
case <-stream.Context().Done():
log.Debugf("Payment status stream %v canceled", paymentHash)
return stream.Context().Err()
}
return nil
}
// marshallFailureReason marshalls the failure reason to the corresponding rpc
// type.
func marshallFailureReason(reason channeldb.FailureReason) (
PaymentState, error) {
switch reason {
case channeldb.FailureReasonTimeout:
return PaymentState_FAILED_TIMEOUT, nil
case channeldb.FailureReasonNoRoute:
return PaymentState_FAILED_NO_ROUTE, nil
case channeldb.FailureReasonError:
return PaymentState_FAILED_ERROR, nil
case channeldb.FailureReasonPaymentDetails:
return PaymentState_FAILED_INCORRECT_PAYMENT_DETAILS, nil
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case channeldb.FailureReasonInsufficientBalance:
return PaymentState_FAILED_INSUFFICIENT_BALANCE, nil
}
return 0, errors.New("unknown failure reason")
}
// BuildRoute builds a route from a list of hop addresses.
func (s *Server) BuildRoute(ctx context.Context,
req *BuildRouteRequest) (*BuildRouteResponse, error) {
// Unmarshall hop list.
hops := make([]route.Vertex, len(req.HopPubkeys))
for i, pubkeyBytes := range req.HopPubkeys {
pubkey, err := route.NewVertexFromBytes(pubkeyBytes)
if err != nil {
return nil, err
}
hops[i] = pubkey
}
// Prepare BuildRoute call parameters from rpc request.
var amt *lnwire.MilliSatoshi
if req.AmtMsat != 0 {
rpcAmt := lnwire.MilliSatoshi(req.AmtMsat)
amt = &rpcAmt
}
var outgoingChan *uint64
if req.OutgoingChanId != 0 {
outgoingChan = &req.OutgoingChanId
}
// Build the route and return it to the caller.
route, err := s.cfg.Router.BuildRoute(
amt, hops, outgoingChan, req.FinalCltvDelta,
)
if err != nil {
return nil, err
}
rpcRoute, err := s.cfg.RouterBackend.MarshallRoute(route)
if err != nil {
return nil, err
}
routeResp := &BuildRouteResponse{
Route: rpcRoute,
}
return routeResp, nil
}