7b56268f70
In this commit we add the ability to intercept forwarded htlc packets straight from the RPC layer. The RPC layer handles a bidrectional stream that comminucates to the client the intercepted packets and handles its response by coordinating with the interceptable switch.
641 lines
18 KiB
Go
641 lines
18 KiB
Go
package routerrpc
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import (
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"context"
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"errors"
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"fmt"
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"io/ioutil"
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"os"
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"path/filepath"
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"sync/atomic"
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"github.com/btcsuite/btcutil"
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"github.com/grpc-ecosystem/grpc-gateway/runtime"
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"github.com/lightningnetwork/lnd/channeldb"
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"github.com/lightningnetwork/lnd/lnrpc"
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"github.com/lightningnetwork/lnd/lntypes"
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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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"google.golang.org/grpc"
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"google.golang.org/grpc/codes"
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"google.golang.org/grpc/status"
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"gopkg.in/macaroon-bakery.v2/bakery"
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)
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const (
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// subServerName is the name of the sub rpc server. We'll use this name
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// to register ourselves, and we also require that the main
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// SubServerConfigDispatcher instance recognize as the name of our
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subServerName = "RouterRPC"
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)
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var (
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errServerShuttingDown = errors.New("routerrpc server shutting down")
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// ErrInterceptorAlreadyExists is an error returned when the a new stream
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// is opened and there is already one active interceptor.
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// The user must disconnect prior to open another stream.
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ErrInterceptorAlreadyExists = errors.New("interceptor already exists")
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// macaroonOps are the set of capabilities that our minted macaroon (if
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// it doesn't already exist) will have.
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macaroonOps = []bakery.Op{
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{
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Entity: "offchain",
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Action: "read",
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},
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{
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Entity: "offchain",
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Action: "write",
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},
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}
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// macPermissions maps RPC calls to the permissions they require.
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macPermissions = map[string][]bakery.Op{
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"/routerrpc.Router/SendPaymentV2": {{
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Entity: "offchain",
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Action: "write",
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}},
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"/routerrpc.Router/SendToRouteV2": {{
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Entity: "offchain",
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Action: "write",
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}},
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"/routerrpc.Router/SendToRoute": {{
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Entity: "offchain",
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Action: "write",
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}},
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"/routerrpc.Router/TrackPaymentV2": {{
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Entity: "offchain",
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Action: "read",
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}},
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"/routerrpc.Router/EstimateRouteFee": {{
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Entity: "offchain",
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Action: "read",
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}},
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"/routerrpc.Router/QueryMissionControl": {{
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Entity: "offchain",
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Action: "read",
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}},
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"/routerrpc.Router/QueryProbability": {{
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Entity: "offchain",
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Action: "read",
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}},
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"/routerrpc.Router/ResetMissionControl": {{
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Entity: "offchain",
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Action: "write",
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}},
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"/routerrpc.Router/BuildRoute": {{
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Entity: "offchain",
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Action: "read",
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}},
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"/routerrpc.Router/SubscribeHtlcEvents": {{
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Entity: "offchain",
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Action: "read",
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}},
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"/routerrpc.Router/SendPayment": {{
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Entity: "offchain",
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Action: "write",
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}},
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"/routerrpc.Router/TrackPayment": {{
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Entity: "offchain",
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Action: "read",
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}},
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"/routerrpc.Router/HtlcInterceptor": {{
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Entity: "offchain",
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Action: "write",
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}},
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}
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// DefaultRouterMacFilename is the default name of the router macaroon
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// that we expect to find via a file handle within the main
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// configuration file in this package.
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DefaultRouterMacFilename = "router.macaroon"
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)
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// Server is a stand alone sub RPC server which exposes functionality that
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// allows clients to route arbitrary payment through the Lightning Network.
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type Server struct {
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started int32 // To be used atomically.
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shutdown int32 // To be used atomically.
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forwardInterceptorActive int32 // To be used atomically.
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cfg *Config
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quit chan struct{}
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}
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// A compile time check to ensure that Server fully implements the RouterServer
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// gRPC service.
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var _ RouterServer = (*Server)(nil)
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// fileExists reports whether the named file or directory exists.
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func fileExists(name string) bool {
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if _, err := os.Stat(name); err != nil {
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if os.IsNotExist(err) {
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return false
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}
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}
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return true
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}
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// New creates a new instance of the RouterServer given a configuration struct
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// that contains all external dependencies. If the target macaroon exists, and
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// we're unable to create it, then an error will be returned. We also return
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// the set of permissions that we require as a server. At the time of writing
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// of this documentation, this is the same macaroon as as the admin macaroon.
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func New(cfg *Config) (*Server, lnrpc.MacaroonPerms, error) {
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// If the path of the router macaroon wasn't generated, then we'll
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// assume that it's found at the default network directory.
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if cfg.RouterMacPath == "" {
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cfg.RouterMacPath = filepath.Join(
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cfg.NetworkDir, DefaultRouterMacFilename,
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)
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}
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// Now that we know the full path of the router macaroon, we can check
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// to see if we need to create it or not.
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macFilePath := cfg.RouterMacPath
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if !fileExists(macFilePath) && cfg.MacService != nil {
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log.Infof("Making macaroons for Router RPC Server at: %v",
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macFilePath)
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// At this point, we know that the router macaroon doesn't yet,
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// exist, so we need to create it with the help of the main
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// macaroon service.
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routerMac, err := cfg.MacService.Oven.NewMacaroon(
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context.Background(), bakery.LatestVersion, nil,
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macaroonOps...,
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)
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if err != nil {
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return nil, nil, err
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}
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routerMacBytes, err := routerMac.M().MarshalBinary()
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if err != nil {
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return nil, nil, err
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}
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err = ioutil.WriteFile(macFilePath, routerMacBytes, 0644)
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if err != nil {
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os.Remove(macFilePath)
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return nil, nil, err
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}
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}
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routerServer := &Server{
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cfg: cfg,
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quit: make(chan struct{}),
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}
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return routerServer, macPermissions, nil
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}
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// Start launches any helper goroutines required for the rpcServer to function.
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//
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// NOTE: This is part of the lnrpc.SubServer interface.
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func (s *Server) Start() error {
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if atomic.AddInt32(&s.started, 1) != 1 {
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return nil
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}
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return nil
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}
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// Stop signals any active goroutines for a graceful closure.
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//
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// NOTE: This is part of the lnrpc.SubServer interface.
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func (s *Server) Stop() error {
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if atomic.AddInt32(&s.shutdown, 1) != 1 {
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return nil
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}
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close(s.quit)
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return nil
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}
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// Name returns a unique string representation of the sub-server. This can be
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// used to identify the sub-server and also de-duplicate them.
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//
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// NOTE: This is part of the lnrpc.SubServer interface.
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func (s *Server) Name() string {
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return subServerName
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}
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// RegisterWithRootServer will be called by the root gRPC server to direct a
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// sub RPC server to register itself with the main gRPC root server. Until this
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// is called, each sub-server won't be able to have requests routed towards it.
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//
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// NOTE: This is part of the lnrpc.SubServer interface.
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func (s *Server) RegisterWithRootServer(grpcServer *grpc.Server) error {
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// We make sure that we register it with the main gRPC server to ensure
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// all our methods are routed properly.
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RegisterRouterServer(grpcServer, s)
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log.Debugf("Router RPC server successfully register with root gRPC " +
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"server")
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return nil
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}
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// RegisterWithRestServer will be called by the root REST mux to direct a sub
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// RPC server to register itself with the main REST mux server. Until this is
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// called, each sub-server won't be able to have requests routed towards it.
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//
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// NOTE: This is part of the lnrpc.SubServer interface.
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func (s *Server) RegisterWithRestServer(ctx context.Context,
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mux *runtime.ServeMux, dest string, opts []grpc.DialOption) error {
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// We make sure that we register it with the main REST server to ensure
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// all our methods are routed properly.
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err := RegisterRouterHandlerFromEndpoint(ctx, mux, dest, opts)
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if err != nil {
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log.Errorf("Could not register Router REST server "+
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"with root REST server: %v", err)
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return err
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}
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log.Debugf("Router REST server successfully registered with " +
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"root REST server")
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return nil
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}
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// SendPaymentV2 attempts to route a payment described by the passed
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// PaymentRequest to the final destination. If we are unable to route the
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// payment, or cannot find a route that satisfies the constraints in the
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// PaymentRequest, then an error will be returned. Otherwise, the payment
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// pre-image, along with the final route will be returned.
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func (s *Server) SendPaymentV2(req *SendPaymentRequest,
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stream Router_SendPaymentV2Server) error {
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payment, err := s.cfg.RouterBackend.extractIntentFromSendRequest(req)
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if err != nil {
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return err
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}
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err = s.cfg.Router.SendPaymentAsync(payment)
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if err != nil {
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// Transform user errors to grpc code.
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if err == channeldb.ErrPaymentInFlight ||
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err == channeldb.ErrAlreadyPaid {
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log.Debugf("SendPayment async result for hash %x: %v",
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payment.PaymentHash, err)
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return status.Error(
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codes.AlreadyExists, err.Error(),
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)
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}
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log.Errorf("SendPayment async error for hash %x: %v",
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payment.PaymentHash, err)
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return err
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}
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return s.trackPayment(payment.PaymentHash, stream, req.NoInflightUpdates)
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}
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// EstimateRouteFee allows callers to obtain a lower bound w.r.t how much it
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// may cost to send an HTLC to the target end destination.
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func (s *Server) EstimateRouteFee(ctx context.Context,
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req *RouteFeeRequest) (*RouteFeeResponse, error) {
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if len(req.Dest) != 33 {
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return nil, errors.New("invalid length destination key")
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}
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var destNode route.Vertex
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copy(destNode[:], req.Dest)
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// Next, we'll convert the amount in satoshis to mSAT, which are the
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// native unit of LN.
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amtMsat := lnwire.NewMSatFromSatoshis(btcutil.Amount(req.AmtSat))
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// Pick a fee limit
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//
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// TODO: Change this into behaviour that makes more sense.
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feeLimit := lnwire.NewMSatFromSatoshis(btcutil.SatoshiPerBitcoin)
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// Finally, we'll query for a route to the destination that can carry
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// that target amount, we'll only request a single route. Set a
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// restriction for the default CLTV limit, otherwise we can find a route
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// that exceeds it and is useless to us.
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route, err := s.cfg.Router.FindRoute(
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s.cfg.RouterBackend.SelfNode, destNode, amtMsat,
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&routing.RestrictParams{
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FeeLimit: feeLimit,
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CltvLimit: s.cfg.RouterBackend.MaxTotalTimelock,
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}, nil, nil, s.cfg.RouterBackend.DefaultFinalCltvDelta,
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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 &RouteFeeResponse{
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RoutingFeeMsat: int64(route.TotalFees()),
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TimeLockDelay: int64(route.TotalTimeLock),
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}, nil
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}
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// SendToRouteV2 sends a payment through a predefined route. The response of this
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// call contains structured error information.
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func (s *Server) SendToRouteV2(ctx context.Context,
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req *SendToRouteRequest) (*lnrpc.HTLCAttempt, error) {
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if req.Route == nil {
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return nil, fmt.Errorf("unable to send, no routes provided")
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}
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route, err := s.cfg.RouterBackend.UnmarshallRoute(req.Route)
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if err != nil {
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return nil, err
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}
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hash, err := lntypes.MakeHash(req.PaymentHash)
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if err != nil {
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return nil, err
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}
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// Pass route to the router. This call returns the full htlc attempt
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// information as it is stored in the database. It is possible that both
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// the attempt return value and err are non-nil. This can happen when
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// the attempt was already initiated before the error happened. In that
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// case, we give precedence to the attempt information as stored in the
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// db.
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attempt, err := s.cfg.Router.SendToRoute(hash, route)
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if attempt != nil {
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rpcAttempt, err := s.cfg.RouterBackend.MarshalHTLCAttempt(
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*attempt,
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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 rpcAttempt, nil
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}
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return nil, err
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}
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// ResetMissionControl clears all mission control state and starts with a clean
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// slate.
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func (s *Server) ResetMissionControl(ctx context.Context,
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req *ResetMissionControlRequest) (*ResetMissionControlResponse, error) {
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err := s.cfg.RouterBackend.MissionControl.ResetHistory()
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if err != nil {
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return nil, err
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}
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return &ResetMissionControlResponse{}, nil
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}
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// QueryMissionControl exposes the internal mission control state to callers. It
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// is a development feature.
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func (s *Server) QueryMissionControl(ctx context.Context,
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req *QueryMissionControlRequest) (*QueryMissionControlResponse, error) {
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snapshot := s.cfg.RouterBackend.MissionControl.GetHistorySnapshot()
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rpcPairs := make([]*PairHistory, 0, len(snapshot.Pairs))
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for _, p := range snapshot.Pairs {
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// Prevent binding to loop variable.
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pair := p
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rpcPair := PairHistory{
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NodeFrom: pair.Pair.From[:],
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NodeTo: pair.Pair.To[:],
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History: toRPCPairData(&pair.TimedPairResult),
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}
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rpcPairs = append(rpcPairs, &rpcPair)
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}
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response := QueryMissionControlResponse{
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Pairs: rpcPairs,
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}
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return &response, nil
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}
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// toRPCPairData marshalls mission control pair data to the rpc struct.
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func toRPCPairData(data *routing.TimedPairResult) *PairData {
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rpcData := PairData{
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FailAmtSat: int64(data.FailAmt.ToSatoshis()),
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FailAmtMsat: int64(data.FailAmt),
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SuccessAmtSat: int64(data.SuccessAmt.ToSatoshis()),
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SuccessAmtMsat: int64(data.SuccessAmt),
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}
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if !data.FailTime.IsZero() {
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rpcData.FailTime = data.FailTime.Unix()
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}
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if !data.SuccessTime.IsZero() {
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rpcData.SuccessTime = data.SuccessTime.Unix()
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}
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return &rpcData
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}
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// QueryProbability returns the current success probability estimate for a
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// given node pair and amount.
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func (s *Server) QueryProbability(ctx context.Context,
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req *QueryProbabilityRequest) (*QueryProbabilityResponse, error) {
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fromNode, err := route.NewVertexFromBytes(req.FromNode)
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if err != nil {
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return nil, err
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}
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toNode, err := route.NewVertexFromBytes(req.ToNode)
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if err != nil {
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return nil, err
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}
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amt := lnwire.MilliSatoshi(req.AmtMsat)
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mc := s.cfg.RouterBackend.MissionControl
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prob := mc.GetProbability(fromNode, toNode, amt)
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history := mc.GetPairHistorySnapshot(fromNode, toNode)
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return &QueryProbabilityResponse{
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Probability: prob,
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History: toRPCPairData(&history),
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}, nil
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}
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// TrackPaymentV2 returns a stream of payment state updates. The stream is
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// closed when the payment completes.
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func (s *Server) TrackPaymentV2(request *TrackPaymentRequest,
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stream Router_TrackPaymentV2Server) error {
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paymentHash, err := lntypes.MakeHash(request.PaymentHash)
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if err != nil {
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return err
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}
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log.Debugf("TrackPayment called for payment %v", paymentHash)
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return s.trackPayment(paymentHash, stream, request.NoInflightUpdates)
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}
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// trackPayment writes payment status updates to the provided stream.
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func (s *Server) trackPayment(paymentHash lntypes.Hash,
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stream Router_TrackPaymentV2Server, noInflightUpdates bool) error {
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router := s.cfg.RouterBackend
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// Subscribe to the outcome of this payment.
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subscription, err := router.Tower.SubscribePayment(
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paymentHash,
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)
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switch {
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case err == channeldb.ErrPaymentNotInitiated:
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return status.Error(codes.NotFound, err.Error())
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case err != nil:
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return err
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}
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defer subscription.Close()
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// Stream updates back to the client. The first update is always the
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// current state of the payment.
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for {
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select {
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case item, ok := <-subscription.Updates:
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if !ok {
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// No more payment updates.
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return nil
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}
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result := item.(*channeldb.MPPayment)
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// Skip in-flight updates unless requested.
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if noInflightUpdates &&
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result.Status == channeldb.StatusInFlight {
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continue
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}
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rpcPayment, err := router.MarshallPayment(result)
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if err != nil {
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return err
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}
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// Send event to the client.
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err = stream.Send(rpcPayment)
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if err != nil {
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return err
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}
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case <-s.quit:
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return errServerShuttingDown
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case <-stream.Context().Done():
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log.Debugf("Payment status stream %v canceled", paymentHash)
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return stream.Context().Err()
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}
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}
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}
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// BuildRoute builds a route from a list of hop addresses.
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|
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
|
|
}
|
|
|
|
// SubscribeHtlcEvents creates a uni-directional stream from the server to
|
|
// the client which delivers a stream of htlc events.
|
|
func (s *Server) SubscribeHtlcEvents(req *SubscribeHtlcEventsRequest,
|
|
stream Router_SubscribeHtlcEventsServer) error {
|
|
|
|
htlcClient, err := s.cfg.RouterBackend.SubscribeHtlcEvents()
|
|
if err != nil {
|
|
return err
|
|
}
|
|
defer htlcClient.Cancel()
|
|
|
|
for {
|
|
select {
|
|
case event := <-htlcClient.Updates():
|
|
rpcEvent, err := rpcHtlcEvent(event)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
if err := stream.Send(rpcEvent); err != nil {
|
|
return err
|
|
}
|
|
|
|
// If the stream's context is cancelled, return an error.
|
|
case <-stream.Context().Done():
|
|
log.Debugf("htlc event stream cancelled")
|
|
return stream.Context().Err()
|
|
|
|
// If the subscribe client terminates, exit with an error.
|
|
case <-htlcClient.Quit():
|
|
return errors.New("htlc event subscription terminated")
|
|
|
|
// If the server has been signalled to shut down, exit.
|
|
case <-s.quit:
|
|
return errServerShuttingDown
|
|
}
|
|
}
|
|
}
|
|
|
|
// HtlcInterceptor is a bidirectional stream for streaming interception
|
|
// requests to the caller.
|
|
// Upon connection it does the following:
|
|
// 1. Check if there is already a live stream, if yes it rejects the request.
|
|
// 2. Regsitered a ForwardInterceptor
|
|
// 3. Delivers to the caller every √√ and detect his answer.
|
|
// It uses a local implementation of holdForwardsStore to keep all the hold
|
|
// forwards and find them when manual resolution is later needed.
|
|
func (s *Server) HtlcInterceptor(stream Router_HtlcInterceptorServer) error {
|
|
// We ensure there is only one interceptor at a time.
|
|
if !atomic.CompareAndSwapInt32(&s.forwardInterceptorActive, 0, 1) {
|
|
return ErrInterceptorAlreadyExists
|
|
}
|
|
defer atomic.CompareAndSwapInt32(&s.forwardInterceptorActive, 1, 0)
|
|
|
|
// run the forward interceptor.
|
|
return newForwardInterceptor(s, stream).run()
|
|
}
|