From cfd6a0d860a43e63b0f365bdaf2a872ef37768cf Mon Sep 17 00:00:00 2001 From: Olaoluwa Osuntokun Date: Mon, 22 Oct 2018 21:45:44 -0700 Subject: [PATCH] lnrpc/routerrpc: add config, implement full RouterServer In this commit, we implement the full RouterServer as specified by the newly added sub-service as defined in router.proto. This new sub-server has its own macaroon state (but overlapping permissions which can be combined with the current admin.macaroon), and gives users a simplified interface for a gRPC service that is able to simply send payment. Much of the error reporting atm, is a place holder, and a follow up commit will put up the infrastructure for a proper set of errors. --- lnrpc/routerrpc/config_active.go | 43 +++++ lnrpc/routerrpc/config_default.go | 7 + lnrpc/routerrpc/driver.go | 62 +++++++ lnrpc/{routerpc => routerrpc}/log.go | 2 +- lnrpc/routerrpc/router_server.go | 258 +++++++++++++++++++++++++++ 5 files changed, 371 insertions(+), 1 deletion(-) create mode 100644 lnrpc/routerrpc/config_active.go create mode 100644 lnrpc/routerrpc/config_default.go create mode 100644 lnrpc/routerrpc/driver.go rename lnrpc/{routerpc => routerrpc}/log.go (98%) create mode 100644 lnrpc/routerrpc/router_server.go diff --git a/lnrpc/routerrpc/config_active.go b/lnrpc/routerrpc/config_active.go new file mode 100644 index 00000000..44b238b3 --- /dev/null +++ b/lnrpc/routerrpc/config_active.go @@ -0,0 +1,43 @@ +// +build routerrpc + +package routerrpc + +import ( + "github.com/btcsuite/btcd/chaincfg" + "github.com/lightningnetwork/lnd/macaroons" + "github.com/lightningnetwork/lnd/routing" +) + +// Config is the main configuration file for the router RPC server. It contains +// all the items required for the router RPC server to carry out its duties. +// The fields with struct tags are meant to be parsed as normal configuration +// options, while if able to be populated, the latter fields MUST also be +// specified. +type Config struct { + // RouterMacPath is the path for the router macaroon. If unspecified + // then we assume that the macaroon will be found under the network + // directory, named DefaultRouterMacFilename. + RouterMacPath string `long:"routermacaroonpath" description:"Path to the router macaroon"` + + // NetworkDir is the main network directory wherein the router rpc + // server will find the macaroon named DefaultRouterMacFilename. + NetworkDir string + + // ActiveNetParams are the network parameters of the primary network + // that the route is operating on. This is necessary so we can ensure + // that we receive payment requests that send to destinations on our + // network. + ActiveNetParams *chaincfg.Params + + // MacService is the main macaroon service that we'll use to handle + // authentication for the Router rpc server. + MacService *macaroons.Service + + // Router is the main channel router instance that backs this RPC + // server. + // + // TODO(roasbeef): make into pkg lvl interface? + // + // TODO(roasbeef): assumes router handles saving payment state + Router *routing.ChannelRouter +} diff --git a/lnrpc/routerrpc/config_default.go b/lnrpc/routerrpc/config_default.go new file mode 100644 index 00000000..9ca27faa --- /dev/null +++ b/lnrpc/routerrpc/config_default.go @@ -0,0 +1,7 @@ +// +build !routerrpc + +package routerrpc + +// Config is the default config for the package. When the build tag isn't +// specified, then we output a blank config. +type Config struct{} diff --git a/lnrpc/routerrpc/driver.go b/lnrpc/routerrpc/driver.go new file mode 100644 index 00000000..05cc0c4b --- /dev/null +++ b/lnrpc/routerrpc/driver.go @@ -0,0 +1,62 @@ +// +build routerrpc + +package routerrpc + +import ( + "fmt" + + "github.com/lightningnetwork/lnd/lnrpc" +) + +// createNewSubServer is a helper method that will create the new router sub +// server given the main config dispatcher method. If we're unable to find the +// config that is meant for us in the config dispatcher, then we'll exit with +// an error. +func createNewSubServer(configRegistry lnrpc.SubServerConfigDispatcher) ( + lnrpc.SubServer, lnrpc.MacaroonPerms, error) { + + // We'll attempt to look up the config that we expect, according to our + // subServerName name. If we can't find this, then we'll exit with an + // error, as we're unable to properly initialize ourselves without this + // config. + routeServerConf, ok := configRegistry.FetchConfig(subServerName) + if !ok { + return nil, nil, fmt.Errorf("unable to find config for "+ + "subserver type %s", subServerName) + } + + // Now that we've found an object mapping to our service name, we'll + // ensure that it's the type we need. + config, ok := routeServerConf.(*Config) + if !ok { + return nil, nil, fmt.Errorf("wrong type of config for "+ + "subserver %s, expected %T got %T", subServerName, + &Config{}, routeServerConf) + } + + // Before we try to make the new router service instance, we'll perform + // some sanity checks on the arguments to ensure that they're useable. + switch { + case config.Router == nil: + return nil, nil, fmt.Errorf("Router must be set to create " + + "Routerpc") + } + + return New(config) +} + +func init() { + subServer := &lnrpc.SubServerDriver{ + SubServerName: subServerName, + New: func(c lnrpc.SubServerConfigDispatcher) (lnrpc.SubServer, lnrpc.MacaroonPerms, error) { + return createNewSubServer(c) + }, + } + + // If the build tag is active, then we'll register ourselves as a + // sub-RPC server within the global lnrpc package namespace. + if err := lnrpc.RegisterSubServer(subServer); err != nil { + panic(fmt.Sprintf("failed to register sub server driver '%s': %v", + subServerName, err)) + } +} diff --git a/lnrpc/routerpc/log.go b/lnrpc/routerrpc/log.go similarity index 98% rename from lnrpc/routerpc/log.go rename to lnrpc/routerrpc/log.go index 7421ad39..4383ce9c 100644 --- a/lnrpc/routerpc/log.go +++ b/lnrpc/routerrpc/log.go @@ -1,4 +1,4 @@ -package routerpc +package routerrpc import ( "github.com/btcsuite/btclog" diff --git a/lnrpc/routerrpc/router_server.go b/lnrpc/routerrpc/router_server.go new file mode 100644 index 00000000..01e92c29 --- /dev/null +++ b/lnrpc/routerrpc/router_server.go @@ -0,0 +1,258 @@ +// +build routerrpc + +package routerrpc + +import ( + "context" + "fmt" + "io/ioutil" + "os" + "path/filepath" + "time" + + "github.com/btcsuite/btcd/btcec" + "github.com/btcsuite/btcutil" + "github.com/lightningnetwork/lnd/lnrpc" + "github.com/lightningnetwork/lnd/lnwire" + "github.com/lightningnetwork/lnd/routing" + "github.com/lightningnetwork/lnd/zpay32" + "google.golang.org/grpc" + "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: "write", + }, + } + + // macPermissions maps RPC calls to the permissions they require. + macPermissions = map[string][]bakery.Op{ + "/routerpc.Router/SendPayment": {{ + Entity: "offchain", + Action: "write", + }}, + "/routerpc.Router/EstimateRouteFee": {{ + 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(ctx context.Context, + req *PaymentRequest) (*PaymentResponse, error) { + + switch { + // If the payment request isn't populated, then we won't be able to + // even attempt a payment. + case req.PayReq == "": + return nil, fmt.Errorf("a valid payment request MUST be specified") + } + + // Now that we know the payment request is present, we'll attempt to + // decode it in order to parse out all the parameters for the route. + payReq, err := zpay32.Decode(req.PayReq, s.cfg.ActiveNetParams) + if err != nil { + return nil, err + } + + // Atm, this service does not support invoices that don't have their + // value fully specified. + if payReq.MilliSat == nil { + return nil, fmt.Errorf("zero value invoices are not supported") + } + + // Now that all the information we need has been parsed, we'll map this + // proto request into a proper request that our backing router can + // understand. + finalDelta := uint16(payReq.MinFinalCLTVExpiry()) + payment := routing.LightningPayment{ + Target: payReq.Destination, + Amount: *payReq.MilliSat, + FeeLimit: lnwire.MilliSatoshi(req.FeeLimitSat), + PaymentHash: *payReq.PaymentHash, + FinalCLTVDelta: &finalDelta, + PayAttemptTimeout: time.Second * time.Duration(req.TimeoutSeconds), + RouteHints: payReq.RouteHints, + } + + // Pin to an outgoing channel if specified. + if req.OutgoingChannelId != 0 { + chanID := uint64(req.OutgoingChannelId) + payment.OutgoingChannelID = &chanID + } + + preImage, _, err := s.cfg.Router.SendPayment(&payment) + if err != nil { + return nil, err + } + + return &PaymentResponse{ + PayHash: (*payReq.PaymentHash)[:], + PreImage: preImage[:], + }, nil +} + +// 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) { + + // First we'll parse out the raw public key into a value that we can + // utilize. + destNode, err := btcec.ParsePubKey(req.Dest, btcec.S256()) + if err != nil { + return nil, err + } + + // Next, we'll convert the amount in satoshis to mSAT, which are the + // native unit of LN. + amtMsat := lnwire.NewMSatFromSatoshis(btcutil.Amount(req.AmtSat)) + + // Finally, we'll query for a route to the destination that can carry + // that target amount, we'll only request a single route. + routes, err := s.cfg.Router.FindRoutes( + destNode, amtMsat, + lnwire.NewMSatFromSatoshis(btcutil.SatoshiPerBitcoin), 1, + ) + if err != nil { + return nil, err + } + + if len(routes) == 0 { + return nil, fmt.Errorf("unable to find route to dest: %v", err) + } + + return &RouteFeeResponse{ + RoutingFeeMsat: int64(routes[0].TotalFees), + TimeLockDelay: int64(routes[0].TotalTimeLock), + }, nil +}