lnd/lnrpc/wtclientrpc/wtclient.go
Johan T. Halseth 4ea494e8c5
lnrpc: wrap subservers in GrpcHandler
In order to be able to register the subservers with the root grpc server
before we have all dependencies available, we wrap them in an
GrpcHandler struct. This struct will initially hold an empty reference
to the subservers, which allows us to register with the GRPC server, and
later populate and create the subserver instance.
2021-03-11 13:05:23 +01:00

408 lines
12 KiB
Go

package wtclientrpc
import (
"context"
"errors"
"fmt"
"net"
"strconv"
"github.com/btcsuite/btcd/btcec"
"github.com/grpc-ecosystem/grpc-gateway/runtime"
"github.com/lightningnetwork/lnd/lncfg"
"github.com/lightningnetwork/lnd/lnrpc"
"github.com/lightningnetwork/lnd/lnwire"
"github.com/lightningnetwork/lnd/watchtower"
"github.com/lightningnetwork/lnd/watchtower/wtclient"
"github.com/lightningnetwork/lnd/watchtower/wtdb"
"github.com/lightningnetwork/lnd/watchtower/wtpolicy"
"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 recognizes it as the name of our
// RPC service.
subServerName = "WatchtowerClientRPC"
)
var (
// macPermissions maps RPC calls to the permissions they require.
//
// TODO(wilmer): create tower macaroon?
macPermissions = map[string][]bakery.Op{
"/wtclientrpc.WatchtowerClient/AddTower": {{
Entity: "offchain",
Action: "write",
}},
"/wtclientrpc.WatchtowerClient/RemoveTower": {{
Entity: "offchain",
Action: "write",
}},
"/wtclientrpc.WatchtowerClient/ListTowers": {{
Entity: "offchain",
Action: "read",
}},
"/wtclientrpc.WatchtowerClient/GetTowerInfo": {{
Entity: "offchain",
Action: "read",
}},
"/wtclientrpc.WatchtowerClient/Stats": {{
Entity: "offchain",
Action: "read",
}},
"/wtclientrpc.WatchtowerClient/Policy": {{
Entity: "offchain",
Action: "read",
}},
}
// ErrWtclientNotActive signals that RPC calls cannot be processed
// because the watchtower client is not active.
ErrWtclientNotActive = errors.New("watchtower client not active")
)
// ServerShell is a shell struct holding a reference to the actual sub-server.
// It is used to register the gRPC sub-server with the root server before we
// have the necessary dependencies to populate the actual sub-server.
type ServerShell struct {
WatchtowerClientServer
}
// WatchtowerClient is the RPC server we'll use to interact with the backing
// active watchtower client.
//
// TODO(wilmer): better name?
type WatchtowerClient struct {
cfg Config
}
// A compile time check to ensure that WatchtowerClient fully implements the
// WatchtowerClientWatchtowerClient gRPC service.
var _ WatchtowerClientServer = (*WatchtowerClient)(nil)
// New returns a new instance of the wtclientrpc WatchtowerClient sub-server.
// We also return the set of permissions for the macaroons that we may create
// within this method. If the macaroons we need aren't found in the filepath,
// then we'll create them on start up. If we're unable to locate, or create the
// macaroons we need, then we'll return with an error.
func New(cfg *Config) (*WatchtowerClient, lnrpc.MacaroonPerms, error) {
return &WatchtowerClient{*cfg}, macPermissions, nil
}
// Start launches any helper goroutines required for the WatchtowerClient to
// function.
//
// NOTE: This is part of the lnrpc.SubWatchtowerClient interface.
func (c *WatchtowerClient) Start() error {
return nil
}
// Stop signals any active goroutines for a graceful closure.
//
// NOTE: This is part of the lnrpc.SubServer interface.
func (c *WatchtowerClient) 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 (c *WatchtowerClient) 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.GrpcHandler interface.
func (r *ServerShell) 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.
RegisterWatchtowerClientServer(grpcServer, r)
return nil
}
// RegisterWithRestServer will be called by the root REST mux to direct a sub
// RPC server to register itself with the main REST mux 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.GrpcHandler interface.
func (r *ServerShell) RegisterWithRestServer(ctx context.Context,
mux *runtime.ServeMux, dest string, opts []grpc.DialOption) error {
// We make sure that we register it with the main REST server to ensure
// all our methods are routed properly.
err := RegisterWatchtowerClientHandlerFromEndpoint(ctx, mux, dest, opts)
if err != nil {
return err
}
return nil
}
// CreateSubServer populates the subserver's dependencies using the passed
// SubServerConfigDispatcher. This method should fully initialize the
// sub-server instance, making it ready for action. It returns the macaroon
// permissions that the sub-server wishes to pass on to the root server for all
// methods routed towards it.
//
// NOTE: This is part of the lnrpc.GrpcHandler interface.
func (r *ServerShell) CreateSubServer(configRegistry lnrpc.SubServerConfigDispatcher) (
lnrpc.SubServer, lnrpc.MacaroonPerms, error) {
subServer, macPermissions, err := createNewSubServer(configRegistry)
if err != nil {
return nil, nil, err
}
r.WatchtowerClientServer = subServer
return subServer, macPermissions, nil
}
// isActive returns nil if the watchtower client is initialized so that we can
// process RPC requests.
func (c *WatchtowerClient) isActive() error {
if c.cfg.Active {
return nil
}
return ErrWtclientNotActive
}
// AddTower adds a new watchtower reachable at the given address and considers
// it for new sessions. If the watchtower already exists, then any new addresses
// included will be considered when dialing it for session negotiations and
// backups.
func (c *WatchtowerClient) AddTower(ctx context.Context,
req *AddTowerRequest) (*AddTowerResponse, error) {
if err := c.isActive(); err != nil {
return nil, err
}
pubKey, err := btcec.ParsePubKey(req.Pubkey, btcec.S256())
if err != nil {
return nil, err
}
addr, err := lncfg.ParseAddressString(
req.Address, strconv.Itoa(watchtower.DefaultPeerPort),
c.cfg.Resolver,
)
if err != nil {
return nil, fmt.Errorf("invalid address %v: %v", req.Address, err)
}
towerAddr := &lnwire.NetAddress{
IdentityKey: pubKey,
Address: addr,
}
// TODO(conner): make atomic via multiplexed client
if err := c.cfg.Client.AddTower(towerAddr); err != nil {
return nil, err
}
if err := c.cfg.AnchorClient.AddTower(towerAddr); err != nil {
return nil, err
}
return &AddTowerResponse{}, nil
}
// RemoveTower removes a watchtower from being considered for future session
// negotiations and from being used for any subsequent backups until it's added
// again. If an address is provided, then this RPC only serves as a way of
// removing the address from the watchtower instead.
func (c *WatchtowerClient) RemoveTower(ctx context.Context,
req *RemoveTowerRequest) (*RemoveTowerResponse, error) {
if err := c.isActive(); err != nil {
return nil, err
}
pubKey, err := btcec.ParsePubKey(req.Pubkey, btcec.S256())
if err != nil {
return nil, err
}
var addr net.Addr
if req.Address != "" {
addr, err = lncfg.ParseAddressString(
req.Address, strconv.Itoa(watchtower.DefaultPeerPort),
c.cfg.Resolver,
)
if err != nil {
return nil, fmt.Errorf("unable to parse tower "+
"address %v: %v", req.Address, err)
}
}
// TODO(conner): make atomic via multiplexed client
err = c.cfg.Client.RemoveTower(pubKey, addr)
if err != nil {
return nil, err
}
err = c.cfg.AnchorClient.RemoveTower(pubKey, addr)
if err != nil {
return nil, err
}
return &RemoveTowerResponse{}, nil
}
// ListTowers returns the list of watchtowers registered with the client.
func (c *WatchtowerClient) ListTowers(ctx context.Context,
req *ListTowersRequest) (*ListTowersResponse, error) {
if err := c.isActive(); err != nil {
return nil, err
}
anchorTowers, err := c.cfg.AnchorClient.RegisteredTowers()
if err != nil {
return nil, err
}
legacyTowers, err := c.cfg.Client.RegisteredTowers()
if err != nil {
return nil, err
}
// Filter duplicates.
towers := make(map[wtdb.TowerID]*wtclient.RegisteredTower)
for _, tower := range anchorTowers {
towers[tower.Tower.ID] = tower
}
for _, tower := range legacyTowers {
towers[tower.Tower.ID] = tower
}
rpcTowers := make([]*Tower, 0, len(towers))
for _, tower := range towers {
rpcTower := marshallTower(tower, req.IncludeSessions)
rpcTowers = append(rpcTowers, rpcTower)
}
return &ListTowersResponse{Towers: rpcTowers}, nil
}
// GetTowerInfo retrieves information for a registered watchtower.
func (c *WatchtowerClient) GetTowerInfo(ctx context.Context,
req *GetTowerInfoRequest) (*Tower, error) {
if err := c.isActive(); err != nil {
return nil, err
}
pubKey, err := btcec.ParsePubKey(req.Pubkey, btcec.S256())
if err != nil {
return nil, err
}
var tower *wtclient.RegisteredTower
tower, err = c.cfg.Client.LookupTower(pubKey)
if err == wtdb.ErrTowerNotFound {
tower, err = c.cfg.AnchorClient.LookupTower(pubKey)
}
if err != nil {
return nil, err
}
return marshallTower(tower, req.IncludeSessions), nil
}
// Stats returns the in-memory statistics of the client since startup.
func (c *WatchtowerClient) Stats(ctx context.Context,
req *StatsRequest) (*StatsResponse, error) {
if err := c.isActive(); err != nil {
return nil, err
}
clientStats := []wtclient.ClientStats{
c.cfg.Client.Stats(),
c.cfg.AnchorClient.Stats(),
}
var stats wtclient.ClientStats
for i := range clientStats {
// Grab a reference to the slice index rather than copying bc
// ClientStats contains a lock which cannot be copied by value.
stat := &clientStats[i]
stats.NumTasksAccepted += stat.NumTasksAccepted
stats.NumTasksIneligible += stat.NumTasksIneligible
stats.NumTasksReceived += stat.NumTasksReceived
stats.NumSessionsAcquired += stat.NumSessionsAcquired
stats.NumSessionsExhausted += stat.NumSessionsExhausted
}
return &StatsResponse{
NumBackups: uint32(stats.NumTasksAccepted),
NumFailedBackups: uint32(stats.NumTasksIneligible),
NumPendingBackups: uint32(stats.NumTasksReceived),
NumSessionsAcquired: uint32(stats.NumSessionsAcquired),
NumSessionsExhausted: uint32(stats.NumSessionsExhausted),
}, nil
}
// Policy returns the active watchtower client policy configuration.
func (c *WatchtowerClient) Policy(ctx context.Context,
req *PolicyRequest) (*PolicyResponse, error) {
if err := c.isActive(); err != nil {
return nil, err
}
var policy wtpolicy.Policy
switch req.PolicyType {
case PolicyType_LEGACY:
policy = c.cfg.Client.Policy()
case PolicyType_ANCHOR:
policy = c.cfg.AnchorClient.Policy()
default:
return nil, fmt.Errorf("unknown policy type: %v",
req.PolicyType)
}
return &PolicyResponse{
MaxUpdates: uint32(policy.MaxUpdates),
SweepSatPerByte: uint32(policy.SweepFeeRate.FeePerKVByte() / 1000),
}, nil
}
// marshallTower converts a client registered watchtower into its corresponding
// RPC type.
func marshallTower(tower *wtclient.RegisteredTower, includeSessions bool) *Tower {
rpcAddrs := make([]string, 0, len(tower.Addresses))
for _, addr := range tower.Addresses {
rpcAddrs = append(rpcAddrs, addr.String())
}
var rpcSessions []*TowerSession
if includeSessions {
rpcSessions = make([]*TowerSession, 0, len(tower.Sessions))
for _, session := range tower.Sessions {
satPerByte := session.Policy.SweepFeeRate.FeePerKVByte() / 1000
rpcSessions = append(rpcSessions, &TowerSession{
NumBackups: uint32(len(session.AckedUpdates)),
NumPendingBackups: uint32(len(session.CommittedUpdates)),
MaxBackups: uint32(session.Policy.MaxUpdates),
SweepSatPerByte: uint32(satPerByte),
})
}
}
return &Tower{
Pubkey: tower.IdentityKey.SerializeCompressed(),
Addresses: rpcAddrs,
ActiveSessionCandidate: tower.ActiveSessionCandidate,
NumSessions: uint32(len(tower.Sessions)),
Sessions: rpcSessions,
}
}