lnd.xprv/lnrpc/wtclientrpc/wtclient.go

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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,
}
}