lnd.xprv/watchtower/wtclient/interface.go
Conner Fromknecht 5ad9530502
watchtower/wtdb: return sorted ClientSession.CommittedUpdates
This commit replaces the map-based CommittedUpdates field with a slice.
When reading from disk, these will already be sorted by bbolt, so the
client restore the updates as presented without needing to sort them
first.

Since the key in the map variant was the sequence number, we refactor
the CommittedUpdate struct to have a sequence number and an embedded
CommittedUpdateBody (which is equivalent to the old CommittedUpdate).
The database is then expected to populate the sequence number from the
key on disk.

Since the sequence number is now directly integrated in the
CommittedUpdate struct, this allow allows us to remove the now redundant
seqNum argument from CommitUpdate.
2019-05-23 20:47:36 -07:00

97 lines
4.0 KiB
Go

package wtclient
import (
"net"
"github.com/btcsuite/btcd/btcec"
"github.com/lightningnetwork/lnd/brontide"
"github.com/lightningnetwork/lnd/keychain"
"github.com/lightningnetwork/lnd/lnwire"
"github.com/lightningnetwork/lnd/watchtower/wtdb"
"github.com/lightningnetwork/lnd/watchtower/wtserver"
)
// DB abstracts the required database operations required by the watchtower
// client.
type DB interface {
// CreateTower initialize an address record used to communicate with a
// watchtower. Each Tower is assigned a unique ID, that is used to
// amortize storage costs of the public key when used by multiple
// sessions.
CreateTower(*lnwire.NetAddress) (*wtdb.Tower, error)
// LoadTower retrieves a tower by its tower ID.
LoadTower(wtdb.TowerID) (*wtdb.Tower, error)
// NextSessionKeyIndex reserves a new session key derivation index for a
// particular tower id. The index is reserved for that tower until
// CreateClientSession is invoked for that tower and index, at which
// point a new index for that tower can be reserved. Multiple calls to
// this method before CreateClientSession is invoked should return the
// same index.
NextSessionKeyIndex(wtdb.TowerID) (uint32, error)
// CreateClientSession saves a newly negotiated client session to the
// client's database. This enables the session to be used across
// restarts.
CreateClientSession(*wtdb.ClientSession) error
// ListClientSessions returns all sessions that have not yet been
// exhausted. This is used on startup to find any sessions which may
// still be able to accept state updates.
ListClientSessions() (map[wtdb.SessionID]*wtdb.ClientSession, error)
// FetchChanPkScripts returns a map of all sweep pkscripts for
// registered channels. This is used on startup to cache the sweep
// pkscripts of registered channels in memory.
FetchChanPkScripts() (map[lnwire.ChannelID][]byte, error)
// AddChanPkScript inserts a newly generated sweep pkscript for the
// given channel.
AddChanPkScript(lnwire.ChannelID, []byte) error
// MarkBackupIneligible records that the state identified by the
// (channel id, commit height) tuple was ineligible for being backed up
// under the current policy. This state can be retried later under a
// different policy.
MarkBackupIneligible(chanID lnwire.ChannelID, commitHeight uint64) error
// CommitUpdate writes the next state update for a particular
// session, so that we can be sure to resend it after a restart if it
// hasn't been ACK'd by the tower. The sequence number of the update
// should be exactly one greater than the existing entry, and less that
// or equal to the session's MaxUpdates.
CommitUpdate(id *wtdb.SessionID,
update *wtdb.CommittedUpdate) (uint16, error)
// AckUpdate records an acknowledgment from the watchtower that the
// update identified by seqNum was received and saved. The returned
// lastApplied will be recorded.
AckUpdate(id *wtdb.SessionID, seqNum, lastApplied uint16) error
}
// Dial connects to an addr using the specified net and returns the connection
// object.
type Dial func(net, addr string) (net.Conn, error)
// AuthDialer connects to a remote node using an authenticated transport, such as
// brontide. The dialer argument is used to specify a resolver, which allows
// this method to be used over Tor or clear net connections.
type AuthDialer func(localPriv *btcec.PrivateKey, netAddr *lnwire.NetAddress,
dialer func(string, string) (net.Conn, error)) (wtserver.Peer, error)
// AuthDial is the watchtower client's default method of dialing.
func AuthDial(localPriv *btcec.PrivateKey, netAddr *lnwire.NetAddress,
dialer func(string, string) (net.Conn, error)) (wtserver.Peer, error) {
return brontide.Dial(localPriv, netAddr, dialer)
}
// SecretKeyRing abstracts the ability to derive HD private keys given a
// description of the derivation path.
type SecretKeyRing interface {
// DerivePrivKey derives the private key from the root seed using a
// key descriptor specifying the key's derivation path.
DerivePrivKey(loc keychain.KeyDescriptor) (*btcec.PrivateKey, error)
}