lnd.xprv/watchtower/wtdb/client_session.go
2019-04-23 20:06:20 -07:00

122 lines
4.3 KiB
Go

package wtdb
import (
"errors"
"github.com/btcsuite/btcd/btcec"
"github.com/lightningnetwork/lnd/lnwire"
"github.com/lightningnetwork/lnd/watchtower/wtpolicy"
)
var (
// ErrClientSessionNotFound signals that the requested client session
// was not found in the database.
ErrClientSessionNotFound = errors.New("client session not found")
// ErrUpdateAlreadyCommitted signals that the chosen sequence number has
// already been committed to an update with a different breach hint.
ErrUpdateAlreadyCommitted = errors.New("update already committed")
// ErrCommitUnorderedUpdate signals the client tried to commit a
// sequence number other than the next unallocated sequence number.
ErrCommitUnorderedUpdate = errors.New("update seqnum not monotonic")
// ErrCommittedUpdateNotFound signals that the tower tried to ACK a
// sequence number that has not yet been allocated by the client.
ErrCommittedUpdateNotFound = errors.New("committed update not found")
// ErrUnallocatedLastApplied signals that the tower tried to provide a
// LastApplied value greater than any allocated sequence number.
ErrUnallocatedLastApplied = errors.New("tower echoed last appiled " +
"greater than allocated seqnum")
// ErrNoReservedKeyIndex signals that a client session could not be
// created because no session key index was reserved.
ErrNoReservedKeyIndex = errors.New("key index not reserved")
// ErrIncorrectKeyIndex signals that the client session could not be
// created because session key index differs from the reserved key
// index.
ErrIncorrectKeyIndex = errors.New("incorrect key index")
)
// ClientSession encapsulates a SessionInfo returned from a successful
// session negotiation, and also records the tower and ephemeral secret used for
// communicating with the tower.
type ClientSession struct {
// ID is the client's public key used when authenticating with the
// tower.
ID SessionID
// SeqNum is the next unallocated sequence number that can be sent to
// the tower.
SeqNum uint16
// TowerLastApplied the last last-applied the tower has echoed back.
TowerLastApplied uint16
// TowerID is the unique, db-assigned identifier that references the
// Tower with which the session is negotiated.
TowerID uint64
// Tower holds the pubkey and address of the watchtower.
//
// NOTE: This value is not serialized. It is recovered by looking up the
// tower with TowerID.
Tower *Tower
// KeyIndex is the index of key locator used to derive the client's
// session key so that it can authenticate with the tower to update its
// session. In order to rederive the private key, the key locator should
// use the keychain.KeyFamilyTowerSession key family.
KeyIndex uint32
// SessionPrivKey is the ephemeral secret key used to connect to the
// watchtower.
//
// NOTE: This value is not serialized. It is derived using the KeyIndex
// on startup to avoid storing private keys on disk.
SessionPrivKey *btcec.PrivateKey
// Policy holds the negotiated session parameters.
Policy wtpolicy.Policy
// RewardPkScript is the pkscript that the tower's reward will be
// deposited to if a sweep transaction confirms and the sessions
// specifies a reward output.
RewardPkScript []byte
// CommittedUpdates is a map from allocated sequence numbers to unacked
// updates. These updates can be resent after a restart if the update
// failed to send or receive an acknowledgment.
CommittedUpdates map[uint16]*CommittedUpdate
// AckedUpdates is a map from sequence number to backup id to record
// which revoked states were uploaded via this session.
AckedUpdates map[uint16]BackupID
}
// BackupID identifies a particular revoked, remote commitment by channel id and
// commitment height.
type BackupID struct {
// ChanID is the channel id of the revoked commitment.
ChanID lnwire.ChannelID
// CommitHeight is the commitment height of the revoked commitment.
CommitHeight uint64
}
// CommittedUpdate holds a state update sent by a client along with its
// SessionID.
type CommittedUpdate struct {
BackupID BackupID
// Hint is the 16-byte prefix of the revoked commitment transaction ID.
Hint BreachHint
// EncryptedBlob is a ciphertext containing the sweep information for
// exacting justice if the commitment transaction matching the breach
// hint is braodcast.
EncryptedBlob []byte
}