lnd.xprv/watchtower/wtwire/state_update.go
2018-10-23 18:28:27 -07:00

89 lines
2.9 KiB
Go

package wtwire
import "io"
// StateUpdate transmits an encrypted state update from the client to the
// watchtower. Each state update is tied to particular session, identified by
// the client's brontine key used to make the request.
type StateUpdate struct {
// SeqNum is a 1-indexed, monotonically incrementing sequence number.
// This number represents to the client's expected sequence number when
// sending updates sent to the watchtower. This value must always be
// less or equal than the negotiated MaxUpdates for the session, and
// greater than the LastApplied sent in the same message.
SeqNum uint16
// LastApplied echos the LastApplied value returned from watchtower,
// allowing the tower to detect faulty clients. This allow provides a
// feedback mechanism for the tower if updates are allowed to stream in
// an async fashion.
LastApplied uint16
// IsComplete is 1 if the watchtower should close the connection after
// responding, and 0 otherwise.
IsComplete uint8
// Hint is the 16-byte prefix of the revoked commitment transaction ID
// for which the encrypted blob can exact justice.
Hint [16]byte
// EncryptedBlob is the serialized ciphertext containing all necessary
// information to sweep the commitment transaction corresponding to the
// Hint. The ciphertext is to be encrypted using the full transaction ID
// of the revoked commitment transaction.
//
// The plaintext MUST be encoded using the negotiated Version for
// this session. In addition, the signatures must be computed over a
// sweep transaction honoring the decided SweepFeeRate, RewardRate, and
// (possibly) reward address returned in the SessionInitReply.
EncryptedBlob []byte
}
// A compile time check to ensure StateUpdate implements the wtwire.Message
// interface.
var _ Message = (*StateUpdate)(nil)
// Decode deserializes a serialized StateUpdate message stored in the passed
// io.Reader observing the specified protocol version.
//
// This is part of the wtwire.Message interface.
func (m *StateUpdate) Decode(r io.Reader, pver uint32) error {
return ReadElements(r,
&m.SeqNum,
&m.LastApplied,
&m.IsComplete,
&m.Hint,
&m.EncryptedBlob,
)
}
// Encode serializes the target StateUpdate into the passed io.Writer
// observing the protocol version specified.
//
// This is part of the wtwire.Message interface.
func (m *StateUpdate) Encode(w io.Writer, pver uint32) error {
return WriteElements(w,
m.SeqNum,
m.LastApplied,
m.IsComplete,
m.Hint,
m.EncryptedBlob,
)
}
// MsgType returns the integer uniquely identifying this message type on the
// wire.
//
// This is part of the wtwire.Message interface.
func (m *StateUpdate) MsgType() MessageType {
return MsgStateUpdate
}
// MaxPayloadLength returns the maximum allowed payload size for a StateUpdate
// complete message observing the specified protocol version.
//
// This is part of the wtwire.Message interface.
func (m *StateUpdate) MaxPayloadLength(uint32) uint32 {
return MaxMessagePayload
}