lnd.xprv/lnwire/revoke_and_ack.go

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package lnwire
import (
"io"
"github.com/btcsuite/btcd/btcec"
)
// RevokeAndAck is sent by either side once a CommitSig message has been
// received, and validated. This message serves to revoke the prior commitment
// transaction, which was the most up to date version until a CommitSig message
// referencing the specified ChannelPoint was received. Additionally, this
// message also piggyback's the next revocation hash that Alice should use when
// constructing the Bob's version of the next commitment transaction (which
// would be done before sending a CommitSig message). This piggybacking allows
// Alice to send the next CommitSig message modifying Bob's commitment
// transaction without first asking for a revocation hash initially.
type RevokeAndAck struct {
// ChanID uniquely identifies to which currently active channel this
// RevokeAndAck applies to.
ChanID ChannelID
// Revocation is the preimage to the revocation hash of the now prior
// commitment transaction.
Revocation [32]byte
// NextRevocationKey is the next commitment point which should be used
// for the next commitment transaction the remote peer creates for us.
// This, in conjunction without revocation base point will be used to
// create the proper revocation key used within the commitment
// transaction.
NextRevocationKey *btcec.PublicKey
}
// NewRevokeAndAck creates a new RevokeAndAck message.
func NewRevokeAndAck() *RevokeAndAck {
return &RevokeAndAck{}
}
// A compile time check to ensure RevokeAndAck implements the lnwire.Message
// interface.
var _ Message = (*RevokeAndAck)(nil)
// Decode deserializes a serialized RevokeAndAck message stored in the
// passed io.Reader observing the specified protocol version.
//
// This is part of the lnwire.Message interface.
func (c *RevokeAndAck) Decode(r io.Reader, pver uint32) error {
return ReadElements(r,
&c.ChanID,
c.Revocation[:],
&c.NextRevocationKey,
)
}
// Encode serializes the target RevokeAndAck into the passed io.Writer
// observing the protocol version specified.
//
// This is part of the lnwire.Message interface.
func (c *RevokeAndAck) Encode(w io.Writer, pver uint32) error {
return WriteElements(w,
c.ChanID,
c.Revocation[:],
c.NextRevocationKey,
)
}
// MsgType returns the integer uniquely identifying this message type on the
// wire.
//
// This is part of the lnwire.Message interface.
func (c *RevokeAndAck) MsgType() MessageType {
return MsgRevokeAndAck
}
// MaxPayloadLength returns the maximum allowed payload size for a RevokeAndAck
// complete message observing the specified protocol version.
//
// This is part of the lnwire.Message interface.
func (c *RevokeAndAck) MaxPayloadLength(uint32) uint32 {
// 32 + 32 + 33
return 97
}
// TargetChanID returns the channel id of the link for which this message is
// intended.
//
// NOTE: Part of peer.LinkUpdater interface.
func (c *RevokeAndAck) TargetChanID() ChannelID {
return c.ChanID
}