lnd.xprv/lnwire/commit_revocation.go

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package lnwire
import (
"io"
"github.com/roasbeef/btcd/btcec"
"github.com/roasbeef/btcd/wire"
)
// CommitRevocation is sent by either side once a CommitSignature 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
// CommitSignature 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 CommitSignature message).
// This piggybacking allows Alice to send the next CommitSignature message
// modifying Bob's commitment transaction without first asking for a revocation
// hash initially.
// TODO(roasbeef): update docs everywhere
type CommitRevocation struct {
// ChannelPoint uniquely identifies to which currently active channel this
// CommitRevocation applies to.
ChannelPoint *wire.OutPoint
// Revocation is the preimage to the revocation hash of the now prior
// commitment transaction.
//
// If the received revocation is the all zeroes hash ('0' * 32), then
// this CommitRevocation is being sent in order to build up the
// sender's initial revocation window (IRW). In this case, the
// CommitRevocation should be added to the receiver's queue of unused
// revocations to be used to construct future commitment transactions.
Revocation [32]byte
// NextRevocationKey is the next revocation key which should be added
// to the queue of unused revocation keys for the remote peer. This key
// will be used within the revocation clause for any new commitment
// transactions created for the remote peer.
NextRevocationKey *btcec.PublicKey
// NextRevocationHash is the next revocation hash which should be added
// to the queue on unused revocation hashes for the remote peer. This
// revocation hash will be used within any HTLCs included within this
// next commitment transaction.
NextRevocationHash [32]byte
}
// NewCommitRevocation creates a new CommitRevocation message.
func NewCommitRevocation() *CommitRevocation {
return &CommitRevocation{}
}
// A compile time check to ensure CommitRevocation implements the lnwire.Message
// interface.
var _ Message = (*CommitRevocation)(nil)
// Decode deserializes a serialized CommitRevocation message stored in the
// passed io.Reader observing the specified protocol version.
//
// This is part of the lnwire.Message interface.
func (c *CommitRevocation) Decode(r io.Reader, pver uint32) error {
// ChannelPoint (8)
// Revocation (32)
// NextRevocationKey (33)
// NextRevocationHash (32)
err := readElements(r,
&c.ChannelPoint,
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&c.Revocation,
&c.NextRevocationKey,
&c.NextRevocationHash,
)
if err != nil {
return err
}
return nil
}
// Encode serializes the target CommitRevocation into the passed io.Writer
// observing the protocol version specified.
//
// This is part of the lnwire.Message interface.
func (c *CommitRevocation) Encode(w io.Writer, pver uint32) error {
err := writeElements(w,
c.ChannelPoint,
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c.Revocation,
c.NextRevocationKey,
c.NextRevocationHash,
)
if err != nil {
return err
}
return nil
}
// Command returns the integer uniquely identifying this message type on the
// wire.
//
// This is part of the lnwire.Message interface.
func (c *CommitRevocation) Command() uint32 {
return CmdCommitRevocation
}
// MaxPayloadLength returns the maximum allowed payload size for a
// CommitRevocation complete message observing the specified protocol version.
//
// This is part of the lnwire.Message interface.
func (c *CommitRevocation) MaxPayloadLength(uint32) uint32 {
// 36 + 32 + 33 + 32
return 133
}
// Validate performs any necessary sanity checks to ensure all fields present
// on the CommitRevocation are valid.
//
// This is part of the lnwire.Message interface.
func (c *CommitRevocation) Validate() error {
// We're good!
return nil
}