package lnwire import ( "fmt" "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 pre-image 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 HTLC's 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, &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, 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 } // String returns the string representation of the target CommitRevocation. // // This is part of the lnwire.Message interface. // TODO(roasbeef): remote all String() methods...spew should be used instead. func (c *CommitRevocation) String() string { return fmt.Sprintf("\n--- Begin CommitRevocation ---\n") + fmt.Sprintf("ChannelPoint:\t%d\n", c.ChannelPoint) + fmt.Sprintf("NextRevocationHash:\t%x\n", c.NextRevocationHash) + fmt.Sprintf("Revocation:\t%x\n", c.Revocation) + fmt.Sprintf("--- End CommitRevocation ---\n") }