package lnwire import ( "fmt" "github.com/roasbeef/btcd/btcec" "github.com/roasbeef/btcd/wire" "github.com/roasbeef/btcutil" "io" ) // CloseRequest is sent by either side in order to initiate the cooperative // closure of a channel. This message is rather sparse as both side implicitly // know to craft a transaction sending the settled funds of both parties to the // final delivery addresses negotiated during the funding workflow. // // NOTE: The requester is able to only send a signature to initiate the // cooperative channel closure as all transactions are assembled observing // BIP 69 which defines a cannonical ordering for input/outputs. Therefore, // both sides are able to arrive at an identical closure transaction as they // know the order of the inputs/outputs. type CloseRequest struct { // ChannelPoint serves to identify which channel is to be closed. ChannelPoint wire.OutPoint // RequesterCloseSig is the signature of the requester for the fully // assembled closing transaction. RequesterCloseSig *btcec.Signature // Fee is the required fee-per-KB the closing transaction must have. // It is recommended that a "sufficient" fee be paid in order to // achieve timely channel closure. // TODO(roasbeef): if initiator always pays fees, then no longer needed. Fee btcutil.Amount } // NewCloseRequest creates a new CloseRequest. func NewCloseRequest(cp wire.OutPoint, sig *btcec.Signature) *CloseRequest { // TODO(roasbeef): update once fees aren't hardcoded return &CloseRequest{ ChannelPoint: cp, RequesterCloseSig: sig, } } // A compile time check to ensure CloseRequest implements the lnwire.Message // interface. var _ Message = (*CloseRequest)(nil) // Decode deserializes a serialized CloseRequest stored in the passed io.Reader // observing the specified protocol version. // // This is part of the lnwire.Message interface. func (c *CloseRequest) Decode(r io.Reader, pver uint32) error { // ChannelPoint (8) // RequesterCloseSig (73) // First byte length then sig // Fee (8) err := readElements(r, &c.ChannelPoint, &c.RequesterCloseSig, &c.Fee) if err != nil { return err } return nil } // Encode serializes the target CloseRequest into the passed io.Writer observing // the protocol version specified. // // This is part of the lnwire.Message interface. func (c *CloseRequest) Encode(w io.Writer, pver uint32) error { // ChannelID // RequesterCloseSig // Fee err := writeElements(w, c.ChannelPoint, c.RequesterCloseSig, c.Fee) 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 *CloseRequest) Command() uint32 { return CmdCloseRequest } // MaxPayloadLength returns the maximum allowed payload size for this message // observing the specified protocol version. // // This is part of the lnwire.Message interface. func (c *CloseRequest) MaxPayloadLength(pver uint32) uint32 { // 36 + 73 + 8 return 117 } // Validate performs any necessary sanity checks to ensure all fields present // on the CloseRequest are valid. // // This is part of the lnwire.Message interface. func (c *CloseRequest) Validate() error { // Fee must be greater than 0. if c.Fee < 0 { return fmt.Errorf("Fee must be greater than zero.") } // We're good! return nil }