lnd/lnwire/single_funding_response.go

211 lines
6.9 KiB
Go

package lnwire
import (
"fmt"
"io"
"github.com/roasbeef/btcd/btcec"
"github.com/roasbeef/btcutil"
)
// SingleFundingResponse is the message Bob sends to Alice after she initiates
// the single funder channel workflow via a SingleFundingRequest message. Once
// Alice receives Bob's reponse, then she has all the items neccessary to
// construct the funding transaction, and both commitment transactions.
type SingleFundingResponse struct {
// ChannelID serves to uniquely identify the future channel created by
// the initiated single funder workflow.
ChannelID uint64
// ChannelDerivationPoint is an secp256k1 point which will be used to
// derive the public key the responder will use for the half of the
// 2-of-2 multi-sig. Using the channel derivation point (CDP), and the
// responder's identity public key (A), the channel public key is
// computed as: C = A + CDP. In order to be valid all CDP's MUST have
// an odd y-coordinate.
ChannelDerivationPoint *btcec.PublicKey
// CommitmentKey is key the responder to the funding workflow wishes to
// use within their versino of the commitment transaction for any
// delayed (CSV) or immediate outputs to them.
CommitmentKey *btcec.PublicKey
// RevocationKey is the initial key to be used for the revocation
// clause within the self-output of the responder's commitment
// transaction. Once an initial new state is created, the responder
// will send a pre-image which will allow the initiator to sweep the
// responder's funds if the violate the contract.
RevocationKey *btcec.PublicKey
// CsvDelay is the number of blocks to use for the relative time lock
// in the pay-to-self output of both commitment transactions.
CsvDelay uint32
// DeliveryPkScript defines the public key script that the initiator
// would like to use to receive their balance in the case of a
// cooperative close. Only the following script templates are
// supported: P2PKH, P2WKH, P2SH, and P2WSH.
DeliveryPkScript PkScript
// DustLimit is the threshold below which no HTLC output should be
// generated for remote commitment transaction; ie. HTLCs below
// this amount are not enforceable onchain for their point of view.
DustLimit btcutil.Amount
}
// NewSingleFundingResponse creates, and returns a new empty
// SingleFundingResponse.
func NewSingleFundingResponse(chanID uint64, rk, ck, cdp *btcec.PublicKey,
delay uint32, deliveryScript PkScript,
dustLimit btcutil.Amount) *SingleFundingResponse {
return &SingleFundingResponse{
ChannelID: chanID,
ChannelDerivationPoint: cdp,
CommitmentKey: ck,
RevocationKey: rk,
CsvDelay: delay,
DeliveryPkScript: deliveryScript,
DustLimit: dustLimit,
}
}
// A compile time check to ensure SingleFundingResponse implements the
// lnwire.Message interface.
var _ Message = (*SingleFundingResponse)(nil)
// Decode deserializes the serialized SingleFundingResponse stored in the passed
// io.Reader into the target SingleFundingResponse using the deserialization
// rules defined by the passed protocol version.
//
// This is part of the lnwire.Message interface.
func (c *SingleFundingResponse) Decode(r io.Reader, pver uint32) error {
// ChannelID (8)
// ChannelDerivationPoint (33)
// CommitmentKey (33)
// RevocationKey (33)
// CsvDelay (4)
// DeliveryPkScript (final delivery)
// DustLimit (8)
err := readElements(r,
&c.ChannelID,
&c.ChannelDerivationPoint,
&c.CommitmentKey,
&c.RevocationKey,
&c.CsvDelay,
&c.DeliveryPkScript,
&c.DustLimit)
if err != nil {
return err
}
return nil
}
// Encode serializes the target SingleFundingResponse into the passed io.Writer
// implementation. Serialization will observe the rules defined by the passed
// protocol version.
//
// This is part of the lnwire.Message interface.
func (c *SingleFundingResponse) Encode(w io.Writer, pver uint32) error {
// ChannelID (8)
// ChannelDerivationPoint (33)
// CommitmentKey (33)
// RevocationKey (33)
// CsvDelay (4)
// DeliveryPkScript (final delivery)
// DustLimit (8)
err := writeElements(w,
c.ChannelID,
c.ChannelDerivationPoint,
c.CommitmentKey,
c.RevocationKey,
c.CsvDelay,
c.DeliveryPkScript,
c.DustLimit)
if err != nil {
return err
}
return nil
}
// Command returns the uint32 code which uniquely identifies this message as a
// SingleFundingRequest on the wire.
//
// This is part of the lnwire.Message interface.
func (c *SingleFundingResponse) Command() uint32 {
return CmdSingleFundingResponse
}
// MaxPayloadLength returns the maximum allowed payload length for a
// SingleFundingResponse. This is calculated by summing the max length of all
// the fields within a SingleFundingResponse. To enforce a maximum
// DeliveryPkScript size, the size of a P2PKH public key script is used.
// Therefore, the final breakdown is: 8 + (33 * 3) + 8 + 25 + 8
//
// This is part of the lnwire.Message interface.
func (c *SingleFundingResponse) MaxPayloadLength(uint32) uint32 {
return 148
}
// Validate examines each populated field within the SingleFundingResponse for
// field sanity. For example, all fields MUST NOT be negative, and all pkScripts
// must belong to the allowed set of public key scripts.
//
// This is part of the lnwire.Message interface.
func (c *SingleFundingResponse) Validate() error {
// The channel derivation point must be non-nil, and have an odd
// y-coordinate.
if c.ChannelDerivationPoint == nil {
return fmt.Errorf("The channel derivation point must be non-nil")
}
//if c.ChannelDerivationPoint.Y.Bit(0) != 1 {
// return fmt.Errorf("The channel derivation point must have an odd " +
// "y-coordinate")
//}
// The delivery pkScript must be amongst the supported script
// templates.
if !isValidPkScript(c.DeliveryPkScript) {
return fmt.Errorf("Valid delivery public key scripts MUST be: " +
"P2PKH, P2WKH, P2SH, or P2WSH.")
}
if c.DustLimit <= 0 {
return fmt.Errorf("Dust limit shouldn't be below or equal to " +
"zero.")
}
// We're good!
return nil
}
// String returns the string representation of the SingleFundingResponse.
//
// This is part of the lnwire.Message interface.
func (c *SingleFundingResponse) String() string {
var cdp []byte
var ck []byte
var rk []byte
if &c.ChannelDerivationPoint != nil {
cdp = c.ChannelDerivationPoint.SerializeCompressed()
}
if &c.CommitmentKey != nil {
ck = c.CommitmentKey.SerializeCompressed()
}
if &c.RevocationKey != nil {
rk = c.RevocationKey.SerializeCompressed()
}
return fmt.Sprintf("\n--- Begin SingleFundingResponse ---\n") +
fmt.Sprintf("ChannelID:\t\t\t%d\n", c.ChannelID) +
fmt.Sprintf("ChannelDerivationPoint:\t\t\t\t%x\n", cdp) +
fmt.Sprintf("CommitmentKey:\t\t\t\t%x\n", ck) +
fmt.Sprintf("RevocationKey:\t\t\t\t%x\n", rk) +
fmt.Sprintf("CsvDelay:\t\t%d\n", c.CsvDelay) +
fmt.Sprintf("DeliveryPkScript:\t\t%x\n", c.DeliveryPkScript) +
fmt.Sprintf("DustLimit:\t\t\t%d\n", c.DustLimit) +
fmt.Sprintf("--- End SingleFundingResponse ---\n")
}