lnd.xprv/lnwire/commit_sig.go
Olaoluwa Osuntokun 364a9a8059
lnwire: add a HtlcSigs field to the CommitSig message
This commit adds a new field to the CommitSig message: HtlcSigs. This
new field will house signatures for each of the HTLC’s on the newly
created commitment state. This addition allows us to implement the new
commitment transaction structure outlined within the specification
which modifies HTLC’s such that the claiming process is now a two-phase
process. The first state transitions an HTLC to the delay+claim state,
and the second state (after the delay has passed) allows the
broadcaster of the commitment transaction to sweep the HTLC’s.

Fixes #61.
2017-07-30 17:47:44 -07:00

90 lines
3.0 KiB
Go

package lnwire
import (
"io"
"github.com/roasbeef/btcd/btcec"
)
// CommitSig is sent by either side to stage any pending HTLC's in the
// receiver's pending set into a new commitment state. Implicitly, the new
// commitment transaction constructed which has been signed by CommitSig
// includes all HTLC's in the remote node's pending set. A CommitSig message
// may be sent after a series of UpdateAddHTLC/UpdateFufillHTLC messages in
// order to batch add several HTLC's with a single signature covering all
// implicitly accepted HTLC's.
type CommitSig struct {
// ChanID uniquely identifies to which currently active channel this
// CommitSig applies to.
ChanID ChannelID
// CommitSig is Alice's signature for Bob's new commitment transaction.
// Alice is able to send this signature without requesting any
// additional data due to the piggybacking of Bob's next revocation
// hash in his prior RevokeAndAck message, as well as the canonical
// ordering used for all inputs/outputs within commitment transactions.
// If initiating a new commitment state, this signature shoud ONLY
// cover all of the sending party's pending log updates, and the log
// updates of the remote party that have been ACK'd.
CommitSig *btcec.Signature
// HtlcSigs is a signature for each relevant HTLC output within the
// created commitment. The order of the signatures is expected to be
// identical to the placement of the HTLC's within the BIP 69 sorted
// commitment transaction. For each outgoing HTLC (from the PoV of the
// sender of this message), a signature for a HTLC timeout transaction
// should be signed, for each incoming HTLC the HTLC timeout
// transaction should be signed.
HtlcSigs []*btcec.Signature
}
// NewCommitSig creates a new empty CommitSig message.
func NewCommitSig() *CommitSig {
return &CommitSig{}
}
// A compile time check to ensure CommitSig implements the lnwire.Message
// interface.
var _ Message = (*CommitSig)(nil)
// Decode deserializes a serialized CommitSig message stored in the
// passed io.Reader observing the specified protocol version.
//
// This is part of the lnwire.Message interface.
func (c *CommitSig) Decode(r io.Reader, pver uint32) error {
return readElements(r,
&c.ChanID,
&c.CommitSig,
&c.HtlcSigs,
)
}
// Encode serializes the target CommitSig into the passed io.Writer
// observing the protocol version specified.
//
// This is part of the lnwire.Message interface.
func (c *CommitSig) Encode(w io.Writer, pver uint32) error {
return writeElements(w,
c.ChanID,
c.CommitSig,
c.HtlcSigs,
)
}
// MsgType returns the integer uniquely identifying this message type on the
// wire.
//
// This is part of the lnwire.Message interface.
func (c *CommitSig) MsgType() MessageType {
return MsgCommitSig
}
// MaxPayloadLength returns the maximum allowed payload size for a
// CommitSig complete message observing the specified protocol version.
//
// This is part of the lnwire.Message interface.
func (c *CommitSig) MaxPayloadLength(uint32) uint32 {
// 32 + 64 + 2 + max_allowed_htlcs
return MaxMessagePayload
}