From 2ef9b377a68320307a8ec0c49b7da7ab279877f6 Mon Sep 17 00:00:00 2001
From: Olaoluwa Osuntokun <laolu32@gmail.com>
Date: Thu, 4 Apr 2024 17:26:03 -0700
Subject: [PATCH] lnwallet: use AuxFundingDesc to populate all custom chan info

With this commit, we'll now populate all the custom channel information within the OpenChannel and ChannelCommitment structs.
---
 lnwallet/reservation.go | 25 +++++++++++++++++++++++--
 lnwallet/wallet.go      | 18 ++++++++++++++----
 2 files changed, 37 insertions(+), 6 deletions(-)

diff --git a/lnwallet/reservation.go b/lnwallet/reservation.go
index 4f0940fe9..f511ffb61 100644
--- a/lnwallet/reservation.go
+++ b/lnwallet/reservation.go
@@ -11,10 +11,12 @@ import (
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/lightningnetwork/lnd/channeldb"
+	"github.com/lightningnetwork/lnd/fn"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/keychain"
 	"github.com/lightningnetwork/lnd/lnwallet/chanfunding"
 	"github.com/lightningnetwork/lnd/lnwire"
+	"github.com/lightningnetwork/lnd/tlv"
 )
 
 // CommitmentType is an enum indicating the commitment type we should use for
@@ -217,6 +219,11 @@ type ChannelReservation struct {
 
 	fundingIntent chanfunding.Intent
 
+	// initAuxLeaves is an optional set of aux commitment leaves that'll
+	// modify the way we construct the commitment transaction, in
+	// particular the tapscript leaves.
+	initAuxLeaves fn.Option[CommitAuxLeaves]
+
 	// nextRevocationKeyLoc stores the key locator information for this
 	// channel.
 	nextRevocationKeyLoc keychain.KeyLocator
@@ -412,7 +419,7 @@ func NewChannelReservation(capacity, localFundingAmt btcutil.Amount,
 		chanType |= channeldb.ScidAliasFeatureBit
 	}
 
-	if req.TapscriptRoot.IsSome() {
+	if req.AuxFundingDesc.IsSome() {
 		chanType |= channeldb.TapscriptRootBit
 	}
 
@@ -437,25 +444,39 @@ func NewChannelReservation(capacity, localFundingAmt btcutil.Amount,
 				RemoteBalance: theirBalance,
 				FeePerKw:      btcutil.Amount(req.CommitFeePerKw),
 				CommitFee:     commitFee,
+				CustomBlob: fn.MapOption(func(desc AuxFundingDesc) tlv.Blob {
+					return desc.CustomLocalCommitBlob
+				})(req.AuxFundingDesc),
 			},
 			RemoteCommitment: channeldb.ChannelCommitment{
 				LocalBalance:  ourBalance,
 				RemoteBalance: theirBalance,
 				FeePerKw:      btcutil.Amount(req.CommitFeePerKw),
 				CommitFee:     commitFee,
+				CustomBlob: fn.MapOption(func(desc AuxFundingDesc) tlv.Blob {
+					return desc.CustomRemoteCommitBlob
+				})(req.AuxFundingDesc),
 			},
 			ThawHeight:           thawHeight,
 			Db:                   wallet.Cfg.Database,
 			InitialLocalBalance:  ourBalance,
 			InitialRemoteBalance: theirBalance,
 			Memo:                 req.Memo,
-			TapscriptRoot:        req.TapscriptRoot,
+			CustomBlob: fn.MapOption(func(desc AuxFundingDesc) tlv.Blob {
+				return desc.CustomFundingBlob
+			})(req.AuxFundingDesc),
+			TapscriptRoot: fn.MapOption(func(desc AuxFundingDesc) chainhash.Hash {
+				return desc.TapscriptRoot
+			})(req.AuxFundingDesc),
 		},
 		pushMSat:      req.PushMSat,
 		pendingChanID: req.PendingChanID,
 		reservationID: id,
 		wallet:        wallet,
 		chanFunder:    req.ChanFunder,
+		initAuxLeaves: fn.MapOption(func(desc AuxFundingDesc) CommitAuxLeaves {
+			return desc.InitAuxLeaves
+		})(req.AuxFundingDesc),
 	}, nil
 }
 
diff --git a/lnwallet/wallet.go b/lnwallet/wallet.go
index dac13f377..fa192d5a5 100644
--- a/lnwallet/wallet.go
+++ b/lnwallet/wallet.go
@@ -229,10 +229,9 @@ type InitFundingReserveMsg struct {
 	// channel that will be useful to our future selves.
 	Memo []byte
 
-	// TapscriptRoot is the root of the tapscript tree that will be used to
-	// create the funding output. This is an optional field that should
-	// only be set for taproot channels.
-	TapscriptRoot fn.Option[chainhash.Hash]
+	// AuxFundingDesc is an optional descriptor that can be used to modify
+	// the way channel funding occurs.
+	AuxFundingDesc fn.Option[AuxFundingDesc]
 
 	// err is a channel in which all errors will be sent across. Will be
 	// nil if this initial set is successful.
@@ -1497,6 +1496,14 @@ func defaultCommitOpts() createCommitOpts {
 	return createCommitOpts{}
 }
 
+// WithAuxLeaves is a functional option that can be used to set the aux leaves
+// for a new commitment transaction.
+func WithAuxLeaves(leaves fn.Option[CommitAuxLeaves]) CreateCommitOpt {
+	return func(o *createCommitOpts) {
+		o.auxLeaves = leaves
+	}
+}
+
 // CreateCommitOpt is a functional option that can be used to modify the way a
 // new commitment transaction is created.
 type CreateCommitOpt func(*createCommitOpts)
@@ -1885,6 +1892,7 @@ func (l *LightningWallet) handleChanPointReady(req *continueContributionMsg) {
 	if pendingReservation.partialState.ChanType.HasLeaseExpiration() {
 		leaseExpiry = pendingReservation.partialState.ThawHeight
 	}
+
 	ourCommitTx, theirCommitTx, err := CreateCommitmentTxns(
 		localBalance, remoteBalance, ourContribution.ChannelConfig,
 		theirContribution.ChannelConfig,
@@ -1892,6 +1900,7 @@ func (l *LightningWallet) handleChanPointReady(req *continueContributionMsg) {
 		theirContribution.FirstCommitmentPoint, fundingTxIn,
 		pendingReservation.partialState.ChanType,
 		pendingReservation.partialState.IsInitiator, leaseExpiry,
+		WithAuxLeaves(pendingReservation.initAuxLeaves),
 	)
 	if err != nil {
 		req.err <- err
@@ -2331,6 +2340,7 @@ func (l *LightningWallet) handleSingleFunderSigs(req *addSingleFunderSigsMsg) {
 		pendingReservation.theirContribution.FirstCommitmentPoint,
 		*fundingTxIn, chanType,
 		pendingReservation.partialState.IsInitiator, leaseExpiry,
+		WithAuxLeaves(pendingReservation.initAuxLeaves),
 	)
 	if err != nil {
 		req.err <- err