lnwallet: expand attributes in ResolutionReq

In this commit, we add some additional attributes to the ResolutionReq
struct. These will be used to make sure that we can properly handle all
the HTLC variants, on chain.

The `AuxSigDesc` will be used to communicate if an HTLC needs to go to
the second level or not. It contains the second-level sig information
needed to finalize a broadcast to the second level.

Author: Roasbeef

lnwallet/aux_resolutions.go

@@ -3,6 +3,7 @@ package lnwallet
 import (
 	"github.com/btcsuite/btcd/btcutil"
 	"github.com/btcsuite/btcd/wire"
+	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/fn"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/lnwire"
@@ -24,13 +25,29 @@ const (
 	Breach
 )
 
+// AuxSigDesc stores optional information related to 2nd level HTLCs for aux
+// channels.
+type AuxSigDesc struct {
+	// AuxSig is the second-level signature for the HTLC that we are trying
+	// to resolve. This is only present if this is a resolution request for
+	// an HTLC on our commitment transaction.
+	AuxSig []byte
+
+	// SignDetails is the sign details for the second-level HTLC. This may
+	// be used to generate the second signature needed for broadcast.
+	SignDetails input.SignDetails
+}
+
 // ResolutionReq is used to ask an outside sub-system for additional
 // information needed to resolve a contract.
 type ResolutionReq struct {
 	// ChanPoint is the channel point of the channel that we are trying to
 	// resolve.
 	ChanPoint wire.OutPoint
 
+	// ChanType is the type of the channel that we are trying to resolve.
+	ChanType channeldb.ChannelType
+
 	// ShortChanID is the short channel ID of the channel that we are
 	// trying to resolve.
 	ShortChanID lnwire.ShortChannelID
@@ -44,6 +61,13 @@ type ResolutionReq struct {
 	// FundingBlob is an optional funding blob for the channel.
 	FundingBlob fn.Option[tlv.Blob]
 
+	// HtlcID is the ID of the HTLC that we are trying to resolve. This is
+	// only set if this is a resolution request for an HTLC.
+	HtlcID fn.Option[input.HtlcIndex]
+
+	// HtlcAmt is the amount of the HTLC that we are trying to resolve.
+	HtlcAmt btcutil.Amount
+
 	// Type is the type of the witness that we are trying to resolve.
 	Type input.WitnessType
 
@@ -69,14 +93,26 @@ type ResolutionReq struct {
 	// CsvDelay is the CSV delay for the local output for this commitment.
 	CsvDelay uint32
 
+	// CommitCsvDelay is the CSV delay for the remote output for this
+	// commitment.
+	CommitCsvDelay uint32
+
 	// BreachCsvDelay is the CSV delay for the remote output. This is only
 	// set when the CloseType is Breach. This indicates the CSV delay to
 	// use for the remote party's to_local delayed output, that is now
 	// rightfully ours in a breach situation.
 	BreachCsvDelay fn.Option[uint32]
 
-	// CltvDelay is the CLTV delay for the outpoint.
+	// CltvDelay is the CLTV delay for the outpoint/transaction.
 	CltvDelay fn.Option[uint32]
+
+	// PayHash is the payment hash for the HTLC that we are trying to
+	// resolve. This is optional as it only applies HTLC outputs.
+	PayHash fn.Option[[32]byte]
+
+	// AuxSigDesc is an optional field that contains additional information
+	// needed to sweep second level HTLCs.
+	AuxSigDesc fn.Option[AuxSigDesc]
 }
 
 // AuxContractResolver is an interface that is used to resolve contracts that