tapchannel: update createSweepVpackets to be second level aware

In this commit, we update `createSweepVpackets` to be second level
aware. This means that if we detect an auxSigInfo, then we know the vPkt
we need to create is actually just the second level vPkt. We also don't
need to generate a new script key either.

Finally, we'll properly set the absolute delay if the sweep desc
indicates as such.

Author: Roasbeef

tapchannel/aux_sweeper.go

@@ -179,6 +179,7 @@ func (a *AuxSweeper) Stop() error {
 // set of asset inputs into the backing wallet.
 func (a *AuxSweeper) createSweepVpackets(sweepInputs []*cmsg.AssetOutput,
 	tapscriptDesc lfn.Result[tapscriptSweepDesc],
+	resReq lnwallet.ResolutionReq,
 ) lfn.Result[[]*tappsbt.VPacket] {
 
 	type returnType = []*tappsbt.VPacket
@@ -192,39 +193,59 @@ func (a *AuxSweeper) createSweepVpackets(sweepInputs []*cmsg.AssetOutput,
 		return lfn.Err[returnType](err)
 	}
 
-	// For each out we want to sweep, we'll construct an allocation that
-	// we'll use to deliver the funds back to the wallet.
-	ctx := context.Background()
 	allocs := make([]*Allocation, 0, len(sweepInputs))
-	for _, localAsset := range sweepInputs {
-		// For each output, we'll need to create a new script key to
-		// use for the sweep transaction.
-		scriptKey, err := a.cfg.AddrBook.NextScriptKey(
-			ctx, asset.TaprootAssetsKeyFamily,
+	ctx := context.Background()
+
+	// If this is a second level HTLC sweep, then we already have
+	// the output information locked in, as this was a pre-signed
+	// transaction.
+	if sweepDesc.auxSigInfo.IsSome() {
+		alloc, err := createSecondLevelHtlcAllocations(
+			resReq.ChanType, resReq.Initiator, sweepInputs,
+			resReq.HtlcAmt, resReq.CommitCsvDelay, *resReq.KeyRing,
+			fn.Some(resReq.ContractPoint.Index),
 		)
 		if err != nil {
 			return lfn.Err[returnType](err)
 		}
 
-		// With the script key created, we can make a new allocation
-		// that will be used to sweep the funds back to our wallet.
-		//
-		// We leave out the internal key here, as we'll make it later
-		// once we actually have the other set of inputs we need to
-		// sweep.
-		allocs = append(allocs, &Allocation{
-			Type: CommitAllocationToLocal,
-			// We don't need to worry about sorting, as we'll
-			// always be the first output index in the transaction.
-			OutputIndex:  0,
-			Amount:       localAsset.Amount.Val,
-			AssetVersion: asset.V1,
-			BtcAmount:    tapsend.DummyAmtSats,
-			ScriptKey:    scriptKey,
-			SortTaprootKeyBytes: schnorr.SerializePubKey(
-				scriptKey.PubKey,
-			),
-		})
+		allocs = append(allocs, alloc...)
+	} else {
+		// Otherwise, for each out we want to sweep, we'll construct an
+		// allocation that we'll use to deliver the funds back to the
+		// wallet.
+		for _, localAsset := range sweepInputs {
+			// For each output, we'll need to create a new script
+			// key to use for the sweep transaction.
+			scriptKey, err := a.cfg.AddrBook.NextScriptKey(
+				ctx, asset.TaprootAssetsKeyFamily,
+			)
+			if err != nil {
+				return lfn.Err[[]*tappsbt.VPacket](err)
+			}
+
+			// With the script key created, we can make a new
+			// allocation that will be used to sweep the funds back
+			// to our wallet.
+			//
+			// We leave out the internal key here, as we'll make it
+			// later once we actually have the other set of inputs
+			// we need to sweep.
+			allocs = append(allocs, &Allocation{
+				Type: CommitAllocationToLocal,
+				// We don't need to worry about sorting, as
+				// we'll always be the first output index in the
+				// transaction.
+				OutputIndex:  0,
+				Amount:       localAsset.Amount.Val,
+				AssetVersion: asset.V1,
+				BtcAmount:    tapsend.DummyAmtSats,
+				ScriptKey:    scriptKey,
+				SortTaprootKeyBytes: schnorr.SerializePubKey(
+					scriptKey.PubKey,
+				),
+			})
+		}
 	}
 
 	log.Infof("Created %v allocations for commit tx sweep: %v",
@@ -268,6 +289,14 @@ func (a *AuxSweeper) createSweepVpackets(sweepInputs []*cmsg.AssetOutput,
 			}
 		})
 
+		// Similarly, if we have an absolute delay, we'll set it for all
+		// the vOuts in this packet.
+		sweepDesc.absoluteDelay.WhenSome(func(expiry uint64) {
+			for _, vOut := range vPackets[idx].Outputs {
+				vOut.LockTime = expiry
+			}
+		})
+
 		err := tapsend.PrepareOutputAssets(ctx, vPackets[idx])
 		if err != nil {
 			return lfn.Errf[returnType]("unable to prepare output "+
@@ -355,7 +384,7 @@ func (a *AuxSweeper) signSweepVpackets(vPackets []*tappsbt.VPacket,
 // createAndSignSweepVpackets creates vPackets that sweep the funds from the
 // channel to the wallet, and then signs them as well.
 func (a *AuxSweeper) createAndSignSweepVpackets(
-	sweepInputs []*cmsg.AssetOutput, signDesc input.SignDescriptor,
+	sweepInputs []*cmsg.AssetOutput, resReq lnwallet.ResolutionReq,
 	sweepDesc lfn.Result[tapscriptSweepDesc],
 ) lfn.Result[[]*tappsbt.VPacket] {
 
@@ -369,7 +398,7 @@ func (a *AuxSweeper) createAndSignSweepVpackets(
 	signPkts := func(vPkts []*tappsbt.VPacket,
 		desc tapscriptSweepDesc) lfn.Result[[]*tappsbt.VPacket] {
 
-		err := a.signSweepVpackets(vPkts, signDesc, desc)
+		err := a.signSweepVpackets(vPkts, resReq.SignDesc, desc)
 		if err != nil {
 			return lfn.Err[returnType](err)
 		}
@@ -378,7 +407,8 @@ func (a *AuxSweeper) createAndSignSweepVpackets(
 	}
 
 	return lfn.AndThen2(
-		a.createSweepVpackets(sweepInputs, sweepDesc), sweepDesc,
+		a.createSweepVpackets(sweepInputs, sweepDesc, resReq),
+		sweepDesc,
 		signPkts,
 	)
 }
@@ -1593,7 +1623,7 @@ func (a *AuxSweeper) resolveContract(
 	// With the sweep desc constructed above, we'll create vPackets for
 	// each of the local assets, then sign them all.
 	sPkts := a.createAndSignSweepVpackets(
-		assetOutputs, req.SignDesc, firstLevelSweepDesc,
+		assetOutputs, req, firstLevelSweepDesc,
 	)
 
 	// With the vPackets fully generated and signed above, we'll serialize