Merge pull request #3165 from halseth/autopilot-spend-coins

[funding+autopilot] Make the funding manager and autopilot fee aware

autopilot/agent.go

@@ -584,6 +584,7 @@ func (a *Agent) openChans(availableFunds btcutil.Amount, numChans uint32,
 
 	// Use the heuristic to calculate a score for each node in the
 	// graph.
+	log.Debugf("Scoring %d nodes for chan_size=%v", len(nodes), chanSize)
 	scores, err := a.cfg.Heuristic.NodeScores(
 		a.cfg.Graph, totalChans, chanSize, nodes,
 	)

autopilot/agent_test.go

@@ -1196,7 +1196,7 @@ func TestAgentChannelSizeAllocation(t *testing.T) {
 	t.Parallel()
 
 	// Total number of nodes in our mock graph.
-	const numNodes = 10
+	const numNodes = 20
 
 	testCtx, cleanup := setup(t, nil)
 	defer cleanup()
@@ -1240,6 +1240,8 @@ func TestAgentChannelSizeAllocation(t *testing.T) {
 		numNewChannels, nodeScores,
 	)
 
+	// We expect the autopilot to have allocated all funds towards
+	// channels.
 	expectedAllocation := testCtx.constraints.MaxChanSize() * btcutil.Amount(numNewChannels)
 	nodes := checkChannelOpens(
 		t, testCtx, expectedAllocation, numNewChannels,
@@ -1259,34 +1261,40 @@ func TestAgentChannelSizeAllocation(t *testing.T) {
 	waitForNumChans := func(expChans int) {
 		t.Helper()
 
+		var (
+			numChans int
+			balance  btcutil.Amount
+		)
+
 	Loop:
 		for {
 			select {
 			case arg := <-testCtx.constraints.moreChanArgs:
+				numChans = len(arg.chans)
+				balance = arg.balance
+
 				// As long as the number of existing channels
 				// is below our expected number of channels,
-				// we'll keep responding with "no more
+				// and the balance is not what we expect, we'll
-				// channels".
+				// keep responding with "no more channels".
-				if len(arg.chans) != expChans {
+				if numChans == expChans &&
+					balance == testCtx.walletBalance {
+					break Loop
+				}
+
 				select {
 				case testCtx.constraints.moreChansResps <- moreChansResp{0, 0}:
 				case <-time.After(time.Second * 3):
-						t.Fatalf("heuristic wasn't " +
+					t.Fatalf("heuristic wasn't queried " +
-							"queried in time")
+						"in time")
 				}
-					continue
-				}
-
-				if arg.balance != testCtx.walletBalance {
-					t.Fatalf("expectd agent to have %v "+
-						"balance, had %v",
-						testCtx.walletBalance,
-						arg.balance)
-				}
-				break Loop
 
 			case <-time.After(time.Second * 3):
-				t.Fatalf("heuristic wasn't queried in time")
+				t.Fatalf("did not receive expected "+
+					"channels(%d) and balance(%d), "+
+					"instead got %d and %d", expChans,
+					testCtx.walletBalance, numChans,
+					balance)
 			}
 		}
 	}
@@ -1308,5 +1316,30 @@ func TestAgentChannelSizeAllocation(t *testing.T) {
 
 	// To stay within the budget, we expect the autopilot to open 2
 	// channels.
-	checkChannelOpens(t, testCtx, channelBudget, 2)
+	expectedAllocation = channelBudget
+	nodes = checkChannelOpens(t, testCtx, expectedAllocation, 2)
+	numExistingChannels = 7
+
+	for _, node := range nodes {
+		delete(nodeScores, node)
+	}
+
+	waitForNumChans(numExistingChannels)
+
+	// Finally check that we make maximum channels if we are well within
+	// our budget.
+	channelBudget = btcutil.SatoshiPerBitcoin * 5
+	numNewChannels = 2
+	respondWithScores(
+		t, testCtx, channelBudget, numExistingChannels,
+		numNewChannels, nodeScores,
+	)
+
+	// We now expect the autopilot to open 2 channels, and since it has
+	// more than enough balance within the budget, they should both be of
+	// maximum size.
+	expectedAllocation = testCtx.constraints.MaxChanSize() *
+		btcutil.Amount(numNewChannels)
+
+	checkChannelOpens(t, testCtx, expectedAllocation, numNewChannels)
 }

autopilot/interface.go

@@ -188,10 +188,11 @@ func init() {
 // open a channel within the graph to a target peer, close targeted channels,
 // or add/remove funds from existing channels via a splice in/out mechanisms.
 type ChannelController interface {
-	// OpenChannel opens a channel to a target peer, with a capacity of the
+	// OpenChannel opens a channel to a target peer, using at most amt
-	// specified amount. This function should un-block immediately after
+	// funds. This means that the resulting channel capacity might be
-	// the funding transaction that marks the channel open has been
+	// slightly less to account for fees. This function should un-block
-	// broadcast.
+	// immediately after the funding transaction that marks the channel
+	// open has been broadcast.
 	OpenChannel(target *btcec.PublicKey, amt btcutil.Amount) error
 
 	// CloseChannel attempts to close out the target channel.

fundingmanager.go

@@ -337,6 +337,14 @@ type fundingConfig struct {
 	// due to fees.
 	MinChanSize btcutil.Amount
 
+	// MaxPendingChannels is the maximum number of pending channels we
+	// allow for each peer.
+	MaxPendingChannels int
+
+	// RejectPush is set true if the fundingmanager should reject any
+	// incoming channels having a non-zero push amount.
+	RejectPush bool
+
 	// NotifyOpenChannelEvent informs the ChannelNotifier when channels
 	// transition from pending open to open.
 	NotifyOpenChannelEvent func(wire.OutPoint)
@@ -1012,7 +1020,7 @@ func (f *fundingManager) handleFundingOpen(fmsg *fundingOpenMsg) {
 
 	// TODO(roasbeef): modify to only accept a _single_ pending channel per
 	// block unless white listed
-	if numPending >= cfg.MaxPendingChannels {
+	if numPending >= f.cfg.MaxPendingChannels {
 		f.failFundingFlow(
 			fmsg.peer, fmsg.msg.PendingChannelID,
 			lnwire.ErrMaxPendingChannels,
@@ -1057,7 +1065,7 @@ func (f *fundingManager) handleFundingOpen(fmsg *fundingOpenMsg) {
 
 	// If request specifies non-zero push amount and 'rejectpush' is set,
 	// signal an error.
-	if cfg.RejectPush && msg.PushAmount > 0 {
+	if f.cfg.RejectPush && msg.PushAmount > 0 {
 		f.failFundingFlow(
 			fmsg.peer, fmsg.msg.PendingChannelID,
 			lnwallet.ErrNonZeroPushAmount())
@@ -1079,8 +1087,8 @@ func (f *fundingManager) handleFundingOpen(fmsg *fundingOpenMsg) {
 		ChainHash:        &chainHash,
 		NodeID:           fmsg.peer.IdentityKey(),
 		NodeAddr:         fmsg.peer.Address(),
-		FundingAmount:   0,
+		LocalFundingAmt:  0,
-		Capacity:        amt,
+		RemoteFundingAmt: amt,
 		CommitFeePerKw:   lnwallet.SatPerKWeight(msg.FeePerKiloWeight),
 		FundingFeePerKw:  0,
 		PushMSat:         msg.PushAmount,
@@ -1714,8 +1722,8 @@ func (f *fundingManager) handleFundingSigned(fmsg *fundingSignedMsg) {
 			return
 		case shortChanID, ok = <-confChan:
 			if !ok {
-				fndgLog.Errorf("waiting for funding confirmation" +
+				fndgLog.Errorf("waiting for funding " +
-					" failed")
+					"confirmation failed")
 				return
 			}
 		}
@@ -1885,8 +1893,9 @@ func makeFundingScript(channel *channeldb.OpenChannel) ([]byte, error) {
 // when a channel has become active for lightning transactions.
 // The wait can be canceled by closing the cancelChan. In case of success,
 // a *lnwire.ShortChannelID will be passed to confChan.
-func (f *fundingManager) waitForFundingConfirmation(completeChan *channeldb.OpenChannel,
+func (f *fundingManager) waitForFundingConfirmation(
-	cancelChan <-chan struct{}, confChan chan<- *lnwire.ShortChannelID) {
+	completeChan *channeldb.OpenChannel, cancelChan <-chan struct{},
+	confChan chan<- *lnwire.ShortChannelID) {
 
 	defer close(confChan)
 
@@ -1896,16 +1905,19 @@ func (f *fundingManager) waitForFundingConfirmation(completeChan *channeldb.Open
 	fundingScript, err := makeFundingScript(completeChan)
 	if err != nil {
 		fndgLog.Errorf("unable to create funding script for "+
-			"ChannelPoint(%v): %v", completeChan.FundingOutpoint, err)
+			"ChannelPoint(%v): %v", completeChan.FundingOutpoint,
+			err)
 		return
 	}
 	numConfs := uint32(completeChan.NumConfsRequired)
 	confNtfn, err := f.cfg.Notifier.RegisterConfirmationsNtfn(
-		&txid, fundingScript, numConfs, completeChan.FundingBroadcastHeight,
+		&txid, fundingScript, numConfs,
+		completeChan.FundingBroadcastHeight,
 	)
 	if err != nil {
 		fndgLog.Errorf("Unable to register for confirmation of "+
-			"ChannelPoint(%v): %v", completeChan.FundingOutpoint, err)
+			"ChannelPoint(%v): %v", completeChan.FundingOutpoint,
+			err)
 		return
 	}
 
@@ -1920,14 +1932,17 @@ func (f *fundingManager) waitForFundingConfirmation(completeChan *channeldb.Open
 	select {
 	case confDetails, ok = <-confNtfn.Confirmed:
 		// fallthrough
+
 	case <-cancelChan:
 		fndgLog.Warnf("canceled waiting for funding confirmation, "+
 			"stopping funding flow for ChannelPoint(%v)",
 			completeChan.FundingOutpoint)
 		return
+
 	case <-f.quit:
 		fndgLog.Warnf("fundingManager shutting down, stopping funding "+
-			"flow for ChannelPoint(%v)", completeChan.FundingOutpoint)
+			"flow for ChannelPoint(%v)",
+			completeChan.FundingOutpoint)
 		return
 	}
 
@@ -1940,6 +1955,18 @@ func (f *fundingManager) waitForFundingConfirmation(completeChan *channeldb.Open
 
 	fundingPoint := completeChan.FundingOutpoint
 	chanID := lnwire.NewChanIDFromOutPoint(&fundingPoint)
+	if int(fundingPoint.Index) >= len(confDetails.Tx.TxOut) {
+		fndgLog.Warnf("Funding point index does not exist for "+
+			"ChannelPoint(%v)", completeChan.FundingOutpoint)
+		return
+	}
+
+	outputAmt := btcutil.Amount(confDetails.Tx.TxOut[fundingPoint.Index].Value)
+	if outputAmt != completeChan.Capacity {
+		fndgLog.Warnf("Invalid output value for ChannelPoint(%v)",
+			completeChan.FundingOutpoint)
+		return
+	}
 
 	fndgLog.Infof("ChannelPoint(%v) is now active: ChannelID(%x)",
 		fundingPoint, chanID[:])
@@ -2734,8 +2761,6 @@ func (f *fundingManager) handleInitFundingMsg(msg *initFundingMsg) {
 	var (
 		peerKey        = msg.peer.IdentityKey()
 		localAmt       = msg.localFundingAmt
-		remoteAmt      = msg.remoteFundingAmt
-		capacity       = localAmt + remoteAmt
 		minHtlc        = msg.minHtlc
 		remoteCsvDelay = msg.remoteCsvDelay
 	)
@@ -2749,10 +2774,11 @@ func (f *fundingManager) handleInitFundingMsg(msg *initFundingMsg) {
 		ourDustLimit = defaultLitecoinDustLimit
 	}
 
-	fndgLog.Infof("Initiating fundingRequest(localAmt=%v, remoteAmt=%v, "+
+	fndgLog.Infof("Initiating fundingRequest(local_amt=%v "+
-		"capacity=%v, chainhash=%v, peer=%x, dustLimit=%v, min_confs=%v)",
+		"(subtract_fees=%v), push_amt=%v, chain_hash=%v, peer=%x, "+
-		localAmt, msg.pushAmt, capacity, msg.chainHash,
+		"dust_limit=%v, min_confs=%v)", localAmt, msg.subtractFees,
-		peerKey.SerializeCompressed(), ourDustLimit, msg.minConfs)
+		msg.pushAmt, msg.chainHash, peerKey.SerializeCompressed(),
+		ourDustLimit, msg.minConfs)
 
 	// First, we'll query the fee estimator for a fee that should get the
 	// commitment transaction confirmed by the next few blocks (conf target
@@ -2779,8 +2805,9 @@ func (f *fundingManager) handleInitFundingMsg(msg *initFundingMsg) {
 		ChainHash:        &msg.chainHash,
 		NodeID:           peerKey,
 		NodeAddr:         msg.peer.Address(),
-		FundingAmount:   localAmt,
+		SubtractFees:     msg.subtractFees,
-		Capacity:        capacity,
+		LocalFundingAmt:  localAmt,
+		RemoteFundingAmt: 0,
 		CommitFeePerKw:   commitFeePerKw,
 		FundingFeePerKw:  msg.fundingFeePerKw,
 		PushMSat:         msg.pushAmt,
@@ -2794,6 +2821,12 @@ func (f *fundingManager) handleInitFundingMsg(msg *initFundingMsg) {
 		return
 	}
 
+	// Now that we have successfully reserved funds for this channel in the
+	// wallet, we can fetch the final channel capacity. This is done at
+	// this point since the final capacity might change in case of
+	// SubtractFees=true.
+	capacity := reservation.Capacity()
+
 	// Obtain a new pending channel ID which is used to track this
 	// reservation throughout its lifetime.
 	chanID := f.nextPendingChanID()

fundingmanager_test.go

@@ -236,7 +236,8 @@ func createTestWallet(cdb *channeldb.DB, netParams *chaincfg.Params,
 }
 
 func createTestFundingManager(t *testing.T, privKey *btcec.PrivateKey,
-	addr *lnwire.NetAddress, tempTestDir string) (*testNode, error) {
+	addr *lnwire.NetAddress, tempTestDir string,
+	options ...cfgOption) (*testNode, error) {
 
 	netParams := activeNetParams.Params
 	estimator := lnwallet.NewStaticFeeEstimator(62500, 0)
@@ -282,7 +283,7 @@ func createTestFundingManager(t *testing.T, privKey *btcec.PrivateKey,
 
 	var chanIDSeed [32]byte
 
-	f, err := newFundingManager(fundingConfig{
+	fundingCfg := fundingConfig{
 		IDKey:        privKey.PubKey(),
 		Wallet:       lnw,
 		Notifier:     chainNotifier,
@@ -363,8 +364,15 @@ func createTestFundingManager(t *testing.T, privKey *btcec.PrivateKey,
 		},
 		ZombieSweeperInterval:  1 * time.Hour,
 		ReservationTimeout:     1 * time.Nanosecond,
+		MaxPendingChannels:     DefaultMaxPendingChannels,
 		NotifyOpenChannelEvent: func(wire.OutPoint) {},
-	})
+	}
+
+	for _, op := range options {
+		op(&fundingCfg)
+	}
+
+	f, err := newFundingManager(fundingCfg)
 	if err != nil {
 		t.Fatalf("failed creating fundingManager: %v", err)
 	}
@@ -468,12 +476,10 @@ func recreateAliceFundingManager(t *testing.T, alice *testNode) {
 	}
 }
 
-func setupFundingManagers(t *testing.T, maxPendingChannels int) (*testNode, *testNode) {
+type cfgOption func(*fundingConfig)
-	// We need to set the global config, as fundingManager uses
+
-	// MaxPendingChannels, and it is usually set in lndMain().
+func setupFundingManagers(t *testing.T,
-	cfg = &config{
+	options ...cfgOption) (*testNode, *testNode) {
-		MaxPendingChannels: maxPendingChannels,
-	}
 
 	aliceTestDir, err := ioutil.TempDir("", "alicelnwallet")
 	if err != nil {
@@ -481,7 +487,7 @@ func setupFundingManagers(t *testing.T, maxPendingChannels int) (*testNode, *tes
 	}
 
 	alice, err := createTestFundingManager(
-		t, alicePrivKey, aliceAddr, aliceTestDir,
+		t, alicePrivKey, aliceAddr, aliceTestDir, options...,
 	)
 	if err != nil {
 		t.Fatalf("failed creating fundingManager: %v", err)
@@ -492,7 +498,9 @@ func setupFundingManagers(t *testing.T, maxPendingChannels int) (*testNode, *tes
 		t.Fatalf("unable to create temp directory: %v", err)
 	}
 
-	bob, err := createTestFundingManager(t, bobPrivKey, bobAddr, bobTestDir)
+	bob, err := createTestFundingManager(
+		t, bobPrivKey, bobAddr, bobTestDir, options...,
+	)
 	if err != nil {
 		t.Fatalf("failed creating fundingManager: %v", err)
 	}
@@ -544,14 +552,35 @@ func tearDownFundingManagers(t *testing.T, a, b *testNode) {
 // transaction is confirmed on-chain. Returns the funding out point.
 func openChannel(t *testing.T, alice, bob *testNode, localFundingAmt,
 	pushAmt btcutil.Amount, numConfs uint32,
-	updateChan chan *lnrpc.OpenStatusUpdate, announceChan bool) *wire.OutPoint {
+	updateChan chan *lnrpc.OpenStatusUpdate, announceChan bool) (
+	*wire.OutPoint, *wire.MsgTx) {
+
+	publ := fundChannel(
+		t, alice, bob, localFundingAmt, pushAmt, false, numConfs,
+		updateChan, announceChan,
+	)
+	fundingOutPoint := &wire.OutPoint{
+		Hash:  publ.TxHash(),
+		Index: 0,
+	}
+	return fundingOutPoint, publ
+}
+
+// fundChannel takes the funding process to the point where the funding
+// transaction is confirmed on-chain. Returns the funding tx.
+func fundChannel(t *testing.T, alice, bob *testNode, localFundingAmt,
+	pushAmt btcutil.Amount, subtractFees bool, numConfs uint32,
+	updateChan chan *lnrpc.OpenStatusUpdate, announceChan bool) *wire.MsgTx {
+
 	// Create a funding request and start the workflow.
 	errChan := make(chan error, 1)
 	initReq := &openChanReq{
 		targetPubkey:    bob.privKey.PubKey(),
 		chainHash:       *activeNetParams.GenesisHash,
+		subtractFees:    subtractFees,
 		localFundingAmt: localFundingAmt,
 		pushAmt:         lnwire.NewMSatFromSatoshis(pushAmt),
+		fundingFeePerKw: 1000,
 		private:         !announceChan,
 		updates:         updateChan,
 		err:             errChan,
@@ -636,17 +665,12 @@ func openChannel(t *testing.T, alice, bob *testNode, localFundingAmt,
 		t.Fatalf("alice did not publish funding tx")
 	}
 
-	fundingOutPoint := &wire.OutPoint{
-		Hash:  publ.TxHash(),
-		Index: 0,
-	}
-
 	// Finally, make sure neither have active reservation for the channel
 	// now pending open in the database.
 	assertNumPendingReservations(t, alice, bobPubKey, 0)
 	assertNumPendingReservations(t, bob, alicePubKey, 0)
 
-	return fundingOutPoint
+	return publ
 }
 
 func assertErrorNotSent(t *testing.T, msgChan chan lnwire.Message) {
@@ -674,6 +698,8 @@ func assertErrorSent(t *testing.T, msgChan chan lnwire.Message) {
 
 func assertFundingMsgSent(t *testing.T, msgChan chan lnwire.Message,
 	msgType string) lnwire.Message {
+	t.Helper()
+
 	var msg lnwire.Message
 	select {
 	case msg = <-msgChan:
@@ -1029,7 +1055,9 @@ func assertHandleFundingLocked(t *testing.T, alice, bob *testNode) {
 }
 
 func TestFundingManagerNormalWorkflow(t *testing.T) {
-	alice, bob := setupFundingManagers(t, DefaultMaxPendingChannels)
+	t.Parallel()
+
+	alice, bob := setupFundingManagers(t)
 	defer tearDownFundingManagers(t, alice, bob)
 
 	// We will consume the channel updates as we go, so no buffering is needed.
@@ -1040,16 +1068,21 @@ func TestFundingManagerNormalWorkflow(t *testing.T) {
 	localAmt := btcutil.Amount(500000)
 	pushAmt := btcutil.Amount(0)
 	capacity := localAmt + pushAmt
-	fundingOutPoint := openChannel(t, alice, bob, localAmt, pushAmt, 1,
+	fundingOutPoint, fundingTx := openChannel(
-		updateChan, true)
+		t, alice, bob, localAmt, pushAmt, 1, updateChan, true,
+	)
 
 	// Check that neither Alice nor Bob sent an error message.
 	assertErrorNotSent(t, alice.msgChan)
 	assertErrorNotSent(t, bob.msgChan)
 
 	// Notify that transaction was mined.
-	alice.mockNotifier.oneConfChannel <- &chainntnfs.TxConfirmation{}
+	alice.mockNotifier.oneConfChannel <- &chainntnfs.TxConfirmation{
-	bob.mockNotifier.oneConfChannel <- &chainntnfs.TxConfirmation{}
+		Tx: fundingTx,
+	}
+	bob.mockNotifier.oneConfChannel <- &chainntnfs.TxConfirmation{
+		Tx: fundingTx,
+	}
 
 	// The funding transaction was mined, so assert that both funding
 	// managers now have the state of this channel 'markedOpen' in their
@@ -1090,8 +1123,12 @@ func TestFundingManagerNormalWorkflow(t *testing.T) {
 	assertHandleFundingLocked(t, alice, bob)
 
 	// Notify that six confirmations has been reached on funding transaction.
-	alice.mockNotifier.sixConfChannel <- &chainntnfs.TxConfirmation{}
+	alice.mockNotifier.sixConfChannel <- &chainntnfs.TxConfirmation{
-	bob.mockNotifier.sixConfChannel <- &chainntnfs.TxConfirmation{}
+		Tx: fundingTx,
+	}
+	bob.mockNotifier.sixConfChannel <- &chainntnfs.TxConfirmation{
+		Tx: fundingTx,
+	}
 
 	// Make sure the fundingManagers exchange announcement signatures.
 	assertAnnouncementSignatures(t, alice, bob)
@@ -1102,7 +1139,9 @@ func TestFundingManagerNormalWorkflow(t *testing.T) {
 }
 
 func TestFundingManagerRestartBehavior(t *testing.T) {
-	alice, bob := setupFundingManagers(t, DefaultMaxPendingChannels)
+	t.Parallel()
+
+	alice, bob := setupFundingManagers(t)
 	defer tearDownFundingManagers(t, alice, bob)
 
 	// Run through the process of opening the channel, up until the funding
@@ -1111,8 +1150,9 @@ func TestFundingManagerRestartBehavior(t *testing.T) {
 	pushAmt := btcutil.Amount(0)
 	capacity := localAmt + pushAmt
 	updateChan := make(chan *lnrpc.OpenStatusUpdate)
-	fundingOutPoint := openChannel(t, alice, bob, localAmt, pushAmt, 1,
+	fundingOutPoint, fundingTx := openChannel(
-		updateChan, true)
+		t, alice, bob, localAmt, pushAmt, 1, updateChan, true,
+	)
 
 	// After the funding transaction gets mined, both nodes will send the
 	// fundingLocked message to the other peer. If the funding node fails
@@ -1133,8 +1173,12 @@ func TestFundingManagerRestartBehavior(t *testing.T) {
 	}
 
 	// Notify that transaction was mined
-	alice.mockNotifier.oneConfChannel <- &chainntnfs.TxConfirmation{}
+	alice.mockNotifier.oneConfChannel <- &chainntnfs.TxConfirmation{
-	bob.mockNotifier.oneConfChannel <- &chainntnfs.TxConfirmation{}
+		Tx: fundingTx,
+	}
+	bob.mockNotifier.oneConfChannel <- &chainntnfs.TxConfirmation{
+		Tx: fundingTx,
+	}
 
 	// The funding transaction was mined, so assert that both funding
 	// managers now have the state of this channel 'markedOpen' in their
@@ -1225,8 +1269,12 @@ func TestFundingManagerRestartBehavior(t *testing.T) {
 	time.Sleep(300 * time.Millisecond)
 
 	// Notify that six confirmations has been reached on funding transaction.
-	alice.mockNotifier.sixConfChannel <- &chainntnfs.TxConfirmation{}
+	alice.mockNotifier.sixConfChannel <- &chainntnfs.TxConfirmation{
-	bob.mockNotifier.sixConfChannel <- &chainntnfs.TxConfirmation{}
+		Tx: fundingTx,
+	}
+	bob.mockNotifier.sixConfChannel <- &chainntnfs.TxConfirmation{
+		Tx: fundingTx,
+	}
 
 	// Make sure the fundingManagers exchange announcement signatures.
 	assertAnnouncementSignatures(t, alice, bob)
@@ -1240,7 +1288,9 @@ func TestFundingManagerRestartBehavior(t *testing.T) {
 // server to notify when the peer comes online, in case sending the
 // fundingLocked message fails the first time.
 func TestFundingManagerOfflinePeer(t *testing.T) {
-	alice, bob := setupFundingManagers(t, DefaultMaxPendingChannels)
+	t.Parallel()
+
+	alice, bob := setupFundingManagers(t)
 	defer tearDownFundingManagers(t, alice, bob)
 
 	// Run through the process of opening the channel, up until the funding
@@ -1249,8 +1299,9 @@ func TestFundingManagerOfflinePeer(t *testing.T) {
 	pushAmt := btcutil.Amount(0)
 	capacity := localAmt + pushAmt
 	updateChan := make(chan *lnrpc.OpenStatusUpdate)
-	fundingOutPoint := openChannel(t, alice, bob, localAmt, pushAmt, 1,
+	fundingOutPoint, fundingTx := openChannel(
-		updateChan, true)
+		t, alice, bob, localAmt, pushAmt, 1, updateChan, true,
+	)
 
 	// After the funding transaction gets mined, both nodes will send the
 	// fundingLocked message to the other peer. If the funding node fails
@@ -1272,8 +1323,12 @@ func TestFundingManagerOfflinePeer(t *testing.T) {
 	}
 
 	// Notify that transaction was mined
-	alice.mockNotifier.oneConfChannel <- &chainntnfs.TxConfirmation{}
+	alice.mockNotifier.oneConfChannel <- &chainntnfs.TxConfirmation{
-	bob.mockNotifier.oneConfChannel <- &chainntnfs.TxConfirmation{}
+		Tx: fundingTx,
+	}
+	bob.mockNotifier.oneConfChannel <- &chainntnfs.TxConfirmation{
+		Tx: fundingTx,
+	}
 
 	// The funding transaction was mined, so assert that both funding
 	// managers now have the state of this channel 'markedOpen' in their
@@ -1358,8 +1413,12 @@ func TestFundingManagerOfflinePeer(t *testing.T) {
 	assertHandleFundingLocked(t, alice, bob)
 
 	// Notify that six confirmations has been reached on funding transaction.
-	alice.mockNotifier.sixConfChannel <- &chainntnfs.TxConfirmation{}
+	alice.mockNotifier.sixConfChannel <- &chainntnfs.TxConfirmation{
-	bob.mockNotifier.sixConfChannel <- &chainntnfs.TxConfirmation{}
+		Tx: fundingTx,
+	}
+	bob.mockNotifier.sixConfChannel <- &chainntnfs.TxConfirmation{
+		Tx: fundingTx,
+	}
 
 	// Make sure both fundingManagers send the expected announcement
 	// signatures.
@@ -1374,7 +1433,9 @@ func TestFundingManagerOfflinePeer(t *testing.T) {
 // will properly clean up a zombie reservation that times out after the
 // initFundingMsg has been handled.
 func TestFundingManagerPeerTimeoutAfterInitFunding(t *testing.T) {
-	alice, bob := setupFundingManagers(t, DefaultMaxPendingChannels)
+	t.Parallel()
+
+	alice, bob := setupFundingManagers(t)
 	defer tearDownFundingManagers(t, alice, bob)
 
 	// We will consume the channel updates as we go, so no buffering is needed.
@@ -1434,7 +1495,9 @@ func TestFundingManagerPeerTimeoutAfterInitFunding(t *testing.T) {
 // will properly clean up a zombie reservation that times out after the
 // fundingOpenMsg has been handled.
 func TestFundingManagerPeerTimeoutAfterFundingOpen(t *testing.T) {
-	alice, bob := setupFundingManagers(t, DefaultMaxPendingChannels)
+	t.Parallel()
+
+	alice, bob := setupFundingManagers(t)
 	defer tearDownFundingManagers(t, alice, bob)
 
 	// We will consume the channel updates as we go, so no buffering is needed.
@@ -1503,7 +1566,9 @@ func TestFundingManagerPeerTimeoutAfterFundingOpen(t *testing.T) {
 // will properly clean up a zombie reservation that times out after the
 // fundingAcceptMsg has been handled.
 func TestFundingManagerPeerTimeoutAfterFundingAccept(t *testing.T) {
-	alice, bob := setupFundingManagers(t, DefaultMaxPendingChannels)
+	t.Parallel()
+
+	alice, bob := setupFundingManagers(t)
 	defer tearDownFundingManagers(t, alice, bob)
 
 	// We will consume the channel updates as we go, so no buffering is needed.
@@ -1577,7 +1642,9 @@ func TestFundingManagerPeerTimeoutAfterFundingAccept(t *testing.T) {
 }
 
 func TestFundingManagerFundingTimeout(t *testing.T) {
-	alice, bob := setupFundingManagers(t, DefaultMaxPendingChannels)
+	t.Parallel()
+
+	alice, bob := setupFundingManagers(t)
 	defer tearDownFundingManagers(t, alice, bob)
 
 	// We will consume the channel updates as we go, so no buffering is needed.
@@ -1585,7 +1652,7 @@ func TestFundingManagerFundingTimeout(t *testing.T) {
 
 	// Run through the process of opening the channel, up until the funding
 	// transaction is broadcasted.
-	_ = openChannel(t, alice, bob, 500000, 0, 1, updateChan, true)
+	_, _ = openChannel(t, alice, bob, 500000, 0, 1, updateChan, true)
 
 	// Bob will at this point be waiting for the funding transaction to be
 	// confirmed, so the channel should be considered pending.
@@ -1621,8 +1688,9 @@ func TestFundingManagerFundingTimeout(t *testing.T) {
 // TestFundingManagerFundingNotTimeoutInitiator checks that if the user was
 // the channel initiator, that it does not timeout when the lnd restarts.
 func TestFundingManagerFundingNotTimeoutInitiator(t *testing.T) {
+	t.Parallel()
 
-	alice, bob := setupFundingManagers(t, DefaultMaxPendingChannels)
+	alice, bob := setupFundingManagers(t)
 	defer tearDownFundingManagers(t, alice, bob)
 
 	// We will consume the channel updates as we go, so no buffering is needed.
@@ -1630,7 +1698,7 @@ func TestFundingManagerFundingNotTimeoutInitiator(t *testing.T) {
 
 	// Run through the process of opening the channel, up until the funding
 	// transaction is broadcasted.
-	_ = openChannel(t, alice, bob, 500000, 0, 1, updateChan, true)
+	_, _ = openChannel(t, alice, bob, 500000, 0, 1, updateChan, true)
 
 	// Alice will at this point be waiting for the funding transaction to be
 	// confirmed, so the channel should be considered pending.
@@ -1689,7 +1757,9 @@ func TestFundingManagerFundingNotTimeoutInitiator(t *testing.T) {
 // continues to operate as expected in case we receive a duplicate fundingLocked
 // message.
 func TestFundingManagerReceiveFundingLockedTwice(t *testing.T) {
-	alice, bob := setupFundingManagers(t, DefaultMaxPendingChannels)
+	t.Parallel()
+
+	alice, bob := setupFundingManagers(t)
 	defer tearDownFundingManagers(t, alice, bob)
 
 	// We will consume the channel updates as we go, so no buffering is needed.
@@ -1700,12 +1770,17 @@ func TestFundingManagerReceiveFundingLockedTwice(t *testing.T) {
 	localAmt := btcutil.Amount(500000)
 	pushAmt := btcutil.Amount(0)
 	capacity := localAmt + pushAmt
-	fundingOutPoint := openChannel(t, alice, bob, localAmt, pushAmt, 1,
+	fundingOutPoint, fundingTx := openChannel(
-		updateChan, true)
+		t, alice, bob, localAmt, pushAmt, 1, updateChan, true,
+	)
 
 	// Notify that transaction was mined
-	alice.mockNotifier.oneConfChannel <- &chainntnfs.TxConfirmation{}
+	alice.mockNotifier.oneConfChannel <- &chainntnfs.TxConfirmation{
-	bob.mockNotifier.oneConfChannel <- &chainntnfs.TxConfirmation{}
+		Tx: fundingTx,
+	}
+	bob.mockNotifier.oneConfChannel <- &chainntnfs.TxConfirmation{
+		Tx: fundingTx,
+	}
 
 	// The funding transaction was mined, so assert that both funding
 	// managers now have the state of this channel 'markedOpen' in their
@@ -1766,8 +1841,12 @@ func TestFundingManagerReceiveFundingLockedTwice(t *testing.T) {
 	}
 
 	// Notify that six confirmations has been reached on funding transaction.
-	alice.mockNotifier.sixConfChannel <- &chainntnfs.TxConfirmation{}
+	alice.mockNotifier.sixConfChannel <- &chainntnfs.TxConfirmation{
-	bob.mockNotifier.sixConfChannel <- &chainntnfs.TxConfirmation{}
+		Tx: fundingTx,
+	}
+	bob.mockNotifier.sixConfChannel <- &chainntnfs.TxConfirmation{
+		Tx: fundingTx,
+	}
 
 	// Make sure the fundingManagers exchange announcement signatures.
 	assertAnnouncementSignatures(t, alice, bob)
@@ -1781,7 +1860,9 @@ func TestFundingManagerReceiveFundingLockedTwice(t *testing.T) {
 // handles receiving a fundingLocked after the its own fundingLocked and channel
 // announcement is sent and gets restarted.
 func TestFundingManagerRestartAfterChanAnn(t *testing.T) {
-	alice, bob := setupFundingManagers(t, DefaultMaxPendingChannels)
+	t.Parallel()
+
+	alice, bob := setupFundingManagers(t)
 	defer tearDownFundingManagers(t, alice, bob)
 
 	// We will consume the channel updates as we go, so no buffering is needed.
@@ -1792,12 +1873,17 @@ func TestFundingManagerRestartAfterChanAnn(t *testing.T) {
 	localAmt := btcutil.Amount(500000)
 	pushAmt := btcutil.Amount(0)
 	capacity := localAmt + pushAmt
-	fundingOutPoint := openChannel(t, alice, bob, localAmt, pushAmt, 1,
+	fundingOutPoint, fundingTx := openChannel(
-		updateChan, true)
+		t, alice, bob, localAmt, pushAmt, 1, updateChan, true,
+	)
 
 	// Notify that transaction was mined
-	alice.mockNotifier.oneConfChannel <- &chainntnfs.TxConfirmation{}
+	alice.mockNotifier.oneConfChannel <- &chainntnfs.TxConfirmation{
-	bob.mockNotifier.oneConfChannel <- &chainntnfs.TxConfirmation{}
+		Tx: fundingTx,
+	}
+	bob.mockNotifier.oneConfChannel <- &chainntnfs.TxConfirmation{
+		Tx: fundingTx,
+	}
 
 	// The funding transaction was mined, so assert that both funding
 	// managers now have the state of this channel 'markedOpen' in their
@@ -1843,8 +1929,12 @@ func TestFundingManagerRestartAfterChanAnn(t *testing.T) {
 	assertHandleFundingLocked(t, alice, bob)
 
 	// Notify that six confirmations has been reached on funding transaction.
-	alice.mockNotifier.sixConfChannel <- &chainntnfs.TxConfirmation{}
+	alice.mockNotifier.sixConfChannel <- &chainntnfs.TxConfirmation{
-	bob.mockNotifier.sixConfChannel <- &chainntnfs.TxConfirmation{}
+		Tx: fundingTx,
+	}
+	bob.mockNotifier.sixConfChannel <- &chainntnfs.TxConfirmation{
+		Tx: fundingTx,
+	}
 
 	// Make sure both fundingManagers send the expected channel announcements.
 	assertAnnouncementSignatures(t, alice, bob)
@@ -1858,7 +1948,9 @@ func TestFundingManagerRestartAfterChanAnn(t *testing.T) {
 // fundingManager continues to operate as expected after it has received
 // fundingLocked and then gets restarted.
 func TestFundingManagerRestartAfterReceivingFundingLocked(t *testing.T) {
-	alice, bob := setupFundingManagers(t, DefaultMaxPendingChannels)
+	t.Parallel()
+
+	alice, bob := setupFundingManagers(t)
 	defer tearDownFundingManagers(t, alice, bob)
 
 	// We will consume the channel updates as we go, so no buffering is needed.
@@ -1869,12 +1961,17 @@ func TestFundingManagerRestartAfterReceivingFundingLocked(t *testing.T) {
 	localAmt := btcutil.Amount(500000)
 	pushAmt := btcutil.Amount(0)
 	capacity := localAmt + pushAmt
-	fundingOutPoint := openChannel(t, alice, bob, localAmt, pushAmt, 1,
+	fundingOutPoint, fundingTx := openChannel(
-		updateChan, true)
+		t, alice, bob, localAmt, pushAmt, 1, updateChan, true,
+	)
 
 	// Notify that transaction was mined
-	alice.mockNotifier.oneConfChannel <- &chainntnfs.TxConfirmation{}
+	alice.mockNotifier.oneConfChannel <- &chainntnfs.TxConfirmation{
-	bob.mockNotifier.oneConfChannel <- &chainntnfs.TxConfirmation{}
+		Tx: fundingTx,
+	}
+	bob.mockNotifier.oneConfChannel <- &chainntnfs.TxConfirmation{
+		Tx: fundingTx,
+	}
 
 	// The funding transaction was mined, so assert that both funding
 	// managers now have the state of this channel 'markedOpen' in their
@@ -1916,8 +2013,12 @@ func TestFundingManagerRestartAfterReceivingFundingLocked(t *testing.T) {
 	assertAddedToRouterGraph(t, alice, bob, fundingOutPoint)
 
 	// Notify that six confirmations has been reached on funding transaction.
-	alice.mockNotifier.sixConfChannel <- &chainntnfs.TxConfirmation{}
+	alice.mockNotifier.sixConfChannel <- &chainntnfs.TxConfirmation{
-	bob.mockNotifier.sixConfChannel <- &chainntnfs.TxConfirmation{}
+		Tx: fundingTx,
+	}
+	bob.mockNotifier.sixConfChannel <- &chainntnfs.TxConfirmation{
+		Tx: fundingTx,
+	}
 
 	// Make sure both fundingManagers send the expected channel announcements.
 	assertAnnouncementSignatures(t, alice, bob)
@@ -1931,7 +2032,9 @@ func TestFundingManagerRestartAfterReceivingFundingLocked(t *testing.T) {
 // (a channel not supposed to be announced to the rest of the network),
 // the announcementSignatures nor the nodeAnnouncement messages are sent.
 func TestFundingManagerPrivateChannel(t *testing.T) {
-	alice, bob := setupFundingManagers(t, DefaultMaxPendingChannels)
+	t.Parallel()
+
+	alice, bob := setupFundingManagers(t)
 	defer tearDownFundingManagers(t, alice, bob)
 
 	// We will consume the channel updates as we go, so no buffering is needed.
@@ -1942,12 +2045,17 @@ func TestFundingManagerPrivateChannel(t *testing.T) {
 	localAmt := btcutil.Amount(500000)
 	pushAmt := btcutil.Amount(0)
 	capacity := localAmt + pushAmt
-	fundingOutPoint := openChannel(t, alice, bob, localAmt, pushAmt, 1,
+	fundingOutPoint, fundingTx := openChannel(
-		updateChan, false)
+		t, alice, bob, localAmt, pushAmt, 1, updateChan, false,
+	)
 
 	// Notify that transaction was mined
-	alice.mockNotifier.oneConfChannel <- &chainntnfs.TxConfirmation{}
+	alice.mockNotifier.oneConfChannel <- &chainntnfs.TxConfirmation{
-	bob.mockNotifier.oneConfChannel <- &chainntnfs.TxConfirmation{}
+		Tx: fundingTx,
+	}
+	bob.mockNotifier.oneConfChannel <- &chainntnfs.TxConfirmation{
+		Tx: fundingTx,
+	}
 
 	// The funding transaction was mined, so assert that both funding
 	// managers now have the state of this channel 'markedOpen' in their
@@ -1985,8 +2093,12 @@ func TestFundingManagerPrivateChannel(t *testing.T) {
 	assertHandleFundingLocked(t, alice, bob)
 
 	// Notify that six confirmations has been reached on funding transaction.
-	alice.mockNotifier.sixConfChannel <- &chainntnfs.TxConfirmation{}
+	alice.mockNotifier.sixConfChannel <- &chainntnfs.TxConfirmation{
-	bob.mockNotifier.sixConfChannel <- &chainntnfs.TxConfirmation{}
+		Tx: fundingTx,
+	}
+	bob.mockNotifier.sixConfChannel <- &chainntnfs.TxConfirmation{
+		Tx: fundingTx,
+	}
 
 	// Since this is a private channel, we shouldn't receive the
 	// announcement signatures.
@@ -2033,7 +2145,9 @@ func TestFundingManagerPrivateChannel(t *testing.T) {
 // announcement signatures nor the node announcement messages are sent upon
 // restart.
 func TestFundingManagerPrivateRestart(t *testing.T) {
-	alice, bob := setupFundingManagers(t, DefaultMaxPendingChannels)
+	t.Parallel()
+
+	alice, bob := setupFundingManagers(t)
 	defer tearDownFundingManagers(t, alice, bob)
 
 	// We will consume the channel updates as we go, so no buffering is needed.
@@ -2044,12 +2158,17 @@ func TestFundingManagerPrivateRestart(t *testing.T) {
 	localAmt := btcutil.Amount(500000)
 	pushAmt := btcutil.Amount(0)
 	capacity := localAmt + pushAmt
-	fundingOutPoint := openChannel(t, alice, bob, localAmt, pushAmt, 1,
+	fundingOutPoint, fundingTx := openChannel(
-		updateChan, false)
+		t, alice, bob, localAmt, pushAmt, 1, updateChan, false,
+	)
 
 	// Notify that transaction was mined
-	alice.mockNotifier.oneConfChannel <- &chainntnfs.TxConfirmation{}
+	alice.mockNotifier.oneConfChannel <- &chainntnfs.TxConfirmation{
-	bob.mockNotifier.oneConfChannel <- &chainntnfs.TxConfirmation{}
+		Tx: fundingTx,
+	}
+	bob.mockNotifier.oneConfChannel <- &chainntnfs.TxConfirmation{
+		Tx: fundingTx,
+	}
 
 	// The funding transaction was mined, so assert that both funding
 	// managers now have the state of this channel 'markedOpen' in their
@@ -2092,8 +2211,12 @@ func TestFundingManagerPrivateRestart(t *testing.T) {
 	assertHandleFundingLocked(t, alice, bob)
 
 	// Notify that six confirmations has been reached on funding transaction.
-	alice.mockNotifier.sixConfChannel <- &chainntnfs.TxConfirmation{}
+	alice.mockNotifier.sixConfChannel <- &chainntnfs.TxConfirmation{
-	bob.mockNotifier.sixConfChannel <- &chainntnfs.TxConfirmation{}
+		Tx: fundingTx,
+	}
+	bob.mockNotifier.sixConfChannel <- &chainntnfs.TxConfirmation{
+		Tx: fundingTx,
+	}
 
 	// Since this is a private channel, we shouldn't receive the public
 	// channel announcement messages.
@@ -2155,7 +2278,9 @@ func TestFundingManagerPrivateRestart(t *testing.T) {
 // TestFundingManagerCustomChannelParameters checks that custom requirements we
 // specify during the channel funding flow is preserved correcly on both sides.
 func TestFundingManagerCustomChannelParameters(t *testing.T) {
-	alice, bob := setupFundingManagers(t, DefaultMaxPendingChannels)
+	t.Parallel()
+
+	alice, bob := setupFundingManagers(t)
 	defer tearDownFundingManagers(t, alice, bob)
 
 	// This is the custom parameters we'll use.
@@ -2348,15 +2473,20 @@ func TestFundingManagerCustomChannelParameters(t *testing.T) {
 	}
 
 	// Wait for Alice to published the funding tx to the network.
+	var fundingTx *wire.MsgTx
 	select {
-	case <-alice.publTxChan:
+	case fundingTx = <-alice.publTxChan:
 	case <-time.After(time.Second * 5):
 		t.Fatalf("alice did not publish funding tx")
 	}
 
 	// Notify that transaction was mined.
-	alice.mockNotifier.oneConfChannel <- &chainntnfs.TxConfirmation{}
+	alice.mockNotifier.oneConfChannel <- &chainntnfs.TxConfirmation{
-	bob.mockNotifier.oneConfChannel <- &chainntnfs.TxConfirmation{}
+		Tx: fundingTx,
+	}
+	bob.mockNotifier.oneConfChannel <- &chainntnfs.TxConfirmation{
+		Tx: fundingTx,
+	}
 
 	// After the funding transaction is mined, Alice will send
 	// fundingLocked to Bob.
@@ -2383,9 +2513,15 @@ func TestFundingManagerCustomChannelParameters(t *testing.T) {
 // TestFundingManagerMaxPendingChannels checks that trying to open another
 // channel with the same peer when MaxPending channels are pending fails.
 func TestFundingManagerMaxPendingChannels(t *testing.T) {
+	t.Parallel()
+
 	const maxPending = 4
 
-	alice, bob := setupFundingManagers(t, maxPending)
+	alice, bob := setupFundingManagers(
+		t, func(cfg *fundingConfig) {
+			cfg.MaxPendingChannels = maxPending
+		},
+	)
 	defer tearDownFundingManagers(t, alice, bob)
 
 	// Create openChanReqs for maxPending+1 channels.
@@ -2483,6 +2619,7 @@ func TestFundingManagerMaxPendingChannels(t *testing.T) {
 	).(*lnwire.Error)
 
 	// Give the FundingSigned messages to Alice.
+	var txs []*wire.MsgTx
 	for i, sign := range signs {
 		alice.fundingMgr.processFundingSigned(sign, bob)
 
@@ -2501,7 +2638,8 @@ func TestFundingManagerMaxPendingChannels(t *testing.T) {
 		}
 
 		select {
-		case <-alice.publTxChan:
+		case tx := <-alice.publTxChan:
+			txs = append(txs, tx)
 		case <-time.After(time.Second * 5):
 			t.Fatalf("alice did not publish funding tx")
 		}
@@ -2518,8 +2656,12 @@ func TestFundingManagerMaxPendingChannels(t *testing.T) {
 
 	// Notify that the transactions were mined.
 	for i := 0; i < maxPending; i++ {
-		alice.mockNotifier.oneConfChannel <- &chainntnfs.TxConfirmation{}
+		alice.mockNotifier.oneConfChannel <- &chainntnfs.TxConfirmation{
-		bob.mockNotifier.oneConfChannel <- &chainntnfs.TxConfirmation{}
+			Tx: txs[i],
+		}
+		bob.mockNotifier.oneConfChannel <- &chainntnfs.TxConfirmation{
+			Tx: txs[i],
+		}
 
 		// Expect both to be sending FundingLocked.
 		_ = assertFundingMsgSent(
@@ -2544,14 +2686,15 @@ func TestFundingManagerMaxPendingChannels(t *testing.T) {
 // TestFundingManagerRejectPush checks behaviour of 'rejectpush'
 // option, namely that non-zero incoming push amounts are disabled.
 func TestFundingManagerRejectPush(t *testing.T) {
+	t.Parallel()
+
 	// Enable 'rejectpush' option and initialize funding managers.
-	alice, bob := setupFundingManagers(t, DefaultMaxPendingChannels)
+	alice, bob := setupFundingManagers(
-	rejectPush := cfg.RejectPush
+		t, func(cfg *fundingConfig) {
 			cfg.RejectPush = true
-	defer func() {
+		},
-		tearDownFundingManagers(t, alice, bob)
+	)
-		cfg.RejectPush = rejectPush
+	defer tearDownFundingManagers(t, alice, bob)
-	}()
 
 	// Create a funding request and start the workflow.
 	updateChan := make(chan *lnrpc.OpenStatusUpdate)
@@ -2607,7 +2750,7 @@ func TestFundingManagerRejectPush(t *testing.T) {
 func TestFundingManagerMaxConfs(t *testing.T) {
 	t.Parallel()
 
-	alice, bob := setupFundingManagers(t, DefaultMaxPendingChannels)
+	alice, bob := setupFundingManagers(t)
 	defer tearDownFundingManagers(t, alice, bob)
 
 	// Create a funding request and start the workflow.
@@ -2669,3 +2812,102 @@ func TestFundingManagerMaxConfs(t *testing.T) {
 			string(err.Data))
 	}
 }
+
+// TestFundingManagerFundAll tests that we can initiate a funding request to
+// use the funds remaining in the wallet. This should produce a funding tx with
+// no change output.
+func TestFundingManagerFundAll(t *testing.T) {
+	t.Parallel()
+
+	// We set up our mock wallet to control a list of UTXOs that sum to
+	// less than the max channel size.
+	allCoins := []*lnwallet.Utxo{
+		{
+			AddressType: lnwallet.WitnessPubKey,
+			Value: btcutil.Amount(
+				0.05 * btcutil.SatoshiPerBitcoin,
+			),
+			PkScript: make([]byte, 22),
+			OutPoint: wire.OutPoint{
+				Hash:  chainhash.Hash{},
+				Index: 0,
+			},
+		},
+		{
+			AddressType: lnwallet.WitnessPubKey,
+			Value: btcutil.Amount(
+				0.06 * btcutil.SatoshiPerBitcoin,
+			),
+			PkScript: make([]byte, 22),
+			OutPoint: wire.OutPoint{
+				Hash:  chainhash.Hash{},
+				Index: 1,
+			},
+		},
+	}
+
+	tests := []struct {
+		spendAmt btcutil.Amount
+		change   bool
+	}{
+		{
+			// We will spend all the funds in the wallet, and
+			// expects no change output.
+			spendAmt: btcutil.Amount(
+				0.11 * btcutil.SatoshiPerBitcoin,
+			),
+			change: false,
+		},
+		{
+			// We spend a little less than the funds in the wallet,
+			// so a change output should be created.
+			spendAmt: btcutil.Amount(
+				0.10 * btcutil.SatoshiPerBitcoin,
+			),
+			change: true,
+		},
+	}
+
+	for _, test := range tests {
+		alice, bob := setupFundingManagers(t)
+		defer tearDownFundingManagers(t, alice, bob)
+
+		alice.fundingMgr.cfg.Wallet.WalletController.(*mockWalletController).utxos = allCoins
+
+		// We will consume the channel updates as we go, so no
+		// buffering is needed.
+		updateChan := make(chan *lnrpc.OpenStatusUpdate)
+
+		// Initiate a fund channel, and inspect the funding tx.
+		pushAmt := btcutil.Amount(0)
+		fundingTx := fundChannel(
+			t, alice, bob, test.spendAmt, pushAmt, true, 1,
+			updateChan, true,
+		)
+
+		// Check whether the expected change output is present.
+		if test.change && len(fundingTx.TxOut) != 2 {
+			t.Fatalf("expected 2 outputs, had %v",
+				len(fundingTx.TxOut))
+		}
+
+		if !test.change && len(fundingTx.TxOut) != 1 {
+			t.Fatalf("expected 1 output, had %v",
+				len(fundingTx.TxOut))
+		}
+
+		// Inputs should be all funds in the wallet.
+		if len(fundingTx.TxIn) != len(allCoins) {
+			t.Fatalf("Had %d inputs, expected %d",
+				len(fundingTx.TxIn), len(allCoins))
+		}
+
+		for i, txIn := range fundingTx.TxIn {
+			if txIn.PreviousOutPoint != allCoins[i].OutPoint {
+				t.Fatalf("expected outpoint to be %v, was %v",
+					allCoins[i].OutPoint,
+					txIn.PreviousOutPoint)
+			}
+		}
+	}
+}

lnwallet/interface_test.go

@@ -418,8 +418,8 @@ func testDualFundingReservationWorkflow(miner *rpctest.Harness,
 		ChainHash:        chainHash,
 		NodeID:           bobPub,
 		NodeAddr:         bobAddr,
-		FundingAmount:   fundingAmount,
+		LocalFundingAmt:  fundingAmount,
-		Capacity:        fundingAmount * 2,
+		RemoteFundingAmt: fundingAmount,
 		CommitFeePerKw:   feePerKw,
 		FundingFeePerKw:  feePerKw,
 		PushMSat:         0,
@@ -461,8 +461,8 @@ func testDualFundingReservationWorkflow(miner *rpctest.Harness,
 		ChainHash:        chainHash,
 		NodeID:           alicePub,
 		NodeAddr:         aliceAddr,
-		FundingAmount:   fundingAmount,
+		LocalFundingAmt:  fundingAmount,
-		Capacity:        fundingAmount * 2,
+		RemoteFundingAmt: fundingAmount,
 		CommitFeePerKw:   feePerKw,
 		FundingFeePerKw:  feePerKw,
 		PushMSat:         0,
@@ -621,8 +621,8 @@ func testFundingTransactionLockedOutputs(miner *rpctest.Harness,
 		ChainHash:        chainHash,
 		NodeID:           bobPub,
 		NodeAddr:         bobAddr,
-		FundingAmount:   fundingAmount,
+		LocalFundingAmt:  fundingAmount,
-		Capacity:        fundingAmount,
+		RemoteFundingAmt: 0,
 		CommitFeePerKw:   feePerKw,
 		FundingFeePerKw:  feePerKw,
 		PushMSat:         0,
@@ -643,8 +643,8 @@ func testFundingTransactionLockedOutputs(miner *rpctest.Harness,
 		ChainHash:        chainHash,
 		NodeID:           bobPub,
 		NodeAddr:         bobAddr,
-		FundingAmount:   amt,
+		LocalFundingAmt:  amt,
-		Capacity:        amt,
+		RemoteFundingAmt: 0,
 		CommitFeePerKw:   feePerKw,
 		FundingFeePerKw:  feePerKw,
 		PushMSat:         0,
@@ -679,8 +679,8 @@ func testFundingCancellationNotEnoughFunds(miner *rpctest.Harness,
 		ChainHash:        chainHash,
 		NodeID:           bobPub,
 		NodeAddr:         bobAddr,
-		FundingAmount:   fundingAmount,
+		LocalFundingAmt:  fundingAmount,
-		Capacity:        fundingAmount,
+		RemoteFundingAmt: 0,
 		CommitFeePerKw:   feePerKw,
 		FundingFeePerKw:  feePerKw,
 		PushMSat:         0,
@@ -753,9 +753,9 @@ func testCancelNonExistentReservation(miner *rpctest.Harness,
 func testReservationInitiatorBalanceBelowDustCancel(miner *rpctest.Harness,
 	alice, _ *lnwallet.LightningWallet, t *testing.T) {
 
-	// We'll attempt to create a new reservation with an extremely high fee
+	// We'll attempt to create a new reservation with an extremely high
-	// rate. This should push our balance into the negative and result in a
+	// commitment fee rate. This should push our balance into the negative
-	// failure to create the reservation.
+	// and result in a failure to create the reservation.
 	const numBTC = 4
 	fundingAmount, err := btcutil.NewAmount(numBTC)
 	if err != nil {
@@ -769,10 +769,10 @@ func testReservationInitiatorBalanceBelowDustCancel(miner *rpctest.Harness,
 		ChainHash:        chainHash,
 		NodeID:           bobPub,
 		NodeAddr:         bobAddr,
-		FundingAmount:   fundingAmount,
+		LocalFundingAmt:  fundingAmount,
-		Capacity:        fundingAmount,
+		RemoteFundingAmt: 0,
 		CommitFeePerKw:   feePerKw,
-		FundingFeePerKw: feePerKw,
+		FundingFeePerKw:  1000,
 		PushMSat:         0,
 		Flags:            lnwire.FFAnnounceChannel,
 	}
@@ -850,8 +850,8 @@ func testSingleFunderReservationWorkflow(miner *rpctest.Harness,
 		ChainHash:        chainHash,
 		NodeID:           bobPub,
 		NodeAddr:         bobAddr,
-		FundingAmount:   fundingAmt,
+		LocalFundingAmt:  fundingAmt,
-		Capacity:        fundingAmt,
+		RemoteFundingAmt: 0,
 		CommitFeePerKw:   feePerKw,
 		FundingFeePerKw:  feePerKw,
 		PushMSat:         pushAmt,
@@ -893,8 +893,8 @@ func testSingleFunderReservationWorkflow(miner *rpctest.Harness,
 		ChainHash:        chainHash,
 		NodeID:           alicePub,
 		NodeAddr:         aliceAddr,
-		FundingAmount:   0,
+		LocalFundingAmt:  0,
-		Capacity:        fundingAmt,
+		RemoteFundingAmt: fundingAmt,
 		CommitFeePerKw:   feePerKw,
 		FundingFeePerKw:  feePerKw,
 		PushMSat:         pushAmt,

lnwallet/reservation.go

@@ -127,7 +127,7 @@ type ChannelReservation struct {
 // used only internally by lnwallet. In order to concurrent safety, the
 // creation of all channel reservations should be carried out via the
 // lnwallet.InitChannelReservation interface.
-func NewChannelReservation(capacity, fundingAmt btcutil.Amount,
+func NewChannelReservation(capacity, localFundingAmt btcutil.Amount,
 	commitFeePerKw SatPerKWeight, wallet *LightningWallet,
 	id uint64, pushMSat lnwire.MilliSatoshi, chainHash *chainhash.Hash,
 	flags lnwire.FundingFlag) (*ChannelReservation, error) {
@@ -139,14 +139,16 @@ func NewChannelReservation(capacity, fundingAmt btcutil.Amount,
 	)
 
 	commitFee := commitFeePerKw.FeeForWeight(input.CommitWeight)
-	fundingMSat := lnwire.NewMSatFromSatoshis(fundingAmt)
+	localFundingMSat := lnwire.NewMSatFromSatoshis(localFundingAmt)
+	// TODO(halseth): make method take remote funding amount direcly
+	// instead of inferring it from capacity and local amt.
 	capacityMSat := lnwire.NewMSatFromSatoshis(capacity)
 	feeMSat := lnwire.NewMSatFromSatoshis(commitFee)
 
 	// If we're the responder to a single-funder reservation, then we have
 	// no initial balance in the channel unless the remote party is pushing
 	// some funds to us within the first commitment state.
-	if fundingAmt == 0 {
+	if localFundingAmt == 0 {
 		ourBalance = pushMSat
 		theirBalance = capacityMSat - feeMSat - pushMSat
 		initiator = false
@@ -163,7 +165,7 @@ func NewChannelReservation(capacity, fundingAmt btcutil.Amount,
 		// TODO(roasbeef): need to rework fee structure in general and
 		// also when we "unlock" dual funder within the daemon
 
-		if capacity == fundingAmt {
+		if capacity == localFundingAmt {
 			// If we're initiating a single funder workflow, then
 			// we pay all the initial fees within the commitment
 			// transaction. We also deduct our balance by the
@@ -174,8 +176,8 @@ func NewChannelReservation(capacity, fundingAmt btcutil.Amount,
 			// Otherwise, this is a dual funder workflow where both
 			// slides split the amount funded and the commitment
 			// fee.
-			ourBalance = fundingMSat - (feeMSat / 2)
+			ourBalance = localFundingMSat - (feeMSat / 2)
-			theirBalance = capacityMSat - fundingMSat - (feeMSat / 2) + pushMSat
+			theirBalance = capacityMSat - localFundingMSat - (feeMSat / 2) + pushMSat
 		}
 
 		initiator = true
@@ -513,6 +515,13 @@ func (r *ChannelReservation) FundingOutpoint() *wire.OutPoint {
 	return &r.partialState.FundingOutpoint
 }
 
+// Capacity returns the channel capacity for this reservation.
+func (r *ChannelReservation) Capacity() btcutil.Amount {
+	r.RLock()
+	defer r.RUnlock()
+	return r.partialState.Capacity
+}
+
 // Cancel abandons this channel reservation. This method should be called in
 // the scenario that communications with the counterparty break down. Upon
 // cancellation, all resources previously reserved for this pending payment

lnwallet/wallet.go

@@ -69,12 +69,20 @@ type InitFundingReserveMsg struct {
 	// workflow.
 	NodeAddr net.Addr
 
-	// FundingAmount is the amount of funds requested for this channel.
+	// SubtractFees should be set if we intend to spend exactly
-	FundingAmount btcutil.Amount
+	// LocalFundingAmt when opening the channel, subtracting the fees from
+	// the funding output. This can be used for instance to use all our
+	// remaining funds to open the channel, since it will take fees into
+	// account.
+	SubtractFees bool
 
-	// Capacity is the total capacity of the channel which includes the
+	// LocalFundingAmt is the amount of funds requested from us for this
-	// amount of funds the remote party contributes (if any).
+	// channel.
-	Capacity btcutil.Amount
+	LocalFundingAmt btcutil.Amount
+
+	// RemoteFundingAmnt is the amount of funds the remote will contribute
+	// to this channel.
+	RemoteFundingAmt btcutil.Amount
 
 	// CommitFeePerKw is the starting accepted satoshis/Kw fee for the set
 	// of initial commitment transactions. In order to ensure timely
@@ -431,7 +439,7 @@ func (l *LightningWallet) InitChannelReservation(
 // validate a funding reservation request.
 func (l *LightningWallet) handleFundingReserveRequest(req *InitFundingReserveMsg) {
 	// It isn't possible to create a channel with zero funds committed.
-	if req.FundingAmount+req.Capacity == 0 {
+	if req.LocalFundingAmt+req.RemoteFundingAmt == 0 {
 		err := ErrZeroCapacity()
 		req.err <- err
 		req.resp <- nil
@@ -449,128 +457,59 @@ func (l *LightningWallet) handleFundingReserveRequest(req *InitFundingReserveMsg
 		return
 	}
 
+	localFundingAmt := req.LocalFundingAmt
+
+	var (
+		selected *coinSelection
+		err      error
+	)
+
+	// If we're on the receiving end of a single funder channel then we
+	// don't need to perform any coin selection, and the remote contributes
+	// all funds. Otherwise, attempt to obtain enough coins to meet the
+	// required funding amount.
+	if req.LocalFundingAmt != 0 {
+		// Coin selection is done on the basis of sat/kw, so we'll use
+		// the fee rate passed in to perform coin selection.
+		var err error
+		selected, err = l.selectCoinsAndChange(
+			req.FundingFeePerKw, req.LocalFundingAmt, req.MinConfs,
+			req.SubtractFees,
+		)
+		if err != nil {
+			req.err <- err
+			req.resp <- nil
+			return
+		}
+
+		localFundingAmt = selected.fundingAmt
+	}
+
+	// The total channel capacity will be the size of the funding output we
+	// created plus the remote contribution.
+	capacity := localFundingAmt + req.RemoteFundingAmt
+
 	id := atomic.AddUint64(&l.nextFundingID, 1)
 	reservation, err := NewChannelReservation(
-		req.Capacity, req.FundingAmount, req.CommitFeePerKw, l, id,
+		capacity, localFundingAmt, req.CommitFeePerKw, l, id,
 		req.PushMSat, l.Cfg.NetParams.GenesisHash, req.Flags,
 	)
 	if err != nil {
+		selected.unlockCoins()
 		req.err <- err
 		req.resp <- nil
 		return
 	}
 
-	// Grab the mutex on the ChannelReservation to ensure thread-safety
+	err = l.initOurContribution(
-	reservation.Lock()
+		reservation, selected, req.NodeAddr, req.NodeID,
-	defer reservation.Unlock()
-
-	reservation.nodeAddr = req.NodeAddr
-	reservation.partialState.IdentityPub = req.NodeID
-
-	// If we're on the receiving end of a single funder channel then we
-	// don't need to perform any coin selection. Otherwise, attempt to
-	// obtain enough coins to meet the required funding amount.
-	if req.FundingAmount != 0 {
-		// Coin selection is done on the basis of sat/kw, so we'll use
-		// the fee rate passed in to perform coin selection.
-		err := l.selectCoinsAndChange(
-			req.FundingFeePerKw, req.FundingAmount, req.MinConfs,
-			reservation.ourContribution,
 	)
 	if err != nil {
+		selected.unlockCoins()
 		req.err <- err
 		req.resp <- nil
 		return
 	}
-	}
-
-	// Next, we'll grab a series of keys from the wallet which will be used
-	// for the duration of the channel. The keys include: our multi-sig
-	// key, the base revocation key, the base htlc key,the base payment
-	// key, and the delayed payment key.
-	//
-	// TODO(roasbeef): "salt" each key as well?
-	reservation.ourContribution.MultiSigKey, err = l.DeriveNextKey(
-		keychain.KeyFamilyMultiSig,
-	)
-	if err != nil {
-		req.err <- err
-		req.resp <- nil
-		return
-	}
-	reservation.ourContribution.RevocationBasePoint, err = l.DeriveNextKey(
-		keychain.KeyFamilyRevocationBase,
-	)
-	if err != nil {
-		req.err <- err
-		req.resp <- nil
-		return
-	}
-	reservation.ourContribution.HtlcBasePoint, err = l.DeriveNextKey(
-		keychain.KeyFamilyHtlcBase,
-	)
-	if err != nil {
-		req.err <- err
-		req.resp <- nil
-		return
-	}
-	reservation.ourContribution.PaymentBasePoint, err = l.DeriveNextKey(
-		keychain.KeyFamilyPaymentBase,
-	)
-	if err != nil {
-		req.err <- err
-		req.resp <- nil
-		return
-	}
-	reservation.ourContribution.DelayBasePoint, err = l.DeriveNextKey(
-		keychain.KeyFamilyDelayBase,
-	)
-	if err != nil {
-		req.err <- err
-		req.resp <- nil
-		return
-	}
-
-	// With the above keys created, we'll also need to initialization our
-	// initial revocation tree state.
-	nextRevocationKeyDesc, err := l.DeriveNextKey(
-		keychain.KeyFamilyRevocationRoot,
-	)
-	if err != nil {
-		req.err <- err
-		req.resp <- nil
-		return
-	}
-	revocationRoot, err := l.DerivePrivKey(nextRevocationKeyDesc)
-	if err != nil {
-		req.err <- err
-		req.resp <- nil
-		return
-	}
-
-	// Once we have the root, we can then generate our shachain producer
-	// and from that generate the per-commitment point.
-	revRoot, err := chainhash.NewHash(revocationRoot.Serialize())
-	if err != nil {
-		req.err <- err
-		req.resp <- nil
-		return
-	}
-	producer := shachain.NewRevocationProducer(*revRoot)
-	firstPreimage, err := producer.AtIndex(0)
-	if err != nil {
-		req.err <- err
-		req.resp <- nil
-		return
-	}
-	reservation.ourContribution.FirstCommitmentPoint = input.ComputeCommitmentPoint(
-		firstPreimage[:],
-	)
-
-	reservation.partialState.RevocationProducer = producer
-	reservation.ourContribution.ChannelConstraints = l.Cfg.DefaultConstraints
-
-	// TODO(roasbeef): turn above into: initContribution()
 
 	// Create a limbo and record entry for this newly pending funding
 	// request.
@@ -585,6 +524,96 @@ func (l *LightningWallet) handleFundingReserveRequest(req *InitFundingReserveMsg
 	req.err <- nil
 }
 
+// initOurContribution initializes the given ChannelReservation with our coins
+// and change reserved for the channel, and derives the keys to use for this
+// channel.
+func (l *LightningWallet) initOurContribution(reservation *ChannelReservation,
+	selected *coinSelection, nodeAddr net.Addr, nodeID *btcec.PublicKey) error {
+
+	// Grab the mutex on the ChannelReservation to ensure thread-safety
+	reservation.Lock()
+	defer reservation.Unlock()
+
+	if selected != nil {
+		reservation.ourContribution.Inputs = selected.coins
+		reservation.ourContribution.ChangeOutputs = selected.change
+	}
+
+	reservation.nodeAddr = nodeAddr
+	reservation.partialState.IdentityPub = nodeID
+
+	// Next, we'll grab a series of keys from the wallet which will be used
+	// for the duration of the channel. The keys include: our multi-sig
+	// key, the base revocation key, the base htlc key,the base payment
+	// key, and the delayed payment key.
+	//
+	// TODO(roasbeef): "salt" each key as well?
+	var err error
+	reservation.ourContribution.MultiSigKey, err = l.DeriveNextKey(
+		keychain.KeyFamilyMultiSig,
+	)
+	if err != nil {
+		return err
+	}
+	reservation.ourContribution.RevocationBasePoint, err = l.DeriveNextKey(
+		keychain.KeyFamilyRevocationBase,
+	)
+	if err != nil {
+		return err
+	}
+	reservation.ourContribution.HtlcBasePoint, err = l.DeriveNextKey(
+		keychain.KeyFamilyHtlcBase,
+	)
+	if err != nil {
+		return err
+	}
+	reservation.ourContribution.PaymentBasePoint, err = l.DeriveNextKey(
+		keychain.KeyFamilyPaymentBase,
+	)
+	if err != nil {
+		return err
+	}
+	reservation.ourContribution.DelayBasePoint, err = l.DeriveNextKey(
+		keychain.KeyFamilyDelayBase,
+	)
+	if err != nil {
+		return err
+	}
+
+	// With the above keys created, we'll also need to initialization our
+	// initial revocation tree state.
+	nextRevocationKeyDesc, err := l.DeriveNextKey(
+		keychain.KeyFamilyRevocationRoot,
+	)
+	if err != nil {
+		return err
+	}
+	revocationRoot, err := l.DerivePrivKey(nextRevocationKeyDesc)
+	if err != nil {
+		return err
+	}
+
+	// Once we have the root, we can then generate our shachain producer
+	// and from that generate the per-commitment point.
+	revRoot, err := chainhash.NewHash(revocationRoot.Serialize())
+	if err != nil {
+		return err
+	}
+	producer := shachain.NewRevocationProducer(*revRoot)
+	firstPreimage, err := producer.AtIndex(0)
+	if err != nil {
+		return err
+	}
+	reservation.ourContribution.FirstCommitmentPoint = input.ComputeCommitmentPoint(
+		firstPreimage[:],
+	)
+
+	reservation.partialState.RevocationProducer = producer
+	reservation.ourContribution.ChannelConstraints = l.Cfg.DefaultConstraints
+
+	return nil
+}
+
 // handleFundingReserveCancel cancels an existing channel reservation. As part
 // of the cancellation, outputs previously selected as inputs for the funding
 // transaction via coin selection are freed allowing future reservations to
@@ -1269,14 +1298,24 @@ func (l *LightningWallet) WithCoinSelectLock(f func() error) error {
 	return f()
 }
 
+// coinSelection holds the result from selectCoinsAndChange.
+type coinSelection struct {
+	coins       []*wire.TxIn
+	change      []*wire.TxOut
+	fundingAmt  btcutil.Amount
+	unlockCoins func()
+}
+
 // selectCoinsAndChange performs coin selection in order to obtain witness
-// outputs which sum to at least 'numCoins' amount of satoshis. If coin
+// outputs which sum to at least 'amt' amount of satoshis. If necessary,
-// selection is successful/possible, then the selected coins are available
+// a change address will also be generated. If coin selection is
-// within the passed contribution's inputs. If necessary, a change address will
+// successful/possible, then the selected coins and change outputs are
-// also be generated.
+// returned, and the value of the resulting funding output. This method locks
+// the selected outputs, and a function closure to unlock them in case of an
+// error is returned.
 func (l *LightningWallet) selectCoinsAndChange(feeRate SatPerKWeight,
-	amt btcutil.Amount, minConfs int32,
+	amt btcutil.Amount, minConfs int32, subtractFees bool) (
-	contribution *ChannelContribution) error {
+	*coinSelection, error) {
 
 	// We hold the coin select mutex while querying for outputs, and
 	// performing coin selection in order to avoid inadvertent double
@@ -1291,21 +1330,66 @@ func (l *LightningWallet) selectCoinsAndChange(feeRate SatPerKWeight,
 	// number of confirmations required.
 	coins, err := l.ListUnspentWitness(minConfs, math.MaxInt32)
 	if err != nil {
-		return err
+		return nil, err
 	}
 
+	var (
+		selectedCoins []*Utxo
+		fundingAmt    btcutil.Amount
+		changeAmt     btcutil.Amount
+	)
+
 	// Perform coin selection over our available, unlocked unspent outputs
 	// in order to find enough coins to meet the funding amount
 	// requirements.
-	selectedCoins, changeAmt, err := coinSelect(feeRate, amt, coins)
+	switch {
+	// In case this request want the fees subtracted from the local amount,
+	// we'll call the specialized method for that. This ensures that we
+	// won't deduct more that the specified balance from our wallet.
+	case subtractFees:
+		dustLimit := l.Cfg.DefaultConstraints.DustLimit
+		selectedCoins, fundingAmt, changeAmt, err = coinSelectSubtractFees(
+			feeRate, amt, dustLimit, coins,
+		)
 		if err != nil {
-		return err
+			return nil, err
+		}
+
+	// Ótherwise do a normal coin selection where we target a given funding
+	// amount.
+	default:
+		fundingAmt = amt
+		selectedCoins, changeAmt, err = coinSelect(feeRate, amt, coins)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	// Record any change output(s) generated as a result of the coin
+	// selection, but only if the addition of the output won't lead to the
+	// creation of dust.
+	var changeOutputs []*wire.TxOut
+	if changeAmt != 0 && changeAmt > DefaultDustLimit() {
+		changeAddr, err := l.NewAddress(WitnessPubKey, true)
+		if err != nil {
+			return nil, err
+		}
+		changeScript, err := txscript.PayToAddrScript(changeAddr)
+		if err != nil {
+			return nil, err
+		}
+
+		changeOutputs = make([]*wire.TxOut, 1)
+		changeOutputs[0] = &wire.TxOut{
+			Value:    int64(changeAmt),
+			PkScript: changeScript,
+		}
 	}
 
 	// Lock the selected coins. These coins are now "reserved", this
 	// prevents concurrent funding requests from referring to and this
 	// double-spending the same set of coins.
-	contribution.Inputs = make([]*wire.TxIn, len(selectedCoins))
+	inputs := make([]*wire.TxIn, len(selectedCoins))
 	for i, coin := range selectedCoins {
 		outpoint := &coin.OutPoint
 		l.lockedOutPoints[*outpoint] = struct{}{}
@@ -1313,30 +1397,26 @@ func (l *LightningWallet) selectCoinsAndChange(feeRate SatPerKWeight,
 
 		// Empty sig script, we'll actually sign if this reservation is
 		// queued up to be completed (the other side accepts).
-		contribution.Inputs[i] = wire.NewTxIn(outpoint, nil, nil)
+		inputs[i] = wire.NewTxIn(outpoint, nil, nil)
 	}
 
-	// Record any change output(s) generated as a result of the coin
+	unlock := func() {
-	// selection, but only if the addition of the output won't lead to the
+		l.coinSelectMtx.Lock()
-	// creation of dust.
+		defer l.coinSelectMtx.Unlock()
-	if changeAmt != 0 && changeAmt > DefaultDustLimit() {
-		changeAddr, err := l.NewAddress(WitnessPubKey, true)
-		if err != nil {
-			return err
-		}
-		changeScript, err := txscript.PayToAddrScript(changeAddr)
-		if err != nil {
-			return err
-		}
 
-		contribution.ChangeOutputs = make([]*wire.TxOut, 1)
+		for _, coin := range selectedCoins {
-		contribution.ChangeOutputs[0] = &wire.TxOut{
+			outpoint := &coin.OutPoint
-			Value:    int64(changeAmt),
+			delete(l.lockedOutPoints, *outpoint)
-			PkScript: changeScript,
+			l.UnlockOutpoint(*outpoint)
 		}
 	}
 
-	return nil
+	return &coinSelection{
+		coins:       inputs,
+		change:      changeOutputs,
+		fundingAmt:  fundingAmt,
+		unlockCoins: unlock,
+	}, nil
 }
 
 // DeriveStateHintObfuscator derives the bytes to be used for obfuscating the
@@ -1416,7 +1496,7 @@ func coinSelect(feeRate SatPerKWeight, amt btcutil.Amount,
 			case NestedWitnessPubKey:
 				weightEstimate.AddNestedP2WKHInput()
 			default:
-				return nil, 0, fmt.Errorf("Unsupported address type: %v",
+				return nil, 0, fmt.Errorf("unsupported address type: %v",
 					utxo.AddressType)
 			}
 		}
@@ -1428,6 +1508,8 @@ func coinSelect(feeRate SatPerKWeight, amt btcutil.Amount,
 		//
 		// TODO: Handle wallets that generate non-witness change
 		// addresses.
+		// TODO(halseth): make coinSelect not estimate change output
+		// for dust change.
 		weightEstimate.AddP2WKHOutput()
 
 		// The difference between the selected amount and the amount
@@ -1453,3 +1535,95 @@ func coinSelect(feeRate SatPerKWeight, amt btcutil.Amount,
 		return selectedUtxos, changeAmt, nil
 	}
 }
+
+// coinSelectSubtractFees attempts to select coins such that we'll spend up to
+// amt in total after fees, adhering to the specified fee rate. The selected
+// coins, the final output and change values are returned.
+func coinSelectSubtractFees(feeRate SatPerKWeight, amt,
+	dustLimit btcutil.Amount, coins []*Utxo) ([]*Utxo, btcutil.Amount,
+	btcutil.Amount, error) {
+
+	// First perform an initial round of coin selection to estimate
+	// the required fee.
+	totalSat, selectedUtxos, err := selectInputs(amt, coins)
+	if err != nil {
+		return nil, 0, 0, err
+	}
+
+	var weightEstimate input.TxWeightEstimator
+	for _, utxo := range selectedUtxos {
+		switch utxo.AddressType {
+		case WitnessPubKey:
+			weightEstimate.AddP2WKHInput()
+		case NestedWitnessPubKey:
+			weightEstimate.AddNestedP2WKHInput()
+		default:
+			return nil, 0, 0, fmt.Errorf("unsupported "+
+				"address type: %v", utxo.AddressType)
+		}
+	}
+
+	// Channel funding multisig output is P2WSH.
+	weightEstimate.AddP2WSHOutput()
+
+	// At this point we've got two possibilities, either create a
+	// change output, or not. We'll first try without creating a
+	// change output.
+	//
+	// Estimate the fee required for a transaction without a change
+	// output.
+	totalWeight := int64(weightEstimate.Weight())
+	requiredFee := feeRate.FeeForWeight(totalWeight)
+
+	// For a transaction without a change output, we'll let everything go
+	// to our multi-sig output after subtracting fees.
+	outputAmt := totalSat - requiredFee
+	changeAmt := btcutil.Amount(0)
+
+	// If the the output is too small after subtracting the fee, the coin
+	// selection cannot be performed with an amount this small.
+	if outputAmt <= dustLimit {
+		return nil, 0, 0, fmt.Errorf("output amount(%v) after "+
+			"subtracting fees(%v) below dust limit(%v)", outputAmt,
+			requiredFee, dustLimit)
+	}
+
+	// We were able to create a transaction with no change from the
+	// selected inputs. We'll remember the resulting values for
+	// now, while we try to add a change output. Assume that change output
+	// is a P2WKH output.
+	weightEstimate.AddP2WKHOutput()
+
+	// Now that we have added the change output, redo the fee
+	// estimate.
+	totalWeight = int64(weightEstimate.Weight())
+	requiredFee = feeRate.FeeForWeight(totalWeight)
+
+	// For a transaction with a change output, everything we don't spend
+	// will go to change.
+	newChange := totalSat - amt
+	newOutput := amt - requiredFee
+
+	// If adding a change output leads to both outputs being above
+	// the dust limit, we'll add the change output. Otherwise we'll
+	// go with the no change tx we originally found.
+	if newChange > dustLimit && newOutput > dustLimit {
+		outputAmt = newOutput
+		changeAmt = newChange
+	}
+
+	// Sanity check the resulting output values to make sure we
+	// don't burn a great part to fees.
+	totalOut := outputAmt + changeAmt
+	fee := totalSat - totalOut
+
+	// Fail if more than 20% goes to fees.
+	// TODO(halseth): smarter fee limit. Make configurable or dynamic wrt
+	// total funding size?
+	if fee > totalOut/5 {
+		return nil, 0, 0, fmt.Errorf("fee %v on total output"+
+			"value %v", fee, totalOut)
+	}
+
+	return selectedUtxos, outputAmt, changeAmt, nil
+}

lnwallet/wallet_test.go

@@ -0,0 +1,350 @@
+package lnwallet
+
+import (
+	"testing"
+
+	"github.com/btcsuite/btcutil"
+	"github.com/lightningnetwork/lnd/input"
+)
+
+// fundingFee is a helper method that returns the fee estimate used for a tx
+// with the given number of inputs and the optional change output. This matches
+// the estimate done by the wallet.
+func fundingFee(feeRate SatPerKWeight, numInput int, change bool) btcutil.Amount {
+	var weightEstimate input.TxWeightEstimator
+
+	// All inputs.
+	for i := 0; i < numInput; i++ {
+		weightEstimate.AddP2WKHInput()
+	}
+
+	// The multisig funding output.
+	weightEstimate.AddP2WSHOutput()
+
+	// Optionally count a change output.
+	if change {
+		weightEstimate.AddP2WKHOutput()
+	}
+
+	totalWeight := int64(weightEstimate.Weight())
+	return feeRate.FeeForWeight(totalWeight)
+}
+
+// TestCoinSelect tests that we pick coins adding up to the expected amount
+// when creating a funding transaction, and that the calculated change is the
+// expected amount.
+//
+// NOTE: coinSelect will always attempt to add a change output, so we must
+// account for this in the tests.
+func TestCoinSelect(t *testing.T) {
+	t.Parallel()
+
+	const feeRate = SatPerKWeight(100)
+	const dust = btcutil.Amount(100)
+
+	type testCase struct {
+		name        string
+		outputValue btcutil.Amount
+		coins       []*Utxo
+
+		expectedInput  []btcutil.Amount
+		expectedChange btcutil.Amount
+		expectErr      bool
+	}
+
+	testCases := []testCase{
+		{
+			// We have 1.0 BTC available, and wants to send 0.5.
+			// This will obviously lead to a change output of
+			// almost 0.5 BTC.
+			name: "big change",
+			coins: []*Utxo{
+				{
+					AddressType: WitnessPubKey,
+					Value:       1 * btcutil.SatoshiPerBitcoin,
+				},
+			},
+			outputValue: 0.5 * btcutil.SatoshiPerBitcoin,
+
+			// The one and only input will be selected.
+			expectedInput: []btcutil.Amount{
+				1 * btcutil.SatoshiPerBitcoin,
+			},
+			// Change will be what's left minus the fee.
+			expectedChange: 0.5*btcutil.SatoshiPerBitcoin - fundingFee(feeRate, 1, true),
+		},
+		{
+			// We have 1 BTC available, and we want to send 1 BTC.
+			// This should lead to an error, as we don't have
+			// enough funds to pay the fee.
+			name: "nothing left for fees",
+			coins: []*Utxo{
+				{
+					AddressType: WitnessPubKey,
+					Value:       1 * btcutil.SatoshiPerBitcoin,
+				},
+			},
+			outputValue: 1 * btcutil.SatoshiPerBitcoin,
+			expectErr:   true,
+		},
+		{
+			// We have a 1 BTC input, and want to create an output
+			// as big as possible, such that the remaining change
+			// will be dust.
+			name: "dust change",
+			coins: []*Utxo{
+				{
+					AddressType: WitnessPubKey,
+					Value:       1 * btcutil.SatoshiPerBitcoin,
+				},
+			},
+			// We tune the output value by subtracting the expected
+			// fee and a small dust amount.
+			outputValue: 1*btcutil.SatoshiPerBitcoin - fundingFee(feeRate, 1, true) - dust,
+
+			expectedInput: []btcutil.Amount{
+				1 * btcutil.SatoshiPerBitcoin,
+			},
+
+			// Change will the dust.
+			expectedChange: dust,
+		},
+		{
+			// We have a 1 BTC input, and want to create an output
+			// as big as possible, such that there is nothing left
+			// for change.
+			name: "no change",
+			coins: []*Utxo{
+				{
+					AddressType: WitnessPubKey,
+					Value:       1 * btcutil.SatoshiPerBitcoin,
+				},
+			},
+			// We tune the output value to be the maximum amount
+			// possible, leaving just enough for fees.
+			outputValue: 1*btcutil.SatoshiPerBitcoin - fundingFee(feeRate, 1, true),
+
+			expectedInput: []btcutil.Amount{
+				1 * btcutil.SatoshiPerBitcoin,
+			},
+			// We have just enough left to pay the fee, so there is
+			// nothing left for change.
+			// TODO(halseth): currently coinselect estimates fees
+			// assuming a change output.
+			expectedChange: 0,
+		},
+	}
+
+	for _, test := range testCases {
+		test := test
+		t.Run(test.name, func(t *testing.T) {
+			t.Parallel()
+
+			selected, changeAmt, err := coinSelect(
+				feeRate, test.outputValue, test.coins,
+			)
+			if !test.expectErr && err != nil {
+				t.Fatalf(err.Error())
+			}
+
+			if test.expectErr && err == nil {
+				t.Fatalf("expected error")
+			}
+
+			// If we got an expected error, there is nothing more to test.
+			if test.expectErr {
+				return
+			}
+
+			// Check that the selected inputs match what we expect.
+			if len(selected) != len(test.expectedInput) {
+				t.Fatalf("expected %v inputs, got %v",
+					len(test.expectedInput), len(selected))
+			}
+
+			for i, coin := range selected {
+				if coin.Value != test.expectedInput[i] {
+					t.Fatalf("expected input %v to have value %v, "+
+						"had %v", i, test.expectedInput[i],
+						coin.Value)
+				}
+			}
+
+			// Assert we got the expected change amount.
+			if changeAmt != test.expectedChange {
+				t.Fatalf("expected %v change amt, got %v",
+					test.expectedChange, changeAmt)
+			}
+		})
+	}
+}
+
+// TestCoinSelectSubtractFees tests that we pick coins adding up to the
+// expected amount when creating a funding transaction, and that a change
+// output is created only when necessary.
+func TestCoinSelectSubtractFees(t *testing.T) {
+	t.Parallel()
+
+	const feeRate = SatPerKWeight(100)
+	const dustLimit = btcutil.Amount(1000)
+	const dust = btcutil.Amount(100)
+
+	type testCase struct {
+		name       string
+		spendValue btcutil.Amount
+		coins      []*Utxo
+
+		expectedInput      []btcutil.Amount
+		expectedFundingAmt btcutil.Amount
+		expectedChange     btcutil.Amount
+		expectErr          bool
+	}
+
+	testCases := []testCase{
+		{
+			// We have 1.0 BTC available, spend them all. This
+			// should lead to a funding TX with one output, the
+			// rest goes to fees.
+			name: "spend all",
+			coins: []*Utxo{
+				{
+					AddressType: WitnessPubKey,
+					Value:       1 * btcutil.SatoshiPerBitcoin,
+				},
+			},
+			spendValue: 1 * btcutil.SatoshiPerBitcoin,
+
+			// The one and only input will be selected.
+			expectedInput: []btcutil.Amount{
+				1 * btcutil.SatoshiPerBitcoin,
+			},
+			expectedFundingAmt: 1*btcutil.SatoshiPerBitcoin - fundingFee(feeRate, 1, false),
+			expectedChange:     0,
+		},
+		{
+			// The total funds available is below the dust limit
+			// after paying fees.
+			name: "dust output",
+			coins: []*Utxo{
+				{
+					AddressType: WitnessPubKey,
+					Value:       fundingFee(feeRate, 1, false) + dust,
+				},
+			},
+			spendValue: fundingFee(feeRate, 1, false) + dust,
+
+			expectErr: true,
+		},
+		{
+			// After subtracting fees, the resulting change output
+			// is below the dust limit. The remainder should go
+			// towards the funding output.
+			name: "dust change",
+			coins: []*Utxo{
+				{
+					AddressType: WitnessPubKey,
+					Value:       1 * btcutil.SatoshiPerBitcoin,
+				},
+			},
+			spendValue: 1*btcutil.SatoshiPerBitcoin - dust,
+
+			expectedInput: []btcutil.Amount{
+				1 * btcutil.SatoshiPerBitcoin,
+			},
+			expectedFundingAmt: 1*btcutil.SatoshiPerBitcoin - fundingFee(feeRate, 1, false),
+			expectedChange:     0,
+		},
+		{
+			// We got just enough funds to create an output above the dust limit.
+			name: "output right above dustlimit",
+			coins: []*Utxo{
+				{
+					AddressType: WitnessPubKey,
+					Value:       fundingFee(feeRate, 1, false) + dustLimit + 1,
+				},
+			},
+			spendValue: fundingFee(feeRate, 1, false) + dustLimit + 1,
+
+			expectedInput: []btcutil.Amount{
+				fundingFee(feeRate, 1, false) + dustLimit + 1,
+			},
+			expectedFundingAmt: dustLimit + 1,
+			expectedChange:     0,
+		},
+		{
+			// Amount left is below dust limit after paying fee for
+			// a change output, resulting in a no-change tx.
+			name: "no amount to pay fee for change",
+			coins: []*Utxo{
+				{
+					AddressType: WitnessPubKey,
+					Value:       fundingFee(feeRate, 1, false) + 2*(dustLimit+1),
+				},
+			},
+			spendValue: fundingFee(feeRate, 1, false) + dustLimit + 1,
+
+			expectedInput: []btcutil.Amount{
+				fundingFee(feeRate, 1, false) + 2*(dustLimit+1),
+			},
+			expectedFundingAmt: 2 * (dustLimit + 1),
+			expectedChange:     0,
+		},
+		{
+			// If more than 20% of funds goes to fees, it should fail.
+			name: "high fee",
+			coins: []*Utxo{
+				{
+					AddressType: WitnessPubKey,
+					Value:       5 * fundingFee(feeRate, 1, false),
+				},
+			},
+			spendValue: 5 * fundingFee(feeRate, 1, false),
+
+			expectErr: true,
+		},
+	}
+
+	for _, test := range testCases {
+		t.Run(test.name, func(t *testing.T) {
+			selected, localFundingAmt, changeAmt, err := coinSelectSubtractFees(
+				feeRate, test.spendValue, dustLimit, test.coins,
+			)
+			if !test.expectErr && err != nil {
+				t.Fatalf(err.Error())
+			}
+
+			if test.expectErr && err == nil {
+				t.Fatalf("expected error")
+			}
+
+			// If we got an expected error, there is nothing more to test.
+			if test.expectErr {
+				return
+			}
+
+			// Check that the selected inputs match what we expect.
+			if len(selected) != len(test.expectedInput) {
+				t.Fatalf("expected %v inputs, got %v",
+					len(test.expectedInput), len(selected))
+			}
+
+			for i, coin := range selected {
+				if coin.Value != test.expectedInput[i] {
+					t.Fatalf("expected input %v to have value %v, "+
+						"had %v", i, test.expectedInput[i],
+						coin.Value)
+				}
+			}
+
+			// Assert we got the expected change amount.
+			if localFundingAmt != test.expectedFundingAmt {
+				t.Fatalf("expected %v local funding amt, got %v",
+					test.expectedFundingAmt, localFundingAmt)
+			}
+			if changeAmt != test.expectedChange {
+				t.Fatalf("expected %v change amt, got %v",
+					test.expectedChange, changeAmt)
+			}
+		})
+	}
+}

mock.go

@@ -231,6 +231,7 @@ type mockWalletController struct {
 	prevAddres            btcutil.Address
 	publishedTransactions chan *wire.MsgTx
 	index                 uint32
+	utxos                 []*lnwallet.Utxo
 }
 
 // BackEnd returns "mock" to signify a mock wallet controller.
@@ -284,6 +285,13 @@ func (*mockWalletController) CreateSimpleTx(outputs []*wire.TxOut,
 // need one unspent for the funding transaction.
 func (m *mockWalletController) ListUnspentWitness(minconfirms,
 	maxconfirms int32) ([]*lnwallet.Utxo, error) {
+
+	// If the mock already has a list of utxos, return it.
+	if m.utxos != nil {
+		return m.utxos, nil
+	}
+
+	// Otherwise create one to return.
 	utxo := &lnwallet.Utxo{
 		AddressType: lnwallet.WitnessPubKey,
 		Value:       btcutil.Amount(10 * btcutil.SatoshiPerBitcoin),

pilot.go

@@ -100,6 +100,7 @@ func (c *chanController) OpenChannel(target *btcec.PublicKey,
 	req := &openChanReq{
 		targetPubkey:    target,
 		chainHash:       *activeNetParams.GenesisHash,
+		subtractFees:    true,
 		localFundingAmt: amt,
 		pushAmt:         0,
 		minHtlc:         minHtlc,

server.go

@@ -1056,6 +1056,8 @@ func newServer(listenAddrs []net.Addr, chanDB *channeldb.DB,
 		ZombieSweeperInterval:  1 * time.Minute,
 		ReservationTimeout:     10 * time.Minute,
 		MinChanSize:            btcutil.Amount(cfg.MinChanSize),
+		MaxPendingChannels:     cfg.MaxPendingChannels,
+		RejectPush:             cfg.RejectPush,
 		NotifyOpenChannelEvent: s.channelNotifier.NotifyOpenChannelEvent,
 	})
 	if err != nil {
@@ -2982,8 +2984,8 @@ type openChanReq struct {
 
 	chainHash chainhash.Hash
 
+	subtractFees    bool
 	localFundingAmt btcutil.Amount
-	remoteFundingAmt btcutil.Amount
 
 	pushAmt lnwire.MilliSatoshi