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lnd_multi-hop_test.go
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lnd_multi-hop_test.go
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package itest
import (
"context"
"fmt"
"testing"
"github.com/btcsuite/btcd/btcutil"
"github.com/btcsuite/btcd/chaincfg/chainhash"
"github.com/btcsuite/btcd/wire"
"github.com/lightningnetwork/lnd/chainreg"
"github.com/lightningnetwork/lnd/lncfg"
"github.com/lightningnetwork/lnd/lnrpc"
"github.com/lightningnetwork/lnd/lnrpc/invoicesrpc"
"github.com/lightningnetwork/lnd/lnrpc/routerrpc"
"github.com/lightningnetwork/lnd/lntest"
"github.com/lightningnetwork/lnd/lntest/node"
"github.com/lightningnetwork/lnd/lntest/rpc"
"github.com/lightningnetwork/lnd/lntypes"
"github.com/lightningnetwork/lnd/routing"
"github.com/stretchr/testify/require"
)
const (
finalCltvDelta = routing.MinCLTVDelta // 18.
thawHeightDelta = finalCltvDelta * 2 // 36.
)
var commitWithZeroConf = []struct {
commitType lnrpc.CommitmentType
zeroConf bool
}{
{
commitType: lnrpc.CommitmentType_ANCHORS,
zeroConf: false,
},
{
commitType: lnrpc.CommitmentType_ANCHORS,
zeroConf: true,
},
{
commitType: lnrpc.CommitmentType_SCRIPT_ENFORCED_LEASE,
zeroConf: false,
},
{
commitType: lnrpc.CommitmentType_SCRIPT_ENFORCED_LEASE,
zeroConf: true,
},
{
commitType: lnrpc.CommitmentType_SIMPLE_TAPROOT,
zeroConf: false,
},
{
commitType: lnrpc.CommitmentType_SIMPLE_TAPROOT,
zeroConf: true,
},
}
// makeRouteHints creates a route hints that will allow Carol to be reached
// using an unadvertised channel created by Bob (Bob -> Carol). If the zeroConf
// bool is set, then the scid alias of Bob will be used in place.
func makeRouteHints(bob, carol *node.HarnessNode,
zeroConf bool) []*lnrpc.RouteHint {
carolChans := carol.RPC.ListChannels(
&lnrpc.ListChannelsRequest{},
)
carolChan := carolChans.Channels[0]
hopHint := &lnrpc.HopHint{
NodeId: carolChan.RemotePubkey,
ChanId: carolChan.ChanId,
FeeBaseMsat: uint32(
chainreg.DefaultBitcoinBaseFeeMSat,
),
FeeProportionalMillionths: uint32(
chainreg.DefaultBitcoinFeeRate,
),
CltvExpiryDelta: chainreg.DefaultBitcoinTimeLockDelta,
}
if zeroConf {
bobChans := bob.RPC.ListChannels(
&lnrpc.ListChannelsRequest{},
)
// Now that we have Bob's channels, scan for the channel he has
// open to Carol so we can use the proper scid.
var found bool
for _, bobChan := range bobChans.Channels {
if bobChan.RemotePubkey == carol.PubKeyStr {
hopHint.ChanId = bobChan.AliasScids[0]
found = true
break
}
}
if !found {
bob.Fatalf("unable to create route hint")
}
}
return []*lnrpc.RouteHint{
{
HopHints: []*lnrpc.HopHint{hopHint},
},
}
}
// caseRunner defines a single test case runner.
type caseRunner func(ht *lntest.HarnessTest, alice, bob *node.HarnessNode,
c lnrpc.CommitmentType, zeroConf bool)
// runMultiHopHtlcClaimTest is a helper method to build test cases based on
// different commitment types and zero-conf config and run them.
func runMultiHopHtlcClaimTest(ht *lntest.HarnessTest, tester caseRunner) {
for _, typeAndConf := range commitWithZeroConf {
typeAndConf := typeAndConf
name := fmt.Sprintf("zeroconf=%v/committype=%v",
typeAndConf.zeroConf, typeAndConf.commitType.String())
// Create the nodes here so that separate logs will be created
// for Alice and Bob.
args := lntest.NodeArgsForCommitType(typeAndConf.commitType)
if typeAndConf.zeroConf {
args = append(
args, "--protocol.option-scid-alias",
"--protocol.zero-conf",
)
}
s := ht.Run(name, func(t1 *testing.T) {
st := ht.Subtest(t1)
alice := st.NewNode("Alice", args)
bob := st.NewNode("Bob", args)
st.ConnectNodes(alice, bob)
// Start each test with the default static fee estimate.
st.SetFeeEstimate(12500)
// Add test name to the logs.
alice.AddToLogf("Running test case: %s", name)
bob.AddToLogf("Running test case: %s", name)
tester(
st, alice, bob,
typeAndConf.commitType, typeAndConf.zeroConf,
)
})
if !s {
return
}
}
}
// testMultiHopHtlcLocalTimeout tests that in a multi-hop HTLC scenario, if the
// outgoing HTLC is about to time out, then we'll go to chain in order to claim
// it using the HTLC timeout transaction. Any dust HTLC's should be immediately
// canceled backwards. Once the timeout has been reached, then we should sweep
// it on-chain, and cancel the HTLC backwards.
func testMultiHopHtlcLocalTimeout(ht *lntest.HarnessTest) {
runMultiHopHtlcClaimTest(ht, runMultiHopHtlcLocalTimeout)
}
func runMultiHopHtlcLocalTimeout(ht *lntest.HarnessTest,
alice, bob *node.HarnessNode, c lnrpc.CommitmentType, zeroConf bool) {
// First, we'll create a three hop network: Alice -> Bob -> Carol, with
// Carol refusing to actually settle or directly cancel any HTLC's
// self.
aliceChanPoint, bobChanPoint, carol := createThreeHopNetwork(
ht, alice, bob, true, c, zeroConf,
)
// Now that our channels are set up, we'll send two HTLC's from Alice
// to Carol. The first HTLC will be universally considered "dust",
// while the second will be a proper fully valued HTLC.
const (
dustHtlcAmt = btcutil.Amount(100)
htlcAmt = btcutil.Amount(300_000)
)
// We'll create two random payment hashes unknown to carol, then send
// each of them by manually specifying the HTLC details.
carolPubKey := carol.PubKey[:]
dustPayHash := ht.Random32Bytes()
payHash := ht.Random32Bytes()
// If this is a taproot channel, then we'll need to make some manual
// route hints so Alice can actually find a route.
var routeHints []*lnrpc.RouteHint
if c == lnrpc.CommitmentType_SIMPLE_TAPROOT {
routeHints = makeRouteHints(bob, carol, zeroConf)
}
alice.RPC.SendPayment(&routerrpc.SendPaymentRequest{
Dest: carolPubKey,
Amt: int64(dustHtlcAmt),
PaymentHash: dustPayHash,
FinalCltvDelta: finalCltvDelta,
TimeoutSeconds: 60,
FeeLimitMsat: noFeeLimitMsat,
RouteHints: routeHints,
})
alice.RPC.SendPayment(&routerrpc.SendPaymentRequest{
Dest: carolPubKey,
Amt: int64(htlcAmt),
PaymentHash: payHash,
FinalCltvDelta: finalCltvDelta,
TimeoutSeconds: 60,
FeeLimitMsat: noFeeLimitMsat,
RouteHints: routeHints,
})
// Verify that all nodes in the path now have two HTLC's with the
// proper parameters.
ht.AssertActiveHtlcs(alice, dustPayHash, payHash)
ht.AssertActiveHtlcs(bob, dustPayHash, payHash)
ht.AssertActiveHtlcs(carol, dustPayHash, payHash)
// Increase the fee estimate so that the following force close tx will
// be cpfp'ed.
ht.SetFeeEstimate(30000)
// We'll now mine enough blocks to trigger Bob's broadcast of his
// commitment transaction due to the fact that the HTLC is about to
// timeout. With the default outgoing broadcast delta of zero, this will
// be the same height as the htlc expiry height.
numBlocks := padCLTV(
uint32(finalCltvDelta - lncfg.DefaultOutgoingBroadcastDelta),
)
ht.MineBlocks(numBlocks)
// Bob's force close transaction should now be found in the mempool. If
// there are anchors, we also expect Bob's anchor sweep.
expectedTxes := 1
hasAnchors := lntest.CommitTypeHasAnchors(c)
if hasAnchors {
expectedTxes = 2
}
ht.Miner.AssertNumTxsInMempool(expectedTxes)
op := ht.OutPointFromChannelPoint(bobChanPoint)
closeTx := ht.Miner.AssertOutpointInMempool(op)
// Mine a block to confirm the closing transaction.
ht.MineBlocksAndAssertNumTxes(1, expectedTxes)
// At this point, Bob should have canceled backwards the dust HTLC
// that we sent earlier. This means Alice should now only have a single
// HTLC on her channel.
ht.AssertActiveHtlcs(alice, payHash)
// With the closing transaction confirmed, we should expect Bob's HTLC
// timeout transaction to be broadcast due to the expiry being reached.
// If there are anchors, we also expect Carol's anchor sweep now.
ht.Miner.AssertNumTxsInMempool(expectedTxes)
// We'll also obtain the expected HTLC timeout transaction hash.
htlcOutpoint := wire.OutPoint{Hash: closeTx.TxHash(), Index: 0}
commitOutpoint := wire.OutPoint{Hash: closeTx.TxHash(), Index: 1}
if hasAnchors {
htlcOutpoint.Index = 2
commitOutpoint.Index = 3
}
htlcTimeoutTxid := ht.Miner.AssertOutpointInMempool(
htlcOutpoint,
).TxHash()
// Mine a block to confirm the expected transactions.
ht.MineBlocksAndAssertNumTxes(1, expectedTxes)
// With Bob's HTLC timeout transaction confirmed, there should be no
// active HTLC's on the commitment transaction from Alice -> Bob.
ht.AssertNumActiveHtlcs(alice, 0)
// At this point, Bob should show that the pending HTLC has advanced to
// the second stage and is ready to be swept once the timelock is up.
pendingChanResp := bob.RPC.PendingChannels()
require.Equal(ht, 1, len(pendingChanResp.PendingForceClosingChannels))
forceCloseChan := pendingChanResp.PendingForceClosingChannels[0]
require.NotZero(ht, forceCloseChan.LimboBalance)
require.Positive(ht, forceCloseChan.BlocksTilMaturity)
require.Equal(ht, 1, len(forceCloseChan.PendingHtlcs))
require.Equal(ht, uint32(2), forceCloseChan.PendingHtlcs[0].Stage)
htlcTimeoutOutpoint := wire.OutPoint{Hash: htlcTimeoutTxid, Index: 0}
if c == lnrpc.CommitmentType_SCRIPT_ENFORCED_LEASE {
// Since Bob is the initiator of the script-enforced leased
// channel between him and Carol, he will incur an additional
// CLTV on top of the usual CSV delay on any outputs that he can
// sweep back to his wallet.
blocksTilMaturity := uint32(forceCloseChan.BlocksTilMaturity)
ht.MineBlocks(blocksTilMaturity)
// Check that the sweep spends the expected inputs.
ht.Miner.AssertOutpointInMempool(commitOutpoint)
ht.Miner.AssertOutpointInMempool(htlcTimeoutOutpoint)
} else {
// Since Bob force closed the channel between him and Carol, he
// will incur the usual CSV delay on any outputs that he can
// sweep back to his wallet. We'll subtract one block from our
// current maturity period to assert on the mempool.
numBlocks := uint32(forceCloseChan.BlocksTilMaturity - 1)
ht.MineBlocks(numBlocks)
// Check that the sweep spends from the mined commitment.
ht.Miner.AssertOutpointInMempool(commitOutpoint)
// Mine a block to confirm Bob's commit sweep tx and assert it
// was in fact mined.
ht.MineBlocksAndAssertNumTxes(1, 1)
// Mine one more block to trigger the timeout path.
ht.MineEmptyBlocks(1)
// Bob's sweeper should now broadcast his second layer sweep
// due to the CSV on the HTLC timeout output.
ht.Miner.AssertOutpointInMempool(htlcTimeoutOutpoint)
}
// Next, we'll mine a final block that should confirm the sweeping
// transactions left.
ht.MineBlocksAndAssertNumTxes(1, 1)
// Once this transaction has been confirmed, Bob should detect that he
// no longer has any pending channels.
ht.AssertNumPendingForceClose(bob, 0)
// Coop close channel, expect no anchors.
ht.CloseChannel(alice, aliceChanPoint)
}
// testMultiHopReceiverChainClaim tests that in the multi-hop setting, if the
// receiver of an HTLC knows the preimage, but wasn't able to settle the HTLC
// off-chain, then it goes on chain to claim the HTLC uing the HTLC success
// transaction. In this scenario, the node that sent the outgoing HTLC should
// extract the preimage from the sweep transaction, and finish settling the
// HTLC backwards into the route.
func testMultiHopReceiverChainClaim(ht *lntest.HarnessTest) {
runMultiHopHtlcClaimTest(ht, runMultiHopReceiverChainClaim)
}
func runMultiHopReceiverChainClaim(ht *lntest.HarnessTest,
alice, bob *node.HarnessNode, c lnrpc.CommitmentType, zeroConf bool) {
// First, we'll create a three hop network: Alice -> Bob -> Carol, with
// Carol refusing to actually settle or directly cancel any HTLC's
// self.
aliceChanPoint, bobChanPoint, carol := createThreeHopNetwork(
ht, alice, bob, false, c, zeroConf,
)
// If this is a taproot channel, then we'll need to make some manual
// route hints so Alice can actually find a route.
var routeHints []*lnrpc.RouteHint
if c == lnrpc.CommitmentType_SIMPLE_TAPROOT {
routeHints = makeRouteHints(bob, carol, zeroConf)
}
// With the network active, we'll now add a new hodl invoice at Carol's
// end. Make sure the cltv expiry delta is large enough, otherwise Bob
// won't send out the outgoing htlc.
const invoiceAmt = 100000
var preimage lntypes.Preimage
copy(preimage[:], ht.Random32Bytes())
payHash := preimage.Hash()
invoiceReq := &invoicesrpc.AddHoldInvoiceRequest{
Value: invoiceAmt,
CltvExpiry: finalCltvDelta,
Hash: payHash[:],
RouteHints: routeHints,
}
carolInvoice := carol.RPC.AddHoldInvoice(invoiceReq)
// Subscribe the invoice.
stream := carol.RPC.SubscribeSingleInvoice(payHash[:])
// Now that we've created the invoice, we'll send a single payment from
// Alice to Carol. We won't wait for the response however, as Carol
// will not immediately settle the payment.
req := &routerrpc.SendPaymentRequest{
PaymentRequest: carolInvoice.PaymentRequest,
TimeoutSeconds: 60,
FeeLimitMsat: noFeeLimitMsat,
}
alice.RPC.SendPayment(req)
// At this point, all 3 nodes should now have an active channel with
// the created HTLC pending on all of them.
ht.AssertActiveHtlcs(alice, payHash[:])
ht.AssertActiveHtlcs(bob, payHash[:])
ht.AssertActiveHtlcs(carol, payHash[:])
// Wait for carol to mark invoice as accepted. There is a small gap to
// bridge between adding the htlc to the channel and executing the exit
// hop logic.
ht.AssertInvoiceState(stream, lnrpc.Invoice_ACCEPTED)
restartBob := ht.SuspendNode(bob)
// Settle invoice. This will just mark the invoice as settled, as there
// is no link anymore to remove the htlc from the commitment tx. For
// this test, it is important to actually settle and not leave the
// invoice in the accepted state, because without a known preimage, the
// channel arbitrator won't go to chain.
carol.RPC.SettleInvoice(preimage[:])
// Increase the fee estimate so that the following force close tx will
// be cpfp'ed.
ht.SetFeeEstimate(30000)
// We now advance the block height to the point where Carol will force
// close her channel with Bob, broadcast the closing tx but keep it
// unconfirmed.
numBlocks := padCLTV(uint32(
invoiceReq.CltvExpiry - lncfg.DefaultIncomingBroadcastDelta,
))
// Now we'll mine enough blocks to prompt carol to actually go to the
// chain in order to sweep her HTLC since the value is high enough.
ht.MineBlocks(numBlocks)
// At this point, Carol should broadcast her active commitment
// transaction in order to go to the chain and sweep her HTLC. If there
// are anchors, Carol also sweeps hers.
expectedTxes := 1
hasAnchors := lntest.CommitTypeHasAnchors(c)
if hasAnchors {
expectedTxes = 2
}
ht.Miner.AssertNumTxsInMempool(expectedTxes)
closingTx := ht.Miner.AssertOutpointInMempool(
ht.OutPointFromChannelPoint(bobChanPoint),
)
closingTxid := closingTx.TxHash()
// Confirm the commitment.
ht.MineBlocksAndAssertNumTxes(1, expectedTxes)
// Restart bob again.
require.NoError(ht, restartBob())
// After the force close transaction is mined, a series of transactions
// should be broadcast by Bob and Carol. When Bob notices Carol's second
// level transaction in the mempool, he will extract the preimage and
// settle the HTLC back off-chain.
switch c {
// Carol should broadcast her second level HTLC transaction and Bob
// should broadcast a sweep tx to sweep his output in the channel with
// Carol.
case lnrpc.CommitmentType_LEGACY:
expectedTxes = 2
// Carol should broadcast her second level HTLC transaction and Bob
// should broadcast a sweep tx to sweep his output in the channel with
// Carol, and another sweep tx to sweep his anchor output.
case lnrpc.CommitmentType_ANCHORS, lnrpc.CommitmentType_SIMPLE_TAPROOT:
expectedTxes = 3
// Carol should broadcast her second level HTLC transaction and Bob
// should broadcast a sweep tx to sweep his anchor output. Bob's commit
// output can't be swept yet as he's incurring an additional CLTV from
// being the channel initiator of a script-enforced leased channel.
case lnrpc.CommitmentType_SCRIPT_ENFORCED_LEASE:
expectedTxes = 2
default:
ht.Fatalf("unhandled commitment type %v", c)
}
// All transactions should be spending from the commitment transaction.
txes := ht.Miner.GetNumTxsFromMempool(expectedTxes)
ht.AssertAllTxesSpendFrom(txes, closingTxid)
// We'll now mine an additional block which should confirm both the
// second layer transactions.
ht.MineBlocksAndAssertNumTxes(1, expectedTxes)
// Carol's pending channel report should now show two outputs under
// limbo: her commitment output, as well as the second-layer claim
// output, and the pending HTLC should also now be in stage 2.
ht.AssertNumHTLCsAndStage(carol, bobChanPoint, 1, 2)
// Once the second-level transaction confirmed, Bob should have
// extracted the preimage from the chain, and sent it back to Alice,
// clearing the HTLC off-chain.
ht.AssertNumActiveHtlcs(alice, 0)
// If we mine 4 additional blocks, then Carol can sweep the second
// level HTLC output once the CSV expires.
ht.MineEmptyBlocks(defaultCSV)
// We should have a new transaction in the mempool.
ht.Miner.AssertNumTxsInMempool(1)
// Finally, if we mine an additional block to confirm Carol's second
// level success transaction. Carol should not show a pending channel
// in her report afterwards.
ht.MineBlocks(1)
ht.AssertNumPendingForceClose(carol, 0)
// The invoice should show as settled for Carol, indicating that it was
// swept on-chain.
ht.AssertInvoiceSettled(carol, carolInvoice.PaymentAddr)
// Finally, check that the Alice's payment is correctly marked
// succeeded.
ht.AssertPaymentStatus(alice, preimage, lnrpc.Payment_SUCCEEDED)
if c == lnrpc.CommitmentType_SCRIPT_ENFORCED_LEASE {
// Bob still has his commit output to sweep to since he incurred
// an additional CLTV from being the channel initiator of a
// script-enforced leased channel, regardless of whether he
// forced closed the channel or not.
pendingChanResp := bob.RPC.PendingChannels()
require.Len(ht, pendingChanResp.PendingForceClosingChannels, 1)
forceCloseChan := pendingChanResp.PendingForceClosingChannels[0]
require.Positive(ht, forceCloseChan.LimboBalance)
require.Positive(ht, forceCloseChan.BlocksTilMaturity)
// TODO: Bob still shows a pending HTLC at this point when he
// shouldn't, as he already extracted the preimage from Carol's
// claim.
// require.Len(t.t, forceCloseChan.PendingHtlcs, 0)
// Mine enough blocks for Bob's commit output's CLTV to expire
// and sweep it.
numBlocks := uint32(forceCloseChan.BlocksTilMaturity)
ht.MineBlocks(numBlocks)
commitOutpoint := wire.OutPoint{Hash: closingTxid, Index: 3}
ht.Miner.AssertOutpointInMempool(commitOutpoint)
ht.MineBlocks(1)
}
ht.AssertNumPendingForceClose(bob, 0)
// We'll close out the channel between Alice and Bob, then shutdown
// carol to conclude the test.
ht.CloseChannel(alice, aliceChanPoint)
}
// testMultiHopLocalForceCloseOnChainHtlcTimeout tests that in a multi-hop HTLC
// scenario, if the node that extended the HTLC to the final node closes their
// commitment on-chain early, then it eventually recognizes this HTLC as one
// that's timed out. At this point, the node should timeout the HTLC using the
// HTLC timeout transaction, then cancel it backwards as normal.
func testMultiHopLocalForceCloseOnChainHtlcTimeout(ht *lntest.HarnessTest) {
runMultiHopHtlcClaimTest(
ht, runMultiHopLocalForceCloseOnChainHtlcTimeout,
)
}
func runMultiHopLocalForceCloseOnChainHtlcTimeout(ht *lntest.HarnessTest,
alice, bob *node.HarnessNode, c lnrpc.CommitmentType, zeroConf bool) {
// First, we'll create a three hop network: Alice -> Bob -> Carol, with
// Carol refusing to actually settle or directly cancel any HTLC's
// self.
aliceChanPoint, bobChanPoint, carol := createThreeHopNetwork(
ht, alice, bob, true, c, zeroConf,
)
// With our channels set up, we'll then send a single HTLC from Alice
// to Carol. As Carol is in hodl mode, she won't settle this HTLC which
// opens up the base for out tests.
const htlcAmt = btcutil.Amount(300_000)
// If this is a taproot channel, then we'll need to make some manual
// route hints so Alice can actually find a route.
var routeHints []*lnrpc.RouteHint
if c == lnrpc.CommitmentType_SIMPLE_TAPROOT {
routeHints = makeRouteHints(bob, carol, zeroConf)
}
// We'll now send a single HTLC across our multi-hop network.
carolPubKey := carol.PubKey[:]
payHash := ht.Random32Bytes()
req := &routerrpc.SendPaymentRequest{
Dest: carolPubKey,
Amt: int64(htlcAmt),
PaymentHash: payHash,
FinalCltvDelta: finalCltvDelta,
TimeoutSeconds: 60,
FeeLimitMsat: noFeeLimitMsat,
RouteHints: routeHints,
}
alice.RPC.SendPayment(req)
// Once the HTLC has cleared, all channels in our mini network should
// have the it locked in.
ht.AssertActiveHtlcs(alice, payHash)
ht.AssertActiveHtlcs(bob, payHash)
ht.AssertActiveHtlcs(carol, payHash)
// blocksMined records how many blocks have mined after the creation of
// the invoice so it can be used to calculate how many more blocks need
// to be mined to trigger a force close later on.
var blocksMined uint32
// Increase the fee estimate so that the following force close tx will
// be cpfp'ed.
ht.SetFeeEstimate(30000)
// Now that all parties have the HTLC locked in, we'll immediately
// force close the Bob -> Carol channel. This should trigger contract
// resolution mode for both of them.
hasAnchors := lntest.CommitTypeHasAnchors(c)
stream, _ := ht.CloseChannelAssertPending(bob, bobChanPoint, true)
closeTx := ht.AssertStreamChannelForceClosed(
bob, bobChanPoint, hasAnchors, stream,
)
// Increase the blocks mined. At this step
// AssertStreamChannelForceClosed mines one block.
blocksMined++
// If the channel closed has anchors, we should expect to see a sweep
// transaction for Carol's anchor.
htlcOutpoint := wire.OutPoint{Hash: *closeTx, Index: 0}
bobCommitOutpoint := wire.OutPoint{Hash: *closeTx, Index: 1}
if hasAnchors {
htlcOutpoint.Index = 2
bobCommitOutpoint.Index = 3
ht.Miner.AssertNumTxsInMempool(1)
}
// Before the HTLC times out, we'll need to assert that Bob broadcasts a
// sweep transaction for his commit output. Note that if the channel has
// a script-enforced lease, then Bob will have to wait for an additional
// CLTV before sweeping it.
if c != lnrpc.CommitmentType_SCRIPT_ENFORCED_LEASE {
// The sweep is broadcast on the block immediately before the
// CSV expires and the commitment was already mined inside
// AssertStreamChannelForceClosed(), so mine one block less
// than defaultCSV in order to perform mempool assertions.
ht.MineBlocks(defaultCSV - 1)
commitSweepTx := ht.Miner.AssertOutpointInMempool(
bobCommitOutpoint,
)
txid := commitSweepTx.TxHash()
block := ht.MineBlocksAndAssertNumTxes(1, 1)[0]
ht.Miner.AssertTxInBlock(block, &txid)
blocksMined += defaultCSV
}
// We'll now mine enough blocks for the HTLC to expire. After this, Bob
// should hand off the now expired HTLC output to the utxo nursery.
numBlocks := padCLTV(uint32(finalCltvDelta) -
lncfg.DefaultOutgoingBroadcastDelta)
ht.MineBlocks(numBlocks - blocksMined)
// Bob's pending channel report should show that he has a single HTLC
// that's now in stage one.
ht.AssertNumHTLCsAndStage(bob, bobChanPoint, 1, 1)
// We should also now find a transaction in the mempool, as Bob should
// have broadcast his second layer timeout transaction.
timeoutTx := ht.Miner.AssertOutpointInMempool(htlcOutpoint).TxHash()
// Next, we'll mine an additional block. This should serve to confirm
// the second layer timeout transaction.
block := ht.MineBlocksAndAssertNumTxes(1, 1)[0]
ht.Miner.AssertTxInBlock(block, &timeoutTx)
// With the second layer timeout transaction confirmed, Bob should have
// canceled backwards the HTLC that carol sent.
ht.AssertNumActiveHtlcs(bob, 0)
// Additionally, Bob should now show that HTLC as being advanced to the
// second stage.
ht.AssertNumHTLCsAndStage(bob, bobChanPoint, 1, 2)
// Bob should now broadcast a transaction that sweeps certain inputs
// depending on the commitment type. We'll need to mine some blocks
// before the broadcast is possible.
resp := bob.RPC.PendingChannels()
require.Len(ht, resp.PendingForceClosingChannels, 1)
forceCloseChan := resp.PendingForceClosingChannels[0]
require.Len(ht, forceCloseChan.PendingHtlcs, 1)
pendingHtlc := forceCloseChan.PendingHtlcs[0]
require.Positive(ht, pendingHtlc.BlocksTilMaturity)
numBlocks = uint32(pendingHtlc.BlocksTilMaturity)
ht.MineBlocks(numBlocks)
// Now that the CSV/CLTV timelock has expired, the transaction should
// either only sweep the HTLC timeout transaction, or sweep both the
// HTLC timeout transaction and Bob's commit output depending on the
// commitment type.
htlcTimeoutOutpoint := wire.OutPoint{Hash: timeoutTx, Index: 0}
sweepTx := ht.Miner.AssertOutpointInMempool(
htlcTimeoutOutpoint,
).TxHash()
if c == lnrpc.CommitmentType_SCRIPT_ENFORCED_LEASE {
ht.Miner.AssertOutpointInMempool(bobCommitOutpoint)
}
block = ht.MineBlocksAndAssertNumTxes(1, 1)[0]
ht.Miner.AssertTxInBlock(block, &sweepTx)
// At this point, Bob should no longer show any channels as pending
// close.
ht.AssertNumPendingForceClose(bob, 0)
// Coop close, no anchors.
ht.CloseChannel(alice, aliceChanPoint)
}
// testMultiHopRemoteForceCloseOnChainHtlcTimeout tests that if we extend a
// multi-hop HTLC, and the final destination of the HTLC force closes the
// channel, then we properly timeout the HTLC directly on *their* commitment
// transaction once the timeout has expired. Once we sweep the transaction, we
// should also cancel back the initial HTLC.
func testMultiHopRemoteForceCloseOnChainHtlcTimeout(ht *lntest.HarnessTest) {
runMultiHopHtlcClaimTest(
ht, runMultiHopRemoteForceCloseOnChainHtlcTimeout,
)
}
func runMultiHopRemoteForceCloseOnChainHtlcTimeout(ht *lntest.HarnessTest,
alice, bob *node.HarnessNode, c lnrpc.CommitmentType, zeroConf bool) {
// First, we'll create a three hop network: Alice -> Bob -> Carol, with
// Carol refusing to actually settle or directly cancel any HTLC's
// self.
aliceChanPoint, bobChanPoint, carol := createThreeHopNetwork(
ht, alice, bob, true, c, zeroConf,
)
// With our channels set up, we'll then send a single HTLC from Alice
// to Carol. As Carol is in hodl mode, she won't settle this HTLC which
// opens up the base for out tests.
const htlcAmt = btcutil.Amount(30000)
// If this is a taproot channel, then we'll need to make some manual
// route hints so Alice can actually find a route.
var routeHints []*lnrpc.RouteHint
if c == lnrpc.CommitmentType_SIMPLE_TAPROOT {
routeHints = makeRouteHints(bob, carol, zeroConf)
}
// We'll now send a single HTLC across our multi-hop network.
var preimage lntypes.Preimage
copy(preimage[:], ht.Random32Bytes())
payHash := preimage.Hash()
invoiceReq := &invoicesrpc.AddHoldInvoiceRequest{
Value: int64(htlcAmt),
CltvExpiry: finalCltvDelta,
Hash: payHash[:],
RouteHints: routeHints,
}
carolInvoice := carol.RPC.AddHoldInvoice(invoiceReq)
// Subscribe the invoice.
stream := carol.RPC.SubscribeSingleInvoice(payHash[:])
req := &routerrpc.SendPaymentRequest{
PaymentRequest: carolInvoice.PaymentRequest,
TimeoutSeconds: 60,
FeeLimitMsat: noFeeLimitMsat,
}
alice.RPC.SendPayment(req)
// blocksMined records how many blocks have mined after the creation of
// the invoice so it can be used to calculate how many more blocks need
// to be mined to trigger a force close later on.
var blocksMined uint32
// Once the HTLC has cleared, all the nodes in our mini network should
// show that the HTLC has been locked in.
ht.AssertActiveHtlcs(alice, payHash[:])
ht.AssertActiveHtlcs(bob, payHash[:])
ht.AssertActiveHtlcs(carol, payHash[:])
// At this point, we'll now instruct Carol to force close the
// transaction. This will let us exercise that Bob is able to sweep the
// expired HTLC on Carol's version of the commitment transaction.
closeStream, _ := ht.CloseChannelAssertPending(
carol, bobChanPoint, true,
)
// For anchor channels, the anchor won't be used for CPFP because
// channel arbitrator thinks Carol doesn't have preimage for her
// incoming HTLC on the commitment transaction Bob->Carol. Although
// Carol created this invoice, because it's a hold invoice, the
// preimage won't be generated automatically.
hasAnchorSweep := false
closeTx := ht.AssertStreamChannelForceClosed(
carol, bobChanPoint, hasAnchorSweep, closeStream,
)
// Increase the blocks mined. At this step
// AssertStreamChannelForceClosed mines one block.
blocksMined++
// At this point, Bob should have a pending force close channel as
// Carol has gone directly to chain.
ht.AssertNumPendingForceClose(bob, 1)
var expectedTxes int
switch c {
// Bob can sweep his commit output immediately.
case lnrpc.CommitmentType_LEGACY:
expectedTxes = 1
// Bob can sweep his commit and anchor outputs immediately. Carol will
// also sweep her anchor.
case lnrpc.CommitmentType_ANCHORS, lnrpc.CommitmentType_SIMPLE_TAPROOT:
expectedTxes = 3
// Bob can't sweep his commit output yet as he was the initiator of a
// script-enforced leased channel, so he'll always incur the additional
// CLTV. He can still sweep his anchor output however.
case lnrpc.CommitmentType_SCRIPT_ENFORCED_LEASE:
expectedTxes = 2
default:
ht.Fatalf("unhandled commitment type %v", c)
}
// We now mine a block to clear up the mempool.
ht.MineBlocksAndAssertNumTxes(1, expectedTxes)
blocksMined++
// Next, we'll mine enough blocks for the HTLC to expire. At this
// point, Bob should hand off the output to his internal utxo nursery,
// which will broadcast a sweep transaction.
numBlocks := padCLTV(uint32(finalCltvDelta) -
lncfg.DefaultOutgoingBroadcastDelta)
ht.MineBlocks(numBlocks - blocksMined)
// If we check Bob's pending channel report, it should show that he has
// a single HTLC that's now in the second stage, as it skipped the
// initial first stage since this is a direct HTLC.
ht.AssertNumHTLCsAndStage(bob, bobChanPoint, 1, 2)
// We need to generate an additional block to trigger the sweep.
ht.MineBlocks(1)
// Bob's sweeping transaction should now be found in the mempool at
// this point.
sweepTx := ht.Miner.AssertNumTxsInMempool(1)[0]
// If we mine an additional block, then this should confirm Bob's
// transaction which sweeps the direct HTLC output.
block := ht.MineBlocksAndAssertNumTxes(1, 1)[0]
ht.Miner.AssertTxInBlock(block, sweepTx)
// Now that the sweeping transaction has been confirmed, Bob should
// cancel back that HTLC. As a result, Alice should not know of any
// active HTLC's.
ht.AssertNumActiveHtlcs(alice, 0)
// Now we'll check Bob's pending channel report. Since this was Carol's
// commitment, he doesn't have to wait for any CSV delays, but he may
// still need to wait for a CLTV on his commit output to expire
// depending on the commitment type.
if c == lnrpc.CommitmentType_SCRIPT_ENFORCED_LEASE {
resp := bob.RPC.PendingChannels()
require.Len(ht, resp.PendingForceClosingChannels, 1)
forceCloseChan := resp.PendingForceClosingChannels[0]
require.Positive(ht, forceCloseChan.BlocksTilMaturity)
numBlocks := uint32(forceCloseChan.BlocksTilMaturity)
ht.MineBlocks(numBlocks)
bobCommitOutpoint := wire.OutPoint{Hash: *closeTx, Index: 3}
bobCommitSweep := ht.Miner.AssertOutpointInMempool(
bobCommitOutpoint,
)
bobCommitSweepTxid := bobCommitSweep.TxHash()
block := ht.MineBlocksAndAssertNumTxes(1, 1)[0]
ht.Miner.AssertTxInBlock(block, &bobCommitSweepTxid)
}
ht.AssertNumPendingForceClose(bob, 0)
// While we're here, we assert that our expired invoice's state is
// correctly updated, and can no longer be settled.
ht.AssertInvoiceState(stream, lnrpc.Invoice_CANCELED)
// We'll close out the test by closing the channel from Alice to Bob,
// and then shutting down the new node we created as its no longer
// needed. Coop close, no anchors.
ht.CloseChannel(alice, aliceChanPoint)
}
// testMultiHopHtlcLocalChainClaim tests that in a multi-hop HTLC scenario, if
// we force close a channel with an incoming HTLC, and later find out the
// preimage via the witness beacon, we properly settle the HTLC on-chain using
// the HTLC success transaction in order to ensure we don't lose any funds.
func testMultiHopHtlcLocalChainClaim(ht *lntest.HarnessTest) {
runMultiHopHtlcClaimTest(ht, runMultiHopHtlcLocalChainClaim)
}
func runMultiHopHtlcLocalChainClaim(ht *lntest.HarnessTest,
alice, bob *node.HarnessNode, c lnrpc.CommitmentType, zeroConf bool) {
// First, we'll create a three hop network: Alice -> Bob -> Carol, with
// Carol refusing to actually settle or directly cancel any HTLC's
// self.
aliceChanPoint, bobChanPoint, carol := createThreeHopNetwork(
ht, alice, bob, false, c, zeroConf,
)
// If this is a taproot channel, then we'll need to make some manual
// route hints so Alice can actually find a route.
var routeHints []*lnrpc.RouteHint
if c == lnrpc.CommitmentType_SIMPLE_TAPROOT {
routeHints = makeRouteHints(bob, carol, zeroConf)
}
// With the network active, we'll now add a new hodl invoice at Carol's
// end. Make sure the cltv expiry delta is large enough, otherwise Bob
// won't send out the outgoing htlc.
const invoiceAmt = 100000
var preimage lntypes.Preimage
copy(preimage[:], ht.Random32Bytes())
payHash := preimage.Hash()
invoiceReq := &invoicesrpc.AddHoldInvoiceRequest{
Value: invoiceAmt,
CltvExpiry: finalCltvDelta,
Hash: payHash[:],
RouteHints: routeHints,
}
carolInvoice := carol.RPC.AddHoldInvoice(invoiceReq)
// Subscribe the invoice.
stream := carol.RPC.SubscribeSingleInvoice(payHash[:])
// Now that we've created the invoice, we'll send a single payment from
// Alice to Carol. We won't wait for the response however, as Carol
// will not immediately settle the payment.
req := &routerrpc.SendPaymentRequest{
PaymentRequest: carolInvoice.PaymentRequest,
TimeoutSeconds: 60,
FeeLimitMsat: noFeeLimitMsat,
}
alice.RPC.SendPayment(req)
// At this point, all 3 nodes should now have an active channel with
// the created HTLC pending on all of them.
ht.AssertActiveHtlcs(alice, payHash[:])
ht.AssertActiveHtlcs(bob, payHash[:])
ht.AssertActiveHtlcs(carol, payHash[:])
// Wait for carol to mark invoice as accepted. There is a small gap to
// bridge between adding the htlc to the channel and executing the exit
// hop logic.
ht.AssertInvoiceState(stream, lnrpc.Invoice_ACCEPTED)
// blocksMined records how many blocks have mined after the creation of
// the invoice so it can be used to calculate how many more blocks need
// to be mined to trigger a force close later on.
var blocksMined uint32
// At this point, Bob decides that he wants to exit the channel
// immediately, so he force closes his commitment transaction.
closeStream, _ := ht.CloseChannelAssertPending(
bob, aliceChanPoint, true,
)
// For anchor channels, the anchor won't be used for CPFP as there's no
// deadline pressure for Bob on the channel Alice->Bob at the moment.
// For Bob's local commitment tx, there's only one incoming HTLC which
// he doesn't have the preimage yet. Thus this anchor won't be
// force-swept.
hasAnchorSweep := false
bobForceClose := ht.AssertStreamChannelForceClosed(
bob, aliceChanPoint, hasAnchorSweep, closeStream,
)
// Increase the blocks mined. At this step
// AssertStreamChannelForceClosed mines one block.
blocksMined++
var expectedTxes int
switch c {
// Alice will sweep her commitment output immediately.
case lnrpc.CommitmentType_LEGACY:
expectedTxes = 1
// Alice will sweep her commitment and anchor output immediately. Bob
// will also sweep his anchor.
case lnrpc.CommitmentType_ANCHORS, lnrpc.CommitmentType_SIMPLE_TAPROOT:
expectedTxes = 3
// Alice will sweep her anchor output immediately. Her commitment
// output cannot be swept yet as it has incurred an additional CLTV due
// to being the initiator of a script-enforced leased channel.