lnd.xprv/lntest/itest/lnd_multi-hop_htlc_remote_chain_claim_test.go
2021-04-05 15:41:04 -07:00

276 lines
9.5 KiB
Go

package itest
import (
"context"
"github.com/btcsuite/btcd/wire"
"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/wait"
"github.com/lightningnetwork/lnd/lntypes"
"github.com/stretchr/testify/require"
)
// testMultiHopHtlcRemoteChainClaim tests that in the multi-hop HTLC scenario,
// if the remote party goes to chain while we have an incoming HTLC, then when
// we found out the preimage via the witness beacon, we properly settle the
// HTLC directly on-chain using the preimage in order to ensure that we don't
// lose any funds.
func testMultiHopHtlcRemoteChainClaim(net *lntest.NetworkHarness, t *harnessTest,
alice, bob *lntest.HarnessNode, c commitType) {
ctxb := context.Background()
// 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(
t, net, alice, bob, false, c,
)
// Clean up carol's node when the test finishes.
defer shutdownAndAssert(net, t, carol)
// 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
preimage := lntypes.Preimage{1, 2, 5}
payHash := preimage.Hash()
invoiceReq := &invoicesrpc.AddHoldInvoiceRequest{
Value: invoiceAmt,
CltvExpiry: 40,
Hash: payHash[:],
}
ctxt, cancel := context.WithTimeout(ctxb, defaultTimeout)
defer cancel()
carolInvoice, err := carol.AddHoldInvoice(ctxt, invoiceReq)
require.NoError(t.t, err)
// 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.
ctx, cancel := context.WithCancel(ctxb)
defer cancel()
_, err = alice.RouterClient.SendPaymentV2(
ctx, &routerrpc.SendPaymentRequest{
PaymentRequest: carolInvoice.PaymentRequest,
TimeoutSeconds: 60,
FeeLimitMsat: noFeeLimitMsat,
},
)
require.NoError(t.t, err)
// At this point, all 3 nodes should now have an active channel with
// the created HTLC pending on all of them.
nodes := []*lntest.HarnessNode{alice, bob, carol}
err = wait.NoError(func() error {
return assertActiveHtlcs(nodes, payHash[:])
}, defaultTimeout)
require.NoError(t.t, err)
// 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.
waitForInvoiceAccepted(t, carol, payHash)
// Increase the fee estimate so that the following force close tx will
// be cpfp'ed.
net.SetFeeEstimate(30000)
// Next, Alice decides that she wants to exit the channel, so she'll
// immediately force close the channel by broadcast her commitment
// transaction.
ctxt, _ = context.WithTimeout(ctxb, channelCloseTimeout)
aliceForceClose := closeChannelAndAssertType(
ctxt, t, net, alice, aliceChanPoint, c == commitTypeAnchors,
true,
)
// Wait for the channel to be marked pending force close.
ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
err = waitForChannelPendingForceClose(ctxt, alice, aliceChanPoint)
require.NoError(t.t, err)
// After closeChannelAndAssertType returns, it has mined a block so now
// bob will attempt to redeem his anchor commitment (if the channel
// type is of that type).
if c == commitTypeAnchors {
_, err = waitForNTxsInMempool(
net.Miner.Client, 1, minerMempoolTimeout,
)
if err != nil {
t.Fatalf("unable to find bob's anchor commit sweep: %v",
err)
}
}
// Mine enough blocks for Alice to sweep her funds from the force
// closed channel. closeChannelAndAssertType() already mined a block
// containing the commitment tx and the commit sweep tx will be
// broadcast immediately before it can be included in a block, so mine
// one less than defaultCSV in order to perform mempool assertions.
_, err = net.Miner.Client.Generate(defaultCSV - 1)
require.NoError(t.t, err)
// Alice should now sweep her funds.
_, err = waitForNTxsInMempool(
net.Miner.Client, 1, minerMempoolTimeout,
)
require.NoError(t.t, err)
// Suspend bob, so Carol is forced to go on chain.
restartBob, err := net.SuspendNode(bob)
require.NoError(t.t, err)
// 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.
ctx, cancel = context.WithTimeout(ctxb, defaultTimeout)
defer cancel()
_, err = carol.SettleInvoice(ctx, &invoicesrpc.SettleInvoiceMsg{
Preimage: preimage[:],
})
require.NoError(t.t, err)
// We'll now mine enough blocks so Carol decides that she needs to go
// on-chain to claim the HTLC as Bob has been inactive.
numBlocks := padCLTV(uint32(
invoiceReq.CltvExpiry-lncfg.DefaultIncomingBroadcastDelta,
) - defaultCSV)
_, err = net.Miner.Client.Generate(numBlocks)
require.NoError(t.t, err)
expectedTxes := 1
if c == commitTypeAnchors {
expectedTxes = 2
}
// Carol's commitment transaction should now be in the mempool. If
// there are anchors, Carol also sweeps her anchor.
_, err = waitForNTxsInMempool(
net.Miner.Client, expectedTxes, minerMempoolTimeout,
)
require.NoError(t.t, err)
bobFundingTxid, err := lnrpc.GetChanPointFundingTxid(bobChanPoint)
require.NoError(t.t, err)
carolFundingPoint := wire.OutPoint{
Hash: *bobFundingTxid,
Index: bobChanPoint.OutputIndex,
}
// The closing transaction should be spending from the funding
// transaction.
closingTx := getSpendingTxInMempool(
t, net.Miner.Client, minerMempoolTimeout, carolFundingPoint,
)
closingTxid := closingTx.TxHash()
// Mine a block, which should contain: the commitment, possibly an
// anchor sweep and the coinbase tx.
block := mineBlocks(t, net, 1, expectedTxes)[0]
require.Len(t.t, block.Transactions, expectedTxes+1)
assertTxInBlock(t, block, &closingTxid)
// Restart bob again.
err = restartBob()
require.NoError(t.t, err)
// After the force close transacion is mined, Carol should broadcast her
// second level HTLC transacion. Bob will broadcast a sweep tx to sweep
// his output in the channel with Carol. He can do this immediately, as
// the output is not timelocked since Carol was the one force closing.
// If there are anchors, Bob should also sweep his.
expectedTxes = 2
if c == commitTypeAnchors {
expectedTxes = 3
}
txes, err := getNTxsFromMempool(
net.Miner.Client, expectedTxes, minerMempoolTimeout,
)
require.NoError(t.t, err)
// All transactions should be pending from the commitment transaction.
assertAllTxesSpendFrom(t, txes, closingTxid)
// Mine a block to confirm the two transactions (+ coinbase).
block = mineBlocks(t, net, 1, expectedTxes)[0]
require.Len(t.t, block.Transactions, expectedTxes+1)
// Keep track of the second level tx maturity.
carolSecondLevelCSV := uint32(defaultCSV)
// When Bob notices Carol's second level transaction in the block, he
// will extract the preimage and broadcast a sweep tx to directly claim
// the HTLC in his (already closed) channel with Alice.
bobHtlcSweep, err := waitForTxInMempool(
net.Miner.Client, minerMempoolTimeout,
)
require.NoError(t.t, err)
// It should spend from the commitment in the channel with Alice.
tx, err := net.Miner.Client.GetRawTransaction(bobHtlcSweep)
require.NoError(t.t, err)
require.Equal(
t.t, *aliceForceClose, tx.MsgTx().TxIn[0].PreviousOutPoint.Hash,
)
// We'll now mine a block which should confirm Bob's HTLC sweep
// transaction.
block = mineBlocks(t, net, 1, 1)[0]
require.Len(t.t, block.Transactions, 2)
assertTxInBlock(t, block, bobHtlcSweep)
carolSecondLevelCSV--
// Now that the sweeping transaction has been confirmed, Bob should now
// recognize that all contracts have been fully resolved, and show no
// pending close channels.
ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
err = waitForNumChannelPendingForceClose(ctxt, bob, 0, nil)
require.NoError(t.t, err)
// If we then mine 3 additional blocks, Carol's second level tx will
// mature, and she should pull the funds.
_, err = net.Miner.Client.Generate(carolSecondLevelCSV)
require.NoError(t.t, err)
carolSweep, err := waitForTxInMempool(
net.Miner.Client, minerMempoolTimeout,
)
require.NoError(t.t, err)
// When Carol's sweep gets confirmed, she should have no more pending
// channels.
block = mineBlocks(t, net, 1, 1)[0]
assertTxInBlock(t, block, carolSweep)
ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
err = waitForNumChannelPendingForceClose(ctxt, carol, 0, nil)
require.NoError(t.t, err)
// The invoice should show as settled for Carol, indicating that it was
// swept on-chain.
invoicesReq := &lnrpc.ListInvoiceRequest{}
invoicesResp, err := carol.ListInvoices(ctxb, invoicesReq)
require.NoError(t.t, err)
require.Len(t.t, invoicesResp.Invoices, 1)
invoice := invoicesResp.Invoices[0]
require.Equal(t.t, lnrpc.Invoice_SETTLED, invoice.State)
require.Equal(t.t, int64(invoiceAmt), invoice.AmtPaidSat)
// Finally, check that the Alice's payment is correctly marked
// succeeded.
ctxt, _ = context.WithTimeout(ctxt, defaultTimeout)
err = checkPaymentStatus(
ctxt, alice, preimage, lnrpc.Payment_SUCCEEDED,
)
require.NoError(t.t, err)
}