lnd.xprv/lntest/itest/psbt.go

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// +build rpctest
package itest
import (
"bytes"
"context"
"crypto/rand"
"fmt"
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"github.com/btcsuite/btcd/wire"
"github.com/btcsuite/btcutil"
"github.com/btcsuite/btcutil/psbt"
"github.com/lightningnetwork/lnd"
"github.com/lightningnetwork/lnd/lnrpc"
"github.com/lightningnetwork/lnd/lntest"
)
// testPsbtChanFunding makes sure a channel can be opened between carol and dave
// by using a Partially Signed Bitcoin Transaction that funds the channel
// multisig funding output.
func testPsbtChanFunding(net *lntest.NetworkHarness, t *harnessTest) {
ctxb := context.Background()
const chanSize = lnd.MaxBtcFundingAmount
// First, we'll create two new nodes that we'll use to open channel
// between for this test.
carol, err := net.NewNode("carol", nil)
if err != nil {
t.Fatalf("unable to start new node: %v", err)
}
defer shutdownAndAssert(net, t, carol)
dave, err := net.NewNode("dave", nil)
if err != nil {
t.Fatalf("unable to start new node: %v", err)
}
defer shutdownAndAssert(net, t, dave)
// Before we start the test, we'll ensure both sides are connected so
// the funding flow can be properly executed.
ctxt, cancel := context.WithTimeout(ctxb, defaultTimeout)
defer cancel()
err = net.EnsureConnected(ctxt, carol, dave)
if err != nil {
t.Fatalf("unable to connect peers: %v", err)
}
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err = net.EnsureConnected(ctxt, carol, net.Alice)
if err != nil {
t.Fatalf("unable to connect peers: %v", err)
}
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// At this point, we can begin our PSBT channel funding workflow. We'll
// start by generating a pending channel ID externally that will be used
// to track this new funding type.
var pendingChanID [32]byte
if _, err := rand.Read(pendingChanID[:]); err != nil {
t.Fatalf("unable to gen pending chan ID: %v", err)
}
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// We'll also test batch funding of two channels so we need another ID.
var pendingChanID2 [32]byte
if _, err := rand.Read(pendingChanID2[:]); err != nil {
t.Fatalf("unable to gen pending chan ID: %v", err)
}
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// Now that we have the pending channel ID, Carol will open the channel
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// by specifying a PSBT shim. We use the NoPublish flag here to avoid
// publishing the whole batch TX too early.
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ctxt, cancel = context.WithTimeout(ctxb, defaultTimeout)
defer cancel()
chanUpdates, psbtBytes, err := openChannelPsbt(
ctxt, carol, dave, lntest.OpenChannelParams{
Amt: chanSize,
FundingShim: &lnrpc.FundingShim{
Shim: &lnrpc.FundingShim_PsbtShim{
PsbtShim: &lnrpc.PsbtShim{
PendingChanId: pendingChanID[:],
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NoPublish: true,
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},
},
},
},
)
if err != nil {
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t.Fatalf("unable to open channel to dave: %v", err)
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}
packet, err := psbt.NewFromRawBytes(bytes.NewReader(psbtBytes), false)
if err != nil {
t.Fatalf("unable to parse returned PSBT: %v", err)
}
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// Let's add a second channel to the batch. This time between carol and
// alice. We will the batch TX once this channel funding is complete.
ctxt, cancel = context.WithTimeout(ctxb, defaultTimeout)
defer cancel()
chanUpdates2, psbtBytes2, err := openChannelPsbt(
ctxt, carol, net.Alice, lntest.OpenChannelParams{
Amt: chanSize,
FundingShim: &lnrpc.FundingShim{
Shim: &lnrpc.FundingShim_PsbtShim{
PsbtShim: &lnrpc.PsbtShim{
PendingChanId: pendingChanID2[:],
NoPublish: false,
},
},
},
},
)
if err != nil {
t.Fatalf("unable to open channel to alice: %v", err)
}
packet2, err := psbt.NewFromRawBytes(bytes.NewReader(psbtBytes2), false)
if err != nil {
t.Fatalf("unable to parse returned PSBT: %v", err)
}
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// We'll now create a fully signed transaction that sends to the outputs
// encoded in the PSBT. We'll let the miner do it and convert the final
// TX into a PSBT, that's way easier than assembling a PSBT manually.
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allOuts := append(packet.UnsignedTx.TxOut, packet2.UnsignedTx.TxOut...)
tx, err := net.Miner.CreateTransaction(allOuts, 5, true)
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if err != nil {
t.Fatalf("unable to create funding transaction: %v", err)
}
// The helper function splits the final TX into the non-witness data
// encoded in a PSBT and the witness data returned separately.
unsignedPsbt, scripts, witnesses, err := createPsbtFromSignedTx(tx)
if err != nil {
t.Fatalf("unable to convert funding transaction into PSBT: %v",
err)
}
// The PSBT will also be checked if there are large enough inputs
// present. We need to add some fake UTXO information to the PSBT to
// tell it what size of inputs we have.
for idx, txIn := range unsignedPsbt.UnsignedTx.TxIn {
utxPrevOut := txIn.PreviousOutPoint.Index
fakeUtxo := &wire.MsgTx{
Version: 2,
TxIn: []*wire.TxIn{{}},
TxOut: make([]*wire.TxOut, utxPrevOut+1),
}
for idx := range fakeUtxo.TxOut {
fakeUtxo.TxOut[idx] = &wire.TxOut{}
}
fakeUtxo.TxOut[utxPrevOut].Value = 10000000000
unsignedPsbt.Inputs[idx].NonWitnessUtxo = fakeUtxo
}
// Serialize the PSBT with the faked UTXO information.
var buf bytes.Buffer
err = unsignedPsbt.Serialize(&buf)
if err != nil {
t.Fatalf("error serializing PSBT: %v", err)
}
// We have a PSBT that has no witness data yet, which is exactly what we
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// need for the next step: Verify the PSBT with the funding intents.
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_, err = carol.FundingStateStep(ctxb, &lnrpc.FundingTransitionMsg{
Trigger: &lnrpc.FundingTransitionMsg_PsbtVerify{
PsbtVerify: &lnrpc.FundingPsbtVerify{
PendingChanId: pendingChanID[:],
FundedPsbt: buf.Bytes(),
},
},
})
if err != nil {
t.Fatalf("error verifying PSBT with funding intent: %v", err)
}
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_, err = carol.FundingStateStep(ctxb, &lnrpc.FundingTransitionMsg{
Trigger: &lnrpc.FundingTransitionMsg_PsbtVerify{
PsbtVerify: &lnrpc.FundingPsbtVerify{
PendingChanId: pendingChanID2[:],
FundedPsbt: buf.Bytes(),
},
},
})
if err != nil {
t.Fatalf("error verifying PSBT with funding intent 2: %v", err)
}
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// Now we'll add the witness data back into the PSBT to make it a
// complete and signed transaction that can be finalized. We'll trick
// a bit by putting the script sig back directly, because we know we
// will only get non-witness outputs from the miner wallet.
for idx := range tx.TxIn {
if len(witnesses[idx]) > 0 {
t.Fatalf("unexpected witness inputs in wallet TX")
}
unsignedPsbt.Inputs[idx].FinalScriptSig = scripts[idx]
}
// We've signed our PSBT now, let's pass it to the intent again.
buf.Reset()
err = unsignedPsbt.Serialize(&buf)
if err != nil {
t.Fatalf("error serializing PSBT: %v", err)
}
_, err = carol.FundingStateStep(ctxb, &lnrpc.FundingTransitionMsg{
Trigger: &lnrpc.FundingTransitionMsg_PsbtFinalize{
PsbtFinalize: &lnrpc.FundingPsbtFinalize{
PendingChanId: pendingChanID[:],
SignedPsbt: buf.Bytes(),
},
},
})
if err != nil {
t.Fatalf("error finalizing PSBT with funding intent: %v", err)
}
// Consume the "channel pending" update. This waits until the funding
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// transaction was fully compiled.
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ctxt, cancel = context.WithTimeout(ctxb, defaultTimeout)
defer cancel()
updateResp, err := receiveChanUpdate(ctxt, chanUpdates)
if err != nil {
t.Fatalf("unable to consume channel update message: %v", err)
}
upd, ok := updateResp.Update.(*lnrpc.OpenStatusUpdate_ChanPending)
if !ok {
t.Fatalf("expected PSBT funding update, instead got %v",
updateResp)
}
chanPoint := &lnrpc.ChannelPoint{
FundingTxid: &lnrpc.ChannelPoint_FundingTxidBytes{
FundingTxidBytes: upd.ChanPending.Txid,
},
OutputIndex: upd.ChanPending.OutputIndex,
}
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// No transaction should have been published yet.
mempool, err := net.Miner.Node.GetRawMempool()
if err != nil {
t.Fatalf("error querying mempool: %v", err)
}
if len(mempool) != 0 {
t.Fatalf("unexpected txes in mempool: %v", mempool)
}
// Let's progress the second channel now.
_, err = carol.FundingStateStep(ctxb, &lnrpc.FundingTransitionMsg{
Trigger: &lnrpc.FundingTransitionMsg_PsbtFinalize{
PsbtFinalize: &lnrpc.FundingPsbtFinalize{
PendingChanId: pendingChanID2[:],
SignedPsbt: buf.Bytes(),
},
},
})
if err != nil {
t.Fatalf("error finalizing PSBT with funding intent 2: %v", err)
}
// Consume the "channel pending" update for the second channel. This
// waits until the funding transaction was fully compiled and in this
// case published.
ctxt, cancel = context.WithTimeout(ctxb, defaultTimeout)
defer cancel()
updateResp2, err := receiveChanUpdate(ctxt, chanUpdates2)
if err != nil {
t.Fatalf("unable to consume channel update message: %v", err)
}
upd2, ok := updateResp2.Update.(*lnrpc.OpenStatusUpdate_ChanPending)
if !ok {
t.Fatalf("expected PSBT funding update, instead got %v",
updateResp2)
}
chanPoint2 := &lnrpc.ChannelPoint{
FundingTxid: &lnrpc.ChannelPoint_FundingTxidBytes{
FundingTxidBytes: upd2.ChanPending.Txid,
},
OutputIndex: upd2.ChanPending.OutputIndex,
}
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// Great, now we can mine a block to get the transaction confirmed, then
// wait for the new channel to be propagated through the network.
txHash := tx.TxHash()
block := mineBlocks(t, net, 6, 1)[0]
assertTxInBlock(t, block, &txHash)
ctxt, cancel = context.WithTimeout(ctxb, defaultTimeout)
defer cancel()
err = carol.WaitForNetworkChannelOpen(ctxt, chanPoint)
if err != nil {
t.Fatalf("carol didn't report channel: %v", err)
}
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err = carol.WaitForNetworkChannelOpen(ctxt, chanPoint2)
if err != nil {
t.Fatalf("carol didn't report channel 2: %v", err)
}
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// With the channel open, ensure that it is counted towards Carol's
// total channel balance.
balReq := &lnrpc.ChannelBalanceRequest{}
ctxt, cancel = context.WithTimeout(ctxb, defaultTimeout)
defer cancel()
balRes, err := carol.ChannelBalance(ctxt, balReq)
if err != nil {
t.Fatalf("unable to get carol's balance: %v", err)
}
if balRes.Balance == 0 {
t.Fatalf("carol has an empty channel balance")
}
// Next, to make sure the channel functions as normal, we'll make some
// payments within the channel.
payAmt := btcutil.Amount(100000)
invoice := &lnrpc.Invoice{
Memo: "new chans",
Value: int64(payAmt),
}
ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
resp, err := dave.AddInvoice(ctxt, invoice)
if err != nil {
t.Fatalf("unable to add invoice: %v", err)
}
ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
err = completePaymentRequests(
ctxt, carol, carol.RouterClient, []string{resp.PaymentRequest},
true,
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)
if err != nil {
t.Fatalf("unable to make payments between Carol and Dave")
}
// To conclude, we'll close the newly created channel between Carol and
// Dave. This function will also block until the channel is closed and
// will additionally assert the relevant channel closing post
// conditions.
ctxt, cancel = context.WithTimeout(ctxb, channelCloseTimeout)
defer cancel()
closeChannelAndAssert(ctxt, t, net, carol, chanPoint, false)
}
// openChannelPsbt attempts to open a channel between srcNode and destNode with
// the passed channel funding parameters. If the passed context has a timeout,
// then if the timeout is reached before the channel pending notification is
// received, an error is returned. An error is returned if the expected step
// of funding the PSBT is not received from the source node.
func openChannelPsbt(ctx context.Context, srcNode, destNode *lntest.HarnessNode,
p lntest.OpenChannelParams) (lnrpc.Lightning_OpenChannelClient, []byte,
error) {
// Wait until srcNode and destNode have the latest chain synced.
// Otherwise, we may run into a check within the funding manager that
// prevents any funding workflows from being kicked off if the chain
// isn't yet synced.
if err := srcNode.WaitForBlockchainSync(ctx); err != nil {
return nil, nil, fmt.Errorf("unable to sync srcNode chain: %v",
err)
}
if err := destNode.WaitForBlockchainSync(ctx); err != nil {
return nil, nil, fmt.Errorf("unable to sync destNode chain: %v",
err)
}
// Send the request to open a channel to the source node now. This will
// open a long-lived stream where we'll receive status updates about the
// progress of the channel.
respStream, err := srcNode.OpenChannel(ctx, &lnrpc.OpenChannelRequest{
NodePubkey: destNode.PubKey[:],
LocalFundingAmount: int64(p.Amt),
PushSat: int64(p.PushAmt),
Private: p.Private,
SpendUnconfirmed: p.SpendUnconfirmed,
MinHtlcMsat: int64(p.MinHtlc),
FundingShim: p.FundingShim,
})
if err != nil {
return nil, nil, fmt.Errorf("unable to open channel between "+
"source and dest: %v", err)
}
// Consume the "PSBT funding ready" update. This waits until the node
// notifies us that the PSBT can now be funded.
resp, err := receiveChanUpdate(ctx, respStream)
if err != nil {
return nil, nil, fmt.Errorf("unable to consume channel update "+
"message: %v", err)
}
upd, ok := resp.Update.(*lnrpc.OpenStatusUpdate_PsbtFund)
if !ok {
return nil, nil, fmt.Errorf("expected PSBT funding update, "+
"instead got %v", resp)
}
return respStream, upd.PsbtFund.Psbt, nil
}
// receiveChanUpdate waits until a message is received on the stream or the
// context is canceled. The context must have a timeout or must be canceled
// in case no message is received, otherwise this function will block forever.
func receiveChanUpdate(ctx context.Context,
stream lnrpc.Lightning_OpenChannelClient) (*lnrpc.OpenStatusUpdate,
error) {
chanMsg := make(chan *lnrpc.OpenStatusUpdate)
errChan := make(chan error)
go func() {
// Consume one message. This will block until the message is
// recieved.
resp, err := stream.Recv()
if err != nil {
errChan <- err
return
}
chanMsg <- resp
}()
select {
case <-ctx.Done():
return nil, fmt.Errorf("timeout reached before chan pending " +
"update sent")
case err := <-errChan:
return nil, err
case updateMsg := <-chanMsg:
return updateMsg, nil
}
}
// createPsbtFromSignedTx is a utility function to create a PSBT from an
// already-signed transaction, so we can test reconstructing, signing and
// extracting it. Returned are: an unsigned transaction serialization, a list
// of scriptSigs, one per input, and a list of witnesses, one per input.
func createPsbtFromSignedTx(tx *wire.MsgTx) (*psbt.Packet, [][]byte,
[]wire.TxWitness, error) {
scriptSigs := make([][]byte, 0, len(tx.TxIn))
witnesses := make([]wire.TxWitness, 0, len(tx.TxIn))
tx2 := tx.Copy()
// Blank out signature info in inputs
for i, tin := range tx2.TxIn {
tin.SignatureScript = nil
scriptSigs = append(scriptSigs, tx.TxIn[i].SignatureScript)
tin.Witness = nil
witnesses = append(witnesses, tx.TxIn[i].Witness)
}
// Outputs always contain: (value, scriptPubkey) so don't need
// amending. Now tx2 is tx with all signing data stripped out
unsignedPsbt, err := psbt.NewFromUnsignedTx(tx2)
if err != nil {
return nil, nil, nil, err
}
return unsignedPsbt, scriptSigs, witnesses, nil
}