package itest import ( "bytes" "context" "crypto/rand" "fmt" "github.com/btcsuite/btcd/wire" "github.com/btcsuite/btcutil" "github.com/lightningnetwork/lnd/funding" "github.com/lightningnetwork/lnd/lnrpc" "github.com/lightningnetwork/lnd/lnrpc/walletrpc" "github.com/lightningnetwork/lnd/lntest" "github.com/stretchr/testify/require" ) // 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 = funding.MaxBtcFundingAmount // First, we'll create two new nodes that we'll use to open channels // between for this test. Dave gets some coins that will be used to // fund the PSBT, just to make sure that Carol has an empty wallet. carol, err := net.NewNode("carol", nil) require.NoError(t.t, err) defer shutdownAndAssert(net, t, carol) dave, err := net.NewNode("dave", nil) require.NoError(t.t, err) defer shutdownAndAssert(net, t, dave) err = net.SendCoins(ctxb, btcutil.SatoshiPerBitcoin, dave) if err != nil { t.Fatalf("unable to send coins to dave: %v", err) } // 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) require.NoError(t.t, err) err = net.EnsureConnected(ctxt, carol, net.Alice) require.NoError(t.t, err) // 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 _, err = rand.Read(pendingChanID[:]) require.NoError(t.t, err) // We'll also test batch funding of two channels so we need another ID. var pendingChanID2 [32]byte _, err = rand.Read(pendingChanID2[:]) require.NoError(t.t, err) // Now that we have the pending channel ID, Carol will open the channel // by specifying a PSBT shim. We use the NoPublish flag here to avoid // publishing the whole batch TX too early. ctxt, cancel = context.WithTimeout(ctxb, defaultTimeout) defer cancel() chanUpdates, tempPsbt, err := openChannelPsbt( ctxt, carol, dave, lntest.OpenChannelParams{ Amt: chanSize, FundingShim: &lnrpc.FundingShim{ Shim: &lnrpc.FundingShim_PsbtShim{ PsbtShim: &lnrpc.PsbtShim{ PendingChanId: pendingChanID[:], NoPublish: true, }, }, }, }, ) require.NoError(t.t, err) // Let's add a second channel to the batch. This time between Carol and // Alice. We will publish 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, BasePsbt: tempPsbt, }, }, }, }, ) require.NoError(t.t, err) // We'll now ask Dave's wallet to fund the PSBT for us. This will return // a packet with inputs and outputs set but without any witness data. // This is exactly what we need for the next step. ctxt, cancel = context.WithTimeout(ctxb, defaultTimeout) defer cancel() fundReq := &walletrpc.FundPsbtRequest{ Template: &walletrpc.FundPsbtRequest_Psbt{ Psbt: psbtBytes2, }, Fees: &walletrpc.FundPsbtRequest_SatPerVbyte{ SatPerVbyte: 2, }, } fundResp, err := dave.WalletKitClient.FundPsbt(ctxt, fundReq) require.NoError(t.t, err) // We have a PSBT that has no witness data yet, which is exactly what we // need for the next step: Verify the PSBT with the funding intents. _, err = carol.FundingStateStep(ctxb, &lnrpc.FundingTransitionMsg{ Trigger: &lnrpc.FundingTransitionMsg_PsbtVerify{ PsbtVerify: &lnrpc.FundingPsbtVerify{ PendingChanId: pendingChanID[:], FundedPsbt: fundResp.FundedPsbt, }, }, }) require.NoError(t.t, err) _, err = carol.FundingStateStep(ctxb, &lnrpc.FundingTransitionMsg{ Trigger: &lnrpc.FundingTransitionMsg_PsbtVerify{ PsbtVerify: &lnrpc.FundingPsbtVerify{ PendingChanId: pendingChanID2[:], FundedPsbt: fundResp.FundedPsbt, }, }, }) require.NoError(t.t, err) // Now we'll ask Dave's wallet to sign the PSBT so we can finish the // funding flow. ctxt, cancel = context.WithTimeout(ctxb, defaultTimeout) defer cancel() finalizeReq := &walletrpc.FinalizePsbtRequest{ FundedPsbt: fundResp.FundedPsbt, } finalizeRes, err := dave.WalletKitClient.FinalizePsbt(ctxt, finalizeReq) require.NoError(t.t, err) // We've signed our PSBT now, let's pass it to the intent again. _, err = carol.FundingStateStep(ctxb, &lnrpc.FundingTransitionMsg{ Trigger: &lnrpc.FundingTransitionMsg_PsbtFinalize{ PsbtFinalize: &lnrpc.FundingPsbtFinalize{ PendingChanId: pendingChanID[:], SignedPsbt: finalizeRes.SignedPsbt, }, }, }) require.NoError(t.t, err) // Consume the "channel pending" update. This waits until the funding // transaction was fully compiled. ctxt, cancel = context.WithTimeout(ctxb, defaultTimeout) defer cancel() updateResp, err := receiveChanUpdate(ctxt, chanUpdates) require.NoError(t.t, err) upd, ok := updateResp.Update.(*lnrpc.OpenStatusUpdate_ChanPending) require.True(t.t, ok) chanPoint := &lnrpc.ChannelPoint{ FundingTxid: &lnrpc.ChannelPoint_FundingTxidBytes{ FundingTxidBytes: upd.ChanPending.Txid, }, OutputIndex: upd.ChanPending.OutputIndex, } // No transaction should have been published yet. mempool, err := net.Miner.Node.GetRawMempool() require.NoError(t.t, err) require.Equal(t.t, 0, len(mempool)) // Let's progress the second channel now. This time we'll use the raw // wire format transaction directly. require.NoError(t.t, err) _, err = carol.FundingStateStep(ctxb, &lnrpc.FundingTransitionMsg{ Trigger: &lnrpc.FundingTransitionMsg_PsbtFinalize{ PsbtFinalize: &lnrpc.FundingPsbtFinalize{ PendingChanId: pendingChanID2[:], FinalRawTx: finalizeRes.RawFinalTx, }, }, }) require.NoError(t.t, 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) require.NoError(t.t, err) upd2, ok := updateResp2.Update.(*lnrpc.OpenStatusUpdate_ChanPending) require.True(t.t, ok) chanPoint2 := &lnrpc.ChannelPoint{ FundingTxid: &lnrpc.ChannelPoint_FundingTxidBytes{ FundingTxidBytes: upd2.ChanPending.Txid, }, OutputIndex: upd2.ChanPending.OutputIndex, } // Great, now we can mine a block to get the transaction confirmed, then // wait for the new channel to be propagated through the network. var finalTx wire.MsgTx err = finalTx.Deserialize(bytes.NewReader(finalizeRes.RawFinalTx)) require.NoError(t.t, err) txHash := finalTx.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) require.NoError(t.t, err) err = carol.WaitForNetworkChannelOpen(ctxt, chanPoint2) require.NoError(t.t, err) // 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) require.NoError(t.t, err) require.NotEqual(t.t, int64(0), balRes.LocalBalance.Sat) // 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) require.NoError(t.t, err) ctxt, _ = context.WithTimeout(ctxb, defaultTimeout) err = completePaymentRequests( ctxt, carol, carol.RouterClient, []string{resp.PaymentRequest}, true, ) require.NoError(t.t, err) // 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 // received. 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 } }