lnd.xprv/lntest/itest/lnd_forward_interceptor_test.go

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package itest
import (
"context"
"encoding/hex"
"fmt"
"sync"
"time"
"github.com/btcsuite/btcd/wire"
"github.com/btcsuite/btcutil"
"github.com/lightningnetwork/lnd/chainreg"
"github.com/lightningnetwork/lnd/lnrpc"
"github.com/lightningnetwork/lnd/lnrpc/routerrpc"
"github.com/lightningnetwork/lnd/lntest"
"github.com/lightningnetwork/lnd/routing/route"
"github.com/stretchr/testify/require"
"google.golang.org/grpc/codes"
"google.golang.org/grpc/status"
)
var (
customTestKey uint64 = 394829
customTestValue = []byte{1, 3, 5}
)
type interceptorTestCase struct {
amountMsat int64
payAddr []byte
invoice *lnrpc.Invoice
shouldHold bool
interceptorAction routerrpc.ResolveHoldForwardAction
}
// testForwardInterceptor tests the forward interceptor RPC layer.
// The test creates a cluster of 3 connected nodes: Alice -> Bob -> Carol
// Alice sends 4 different payments to Carol while the interceptor handles
// differently the htlcs.
// The test ensures that:
// 1. Intercepted failed htlcs result in no payment (invoice is not settled).
// 2. Intercepted resumed htlcs result in a payment (invoice is settled).
// 3. Intercepted held htlcs result in no payment (invoice is not settled).
// 4. When Interceptor disconnects it resumes all held htlcs, which result in
// valid payment (invoice is settled).
func testForwardInterceptor(net *lntest.NetworkHarness, t *harnessTest) {
// Initialize the test context with 3 connected nodes.
alice, err := net.NewNode("alice", nil)
require.NoError(t.t, err, "unable to create alice")
defer shutdownAndAssert(net, t, alice)
bob, err := net.NewNode("bob", nil)
require.NoError(t.t, err, "unable to create bob")
defer shutdownAndAssert(net, t, alice)
carol, err := net.NewNode("carol", nil)
require.NoError(t.t, err, "unable to create carol")
defer shutdownAndAssert(net, t, alice)
testContext := newInterceptorTestContext(t, net, alice, bob, carol)
const (
chanAmt = btcutil.Amount(300000)
)
// Open and wait for channels.
testContext.openChannel(testContext.alice, testContext.bob, chanAmt)
testContext.openChannel(testContext.bob, testContext.carol, chanAmt)
defer testContext.closeChannels()
testContext.waitForChannels()
// Connect the interceptor.
ctx := context.Background()
ctxt, cancelInterceptor := context.WithTimeout(ctx, defaultTimeout)
interceptor, err := testContext.bob.RouterClient.HtlcInterceptor(ctxt)
require.NoError(t.t, err, "failed to create HtlcInterceptor")
// Prepare the test cases.
testCases := testContext.prepareTestCases()
// A channel for the interceptor go routine to send the requested packets.
interceptedChan := make(chan *routerrpc.ForwardHtlcInterceptRequest,
len(testCases))
// Run the interceptor loop in its own go routine.
var wg sync.WaitGroup
wg.Add(1)
go func() {
defer wg.Done()
for {
request, err := interceptor.Recv()
if err != nil {
// If it is just the error result of the context cancellation
// the we exit silently.
status, ok := status.FromError(err)
if ok && status.Code() == codes.Canceled {
return
}
// Otherwise it an unexpected error, we fail the test.
require.NoError(t.t, err, "unexpected error in interceptor.Recv()")
return
}
interceptedChan <- request
}
}()
// For each test case make sure we initiate a payment from Alice to Carol
// routed through Bob. For each payment we also test its final status
// according to the interceptorAction specified in the test case.
wg.Add(1)
go func() {
defer wg.Done()
for _, tc := range testCases {
attempt, err := testContext.sendAliceToCarolPayment(
context.Background(), tc.invoice.ValueMsat,
tc.invoice.RHash, tc.payAddr,
)
if t.t.Failed() {
return
}
if err != nil {
require.NoError(t.t, err, "failed to send payment")
}
switch tc.interceptorAction {
// For 'fail' interceptor action we make sure the payment failed.
case routerrpc.ResolveHoldForwardAction_FAIL:
require.Equal(t.t, lnrpc.HTLCAttempt_FAILED,
attempt.Status, "expected payment to fail")
// Assert that we get a temporary channel
// failure which has a channel update.
require.NotNil(t.t, attempt.Failure)
require.NotNil(t.t, attempt.Failure.ChannelUpdate)
require.Equal(t.t,
lnrpc.Failure_TEMPORARY_CHANNEL_FAILURE,
attempt.Failure.Code)
// For settle and resume we make sure the payment is successful.
case routerrpc.ResolveHoldForwardAction_SETTLE:
fallthrough
case routerrpc.ResolveHoldForwardAction_RESUME:
require.Equal(t.t, lnrpc.HTLCAttempt_SUCCEEDED,
attempt.Status, "expected payment to succeed")
}
}
}()
// We make sure here the interceptor has processed all packets before we
// check the payment statuses.
for i := 0; i < len(testCases); i++ {
select {
case request := <-interceptedChan:
// Assert sanity of informational packet data.
require.NotZero(t.t, request.OutgoingRequestedChanId)
require.NotZero(t.t, request.IncomingExpiry)
require.NotZero(t.t, request.IncomingAmountMsat)
require.Less(
t.t,
request.OutgoingExpiry, request.IncomingExpiry,
)
require.Less(
t.t,
request.OutgoingAmountMsat,
request.IncomingAmountMsat,
)
value, ok := request.CustomRecords[customTestKey]
require.True(t.t, ok, "expected custom record")
require.Equal(t.t, customTestValue, value)
testCase := testCases[i]
// For held packets we ignore, keeping them in hold status.
if testCase.shouldHold {
continue
}
// For all other packets we resolve according to the test case.
_ = interceptor.Send(&routerrpc.ForwardHtlcInterceptResponse{
IncomingCircuitKey: request.IncomingCircuitKey,
Action: testCase.interceptorAction,
Preimage: testCase.invoice.RPreimage,
})
case <-time.After(defaultTimeout):
t.Fatalf("response from interceptor was not received %v", i)
}
}
// At this point we are left with the held packets, we want to make sure
// each one of them has a corresponding 'in-flight' payment at
// Alice's node.
payments, err := testContext.alice.ListPayments(context.Background(),
&lnrpc.ListPaymentsRequest{IncludeIncomplete: true})
require.NoError(t.t, err, "failed to fetch payment")
for _, testCase := range testCases {
if testCase.shouldHold {
hashStr := hex.EncodeToString(testCase.invoice.RHash)
var foundPayment *lnrpc.Payment
expectedAmt := testCase.invoice.ValueMsat
for _, p := range payments.Payments {
if p.PaymentHash == hashStr {
foundPayment = p
break
}
}
require.NotNil(t.t, foundPayment, fmt.Sprintf("expected "+
"to find pending payment for held htlc %v",
hashStr))
require.Equal(t.t, lnrpc.Payment_IN_FLIGHT,
foundPayment.Status, "expected payment to be "+
"in flight")
require.Equal(t.t, expectedAmt, foundPayment.ValueMsat,
"incorrect in flight amount")
}
}
// Disconnect interceptor should cause resume held packets.
// After that we wait for all go routines to finish, including the one
// that tests the payment final status for the held payment.
cancelInterceptor()
wg.Wait()
}
// interceptorTestContext is a helper struct to hold the test context and
// provide the needed functionality.
type interceptorTestContext struct {
t *harnessTest
net *lntest.NetworkHarness
// Keep a list of all our active channels.
networkChans []*lnrpc.ChannelPoint
closeChannelFuncs []func()
alice, bob, carol *lntest.HarnessNode
nodes []*lntest.HarnessNode
}
func newInterceptorTestContext(t *harnessTest,
net *lntest.NetworkHarness,
alice, bob, carol *lntest.HarnessNode) *interceptorTestContext {
ctxb := context.Background()
// Connect nodes
nodes := []*lntest.HarnessNode{alice, bob, carol}
for i := 0; i < len(nodes); i++ {
for j := i + 1; j < len(nodes); j++ {
ctxt, _ := context.WithTimeout(ctxb, defaultTimeout)
err := net.EnsureConnected(ctxt, nodes[i], nodes[j])
require.NoError(t.t, err, "unable to connect nodes")
}
}
ctx := interceptorTestContext{
t: t,
net: net,
alice: alice,
bob: bob,
carol: carol,
nodes: nodes,
}
return &ctx
}
// prepareTestCases prepares 4 tests:
// 1. failed htlc.
// 2. resumed htlc.
// 3. settling htlc externally.
// 4. held htlc that is resumed later.
func (c *interceptorTestContext) prepareTestCases() []*interceptorTestCase {
cases := []*interceptorTestCase{
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{amountMsat: 1000, shouldHold: false,
interceptorAction: routerrpc.ResolveHoldForwardAction_FAIL},
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{amountMsat: 1000, shouldHold: false,
interceptorAction: routerrpc.ResolveHoldForwardAction_RESUME},
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{amountMsat: 1000, shouldHold: false,
interceptorAction: routerrpc.ResolveHoldForwardAction_SETTLE},
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{amountMsat: 1000, shouldHold: true,
interceptorAction: routerrpc.ResolveHoldForwardAction_RESUME},
}
for _, t := range cases {
addResponse, err := c.carol.AddInvoice(context.Background(), &lnrpc.Invoice{
ValueMsat: t.amountMsat,
})
require.NoError(c.t.t, err, "unable to add invoice")
invoice, err := c.carol.LookupInvoice(context.Background(), &lnrpc.PaymentHash{
RHashStr: hex.EncodeToString(addResponse.RHash),
})
require.NoError(c.t.t, err, "unable to find invoice")
// We'll need to also decode the returned invoice so we can
// grab the payment address which is now required for ALL
// payments.
payReq, err := c.carol.DecodePayReq(context.Background(), &lnrpc.PayReqString{
PayReq: invoice.PaymentRequest,
})
require.NoError(c.t.t, err, "unable to decode invoice")
t.invoice = invoice
t.payAddr = payReq.PaymentAddr
}
return cases
}
func (c *interceptorTestContext) openChannel(from, to *lntest.HarnessNode,
chanSize btcutil.Amount) {
ctxb := context.Background()
ctxt, _ := context.WithTimeout(ctxb, defaultTimeout)
err := c.net.SendCoins(ctxt, btcutil.SatoshiPerBitcoin, from)
require.NoError(c.t.t, err, "unable to send coins")
ctxt, _ = context.WithTimeout(ctxb, channelOpenTimeout)
chanPoint := openChannelAndAssert(
ctxt, c.t, c.net, from, to,
lntest.OpenChannelParams{
Amt: chanSize,
},
)
c.closeChannelFuncs = append(c.closeChannelFuncs, func() {
ctxt, _ := context.WithTimeout(ctxb, channelCloseTimeout)
closeChannelAndAssert(
ctxt, c.t, c.net, from, chanPoint, false,
)
})
c.networkChans = append(c.networkChans, chanPoint)
}
func (c *interceptorTestContext) closeChannels() {
for _, f := range c.closeChannelFuncs {
f()
}
}
func (c *interceptorTestContext) waitForChannels() {
ctxb := context.Background()
// Wait for all nodes to have seen all channels.
for _, chanPoint := range c.networkChans {
for _, node := range c.nodes {
txid, err := lnrpc.GetChanPointFundingTxid(chanPoint)
require.NoError(c.t.t, err, "unable to get txid")
point := wire.OutPoint{
Hash: *txid,
Index: chanPoint.OutputIndex,
}
ctxt, _ := context.WithTimeout(ctxb, defaultTimeout)
err = node.WaitForNetworkChannelOpen(ctxt, chanPoint)
require.NoError(c.t.t, err, fmt.Sprintf("(%d): timeout "+
"waiting for channel(%s) open", node.NodeID,
point))
}
}
}
// sendAliceToCarolPayment sends a payment from alice to carol and make an
// attempt to pay. The lnrpc.HTLCAttempt is returned.
func (c *interceptorTestContext) sendAliceToCarolPayment(ctx context.Context,
amtMsat int64,
paymentHash, paymentAddr []byte) (*lnrpc.HTLCAttempt, error) {
// Build a route from alice to carol.
route, err := c.buildRoute(
ctx, amtMsat, []*lntest.HarnessNode{c.bob, c.carol},
paymentAddr,
)
if err != nil {
return nil, err
}
sendReq := &routerrpc.SendToRouteRequest{
PaymentHash: paymentHash,
Route: route,
}
// Send a custom record to the forwarding node.
route.Hops[0].CustomRecords = map[uint64][]byte{
customTestKey: customTestValue,
}
// Send the payment.
return c.alice.RouterClient.SendToRouteV2(ctx, sendReq)
}
// buildRoute is a helper function to build a route with given hops.
func (c *interceptorTestContext) buildRoute(ctx context.Context, amtMsat int64,
hops []*lntest.HarnessNode, payAddr []byte) (*lnrpc.Route, error) {
rpcHops := make([][]byte, 0, len(hops))
for _, hop := range hops {
k := hop.PubKeyStr
pubkey, err := route.NewVertexFromStr(k)
if err != nil {
return nil, fmt.Errorf("error parsing %v: %v",
k, err)
}
rpcHops = append(rpcHops, pubkey[:])
}
req := &routerrpc.BuildRouteRequest{
AmtMsat: amtMsat,
FinalCltvDelta: chainreg.DefaultBitcoinTimeLockDelta,
HopPubkeys: rpcHops,
PaymentAddr: payAddr,
}
routeResp, err := c.alice.RouterClient.BuildRoute(ctx, req)
if err != nil {
return nil, err
}
return routeResp.Route, nil
}