multi: rename experimental endorsement signal to accountable

Renames the endorsement signal to accountable to
match the latest proposal https://github.com/lightning/blips/pull/67

itest/lnd_experimental_accountability.go

@@ -0,0 +1,113 @@
+package itest
+
+import (
+	"math"
+
+	"github.com/btcsuite/btcd/btcutil"
+	"github.com/lightningnetwork/lnd/lnrpc"
+	"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/lntest/wait"
+	"github.com/lightningnetwork/lnd/lntypes"
+	"github.com/lightningnetwork/lnd/lnwire"
+	"github.com/stretchr/testify/require"
+)
+
+// testExperimentalAccountability tests setting of positive and negative
+// experimental accountable signals.
+func testExperimentalAccountability(ht *lntest.HarnessTest) {
+	testAccountability(ht, true)
+	testAccountability(ht, false)
+}
+
+// testAccountability sets up a 5 hop network and tests propagation of
+// experimental accountable signals.
+func testAccountability(ht *lntest.HarnessTest, aliceAccountable bool) {
+	cfg := node.CfgAnchor
+	carolCfg := append(
+		[]string{"--protocol.no-experimental-accountability"}, cfg...,
+	)
+	cfgs := [][]string{cfg, cfg, carolCfg, cfg, cfg}
+
+	const chanAmt = btcutil.Amount(300000)
+	p := lntest.OpenChannelParams{Amt: chanAmt}
+
+	_, nodes := ht.CreateSimpleNetwork(cfgs, p)
+	alice, bob, carol, dave, eve := nodes[0], nodes[1], nodes[2], nodes[3],
+		nodes[4]
+
+	bobIntercept, cancelBob := bob.RPC.HtlcInterceptor()
+	defer cancelBob()
+
+	carolIntercept, cancelCarol := carol.RPC.HtlcInterceptor()
+	defer cancelCarol()
+
+	daveIntercept, cancelDave := dave.RPC.HtlcInterceptor()
+	defer cancelDave()
+
+	req := &lnrpc.Invoice{ValueMsat: 1000}
+	addResponse := eve.RPC.AddInvoice(req)
+	invoice := eve.RPC.LookupInvoice(addResponse.RHash)
+
+	sendReq := &routerrpc.SendPaymentRequest{
+		PaymentRequest: invoice.PaymentRequest,
+		TimeoutSeconds: int32(wait.PaymentTimeout.Seconds()),
+		FeeLimitMsat:   math.MaxInt64,
+	}
+
+	var expectedValue []byte
+	hasAccountability := lntest.ExperimentalAccountabilityActive()
+
+	if hasAccountability {
+		if aliceAccountable {
+			expectedValue = []byte{lnwire.ExperimentalAccountable}
+			t := uint64(lnwire.ExperimentalAccountableType)
+			sendReq.FirstHopCustomRecords = map[uint64][]byte{
+				t: expectedValue,
+			}
+		} else {
+			expectedValue = []byte{lnwire.ExperimentalUnaccountable}
+		}
+	}
+
+	_ = alice.RPC.SendPayment(sendReq)
+
+	// Validate that our signal (positive or zero) propagates until carol
+	// and then is dropped because she has disabled the feature.
+	// When the accountability experiment is not active, no signal is sent.
+	validateAccountableAndResume(
+		ht, bobIntercept, hasAccountability, expectedValue,
+	)
+	validateAccountableAndResume(
+		ht, carolIntercept, hasAccountability, expectedValue,
+	)
+	validateAccountableAndResume(ht, daveIntercept, false, nil)
+
+	var preimage lntypes.Preimage
+	copy(preimage[:], invoice.RPreimage)
+	ht.AssertPaymentStatus(alice, preimage.Hash(), lnrpc.Payment_SUCCEEDED)
+}
+
+func validateAccountableAndResume(ht *lntest.HarnessTest,
+	interceptor rpc.InterceptorClient, hasAccountable bool,
+	expectedValue []byte) {
+
+	packet := ht.ReceiveHtlcInterceptor(interceptor)
+
+	var expectedRecords map[uint64][]byte
+	if hasAccountable {
+		u64Type := uint64(lnwire.ExperimentalAccountableType)
+		expectedRecords = map[uint64][]byte{
+			u64Type: expectedValue,
+		}
+	}
+	require.Equal(ht, expectedRecords, packet.InWireCustomRecords)
+
+	err := interceptor.Send(&routerrpc.ForwardHtlcInterceptResponse{
+		IncomingCircuitKey: packet.IncomingCircuitKey,
+		Action:             routerrpc.ResolveHoldForwardAction_RESUME,
+	})
+	require.NoError(ht, err)
+}