lnd.xprv/routing/pathfind_test.go
Olaoluwa Osuntokun b07e7fb7cc
routing: hop-payload for last hop should be the absolute timeout, not delta
This commit fixes an oversight in the path finding code when converting
a path into a route. Currently, for the last hop, we’d emplace the
expiry delta of the last hop within the per-hop payload. This was left
over from a prior version of the specification.

To fix this, we’ll now emplace the _absolute_ final HTLC expiry with
the payload, such that, the final hop that verify that the HTLC has not
been tampered with in flight.
2017-09-12 21:27:47 +02:00

633 lines
19 KiB
Go

package routing
import (
"bytes"
"encoding/binary"
"encoding/hex"
"encoding/json"
"errors"
"io/ioutil"
"math/big"
"net"
"os"
"strings"
"testing"
"time"
"github.com/lightningnetwork/lnd/channeldb"
"github.com/lightningnetwork/lnd/lnwire"
"github.com/roasbeef/btcd/btcec"
"github.com/roasbeef/btcd/chaincfg/chainhash"
"github.com/roasbeef/btcd/wire"
"github.com/roasbeef/btcutil"
prand "math/rand"
)
const (
// basicGraphFilePath is the file path for a basic graph used within
// the tests. The basic graph consists of 5 nodes with 5 channels
// connecting them.
basicGraphFilePath = "testdata/basic_graph.json"
// excessiveHopsGraphFilePath is a file path which stores the JSON dump
// of a graph which was previously triggering an erroneous excessive
// hops error. The error has since been fixed, but a test case
// exercising it is kept around to guard against regressions.
excessiveHopsGraphFilePath = "testdata/excessive_hops.json"
)
var (
randSource = prand.NewSource(time.Now().Unix())
randInts = prand.New(randSource)
testSig = &btcec.Signature{
R: new(big.Int),
S: new(big.Int),
}
_, _ = testSig.R.SetString("63724406601629180062774974542967536251589935445068131219452686511677818569431", 10)
_, _ = testSig.S.SetString("18801056069249825825291287104931333862866033135609736119018462340006816851118", 10)
testAuthProof = channeldb.ChannelAuthProof{
NodeSig1: testSig,
NodeSig2: testSig,
BitcoinSig1: testSig,
BitcoinSig2: testSig,
}
)
// testGraph is the struct which corresponds to the JSON format used to encode
// graphs within the files in the testdata directory.
//
// TODO(roasbeef): add test graph auto-generator
type testGraph struct {
Info []string `json:"info"`
Nodes []testNode `json:"nodes"`
Edges []testChan `json:"edges"`
}
// testNode represents a node within the test graph above. We skip certain
// information such as the node's IP address as that information isn't needed
// for our tests.
type testNode struct {
Source bool `json:"source"`
PubKey string `json:"pubkey"`
Alias string `json:"alias"`
}
// testChan represents the JSON version of a payment channel. This struct
// matches the Json that's encoded under the "edges" key within the test graph.
type testChan struct {
Node1 string `json:"node_1"`
Node2 string `json:"node_2"`
ChannelID uint64 `json:"channel_id"`
ChannelPoint string `json:"channel_point"`
Flags uint16 `json:"flags"`
Expiry uint16 `json:"expiry"`
MinHTLC int64 `json:"min_htlc"`
FeeBaseMsat int64 `json:"fee_base_msat"`
FeeRate float64 `json:"fee_rate"`
Capacity int64 `json:"capacity"`
}
// makeTestGraph creates a new instance of a channeldb.ChannelGraph for testing
// purposes. A callback which cleans up the created temporary directories is
// also returned and intended to be executed after the test completes.
func makeTestGraph() (*channeldb.ChannelGraph, func(), error) {
// First, create a temporary directory to be used for the duration of
// this test.
tempDirName, err := ioutil.TempDir("", "channeldb")
if err != nil {
return nil, nil, err
}
// Next, create channeldb for the first time.
cdb, err := channeldb.Open(tempDirName)
if err != nil {
return nil, nil, err
}
cleanUp := func() {
cdb.Close()
os.RemoveAll(tempDirName)
}
return cdb.ChannelGraph(), cleanUp, nil
}
// aliasMap is a map from a node's alias to its public key. This type is
// provided in order to allow easily look up from the human rememberable alias
// to an exact node's public key.
type aliasMap map[string]*btcec.PublicKey
// parseTestGraph returns a fully populated ChannelGraph given a path to a JSON
// file which encodes a test graph.
func parseTestGraph(path string) (*channeldb.ChannelGraph, func(), aliasMap, error) {
graphJSON, err := ioutil.ReadFile(path)
if err != nil {
return nil, nil, nil, err
}
// First unmarshal the JSON graph into an instance of the testGraph
// struct. Using the struct tags created above in the struct, the JSON
// will be properly parsed into the struct above.
var g testGraph
if err := json.Unmarshal(graphJSON, &g); err != nil {
return nil, nil, nil, err
}
// We'll use this fake address for the IP address of all the nodes in
// our tests. This value isn't needed for path finding so it doesn't
// need to be unique.
var testAddrs []net.Addr
testAddr, err := net.ResolveTCPAddr("tcp", "192.0.0.1:8888")
if err != nil {
return nil, nil, nil, err
}
testAddrs = append(testAddrs, testAddr)
// Next, create a temporary graph database for usage within the test.
graph, cleanUp, err := makeTestGraph()
if err != nil {
return nil, nil, nil, err
}
aliasMap := make(map[string]*btcec.PublicKey)
var source *channeldb.LightningNode
// First we insert all the nodes within the graph as vertexes.
for _, node := range g.Nodes {
pubBytes, err := hex.DecodeString(node.PubKey)
if err != nil {
return nil, nil, nil, err
}
pub, err := btcec.ParsePubKey(pubBytes, btcec.S256())
if err != nil {
return nil, nil, nil, err
}
dbNode := &channeldb.LightningNode{
HaveNodeAnnouncement: true,
AuthSig: testSig,
LastUpdate: time.Now(),
Addresses: testAddrs,
PubKey: pub,
Alias: node.Alias,
Features: testFeatures,
}
// We require all aliases within the graph to be unique for our
// tests.
if _, ok := aliasMap[node.Alias]; ok {
return nil, nil, nil, errors.New("aliases for nodes " +
"must be unique!")
}
// If the alias is unique, then add the node to the
// alias map for easy lookup.
aliasMap[node.Alias] = pub
// If the node is tagged as the source, then we create a
// pointer to is so we can mark the source in the graph
// properly.
if node.Source {
// If we come across a node that's marked as the
// source, and we've already set the source in a prior
// iteration, then the JSON has an error as only ONE
// node can be the source in the graph.
if source != nil {
return nil, nil, nil, errors.New("JSON is invalid " +
"multiple nodes are tagged as the source")
}
source = dbNode
}
// With the node fully parsed, add it as a vertex within the
// graph.
if err := graph.AddLightningNode(dbNode); err != nil {
return nil, nil, nil, err
}
}
// Set the selected source node
if err := graph.SetSourceNode(source); err != nil {
return nil, nil, nil, err
}
// With all the vertexes inserted, we can now insert the edges into the
// test graph.
for _, edge := range g.Edges {
node1Bytes, err := hex.DecodeString(edge.Node1)
if err != nil {
return nil, nil, nil, err
}
node1Pub, err := btcec.ParsePubKey(node1Bytes, btcec.S256())
if err != nil {
return nil, nil, nil, err
}
node2Bytes, err := hex.DecodeString(edge.Node2)
if err != nil {
return nil, nil, nil, err
}
node2Pub, err := btcec.ParsePubKey(node2Bytes, btcec.S256())
if err != nil {
return nil, nil, nil, err
}
fundingTXID := strings.Split(edge.ChannelPoint, ":")[0]
txidBytes, err := chainhash.NewHashFromStr(fundingTXID)
if err != nil {
return nil, nil, nil, err
}
fundingPoint := wire.OutPoint{
Hash: *txidBytes,
Index: 0,
}
// We first insert the existence of the edge between the two
// nodes.
edgeInfo := channeldb.ChannelEdgeInfo{
ChannelID: edge.ChannelID,
NodeKey1: node1Pub,
NodeKey2: node2Pub,
BitcoinKey1: node1Pub,
BitcoinKey2: node2Pub,
AuthProof: &testAuthProof,
ChannelPoint: fundingPoint,
Capacity: btcutil.Amount(edge.Capacity),
}
if err := graph.AddChannelEdge(&edgeInfo); err != nil {
return nil, nil, nil, err
}
edgePolicy := &channeldb.ChannelEdgePolicy{
Signature: testSig,
ChannelID: edge.ChannelID,
LastUpdate: time.Now(),
TimeLockDelta: edge.Expiry,
MinHTLC: lnwire.MilliSatoshi(edge.MinHTLC),
FeeBaseMSat: lnwire.MilliSatoshi(edge.FeeBaseMsat),
FeeProportionalMillionths: lnwire.MilliSatoshi(edge.FeeRate),
}
// As the graph itself is directed, we need to insert two edges
// into the graph: one from node1->node2 and one from
// node2->node1. A flag of 0 indicates this is the routing
// policy for the first node, and a flag of 1 indicates its the
// information for the second node.
edgePolicy.Flags = 0
if err := graph.UpdateEdgePolicy(edgePolicy); err != nil {
return nil, nil, nil, err
}
edgePolicy.Flags = 1
if err := graph.UpdateEdgePolicy(edgePolicy); err != nil {
return nil, nil, nil, err
}
}
return graph, cleanUp, aliasMap, nil
}
func TestBasicGraphPathFinding(t *testing.T) {
t.Parallel()
graph, cleanUp, aliases, err := parseTestGraph(basicGraphFilePath)
defer cleanUp()
if err != nil {
t.Fatalf("unable to create graph: %v", err)
}
sourceNode, err := graph.SourceNode()
if err != nil {
t.Fatalf("unable to fetch source node: %v", err)
}
ignoredEdges := make(map[uint64]struct{})
ignoredVertexes := make(map[vertex]struct{})
// With the test graph loaded, we'll test some basic path finding using
// the pre-generated graph. Consult the testdata/basic_graph.json file
// to follow along with the assumptions we'll use to test the path
// finding.
const startingHeight = 100
paymentAmt := lnwire.NewMSatFromSatoshis(100)
target := aliases["sophon"]
path, err := findPath(graph, sourceNode, target, ignoredVertexes,
ignoredEdges, paymentAmt)
if err != nil {
t.Fatalf("unable to find path: %v", err)
}
route, err := newRoute(paymentAmt, path, startingHeight)
if err != nil {
t.Fatalf("unable to create path: %v", err)
}
// The length of the route selected should be of exactly length two.
if len(route.Hops) != 2 {
t.Fatalf("route is of incorrect length, expected %v got %v", 2,
len(route.Hops))
}
// As each hop only decrements a single block from the time-lock, the
// total time lock value should two more than our starting block
// height.
if route.TotalTimeLock != 102 {
t.Fatalf("expected time lock of %v, instead have %v", 2,
route.TotalTimeLock)
}
// The first hop in the path should be an edge from roasbeef to goku.
if !route.Hops[0].Channel.Node.PubKey.IsEqual(aliases["songoku"]) {
t.Fatalf("first hop should be goku, is instead: %v",
route.Hops[0].Channel.Node.Alias)
}
// The second hop should be from goku to sophon.
if !route.Hops[1].Channel.Node.PubKey.IsEqual(aliases["sophon"]) {
t.Fatalf("second hop should be sophon, is instead: %v",
route.Hops[0].Channel.Node.Alias)
}
// Next, we'll assert that the "next hop" field in each route payload
// properly points to the channel ID that the HTLC should be forwarded
// along.
hopPayloads := route.ToHopPayloads()
if len(hopPayloads) != 2 {
t.Fatalf("incorrect number of hop payloads: expected %v, got %v",
2, len(hopPayloads))
}
// The first hop should point to the second hop.
var expectedHop [8]byte
binary.BigEndian.PutUint64(expectedHop[:], route.Hops[1].Channel.ChannelID)
if !bytes.Equal(hopPayloads[0].NextAddress[:], expectedHop[:]) {
t.Fatalf("first hop has incorrect next hop: expected %x, got %x",
expectedHop[:], hopPayloads[0].NextAddress)
}
// The second hop should have a next hop value of all zeroes in order
// to indicate it's the exit hop.
var exitHop [8]byte
if !bytes.Equal(hopPayloads[1].NextAddress[:], exitHop[:]) {
t.Fatalf("first hop has incorrect next hop: expected %x, got %x",
exitHop[:], hopPayloads[0].NextAddress)
}
// We'll also assert that the outgoing CLTV value for each hop was set
// accordingly.
if route.Hops[0].OutgoingTimeLock != 101 {
t.Fatalf("expected outgoing time-lock of %v, instead have %v",
1, route.Hops[0].OutgoingTimeLock)
}
if route.Hops[1].OutgoingTimeLock != 101 {
t.Fatalf("outgoing time-lock for final hop is incorrect: "+
"expected %v, got %v", 1, route.Hops[1].OutgoingTimeLock)
}
// Additionally, we'll ensure that the amount to forward, and fees
// computed for each hop are correct.
firstHopFee := route.Hops[0].Channel.FeeBaseMSat
if route.TotalAmount != paymentAmt+firstHopFee {
t.Fatalf("first hop forwarding amount incorrect: expected %v, got %v",
paymentAmt+firstHopFee, route.Hops[0].AmtToForward)
}
if route.Hops[0].Fee != firstHopFee {
t.Fatalf("first hop fee incorrect: expected %v, got %v",
firstHopFee, route.Hops[0].Fee)
}
if route.Hops[1].AmtToForward != paymentAmt {
t.Fatalf("second hop forwarding amount incorrect: expected %v, got %v",
paymentAmt+firstHopFee, route.Hops[0].AmtToForward)
}
if route.Hops[1].Fee != 0 {
t.Fatalf("second hop fee incorrect: expected %v, got %v",
0, route.Hops[1].Fee)
}
// Next, attempt to query for a path to Luo Ji for 100 satoshis, there
// exist two possible paths in the graph, but the shorter (1 hop) path
// should be selected.
target = aliases["luoji"]
path, err = findPath(graph, sourceNode, target, ignoredVertexes,
ignoredEdges, paymentAmt)
if err != nil {
t.Fatalf("unable to find route: %v", err)
}
route, err = newRoute(paymentAmt, path, startingHeight)
if err != nil {
t.Fatalf("unable to create path: %v", err)
}
// The length of the path should be exactly one hop as it's the
// "shortest" known path in the graph.
if len(route.Hops) != 1 {
t.Fatalf("shortest path not selected, should be of length 1, "+
"is instead: %v", len(route.Hops))
}
// As we have a direct path, the total time lock value should be
// exactly the current block height plus one.
if route.TotalTimeLock != 101 {
t.Fatalf("expected time lock of %v, instead have %v", 1,
route.TotalTimeLock)
}
// Additionally, since this is a single-hop payment, we shouldn't have
// to pay any fees in total, so the total amount should be the payment
// amount.
if route.TotalAmount != paymentAmt {
t.Fatalf("incorrect total amount, expected %v got %v",
paymentAmt, route.TotalAmount)
}
}
func TestKShortestPathFinding(t *testing.T) {
t.Parallel()
graph, cleanUp, aliases, err := parseTestGraph(basicGraphFilePath)
defer cleanUp()
if err != nil {
t.Fatalf("unable to create graph: %v", err)
}
sourceNode, err := graph.SourceNode()
if err != nil {
t.Fatalf("unable to fetch source node: %v", err)
}
// In this test we'd like to ensure that our algoirthm to find the
// k-shortest paths from a given source node to any destination node
// works as exepcted.
// In our basic_graph.json, there exist two paths from roasbeef to luo
// ji. Our algorithm should properly find both paths, and also rank
// them in order of their total "distance".
paymentAmt := lnwire.NewMSatFromSatoshis(100)
target := aliases["luoji"]
paths, err := findPaths(graph, sourceNode, target, paymentAmt)
if err != nil {
t.Fatalf("unable to find paths between roasbeef and "+
"luo ji: %v", err)
}
// The algorithm should've found two paths from roasbeef to luo ji.
if len(paths) != 2 {
t.Fatalf("two path shouldn't been found, instead %v were",
len(paths))
}
// Additinoally, the total hop length of the first path returned should
// be _less_ than that of the second path returned.
if len(paths[0]) > len(paths[1]) {
t.Fatalf("paths found not ordered properly")
}
// Finally, we'll assert the exact expected ordering of both paths
// found.
assertExpectedPath := func(path []*ChannelHop, nodeAliases ...string) {
for i, hop := range path {
if hop.Node.Alias != nodeAliases[i] {
t.Fatalf("expected %v to be pos #%v in hop, "+
"instead %v was", nodeAliases[i], i,
hop.Node.Alias)
}
}
}
// The first route should be a direct route to luo ji.
assertExpectedPath(paths[0], "roasbeef", "luoji")
// The second route should be a route to luo ji via satoshi.
assertExpectedPath(paths[1], "roasbeef", "satoshi", "luoji")
}
func TestNewRoutePathTooLong(t *testing.T) {
t.Parallel()
// Ensure that potential paths which are over the maximum hop-limit are
// rejected.
graph, cleanUp, aliases, err := parseTestGraph(excessiveHopsGraphFilePath)
defer cleanUp()
if err != nil {
t.Fatalf("unable to create graph: %v", err)
}
sourceNode, err := graph.SourceNode()
if err != nil {
t.Fatalf("unable to fetch source node: %v", err)
}
ignoredEdges := make(map[uint64]struct{})
ignoredVertexes := make(map[vertex]struct{})
paymentAmt := lnwire.NewMSatFromSatoshis(100)
// We start by confirminig that routing a payment 20 hops away is possible.
// Alice should be able to find a valid route to ursula.
target := aliases["ursula"]
_, err = findPath(graph, sourceNode, target, ignoredVertexes,
ignoredEdges, paymentAmt)
if err != nil {
t.Fatalf("path should have been found")
}
// Vincent is 21 hops away from Alice, and thus no valid route should be
// presented to Alice.
target = aliases["vincent"]
path, err := findPath(graph, sourceNode, target, ignoredVertexes,
ignoredEdges, paymentAmt)
if err == nil {
t.Fatalf("should not have been able to find path, supposed to be "+
"greater than 20 hops, found route with %v hops",
len(path))
}
}
func TestPathNotAvailable(t *testing.T) {
t.Parallel()
graph, cleanUp, _, err := parseTestGraph(basicGraphFilePath)
defer cleanUp()
if err != nil {
t.Fatalf("unable to create graph: %v", err)
}
sourceNode, err := graph.SourceNode()
if err != nil {
t.Fatalf("unable to fetch source node: %v", err)
}
ignoredEdges := make(map[uint64]struct{})
ignoredVertexes := make(map[vertex]struct{})
// With the test graph loaded, we'll test that queries for target that
// are either unreachable within the graph, or unknown result in an
// error.
unknownNodeStr := "03dd46ff29a6941b4a2607525b043ec9b020b3f318a1bf281536fd7011ec59c882"
unknownNodeBytes, err := hex.DecodeString(unknownNodeStr)
if err != nil {
t.Fatalf("unable to parse bytes: %v", err)
}
unknownNode, err := btcec.ParsePubKey(unknownNodeBytes, btcec.S256())
if err != nil {
t.Fatalf("unable to parse pubkey: %v", err)
}
_, err = findPath(graph, sourceNode, unknownNode, ignoredVertexes,
ignoredEdges, 100)
if !IsError(err, ErrNoPathFound) {
t.Fatalf("path shouldn't have been found: %v", err)
}
}
func TestPathInsufficientCapacity(t *testing.T) {
t.Parallel()
graph, cleanUp, aliases, err := parseTestGraph(basicGraphFilePath)
defer cleanUp()
if err != nil {
t.Fatalf("unable to create graph: %v", err)
}
sourceNode, err := graph.SourceNode()
if err != nil {
t.Fatalf("unable to fetch source node: %v", err)
}
ignoredEdges := make(map[uint64]struct{})
ignoredVertexes := make(map[vertex]struct{})
// Next, test that attempting to find a path in which the current
// channel graph cannot support due to insufficient capacity triggers
// an error.
// To test his we'll attempt to make a payment of 1 BTC, or 100 million
// satoshis. The largest channel in the basic graph is of size 100k
// satoshis, so we shouldn't be able to find a path to sophon even
// though we have a 2-hop link.
target := aliases["sophon"]
const payAmt = btcutil.SatoshiPerBitcoin
_, err = findPath(graph, sourceNode, target, ignoredVertexes,
ignoredEdges, payAmt)
if !IsError(err, ErrNoPathFound) {
t.Fatalf("graph shouldn't be able to support payment: %v", err)
}
}
func TestPathInsufficientCapacityWithFee(t *testing.T) {
t.Parallel()
// TODO(roasbeef): encode live graph to json
// TODO(roasbeef): need to add a case, or modify the fee ratio for one
// to ensure that has going forward, but when fees are applied doesn't
// work
}
// TODO(roasbeef): more time-lock calvulation tests