path: root/p2p/discover/table_test.go

package discover

import (
    "crypto/ecdsa"
    "errors"
    "fmt"
    "math/big"
    "math/rand"
    "net"
    "reflect"
    "testing"
    "testing/quick"
    "time"

    "github.com/ethereum/go-ethereum/crypto"
)

var (
    quickrand = rand.New(rand.NewSource(time.Now().Unix()))
    quickcfg  = &quick.Config{MaxCount: 5000, Rand: quickrand}
)

func TestHexID(t *testing.T) {
    ref := NodeID{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 128, 106, 217, 182, 31, 165, 174, 1, 67, 7, 235, 220, 150, 66, 83, 173, 205, 159, 44, 10, 57, 42, 161, 26, 188}
    id1 := HexID("0x000000000000000000000000000000000000000000000000000000000000000000000000000000806ad9b61fa5ae014307ebdc964253adcd9f2c0a392aa11abc")
    id2 := HexID("000000000000000000000000000000000000000000000000000000000000000000000000000000806ad9b61fa5ae014307ebdc964253adcd9f2c0a392aa11abc")

    if id1 != ref {
        t.Errorf("wrong id1\ngot  %v\nwant %v", id1[:], ref[:])
    }
    if id2 != ref {
        t.Errorf("wrong id2\ngot  %v\nwant %v", id2[:], ref[:])
    }
}

func TestNodeID_recover(t *testing.T) {
    prv := newkey()
    hash := make([]byte, 32)
    sig, err := crypto.Sign(hash, prv)
    if err != nil {
        t.Fatalf("signing error: %v", err)
    }

    pub := newNodeID(prv)
    recpub, err := recoverNodeID(hash, sig)
    if err != nil {
        t.Fatalf("recovery error: %v", err)
    }
    if pub != recpub {
        t.Errorf("recovered wrong pubkey:\ngot:  %v\nwant: %v", recpub, pub)
    }
}

func TestNodeID_distcmp(t *testing.T) {
    distcmpBig := func(target, a, b NodeID) int {
        tbig := new(big.Int).SetBytes(target[:])
        abig := new(big.Int).SetBytes(a[:])
        bbig := new(big.Int).SetBytes(b[:])
        return new(big.Int).Xor(tbig, abig).Cmp(new(big.Int).Xor(tbig, bbig))
    }
    if err := quick.CheckEqual(distcmp, distcmpBig, quickcfg); err != nil {
        t.Error(err)
    }
}

// the random tests is likely to miss the case where they're equal.
func TestNodeID_distcmpEqual(t *testing.T) {
    base := NodeID{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15}
    x := NodeID{15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0}
    if distcmp(base, x, x) != 0 {
        t.Errorf("distcmp(base, x, x) != 0")
    }
}

func TestNodeID_logdist(t *testing.T) {
    logdistBig := func(a, b NodeID) int {
        abig, bbig := new(big.Int).SetBytes(a[:]), new(big.Int).SetBytes(b[:])
        return new(big.Int).Xor(abig, bbig).BitLen()
    }
    if err := quick.CheckEqual(logdist, logdistBig, quickcfg); err != nil {
        t.Error(err)
    }
}

// the random tests is likely to miss the case where they're equal.
func TestNodeID_logdistEqual(t *testing.T) {
    x := NodeID{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15}
    if logdist(x, x) != 0 {
        t.Errorf("logdist(x, x) != 0")
    }
}

func TestNodeID_randomID(t *testing.T) {
    // we don't use quick.Check here because its output isn't
    // very helpful when the test fails.
    for i := 0; i < quickcfg.MaxCount; i++ {
        a := gen(NodeID{}, quickrand).(NodeID)
        dist := quickrand.Intn(len(NodeID{}) * 8)
        result := randomID(a, dist)
        actualdist := logdist(result, a)

        if dist != actualdist {
            t.Log("a:     ", a)
            t.Log("result:", result)
            t.Fatalf("#%d: distance of result is %d, want %d", i, actualdist, dist)
        }
    }
}

func (NodeID) Generate(rand *rand.Rand, size int) reflect.Value {
    var id NodeID
    m := rand.Intn(len(id))
    for i := len(id) - 1; i > m; i-- {
        id[i] = byte(rand.Uint32())
    }
    return reflect.ValueOf(id)
}

func TestTable_bumpOrAddPingReplace(t *testing.T) {
    pingC := make(pingC)
    tab := newTable(pingC, NodeID{}, &net.UDPAddr{})
    last := fillBucket(tab, 200)

    // this bumpOrAdd should not replace the last node
    // because the node replies to ping.
    new := tab.bumpOrAdd(randomID(tab.self.ID, 200), nil)

    pinged := <-pingC
    if pinged != last.ID {
        t.Fatalf("pinged wrong node: %v\nwant %v", pinged, last.ID)
    }

    tab.mutex.Lock()
    defer tab.mutex.Unlock()
    if l := len(tab.buckets[200].entries); l != bucketSize {
        t.Errorf("wrong bucket size after bumpOrAdd: got %d, want %d", bucketSize, l)
    }
    if !contains(tab.buckets[200].entries, last.ID) {
        t.Error("last entry was removed")
    }
    if contains(tab.buckets[200].entries, new.ID) {
        t.Error("new entry was added")
    }
}

func TestTable_bumpOrAddPingTimeout(t *testing.T) {
    tab := newTable(pingC(nil), NodeID{}, &net.UDPAddr{})
    last := fillBucket(tab, 200)

    // this bumpOrAdd should replace the last node
    // because the node does not reply to ping.
    new := tab.bumpOrAdd(randomID(tab.self.ID, 200), nil)

    // wait for async bucket update. damn. this needs to go away.
    time.Sleep(2 * time.Millisecond)

    tab.mutex.Lock()
    defer tab.mutex.Unlock()
    if l := len(tab.buckets[200].entries); l != bucketSize {
        t.Errorf("wrong bucket size after bumpOrAdd: got %d, want %d", bucketSize, l)
    }
    if contains(tab.buckets[200].entries, last.ID) {
        t.Error("last entry was not removed")
    }
    if !contains(tab.buckets[200].entries, new.ID) {
        t.Error("new entry was not added")
    }
}

func fillBucket(tab *Table, ld int) (last *Node) {
    b := tab.buckets[ld]
    for len(b.entries) < bucketSize {
        b.entries = append(b.entries, &Node{ID: randomID(tab.self.ID, ld)})
    }
    return b.entries[bucketSize-1]
}

type pingC chan NodeID

func (t pingC) findnode(n *Node, target NodeID) ([]*Node, error) {
    panic("findnode called on pingRecorder")
}
func (t pingC) close() {
    panic("close called on pingRecorder")
}
func (t pingC) ping(n *Node) error {
    if t == nil {
        return errTimeout
    }
    t <- n.ID
    return nil
}

func TestTable_bump(t *testing.T) {
    tab := newTable(nil, NodeID{}, &net.UDPAddr{})

    // add an old entry and two recent ones
    oldactive := time.Now().Add(-2 * time.Minute)
    old := &Node{ID: randomID(tab.self.ID, 200), active: oldactive}
    others := []*Node{
        &Node{ID: randomID(tab.self.ID, 200), active: time.Now()},
        &Node{ID: randomID(tab.self.ID, 200), active: time.Now()},
    }
    tab.add(append(others, old))
    if tab.buckets[200].entries[0] == old {
        t.Fatal("old entry is at front of bucket")
    }

    // bumping the old entry should move it to the front
    tab.bump(old.ID)
    if old.active == oldactive {
        t.Error("activity timestamp not updated")
    }
    if tab.buckets[200].entries[0] != old {
        t.Errorf("bumped entry did not move to the front of bucket")
    }
}

func TestTable_closest(t *testing.T) {
    t.Parallel()

    test := func(test *closeTest) bool {
        // for any node table, Target and N
        tab := newTable(nil, test.Self, &net.UDPAddr{})
        tab.add(test.All)

        // check that doClosest(Target, N) returns nodes
        result := tab.closest(test.Target, test.N).entries
        if hasDuplicates(result) {
            t.Errorf("result contains duplicates")
            return false
        }
        if !sortedByDistanceTo(test.Target, result) {
            t.Errorf("result is not sorted by distance to target")
            return false
        }

        // check that the number of results is min(N, tablen)
        wantN := test.N
        if tlen := tab.len(); tlen < test.N {
            wantN = tlen
        }
        if len(result) != wantN {
            t.Errorf("wrong number of nodes: got %d, want %d", len(result), wantN)
            return false
        } else if len(result) == 0 {
            return true // no need to check distance
        }

        // check that the result nodes have minimum distance to target.
        for _, b := range tab.buckets {
            for _, n := range b.entries {
                if contains(result, n.ID) {
                    continue // don't run the check below for nodes in result
                }
                farthestResult := result[len(result)-1].ID
                if distcmp(test.Target, n.ID, farthestResult) < 0 {
                    t.Errorf("table contains node that is closer to target but it's not in result")
                    t.Logf("  Target:          %v", test.Target)
                    t.Logf("  Farthest Result: %v", farthestResult)
                    t.Logf("  ID:              %v", n.ID)
                    return false
                }
            }
        }
        return true
    }
    if err := quick.Check(test, quickcfg); err != nil {
        t.Error(err)
    }
}

type closeTest struct {
    Self   NodeID
    Target NodeID
    All    []*Node
    N      int
}

func (*closeTest) Generate(rand *rand.Rand, size int) reflect.Value {
    t := &closeTest{
        Self:   gen(NodeID{}, rand).(NodeID),
        Target: gen(NodeID{}, rand).(NodeID),
        N:      rand.Intn(bucketSize),
    }
    for _, id := range gen([]NodeID{}, rand).([]NodeID) {
        t.All = append(t.All, &Node{ID: id})
    }
    return reflect.ValueOf(t)
}

func TestTable_Lookup(t *testing.T) {
    self := gen(NodeID{}, quickrand).(NodeID)
    target := randomID(self, 200)
    transport := findnodeOracle{t, target}
    tab := newTable(transport, self, &net.UDPAddr{})

    // lookup on empty table returns no nodes
    if results := tab.Lookup(target); len(results) > 0 {
        t.Fatalf("lookup on empty table returned %d results: %#v", len(results), results)
    }
    // seed table with initial node (otherwise lookup will terminate immediately)
    tab.bumpOrAdd(randomID(target, 200), &net.UDPAddr{Port: 200})

    results := tab.Lookup(target)
    t.Logf("results:")
    for _, e := range results {
        t.Logf("  ld=%d, %v", logdist(target, e.ID), e.ID)
    }
    if len(results) != bucketSize {
        t.Errorf("wrong number of results: got %d, want %d", len(results), bucketSize)
    }
    if hasDuplicates(results) {
        t.Errorf("result set contains duplicate entries")
    }
    if !sortedByDistanceTo(target, results) {
        t.Errorf("result set not sorted by distance to target")
    }
    if !contains(results, target) {
        t.Errorf("result set does not contain target")
    }
}

// findnode on this transport always returns at least one node
// that is one bucket closer to the target.
type findnodeOracle struct {
    t      *testing.T
    target NodeID
}

func (t findnodeOracle) findnode(n *Node, target NodeID) ([]*Node, error) {
    t.t.Logf("findnode query at dist %d", n.Addr.Port)
    // current log distance is encoded in port number
    var result []*Node
    switch port := n.Addr.Port; port {
    case 0:
        panic("query to node at distance 0")
    case 1:
        result = append(result, &Node{ID: t.target, Addr: &net.UDPAddr{Port: 0}})
    default:
        // TODO: add more randomness to distances
        port--
        for i := 0; i < bucketSize; i++ {
            result = append(result, &Node{ID: randomID(t.target, port), Addr: &net.UDPAddr{Port: port}})
        }
    }
    return result, nil
}

func (t findnodeOracle) close() {}

func (t findnodeOracle) ping(n *Node) error {
    return errors.New("ping is not supported by this transport")
}

func hasDuplicates(slice []*Node) bool {
    seen := make(map[NodeID]bool)
    for _, e := range slice {
        if seen[e.ID] {
            return true
        }
        seen[e.ID] = true
    }
    return false
}

func sortedByDistanceTo(distbase NodeID, slice []*Node) bool {
    var last NodeID
    for i, e := range slice {
        if i > 0 && distcmp(distbase, e.ID, last) < 0 {
            return false
        }
        last = e.ID
    }
    return true
}

func contains(ns []*Node, id NodeID) bool {
    for _, n := range ns {
        if n.ID == id {
            return true
        }
    }
    return false
}

// gen wraps quick.Value so it's easier to use.
// it generates a random value of the given value's type.
func gen(typ interface{}, rand *rand.Rand) interface{} {
    v, ok := quick.Value(reflect.TypeOf(typ), rand)
    if !ok {
        panic(fmt.Sprintf("couldn't generate random value of type %T", typ))
    }
    return v.Interface()
}

func newkey() *ecdsa.PrivateKey {
    key, err := crypto.GenerateKey()
    if err != nil {
        panic("couldn't generate key: " + err.Error())
    }
    return key
}