path: root/p2p/discover/table_test.go

package discover

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

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

func TestTable_pingReplace(t *testing.T) {
    doit := func(newNodeIsResponding, lastInBucketIsResponding bool) {
        transport := newPingRecorder()
        tab := newTable(transport, NodeID{}, &net.UDPAddr{})
        last := fillBucket(tab, 200)
        pingSender := randomID(tab.self.ID, 200)

        // this gotPing should replace the last node
        // if the last node is not responding.
        transport.responding[last.ID] = lastInBucketIsResponding
        transport.responding[pingSender] = newNodeIsResponding
        tab.bond(true, pingSender, &net.UDPAddr{}, 0)

        // first ping goes to sender (bonding pingback)
        if !transport.pinged[pingSender] {
            t.Error("table did not ping back sender")
        }
        if newNodeIsResponding {
            // second ping goes to oldest node in bucket
            // to see whether it is still alive.
            if !transport.pinged[last.ID] {
                t.Error("table did not ping last node in bucket")
            }
        }

        tab.mutex.Lock()
        defer tab.mutex.Unlock()
        if l := len(tab.buckets[200].entries); l != bucketSize {
            t.Errorf("wrong bucket size after gotPing: got %d, want %d", bucketSize, l)
        }

        if lastInBucketIsResponding || !newNodeIsResponding {
            if !contains(tab.buckets[200].entries, last.ID) {
                t.Error("last entry was removed")
            }
            if contains(tab.buckets[200].entries, pingSender) {
                t.Error("new entry was added")
            }
        } else {
            if contains(tab.buckets[200].entries, last.ID) {
                t.Error("last entry was not removed")
            }
            if !contains(tab.buckets[200].entries, pingSender) {
                t.Error("new entry was not added")
            }
        }
    }

    doit(true, true)
    doit(false, true)
    doit(false, true)
    doit(false, false)
}

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 pingRecorder struct{ responding, pinged map[NodeID]bool }

func newPingRecorder() *pingRecorder {
    return &pingRecorder{make(map[NodeID]bool), make(map[NodeID]bool)}
}

func (t *pingRecorder) findnode(toid NodeID, toaddr *net.UDPAddr, target NodeID) ([]*Node, error) {
    panic("findnode called on pingRecorder")
}
func (t *pingRecorder) close() {
    panic("close called on pingRecorder")
}
func (t *pingRecorder) waitping(from NodeID) error {
    return nil // remote always pings
}
func (t *pingRecorder) ping(toid NodeID, toaddr *net.UDPAddr) error {
    t.pinged[toid] = true
    if t.responding[toid] {
        return nil
    } else {
        return errTimeout
    }
}

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

func (t findnodeOracle) close()                                      {}
func (t findnodeOracle) waitping(from NodeID) error                  { return nil }
func (t findnodeOracle) ping(toid NodeID, toaddr *net.UDPAddr) error { return nil }

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
}