erigon-pulse/p2p/dnsdisc/client_test.go
Felix Lange b958c6447a p2p/dnsdisc: fix hot-spin when all trees are empty (#22313)
In the random sync algorithm used by the DNS node iterator, we first pick a random
tree and then perform one sync action on that tree. This happens in a loop until any
node is found. If no trees contain any nodes, the iterator will enter a hot loop spinning
at 100% CPU.

The fix is complicated. The iterator now checks if a meaningful sync action can
be performed on any tree. If there is nothing to do, it waits for the next root record
recheck time to arrive and then tries again.

Fixes #22306
2021-03-10 14:31:53 +01:00

445 lines
13 KiB
Go

// Copyright 2018 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
package dnsdisc
import (
"context"
"crypto/ecdsa"
"errors"
"math/rand"
"reflect"
"testing"
"time"
"github.com/davecgh/go-spew/spew"
"github.com/ledgerwatch/turbo-geth/common/mclock"
"github.com/ledgerwatch/turbo-geth/crypto"
"github.com/ledgerwatch/turbo-geth/internal/testlog"
"github.com/ledgerwatch/turbo-geth/log"
"github.com/ledgerwatch/turbo-geth/p2p/enode"
"github.com/ledgerwatch/turbo-geth/p2p/enr"
)
const (
signingKeySeed = 0x111111
nodesSeed1 = 0x2945237
nodesSeed2 = 0x4567299
)
func TestClientSyncTree(t *testing.T) {
r := mapResolver{
"n": "enrtree-root:v1 e=JWXYDBPXYWG6FX3GMDIBFA6CJ4 l=C7HRFPF3BLGF3YR4DY5KX3SMBE seq=1 sig=o908WmNp7LibOfPsr4btQwatZJ5URBr2ZAuxvK4UWHlsB9sUOTJQaGAlLPVAhM__XJesCHxLISo94z5Z2a463gA",
"C7HRFPF3BLGF3YR4DY5KX3SMBE.n": "enrtree://AM5FCQLWIZX2QFPNJAP7VUERCCRNGRHWZG3YYHIUV7BVDQ5FDPRT2@morenodes.example.org",
"JWXYDBPXYWG6FX3GMDIBFA6CJ4.n": "enrtree-branch:2XS2367YHAXJFGLZHVAWLQD4ZY,H4FHT4B454P6UXFD7JCYQ5PWDY,MHTDO6TMUBRIA2XWG5LUDACK24",
"2XS2367YHAXJFGLZHVAWLQD4ZY.n": "enr:-HW4QOFzoVLaFJnNhbgMoDXPnOvcdVuj7pDpqRvh6BRDO68aVi5ZcjB3vzQRZH2IcLBGHzo8uUN3snqmgTiE56CH3AMBgmlkgnY0iXNlY3AyNTZrMaECC2_24YYkYHEgdzxlSNKQEnHhuNAbNlMlWJxrJxbAFvA",
"H4FHT4B454P6UXFD7JCYQ5PWDY.n": "enr:-HW4QAggRauloj2SDLtIHN1XBkvhFZ1vtf1raYQp9TBW2RD5EEawDzbtSmlXUfnaHcvwOizhVYLtr7e6vw7NAf6mTuoCgmlkgnY0iXNlY3AyNTZrMaECjrXI8TLNXU0f8cthpAMxEshUyQlK-AM0PW2wfrnacNI",
"MHTDO6TMUBRIA2XWG5LUDACK24.n": "enr:-HW4QLAYqmrwllBEnzWWs7I5Ev2IAs7x_dZlbYdRdMUx5EyKHDXp7AV5CkuPGUPdvbv1_Ms1CPfhcGCvSElSosZmyoqAgmlkgnY0iXNlY3AyNTZrMaECriawHKWdDRk2xeZkrOXBQ0dfMFLHY4eENZwdufn1S1o",
}
var (
wantNodes = testNodes(0x29452, 3)
wantLinks = []string{"enrtree://AM5FCQLWIZX2QFPNJAP7VUERCCRNGRHWZG3YYHIUV7BVDQ5FDPRT2@morenodes.example.org"}
wantSeq = uint(1)
)
c := NewClient(Config{Resolver: r, Logger: testlog.Logger(t, log.LvlTrace)})
stree, err := c.SyncTree("enrtree://AKPYQIUQIL7PSIACI32J7FGZW56E5FKHEFCCOFHILBIMW3M6LWXS2@n")
if err != nil {
t.Fatal("sync error:", err)
}
if !reflect.DeepEqual(sortByID(stree.Nodes()), sortByID(wantNodes)) {
t.Errorf("wrong nodes in synced tree:\nhave %v\nwant %v", spew.Sdump(stree.Nodes()), spew.Sdump(wantNodes))
}
if !reflect.DeepEqual(stree.Links(), wantLinks) {
t.Errorf("wrong links in synced tree: %v", stree.Links())
}
if stree.Seq() != wantSeq {
t.Errorf("synced tree has wrong seq: %d", stree.Seq())
}
}
// In this test, syncing the tree fails because it contains an invalid ENR entry.
func TestClientSyncTreeBadNode(t *testing.T) {
// var b strings.Builder
// b.WriteString(enrPrefix)
// b.WriteString("-----")
// badHash := subdomain(&b)
// tree, _ := MakeTree(3, nil, []string{"enrtree://AM5FCQLWIZX2QFPNJAP7VUERCCRNGRHWZG3YYHIUV7BVDQ5FDPRT2@morenodes.example.org"})
// tree.entries[badHash] = &b
// tree.root.eroot = badHash
// url, _ := tree.Sign(testKey(signingKeySeed), "n")
// fmt.Println(url)
// fmt.Printf("%#v\n", tree.ToTXT("n"))
r := mapResolver{
"n": "enrtree-root:v1 e=INDMVBZEEQ4ESVYAKGIYU74EAA l=C7HRFPF3BLGF3YR4DY5KX3SMBE seq=3 sig=Vl3AmunLur0JZ3sIyJPSH6A3Vvdp4F40jWQeCmkIhmcgwE4VC5U9wpK8C_uL_CMY29fd6FAhspRvq2z_VysTLAA",
"C7HRFPF3BLGF3YR4DY5KX3SMBE.n": "enrtree://AM5FCQLWIZX2QFPNJAP7VUERCCRNGRHWZG3YYHIUV7BVDQ5FDPRT2@morenodes.example.org",
"INDMVBZEEQ4ESVYAKGIYU74EAA.n": "enr:-----",
}
c := NewClient(Config{Resolver: r, Logger: testlog.Logger(t, log.LvlTrace)})
_, err := c.SyncTree("enrtree://AKPYQIUQIL7PSIACI32J7FGZW56E5FKHEFCCOFHILBIMW3M6LWXS2@n")
wantErr := nameError{name: "INDMVBZEEQ4ESVYAKGIYU74EAA.n", err: entryError{typ: "enr", err: errInvalidENR}}
if err != wantErr {
t.Fatalf("expected sync error %q, got %q", wantErr, err)
}
}
// This test checks that randomIterator finds all entries.
func TestIterator(t *testing.T) {
nodes := testNodes(nodesSeed1, 30)
tree, url := makeTestTree("n", nodes, nil)
r := mapResolver(tree.ToTXT("n"))
c := NewClient(Config{
Resolver: r,
Logger: testlog.Logger(t, log.LvlTrace),
RateLimit: 500,
})
it, err := c.NewIterator(url)
if err != nil {
t.Fatal(err)
}
checkIterator(t, it, nodes)
}
// This test checks if closing randomIterator races.
func TestIteratorClose(t *testing.T) {
nodes := testNodes(nodesSeed1, 500)
tree1, url1 := makeTestTree("t1", nodes, nil)
c := NewClient(Config{Resolver: newMapResolver(tree1.ToTXT("t1"))})
it, err := c.NewIterator(url1)
if err != nil {
t.Fatal(err)
}
done := make(chan struct{})
go func() {
for it.Next() {
_ = it.Node()
}
close(done)
}()
time.Sleep(50 * time.Millisecond)
it.Close()
<-done
}
// This test checks that randomIterator traverses linked trees as well as explicitly added trees.
func TestIteratorLinks(t *testing.T) {
nodes := testNodes(nodesSeed1, 40)
tree1, url1 := makeTestTree("t1", nodes[:10], nil)
tree2, url2 := makeTestTree("t2", nodes[10:], []string{url1})
c := NewClient(Config{
Resolver: newMapResolver(tree1.ToTXT("t1"), tree2.ToTXT("t2")),
Logger: testlog.Logger(t, log.LvlTrace),
RateLimit: 500,
})
it, err := c.NewIterator(url2)
if err != nil {
t.Fatal(err)
}
checkIterator(t, it, nodes)
}
// This test verifies that randomIterator re-checks the root of the tree to catch
// updates to nodes.
func TestIteratorNodeUpdates(t *testing.T) {
var (
clock = new(mclock.Simulated)
nodes = testNodes(nodesSeed1, 30)
resolver = newMapResolver()
c = NewClient(Config{
Resolver: resolver,
Logger: testlog.Logger(t, log.LvlTrace),
RecheckInterval: 20 * time.Minute,
RateLimit: 500,
})
)
c.clock = clock
tree1, url := makeTestTree("n", nodes[:25], nil)
it, err := c.NewIterator(url)
if err != nil {
t.Fatal(err)
}
// Sync the original tree.
resolver.add(tree1.ToTXT("n"))
checkIterator(t, it, nodes[:25])
// Ensure RandomNode returns the new nodes after the tree is updated.
updateSomeNodes(nodesSeed1, nodes)
tree2, _ := makeTestTree("n", nodes, nil)
resolver.clear()
resolver.add(tree2.ToTXT("n"))
t.Log("tree updated")
clock.Run(c.cfg.RecheckInterval + 1*time.Second)
checkIterator(t, it, nodes)
}
// This test checks that the tree root is rechecked when a couple of leaf
// requests have failed. The test is just like TestIteratorNodeUpdates, but
// without advancing the clock by recheckInterval after the tree update.
func TestIteratorRootRecheckOnFail(t *testing.T) {
var (
clock = new(mclock.Simulated)
nodes = testNodes(nodesSeed1, 30)
resolver = newMapResolver()
c = NewClient(Config{
Resolver: resolver,
Logger: testlog.Logger(t, log.LvlTrace),
RecheckInterval: 20 * time.Minute,
RateLimit: 500,
// Disabling the cache is required for this test because the client doesn't
// notice leaf failures if all records are cached.
CacheLimit: 1,
})
)
c.clock = clock
tree1, url := makeTestTree("n", nodes[:25], nil)
it, err := c.NewIterator(url)
if err != nil {
t.Fatal(err)
}
// Sync the original tree.
resolver.add(tree1.ToTXT("n"))
checkIterator(t, it, nodes[:25])
// Ensure RandomNode returns the new nodes after the tree is updated.
updateSomeNodes(nodesSeed1, nodes)
tree2, _ := makeTestTree("n", nodes, nil)
resolver.clear()
resolver.add(tree2.ToTXT("n"))
t.Log("tree updated")
checkIterator(t, it, nodes)
}
// This test checks that the iterator works correctly when the tree is initially empty.
func TestIteratorEmptyTree(t *testing.T) {
var (
clock = new(mclock.Simulated)
nodes = testNodes(nodesSeed1, 1)
resolver = newMapResolver()
c = NewClient(Config{
Resolver: resolver,
Logger: testlog.Logger(t, log.LvlTrace),
RecheckInterval: 20 * time.Minute,
RateLimit: 500,
})
)
c.clock = clock
tree1, url := makeTestTree("n", nil, nil)
tree2, _ := makeTestTree("n", nodes, nil)
resolver.add(tree1.ToTXT("n"))
// Start the iterator.
node := make(chan *enode.Node)
it, err := c.NewIterator(url)
if err != nil {
t.Fatal(err)
}
go func() {
it.Next()
node <- it.Node()
}()
// Wait for the client to get stuck in waitForRootUpdates.
clock.WaitForTimers(1)
// Now update the root.
resolver.add(tree2.ToTXT("n"))
// Wait for it to pick up the root change.
clock.Run(c.cfg.RecheckInterval)
select {
case n := <-node:
if n.ID() != nodes[0].ID() {
t.Fatalf("wrong node returned")
}
case <-time.After(5 * time.Second):
t.Fatal("it.Next() did not unblock within 5s of real time")
}
}
// updateSomeNodes applies ENR updates to some of the given nodes.
func updateSomeNodes(_ int64, nodes []*enode.Node) {
keys := testKeys(nodesSeed1, len(nodes))
for i, n := range nodes[:len(nodes)/2] {
r := n.Record()
r.Set(enr.IP{127, 0, 0, 1})
r.SetSeq(55)
enode.SignV4(r, keys[i])
n2, _ := enode.New(enode.ValidSchemes, r)
nodes[i] = n2
}
}
// This test verifies that randomIterator re-checks the root of the tree to catch
// updates to links.
func TestIteratorLinkUpdates(t *testing.T) {
var (
clock = new(mclock.Simulated)
nodes = testNodes(nodesSeed1, 30)
resolver = newMapResolver()
c = NewClient(Config{
Resolver: resolver,
Logger: testlog.Logger(t, log.LvlTrace),
RecheckInterval: 20 * time.Minute,
RateLimit: 500,
})
)
c.clock = clock
tree3, url3 := makeTestTree("t3", nodes[20:30], nil)
tree2, url2 := makeTestTree("t2", nodes[10:20], nil)
tree1, url1 := makeTestTree("t1", nodes[0:10], []string{url2})
resolver.add(tree1.ToTXT("t1"))
resolver.add(tree2.ToTXT("t2"))
resolver.add(tree3.ToTXT("t3"))
it, err := c.NewIterator(url1)
if err != nil {
t.Fatal(err)
}
// Sync tree1 using RandomNode.
checkIterator(t, it, nodes[:20])
// Add link to tree3, remove link to tree2.
tree1, _ = makeTestTree("t1", nodes[:10], []string{url3})
resolver.add(tree1.ToTXT("t1"))
t.Log("tree1 updated")
clock.Run(c.cfg.RecheckInterval + 1*time.Second)
var wantNodes []*enode.Node
wantNodes = append(wantNodes, tree1.Nodes()...)
wantNodes = append(wantNodes, tree3.Nodes()...)
checkIterator(t, it, wantNodes)
// Check that linked trees are GCed when they're no longer referenced.
knownTrees := it.(*randomIterator).trees
if len(knownTrees) != 2 {
t.Errorf("client knows %d trees, want 2", len(knownTrees))
}
}
func checkIterator(t *testing.T, it enode.Iterator, wantNodes []*enode.Node) {
t.Helper()
var (
want = make(map[enode.ID]*enode.Node)
maxCalls = len(wantNodes) * 3
calls = 0
)
for _, n := range wantNodes {
want[n.ID()] = n
}
for ; len(want) > 0 && calls < maxCalls; calls++ {
if !it.Next() {
t.Fatalf("Next returned false (call %d)", calls)
}
n := it.Node()
delete(want, n.ID())
}
t.Logf("checkIterator called Next %d times to find %d nodes", calls, len(wantNodes))
for _, n := range want {
t.Errorf("iterator didn't discover node %v", n.ID())
}
}
func makeTestTree(domain string, nodes []*enode.Node, links []string) (*Tree, string) {
tree, err := MakeTree(1, nodes, links)
if err != nil {
panic(err)
}
url, err := tree.Sign(testKey(signingKeySeed), domain)
if err != nil {
panic(err)
}
return tree, url
}
// testKeys creates deterministic private keys for testing.
func testKeys(seed int64, n int) []*ecdsa.PrivateKey {
rand := rand.New(rand.NewSource(seed))
keys := make([]*ecdsa.PrivateKey, n)
for i := 0; i < n; i++ {
key, err := ecdsa.GenerateKey(crypto.S256(), rand)
if err != nil {
panic("can't generate key: " + err.Error())
}
keys[i] = key
}
return keys
}
func testKey(seed int64) *ecdsa.PrivateKey {
return testKeys(seed, 1)[0]
}
func testNodes(seed int64, n int) []*enode.Node {
keys := testKeys(seed, n)
nodes := make([]*enode.Node, n)
for i, key := range keys {
record := new(enr.Record)
record.SetSeq(uint64(i))
enode.SignV4(record, key)
n, err := enode.New(enode.ValidSchemes, record)
if err != nil {
panic(err)
}
nodes[i] = n
}
return nodes
}
func testNode(seed int64) *enode.Node {
return testNodes(seed, 1)[0]
}
type mapResolver map[string]string
func newMapResolver(maps ...map[string]string) mapResolver {
mr := make(mapResolver)
for _, m := range maps {
mr.add(m)
}
return mr
}
func (mr mapResolver) clear() {
for k := range mr {
delete(mr, k)
}
}
func (mr mapResolver) add(m map[string]string) {
for k, v := range m {
mr[k] = v
}
}
func (mr mapResolver) LookupTXT(ctx context.Context, name string) ([]string, error) {
if record, ok := mr[name]; ok {
return []string{record}, nil
}
return nil, errors.New("not found")
}