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tailscale/derp/derp_test.go

394 lines
8.6 KiB
Go

// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package derp
import (
"bufio"
"context"
crand "crypto/rand"
"errors"
"expvar"
"fmt"
"io"
"net"
"testing"
"time"
"tailscale.com/net/nettest"
"tailscale.com/types/key"
)
func newPrivateKey(t *testing.T) (k key.Private) {
t.Helper()
if _, err := crand.Read(k[:]); err != nil {
t.Fatal(err)
}
return
}
func TestSendRecv(t *testing.T) {
serverPrivateKey := newPrivateKey(t)
s := NewServer(serverPrivateKey, t.Logf)
defer s.Close()
const numClients = 3
var clientPrivateKeys []key.Private
var clientKeys []key.Public
for i := 0; i < numClients; i++ {
priv := newPrivateKey(t)
clientPrivateKeys = append(clientPrivateKeys, priv)
clientKeys = append(clientKeys, priv.Public())
}
ln, err := net.Listen("tcp", ":0")
if err != nil {
t.Fatal(err)
}
defer ln.Close()
var clients []*Client
var connsOut []Conn
var recvChs []chan []byte
errCh := make(chan error, 3)
for i := 0; i < numClients; i++ {
t.Logf("Connecting client %d ...", i)
cout, err := net.Dial("tcp", ln.Addr().String())
if err != nil {
t.Fatal(err)
}
defer cout.Close()
connsOut = append(connsOut, cout)
cin, err := ln.Accept()
if err != nil {
t.Fatal(err)
}
defer cin.Close()
brwServer := bufio.NewReadWriter(bufio.NewReader(cin), bufio.NewWriter(cin))
go s.Accept(cin, brwServer, fmt.Sprintf("test-client-%d", i))
key := clientPrivateKeys[i]
brw := bufio.NewReadWriter(bufio.NewReader(cout), bufio.NewWriter(cout))
c, err := NewClient(key, cout, brw, t.Logf)
if err != nil {
t.Fatalf("client %d: %v", i, err)
}
clients = append(clients, c)
recvChs = append(recvChs, make(chan []byte))
t.Logf("Connected client %d.", i)
}
var peerGoneCount expvar.Int
t.Logf("Starting read loops")
for i := 0; i < numClients; i++ {
go func(i int) {
for {
b := make([]byte, 1<<16)
m, err := clients[i].Recv(b)
if err != nil {
errCh <- err
return
}
switch m := m.(type) {
default:
t.Errorf("unexpected message type %T", m)
continue
case PeerGoneMessage:
peerGoneCount.Add(1)
case ReceivedPacket:
if m.Source.IsZero() {
t.Errorf("zero Source address in ReceivedPacket")
}
recvChs[i] <- m.Data
}
}
}(i)
}
recv := func(i int, want string) {
t.Helper()
select {
case b := <-recvChs[i]:
if got := string(b); got != want {
t.Errorf("client1.Recv=%q, want %q", got, want)
}
case <-time.After(1 * time.Second):
t.Errorf("client%d.Recv, got nothing, want %q", i, want)
}
}
recvNothing := func(i int) {
t.Helper()
select {
case b := <-recvChs[0]:
t.Errorf("client%d.Recv=%q, want nothing", i, string(b))
default:
}
}
wantActive := func(total, home int64) {
t.Helper()
dl := time.Now().Add(5 * time.Second)
var gotTotal, gotHome int64
for time.Now().Before(dl) {
gotTotal, gotHome = s.curClients.Value(), s.curHomeClients.Value()
if gotTotal == total && gotHome == home {
return
}
time.Sleep(10 * time.Millisecond)
}
t.Errorf("total/home=%v/%v; want %v/%v", gotTotal, gotHome, total, home)
}
wantClosedPeers := func(want int64) {
t.Helper()
var got int64
dl := time.Now().Add(5 * time.Second)
for time.Now().Before(dl) {
if got = peerGoneCount.Value(); got == want {
return
}
}
t.Errorf("peer gone count = %v; want %v", got, want)
}
msg1 := []byte("hello 0->1\n")
if err := clients[0].Send(clientKeys[1], msg1); err != nil {
t.Fatal(err)
}
recv(1, string(msg1))
recvNothing(0)
recvNothing(2)
msg2 := []byte("hello 1->2\n")
if err := clients[1].Send(clientKeys[2], msg2); err != nil {
t.Fatal(err)
}
recv(2, string(msg2))
recvNothing(0)
recvNothing(1)
wantActive(3, 0)
clients[0].NotePreferred(true)
wantActive(3, 1)
clients[0].NotePreferred(true)
wantActive(3, 1)
clients[0].NotePreferred(false)
wantActive(3, 0)
clients[0].NotePreferred(false)
wantActive(3, 0)
clients[1].NotePreferred(true)
wantActive(3, 1)
connsOut[1].Close()
wantActive(2, 0)
wantClosedPeers(1)
clients[2].NotePreferred(true)
wantActive(2, 1)
clients[2].NotePreferred(false)
wantActive(2, 0)
connsOut[2].Close()
wantActive(1, 0)
wantClosedPeers(1)
t.Logf("passed")
s.Close()
}
func TestSendFreeze(t *testing.T) {
serverPrivateKey := newPrivateKey(t)
s := NewServer(serverPrivateKey, t.Logf)
defer s.Close()
s.WriteTimeout = 100 * time.Millisecond
// We send two streams of messages:
//
// alice --> bob
// alice --> cathy
//
// Then cathy stops processing messsages.
// That should not interfere with alice talking to bob.
newClient := func(name string, k key.Private) (c *Client, clientConn nettest.Conn) {
t.Helper()
c1, c2 := nettest.NewConn(name, 1024)
go s.Accept(c1, bufio.NewReadWriter(bufio.NewReader(c1), bufio.NewWriter(c1)), name)
brw := bufio.NewReadWriter(bufio.NewReader(c2), bufio.NewWriter(c2))
c, err := NewClient(k, c2, brw, t.Logf)
if err != nil {
t.Fatal(err)
}
return c, c2
}
aliceKey := newPrivateKey(t)
aliceClient, aliceConn := newClient("alice", aliceKey)
bobKey := newPrivateKey(t)
bobClient, bobConn := newClient("bob", bobKey)
cathyKey := newPrivateKey(t)
cathyClient, cathyConn := newClient("cathy", cathyKey)
var (
aliceCh = make(chan struct{}, 32)
bobCh = make(chan struct{}, 32)
cathyCh = make(chan struct{}, 32)
)
chs := func(name string) chan struct{} {
switch name {
case "alice":
return aliceCh
case "bob":
return bobCh
case "cathy":
return cathyCh
default:
panic("unknown ch: " + name)
}
}
errCh := make(chan error, 4)
recv := func(name string, client *Client) {
ch := chs(name)
for {
b := make([]byte, 1<<9)
m, err := client.Recv(b)
if err != nil {
errCh <- fmt.Errorf("%s: %w", name, err)
return
}
switch m := m.(type) {
default:
errCh <- fmt.Errorf("%s: unexpected message type %T", name, m)
return
case ReceivedPacket:
if m.Source.IsZero() {
errCh <- fmt.Errorf("%s: zero Source address in ReceivedPacket", name)
return
}
select {
case ch <- struct{}{}:
default:
}
}
}
}
go recv("alice", aliceClient)
go recv("bob", bobClient)
go recv("cathy", cathyClient)
var cancel func()
go func() {
t := time.NewTicker(2 * time.Millisecond)
defer t.Stop()
var ctx context.Context
ctx, cancel = context.WithCancel(context.Background())
for {
select {
case <-t.C:
case <-ctx.Done():
errCh <- nil
return
}
msg1 := []byte("hello alice->bob\n")
if err := aliceClient.Send(bobKey.Public(), msg1); err != nil {
errCh <- fmt.Errorf("alice send to bob: %w", err)
return
}
msg2 := []byte("hello alice->cathy\n")
// TODO: an error is expected here.
// We ignore it, maybe we should log it somehow?
aliceClient.Send(cathyKey.Public(), msg2)
}
}()
drainAny := func(ch chan struct{}) {
// We are draining potentially infinite sources,
// so place some reasonable upper limit.
//
// The important thing here is to make sure that
// if any tokens remain in the channel, they
// must have been generated after drainAny was
// called.
for i := 0; i < cap(ch); i++ {
select {
case <-ch:
default:
return
}
}
}
drain := func(t *testing.T, name string) bool {
t.Helper()
timer := time.NewTimer(1 * time.Second)
defer timer.Stop()
// Ensure ch has at least one element.
ch := chs(name)
select {
case <-ch:
case <-timer.C:
t.Errorf("no packet received by %s", name)
return false
}
// Drain remaining.
drainAny(ch)
return true
}
isEmpty := func(t *testing.T, name string) {
t.Helper()
select {
case <-chs(name):
t.Errorf("packet received by %s, want none", name)
default:
}
}
t.Run("initial send", func(t *testing.T) {
drain(t, "bob")
drain(t, "cathy")
isEmpty(t, "alice")
})
t.Run("block cathy", func(t *testing.T) {
// Block cathy. Now the cathyConn buffer will fill up quickly,
// and the derp server will back up.
cathyConn.SetReadBlock(true)
time.Sleep(2 * s.WriteTimeout)
drain(t, "bob")
drainAny(chs("cathy"))
isEmpty(t, "alice")
// Now wait a little longer, and ensure packets still flow to bob
if !drain(t, "bob") {
t.Errorf("connection alice->bob frozen by alice->cathy")
}
})
// Cleanup, make sure we process all errors.
t.Logf("TEST COMPLETE, cancelling sender")
cancel()
t.Logf("closing connections")
aliceConn.Close()
bobConn.Close()
cathyConn.Close()
for i := 0; i < cap(errCh); i++ {
err := <-errCh
if err != nil {
if errors.Is(err, io.EOF) {
continue
}
t.Error(err)
}
}
}