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// Copyright 2016 The Go 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 nettest
import (
"bytes"
"encoding/binary"
"io"
"io/ioutil"
"math/rand"
"net"
"runtime"
"sync"
"testing"
"time"
)
// MakePipe creates a connection between two endpoints and returns the pair
// as c1 and c2, such that anything written to c1 is read by c2 and vice-versa.
// The stop function closes all resources, including c1, c2, and the underlying
// net.Listener (if there is one), and should not be nil.
type MakePipe func() (c1, c2 net.Conn, stop func(), err error)
// TestConn tests that a net.Conn implementation properly satisfies the interface.
// The tests should not produce any false positives, but may experience
// false negatives. Thus, some issues may only be detected when the test is
// run multiple times. For maximal effectiveness, run the tests under the
// race detector.
func TestConn(t *testing.T, mp MakePipe) {
t.Run("BasicIO", func(t *testing.T) { timeoutWrapper(t, mp, testBasicIO) })
t.Run("PingPong", func(t *testing.T) { timeoutWrapper(t, mp, testPingPong) })
t.Run("RacyRead", func(t *testing.T) { timeoutWrapper(t, mp, testRacyRead) })
t.Run("RacyWrite", func(t *testing.T) { timeoutWrapper(t, mp, testRacyWrite) })
t.Run("ReadTimeout", func(t *testing.T) { timeoutWrapper(t, mp, testReadTimeout) })
t.Run("WriteTimeout", func(t *testing.T) { timeoutWrapper(t, mp, testWriteTimeout) })
t.Run("PastTimeout", func(t *testing.T) { timeoutWrapper(t, mp, testPastTimeout) })
t.Run("PresentTimeout", func(t *testing.T) { timeoutWrapper(t, mp, testPresentTimeout) })
t.Run("FutureTimeout", func(t *testing.T) { timeoutWrapper(t, mp, testFutureTimeout) })
t.Run("CloseTimeout", func(t *testing.T) { timeoutWrapper(t, mp, testCloseTimeout) })
t.Run("ConcurrentMethods", func(t *testing.T) { timeoutWrapper(t, mp, testConcurrentMethods) })
}
type connTester func(t *testing.T, c1, c2 net.Conn)
func timeoutWrapper(t *testing.T, mp MakePipe, f connTester) {
t.Helper()
c1, c2, stop, err := mp()
if err != nil {
t.Fatalf("unable to make pipe: %v", err)
}
var once sync.Once
defer once.Do(func() { stop() })
timer := time.AfterFunc(time.Minute, func() {
once.Do(func() {
t.Error("test timed out; terminating pipe")
stop()
})
})
defer timer.Stop()
f(t, c1, c2)
}
// testBasicIO tests that the data sent on c1 is properly received on c2.
func testBasicIO(t *testing.T, c1, c2 net.Conn) {
want := make([]byte, 1<<20)
rand.New(rand.NewSource(0)).Read(want)
dataCh := make(chan []byte)
go func() {
rd := bytes.NewReader(want)
if err := chunkedCopy(c1, rd); err != nil {
t.Errorf("unexpected c1.Write error: %v", err)
}
if err := c1.Close(); err != nil {
t.Errorf("unexpected c1.Close error: %v", err)
}
}()
go func() {
wr := new(bytes.Buffer)
if err := chunkedCopy(wr, c2); err != nil {
t.Errorf("unexpected c2.Read error: %v", err)
}
if err := c2.Close(); err != nil {
t.Errorf("unexpected c2.Close error: %v", err)
}
dataCh <- wr.Bytes()
}()
if got := <-dataCh; !bytes.Equal(got, want) {
t.Error("transmitted data differs")
}
}
// testPingPong tests that the two endpoints can synchronously send data to
// each other in a typical request-response pattern.
func testPingPong(t *testing.T, c1, c2 net.Conn) {
var wg sync.WaitGroup
defer wg.Wait()
pingPonger := func(c net.Conn) {
defer wg.Done()
buf := make([]byte, 8)
var prev uint64
for {
if _, err := io.ReadFull(c, buf); err != nil {
if err == io.EOF {
break
}
t.Errorf("unexpected Read error: %v", err)
}
v := binary.LittleEndian.Uint64(buf)
binary.LittleEndian.PutUint64(buf, v+1)
if prev != 0 && prev+2 != v {
t.Errorf("mismatching value: got %d, want %d", v, prev+2)
}
prev = v
if v == 1000 {
break
}
if _, err := c.Write(buf); err != nil {
t.Errorf("unexpected Write error: %v", err)
break
}
}
if err := c.Close(); err != nil {
t.Errorf("unexpected Close error: %v", err)
}
}
wg.Add(2)
go pingPonger(c1)
go pingPonger(c2)
// Start off the chain reaction.
if _, err := c1.Write(make([]byte, 8)); err != nil {
t.Errorf("unexpected c1.Write error: %v", err)
}
}
// testRacyRead tests that it is safe to mutate the input Read buffer
// immediately after cancelation has occurred.
func testRacyRead(t *testing.T, c1, c2 net.Conn) {
go chunkedCopy(c2, rand.New(rand.NewSource(0)))
var wg sync.WaitGroup
defer wg.Wait()
c1.SetReadDeadline(time.Now().Add(time.Millisecond))
for i := 0; i < 10; i++ {
wg.Add(1)
go func() {
defer wg.Done()
b1 := make([]byte, 1024)
b2 := make([]byte, 1024)
for j := 0; j < 100; j++ {
_, err := c1.Read(b1)
copy(b1, b2) // Mutate b1 to trigger potential race
if err != nil {
checkForTimeoutError(t, err)
c1.SetReadDeadline(time.Now().Add(time.Millisecond))
}
}
}()
}
}
// testRacyWrite tests that it is safe to mutate the input Write buffer
// immediately after cancelation has occurred.
func testRacyWrite(t *testing.T, c1, c2 net.Conn) {
go chunkedCopy(ioutil.Discard, c2)
var wg sync.WaitGroup
defer wg.Wait()
c1.SetWriteDeadline(time.Now().Add(time.Millisecond))
for i := 0; i < 10; i++ {
wg.Add(1)
go func() {
defer wg.Done()
b1 := make([]byte, 1024)
b2 := make([]byte, 1024)
for j := 0; j < 100; j++ {
_, err := c1.Write(b1)
copy(b1, b2) // Mutate b1 to trigger potential race
if err != nil {
checkForTimeoutError(t, err)
c1.SetWriteDeadline(time.Now().Add(time.Millisecond))
}
}
}()
}
}
// testReadTimeout tests that Read timeouts do not affect Write.
func testReadTimeout(t *testing.T, c1, c2 net.Conn) {
go chunkedCopy(ioutil.Discard, c2)
c1.SetReadDeadline(aLongTimeAgo)
_, err := c1.Read(make([]byte, 1024))
checkForTimeoutError(t, err)
if _, err := c1.Write(make([]byte, 1024)); err != nil {
t.Errorf("unexpected Write error: %v", err)
}
}
// testWriteTimeout tests that Write timeouts do not affect Read.
func testWriteTimeout(t *testing.T, c1, c2 net.Conn) {
go chunkedCopy(c2, rand.New(rand.NewSource(0)))
c1.SetWriteDeadline(aLongTimeAgo)
_, err := c1.Write(make([]byte, 1024))
checkForTimeoutError(t, err)
if _, err := c1.Read(make([]byte, 1024)); err != nil {
t.Errorf("unexpected Read error: %v", err)
}
}
// testPastTimeout tests that a deadline set in the past immediately times out
// Read and Write requests.
func testPastTimeout(t *testing.T, c1, c2 net.Conn) {
go chunkedCopy(c2, c2)
testRoundtrip(t, c1)
c1.SetDeadline(aLongTimeAgo)
n, err := c1.Write(make([]byte, 1024))
if n != 0 {
t.Errorf("unexpected Write count: got %d, want 0", n)
}
checkForTimeoutError(t, err)
n, err = c1.Read(make([]byte, 1024))
if n != 0 {
t.Errorf("unexpected Read count: got %d, want 0", n)
}
checkForTimeoutError(t, err)
testRoundtrip(t, c1)
}
// testPresentTimeout tests that a past deadline set while there are pending
// Read and Write operations immediately times out those operations.
func testPresentTimeout(t *testing.T, c1, c2 net.Conn) {
var wg sync.WaitGroup
defer wg.Wait()
wg.Add(3)
deadlineSet := make(chan bool, 1)
go func() {
defer wg.Done()
time.Sleep(100 * time.Millisecond)
deadlineSet <- true
c1.SetReadDeadline(aLongTimeAgo)
c1.SetWriteDeadline(aLongTimeAgo)
}()
go func() {
defer wg.Done()
n, err := c1.Read(make([]byte, 1024))
if n != 0 {
t.Errorf("unexpected Read count: got %d, want 0", n)
}
checkForTimeoutError(t, err)
if len(deadlineSet) == 0 {
t.Error("Read timed out before deadline is set")
}
}()
go func() {
defer wg.Done()
var err error
for err == nil {
_, err = c1.Write(make([]byte, 1024))
}
checkForTimeoutError(t, err)
if len(deadlineSet) == 0 {
t.Error("Write timed out before deadline is set")
}
}()
}
// testFutureTimeout tests that a future deadline will eventually time out
// Read and Write operations.
func testFutureTimeout(t *testing.T, c1, c2 net.Conn) {
var wg sync.WaitGroup
wg.Add(2)
c1.SetDeadline(time.Now().Add(100 * time.Millisecond))
go func() {
defer wg.Done()
_, err := c1.Read(make([]byte, 1024))
checkForTimeoutError(t, err)
}()
go func() {
defer wg.Done()
var err error
for err == nil {
_, err = c1.Write(make([]byte, 1024))
}
checkForTimeoutError(t, err)
}()
wg.Wait()
go chunkedCopy(c2, c2)
resyncConn(t, c1)
testRoundtrip(t, c1)
}
// testCloseTimeout tests that calling Close immediately times out pending
// Read and Write operations.
func testCloseTimeout(t *testing.T, c1, c2 net.Conn) {
go chunkedCopy(c2, c2)
var wg sync.WaitGroup
defer wg.Wait()
wg.Add(3)
// Test for cancelation upon connection closure.
c1.SetDeadline(neverTimeout)
go func() {
defer wg.Done()
time.Sleep(100 * time.Millisecond)
c1.Close()
}()
go func() {
defer wg.Done()
var err error
buf := make([]byte, 1024)
for err == nil {
_, err = c1.Read(buf)
}
}()
go func() {
defer wg.Done()
var err error
buf := make([]byte, 1024)
for err == nil {
_, err = c1.Write(buf)
}
}()
}
// testConcurrentMethods tests that the methods of net.Conn can safely
// be called concurrently.
func testConcurrentMethods(t *testing.T, c1, c2 net.Conn) {
if runtime.GOOS == "plan9" {
t.Skip("skipping on plan9; see https://golang.org/issue/20489")
}
go chunkedCopy(c2, c2)
// The results of the calls may be nonsensical, but this should
// not trigger a race detector warning.
var wg sync.WaitGroup
for i := 0; i < 100; i++ {
wg.Add(7)
go func() {
defer wg.Done()
c1.Read(make([]byte, 1024))
}()
go func() {
defer wg.Done()
c1.Write(make([]byte, 1024))
}()
go func() {
defer wg.Done()
c1.SetDeadline(time.Now().Add(10 * time.Millisecond))
}()
go func() {
defer wg.Done()
c1.SetReadDeadline(aLongTimeAgo)
}()
go func() {
defer wg.Done()
c1.SetWriteDeadline(aLongTimeAgo)
}()
go func() {
defer wg.Done()
c1.LocalAddr()
}()
go func() {
defer wg.Done()
c1.RemoteAddr()
}()
}
wg.Wait() // At worst, the deadline is set 10ms into the future
resyncConn(t, c1)
testRoundtrip(t, c1)
}
// checkForTimeoutError checks that the error satisfies the Error interface
// and that Timeout returns true.
func checkForTimeoutError(t *testing.T, err error) {
t.Helper()
if nerr, ok := err.(net.Error); ok {
if !nerr.Timeout() {
t.Errorf("err.Timeout() = false, want true")
}
} else {
t.Errorf("got %T, want net.Error", err)
}
}
// testRoundtrip writes something into c and reads it back.
// It assumes that everything written into c is echoed back to itself.
func testRoundtrip(t *testing.T, c net.Conn) {
t.Helper()
if err := c.SetDeadline(neverTimeout); err != nil {
t.Errorf("roundtrip SetDeadline error: %v", err)
}
const s = "Hello, world!"
buf := []byte(s)
if _, err := c.Write(buf); err != nil {
t.Errorf("roundtrip Write error: %v", err)
}
if _, err := io.ReadFull(c, buf); err != nil {
t.Errorf("roundtrip Read error: %v", err)
}
if string(buf) != s {
t.Errorf("roundtrip data mismatch: got %q, want %q", buf, s)
}
}
// resyncConn resynchronizes the connection into a sane state.
// It assumes that everything written into c is echoed back to itself.
// It assumes that 0xff is not currently on the wire or in the read buffer.
func resyncConn(t *testing.T, c net.Conn) {
t.Helper()
c.SetDeadline(neverTimeout)
errCh := make(chan error)
go func() {
_, err := c.Write([]byte{0xff})
errCh <- err
}()
buf := make([]byte, 1024)
for {
n, err := c.Read(buf)
if n > 0 && bytes.IndexByte(buf[:n], 0xff) == n-1 {
break
}
if err != nil {
t.Errorf("unexpected Read error: %v", err)
break
}
}
if err := <-errCh; err != nil {
t.Errorf("unexpected Write error: %v", err)
}
}
// chunkedCopy copies from r to w in fixed-width chunks to avoid
// causing a Write that exceeds the maximum packet size for packet-based
// connections like "unixpacket".
// We assume that the maximum packet size is at least 1024.
func chunkedCopy(w io.Writer, r io.Reader) error {
b := make([]byte, 1024)
_, err := io.CopyBuffer(struct{ io.Writer }{w}, struct{ io.Reader }{r}, b)
return err
}