--- /dev/null
+// 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 provides utilities for network testing.
+package nettest
+
+import (
+ "bytes"
+ "encoding/binary"
+ "io"
+ "io/ioutil"
+ "math/rand"
+ "net"
+ "runtime"
+ "sync"
+ "testing"
+ "time"
+)
+
+var (
+ aLongTimeAgo = time.Unix(233431200, 0)
+ neverTimeout = time.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) {
+ testConn(t, mp)
+}
+
+type connTester func(t *testing.T, c1, c2 net.Conn)
+
+func timeoutWrapper(t *testing.T, mp MakePipe, f connTester) {
+ 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.Errorf("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 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) {
+ 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) {
+ 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) {
+ 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
+}
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