// Copyright 2012 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 tls import ( "bytes" "crypto/x509" "errors" "fmt" "internal/testenv" "io" "io/ioutil" "math" "math/rand" "net" "os" "reflect" "strings" "testing" "testing/quick" "time" ) var rsaCertPEM = `-----BEGIN CERTIFICATE----- MIIB0zCCAX2gAwIBAgIJAI/M7BYjwB+uMA0GCSqGSIb3DQEBBQUAMEUxCzAJBgNV BAYTAkFVMRMwEQYDVQQIDApTb21lLVN0YXRlMSEwHwYDVQQKDBhJbnRlcm5ldCBX aWRnaXRzIFB0eSBMdGQwHhcNMTIwOTEyMjE1MjAyWhcNMTUwOTEyMjE1MjAyWjBF MQswCQYDVQQGEwJBVTETMBEGA1UECAwKU29tZS1TdGF0ZTEhMB8GA1UECgwYSW50 ZXJuZXQgV2lkZ2l0cyBQdHkgTHRkMFwwDQYJKoZIhvcNAQEBBQADSwAwSAJBANLJ hPHhITqQbPklG3ibCVxwGMRfp/v4XqhfdQHdcVfHap6NQ5Wok/4xIA+ui35/MmNa rtNuC+BdZ1tMuVCPFZcCAwEAAaNQME4wHQYDVR0OBBYEFJvKs8RfJaXTH08W+SGv zQyKn0H8MB8GA1UdIwQYMBaAFJvKs8RfJaXTH08W+SGvzQyKn0H8MAwGA1UdEwQF MAMBAf8wDQYJKoZIhvcNAQEFBQADQQBJlffJHybjDGxRMqaRmDhX0+6v02TUKZsW r5QuVbpQhH6u+0UgcW0jp9QwpxoPTLTWGXEWBBBurxFwiCBhkQ+V -----END CERTIFICATE----- ` var rsaKeyPEM = `-----BEGIN RSA PRIVATE KEY----- MIIBOwIBAAJBANLJhPHhITqQbPklG3ibCVxwGMRfp/v4XqhfdQHdcVfHap6NQ5Wo k/4xIA+ui35/MmNartNuC+BdZ1tMuVCPFZcCAwEAAQJAEJ2N+zsR0Xn8/Q6twa4G 6OB1M1WO+k+ztnX/1SvNeWu8D6GImtupLTYgjZcHufykj09jiHmjHx8u8ZZB/o1N MQIhAPW+eyZo7ay3lMz1V01WVjNKK9QSn1MJlb06h/LuYv9FAiEA25WPedKgVyCW SmUwbPw8fnTcpqDWE3yTO3vKcebqMSsCIBF3UmVue8YU3jybC3NxuXq3wNm34R8T xVLHwDXh/6NJAiEAl2oHGGLz64BuAfjKrqwz7qMYr9HCLIe/YsoWq/olzScCIQDi D2lWusoe2/nEqfDVVWGWlyJ7yOmqaVm/iNUN9B2N2g== -----END RSA PRIVATE KEY----- ` // keyPEM is the same as rsaKeyPEM, but declares itself as just // "PRIVATE KEY", not "RSA PRIVATE KEY". https://golang.org/issue/4477 var keyPEM = `-----BEGIN PRIVATE KEY----- MIIBOwIBAAJBANLJhPHhITqQbPklG3ibCVxwGMRfp/v4XqhfdQHdcVfHap6NQ5Wo k/4xIA+ui35/MmNartNuC+BdZ1tMuVCPFZcCAwEAAQJAEJ2N+zsR0Xn8/Q6twa4G 6OB1M1WO+k+ztnX/1SvNeWu8D6GImtupLTYgjZcHufykj09jiHmjHx8u8ZZB/o1N MQIhAPW+eyZo7ay3lMz1V01WVjNKK9QSn1MJlb06h/LuYv9FAiEA25WPedKgVyCW SmUwbPw8fnTcpqDWE3yTO3vKcebqMSsCIBF3UmVue8YU3jybC3NxuXq3wNm34R8T xVLHwDXh/6NJAiEAl2oHGGLz64BuAfjKrqwz7qMYr9HCLIe/YsoWq/olzScCIQDi D2lWusoe2/nEqfDVVWGWlyJ7yOmqaVm/iNUN9B2N2g== -----END PRIVATE KEY----- ` var ecdsaCertPEM = `-----BEGIN CERTIFICATE----- MIIB/jCCAWICCQDscdUxw16XFDAJBgcqhkjOPQQBMEUxCzAJBgNVBAYTAkFVMRMw EQYDVQQIEwpTb21lLVN0YXRlMSEwHwYDVQQKExhJbnRlcm5ldCBXaWRnaXRzIFB0 eSBMdGQwHhcNMTIxMTE0MTI0MDQ4WhcNMTUxMTE0MTI0MDQ4WjBFMQswCQYDVQQG EwJBVTETMBEGA1UECBMKU29tZS1TdGF0ZTEhMB8GA1UEChMYSW50ZXJuZXQgV2lk Z2l0cyBQdHkgTHRkMIGbMBAGByqGSM49AgEGBSuBBAAjA4GGAAQBY9+my9OoeSUR lDQdV/x8LsOuLilthhiS1Tz4aGDHIPwC1mlvnf7fg5lecYpMCrLLhauAc1UJXcgl 01xoLuzgtAEAgv2P/jgytzRSpUYvgLBt1UA0leLYBy6mQQbrNEuqT3INapKIcUv8 XxYP0xMEUksLPq6Ca+CRSqTtrd/23uTnapkwCQYHKoZIzj0EAQOBigAwgYYCQXJo A7Sl2nLVf+4Iu/tAX/IF4MavARKC4PPHK3zfuGfPR3oCCcsAoz3kAzOeijvd0iXb H5jBImIxPL4WxQNiBTexAkF8D1EtpYuWdlVQ80/h/f4pBcGiXPqX5h2PQSQY7hP1 +jwM1FGS4fREIOvlBYr/SzzQRtwrvrzGYxDEDbsC0ZGRnA== -----END CERTIFICATE----- ` var ecdsaKeyPEM = `-----BEGIN EC PARAMETERS----- BgUrgQQAIw== -----END EC PARAMETERS----- -----BEGIN EC PRIVATE KEY----- MIHcAgEBBEIBrsoKp0oqcv6/JovJJDoDVSGWdirrkgCWxrprGlzB9o0X8fV675X0 NwuBenXFfeZvVcwluO7/Q9wkYoPd/t3jGImgBwYFK4EEACOhgYkDgYYABAFj36bL 06h5JRGUNB1X/Hwuw64uKW2GGJLVPPhoYMcg/ALWaW+d/t+DmV5xikwKssuFq4Bz VQldyCXTXGgu7OC0AQCC/Y/+ODK3NFKlRi+AsG3VQDSV4tgHLqZBBus0S6pPcg1q kohxS/xfFg/TEwRSSws+roJr4JFKpO2t3/be5OdqmQ== -----END EC PRIVATE KEY----- ` var keyPairTests = []struct { algo string cert string key string }{ {"ECDSA", ecdsaCertPEM, ecdsaKeyPEM}, {"RSA", rsaCertPEM, rsaKeyPEM}, {"RSA-untyped", rsaCertPEM, keyPEM}, // golang.org/issue/4477 } func TestX509KeyPair(t *testing.T) { t.Parallel() var pem []byte for _, test := range keyPairTests { pem = []byte(test.cert + test.key) if _, err := X509KeyPair(pem, pem); err != nil { t.Errorf("Failed to load %s cert followed by %s key: %s", test.algo, test.algo, err) } pem = []byte(test.key + test.cert) if _, err := X509KeyPair(pem, pem); err != nil { t.Errorf("Failed to load %s key followed by %s cert: %s", test.algo, test.algo, err) } } } func TestX509KeyPairErrors(t *testing.T) { _, err := X509KeyPair([]byte(rsaKeyPEM), []byte(rsaCertPEM)) if err == nil { t.Fatalf("X509KeyPair didn't return an error when arguments were switched") } if subStr := "been switched"; !strings.Contains(err.Error(), subStr) { t.Fatalf("Expected %q in the error when switching arguments to X509KeyPair, but the error was %q", subStr, err) } _, err = X509KeyPair([]byte(rsaCertPEM), []byte(rsaCertPEM)) if err == nil { t.Fatalf("X509KeyPair didn't return an error when both arguments were certificates") } if subStr := "certificate"; !strings.Contains(err.Error(), subStr) { t.Fatalf("Expected %q in the error when both arguments to X509KeyPair were certificates, but the error was %q", subStr, err) } const nonsensePEM = ` -----BEGIN NONSENSE----- Zm9vZm9vZm9v -----END NONSENSE----- ` _, err = X509KeyPair([]byte(nonsensePEM), []byte(nonsensePEM)) if err == nil { t.Fatalf("X509KeyPair didn't return an error when both arguments were nonsense") } if subStr := "NONSENSE"; !strings.Contains(err.Error(), subStr) { t.Fatalf("Expected %q in the error when both arguments to X509KeyPair were nonsense, but the error was %q", subStr, err) } } func TestX509MixedKeyPair(t *testing.T) { if _, err := X509KeyPair([]byte(rsaCertPEM), []byte(ecdsaKeyPEM)); err == nil { t.Error("Load of RSA certificate succeeded with ECDSA private key") } if _, err := X509KeyPair([]byte(ecdsaCertPEM), []byte(rsaKeyPEM)); err == nil { t.Error("Load of ECDSA certificate succeeded with RSA private key") } } func newLocalListener(t testing.TB) net.Listener { ln, err := net.Listen("tcp", "127.0.0.1:0") if err != nil { ln, err = net.Listen("tcp6", "[::1]:0") } if err != nil { t.Fatal(err) } return ln } func TestDialTimeout(t *testing.T) { if testing.Short() { t.Skip("skipping in short mode") } listener := newLocalListener(t) addr := listener.Addr().String() defer listener.Close() complete := make(chan bool) defer close(complete) go func() { conn, err := listener.Accept() if err != nil { t.Error(err) return } <-complete conn.Close() }() dialer := &net.Dialer{ Timeout: 10 * time.Millisecond, } var err error if _, err = DialWithDialer(dialer, "tcp", addr, nil); err == nil { t.Fatal("DialWithTimeout completed successfully") } if !isTimeoutError(err) { t.Errorf("resulting error not a timeout: %v\nType %T: %#v", err, err, err) } } func isTimeoutError(err error) bool { if ne, ok := err.(net.Error); ok { return ne.Timeout() } return false } // tests that Conn.Read returns (non-zero, io.EOF) instead of // (non-zero, nil) when a Close (alertCloseNotify) is sitting right // behind the application data in the buffer. func TestConnReadNonzeroAndEOF(t *testing.T) { // This test is racy: it assumes that after a write to a // localhost TCP connection, the peer TCP connection can // immediately read it. Because it's racy, we skip this test // in short mode, and then retry it several times with an // increasing sleep in between our final write (via srv.Close // below) and the following read. if testing.Short() { t.Skip("skipping in short mode") } var err error for delay := time.Millisecond; delay <= 64*time.Millisecond; delay *= 2 { if err = testConnReadNonzeroAndEOF(t, delay); err == nil { return } } t.Error(err) } func testConnReadNonzeroAndEOF(t *testing.T, delay time.Duration) error { ln := newLocalListener(t) defer ln.Close() srvCh := make(chan *Conn, 1) var serr error go func() { sconn, err := ln.Accept() if err != nil { serr = err srvCh <- nil return } serverConfig := testConfig.Clone() srv := Server(sconn, serverConfig) if err := srv.Handshake(); err != nil { serr = fmt.Errorf("handshake: %v", err) srvCh <- nil return } srvCh <- srv }() clientConfig := testConfig.Clone() conn, err := Dial("tcp", ln.Addr().String(), clientConfig) if err != nil { t.Fatal(err) } defer conn.Close() srv := <-srvCh if srv == nil { return serr } buf := make([]byte, 6) srv.Write([]byte("foobar")) n, err := conn.Read(buf) if n != 6 || err != nil || string(buf) != "foobar" { return fmt.Errorf("Read = %d, %v, data %q; want 6, nil, foobar", n, err, buf) } srv.Write([]byte("abcdef")) srv.Close() time.Sleep(delay) n, err = conn.Read(buf) if n != 6 || string(buf) != "abcdef" { return fmt.Errorf("Read = %d, buf= %q; want 6, abcdef", n, buf) } if err != io.EOF { return fmt.Errorf("Second Read error = %v; want io.EOF", err) } return nil } func TestTLSUniqueMatches(t *testing.T) { ln := newLocalListener(t) defer ln.Close() serverTLSUniques := make(chan []byte) go func() { for i := 0; i < 2; i++ { sconn, err := ln.Accept() if err != nil { t.Fatal(err) } serverConfig := testConfig.Clone() srv := Server(sconn, serverConfig) if err := srv.Handshake(); err != nil { t.Fatal(err) } serverTLSUniques <- srv.ConnectionState().TLSUnique } }() clientConfig := testConfig.Clone() clientConfig.ClientSessionCache = NewLRUClientSessionCache(1) conn, err := Dial("tcp", ln.Addr().String(), clientConfig) if err != nil { t.Fatal(err) } if !bytes.Equal(conn.ConnectionState().TLSUnique, <-serverTLSUniques) { t.Error("client and server channel bindings differ") } conn.Close() conn, err = Dial("tcp", ln.Addr().String(), clientConfig) if err != nil { t.Fatal(err) } defer conn.Close() if !conn.ConnectionState().DidResume { t.Error("second session did not use resumption") } if !bytes.Equal(conn.ConnectionState().TLSUnique, <-serverTLSUniques) { t.Error("client and server channel bindings differ when session resumption is used") } } func TestVerifyHostname(t *testing.T) { testenv.MustHaveExternalNetwork(t) c, err := Dial("tcp", "www.google.com:https", nil) if err != nil { t.Fatal(err) } if err := c.VerifyHostname("www.google.com"); err != nil { t.Fatalf("verify www.google.com: %v", err) } if err := c.VerifyHostname("www.yahoo.com"); err == nil { t.Fatalf("verify www.yahoo.com succeeded") } c, err = Dial("tcp", "www.google.com:https", &Config{InsecureSkipVerify: true}) if err != nil { t.Fatal(err) } if err := c.VerifyHostname("www.google.com"); err == nil { t.Fatalf("verify www.google.com succeeded with InsecureSkipVerify=true") } if err := c.VerifyHostname("www.yahoo.com"); err == nil { t.Fatalf("verify www.google.com succeeded with InsecureSkipVerify=true") } } func TestVerifyHostnameResumed(t *testing.T) { testenv.MustHaveExternalNetwork(t) config := &Config{ ClientSessionCache: NewLRUClientSessionCache(32), } for i := 0; i < 2; i++ { c, err := Dial("tcp", "www.google.com:https", config) if err != nil { t.Fatalf("Dial #%d: %v", i, err) } cs := c.ConnectionState() if i > 0 && !cs.DidResume { t.Fatalf("Subsequent connection unexpectedly didn't resume") } if cs.VerifiedChains == nil { t.Fatalf("Dial #%d: cs.VerifiedChains == nil", i) } if err := c.VerifyHostname("www.google.com"); err != nil { t.Fatalf("verify www.google.com #%d: %v", i, err) } c.Close() } } func TestConnCloseBreakingWrite(t *testing.T) { ln := newLocalListener(t) defer ln.Close() srvCh := make(chan *Conn, 1) var serr error var sconn net.Conn go func() { var err error sconn, err = ln.Accept() if err != nil { serr = err srvCh <- nil return } serverConfig := testConfig.Clone() srv := Server(sconn, serverConfig) if err := srv.Handshake(); err != nil { serr = fmt.Errorf("handshake: %v", err) srvCh <- nil return } srvCh <- srv }() cconn, err := net.Dial("tcp", ln.Addr().String()) if err != nil { t.Fatal(err) } defer cconn.Close() conn := &changeImplConn{ Conn: cconn, } clientConfig := testConfig.Clone() tconn := Client(conn, clientConfig) if err := tconn.Handshake(); err != nil { t.Fatal(err) } srv := <-srvCh if srv == nil { t.Fatal(serr) } defer sconn.Close() connClosed := make(chan struct{}) conn.closeFunc = func() error { close(connClosed) return nil } inWrite := make(chan bool, 1) var errConnClosed = errors.New("conn closed for test") conn.writeFunc = func(p []byte) (n int, err error) { inWrite <- true <-connClosed return 0, errConnClosed } closeReturned := make(chan bool, 1) go func() { <-inWrite tconn.Close() // test that this doesn't block forever. closeReturned <- true }() _, err = tconn.Write([]byte("foo")) if err != errConnClosed { t.Errorf("Write error = %v; want errConnClosed", err) } <-closeReturned if err := tconn.Close(); err != errClosed { t.Errorf("Close error = %v; want errClosed", err) } } func TestConnCloseWrite(t *testing.T) { ln := newLocalListener(t) defer ln.Close() clientDoneChan := make(chan struct{}) serverCloseWrite := func() error { sconn, err := ln.Accept() if err != nil { return fmt.Errorf("accept: %v", err) } defer sconn.Close() serverConfig := testConfig.Clone() srv := Server(sconn, serverConfig) if err := srv.Handshake(); err != nil { return fmt.Errorf("handshake: %v", err) } defer srv.Close() data, err := ioutil.ReadAll(srv) if err != nil { return err } if len(data) > 0 { return fmt.Errorf("Read data = %q; want nothing", data) } if err := srv.CloseWrite(); err != nil { return fmt.Errorf("server CloseWrite: %v", err) } // Wait for clientCloseWrite to finish, so we know we // tested the CloseWrite before we defer the // sconn.Close above, which would also cause the // client to unblock like CloseWrite. <-clientDoneChan return nil } clientCloseWrite := func() error { defer close(clientDoneChan) clientConfig := testConfig.Clone() conn, err := Dial("tcp", ln.Addr().String(), clientConfig) if err != nil { return err } if err := conn.Handshake(); err != nil { return err } defer conn.Close() if err := conn.CloseWrite(); err != nil { return fmt.Errorf("client CloseWrite: %v", err) } if _, err := conn.Write([]byte{0}); err != errShutdown { return fmt.Errorf("CloseWrite error = %v; want errShutdown", err) } data, err := ioutil.ReadAll(conn) if err != nil { return err } if len(data) > 0 { return fmt.Errorf("Read data = %q; want nothing", data) } return nil } errChan := make(chan error, 2) go func() { errChan <- serverCloseWrite() }() go func() { errChan <- clientCloseWrite() }() for i := 0; i < 2; i++ { select { case err := <-errChan: if err != nil { t.Fatal(err) } case <-time.After(10 * time.Second): t.Fatal("deadlock") } } // Also test CloseWrite being called before the handshake is // finished: { ln2 := newLocalListener(t) defer ln2.Close() netConn, err := net.Dial("tcp", ln2.Addr().String()) if err != nil { t.Fatal(err) } defer netConn.Close() conn := Client(netConn, testConfig.Clone()) if err := conn.CloseWrite(); err != errEarlyCloseWrite { t.Errorf("CloseWrite error = %v; want errEarlyCloseWrite", err) } } } func TestClone(t *testing.T) { var c1 Config v := reflect.ValueOf(&c1).Elem() rnd := rand.New(rand.NewSource(time.Now().Unix())) typ := v.Type() for i := 0; i < typ.NumField(); i++ { f := v.Field(i) if !f.CanSet() { // unexported field; not cloned. continue } // testing/quick can't handle functions or interfaces. fn := typ.Field(i).Name switch fn { case "Rand": f.Set(reflect.ValueOf(io.Reader(os.Stdin))) continue case "Time", "GetCertificate", "GetConfigForClient", "VerifyPeerCertificate", "GetClientCertificate": // DeepEqual can't compare functions. continue case "Certificates": f.Set(reflect.ValueOf([]Certificate{ {Certificate: [][]byte{{'b'}}}, })) continue case "NameToCertificate": f.Set(reflect.ValueOf(map[string]*Certificate{"a": nil})) continue case "RootCAs", "ClientCAs": f.Set(reflect.ValueOf(x509.NewCertPool())) continue case "ClientSessionCache": f.Set(reflect.ValueOf(NewLRUClientSessionCache(10))) continue case "KeyLogWriter": f.Set(reflect.ValueOf(io.Writer(os.Stdout))) continue } q, ok := quick.Value(f.Type(), rnd) if !ok { t.Fatalf("quick.Value failed on field %s", fn) } f.Set(q) } c2 := c1.Clone() // DeepEqual also compares unexported fields, thus c2 needs to have run // serverInit in order to be DeepEqual to c1. Cloning it and discarding // the result is sufficient. c2.Clone() if !reflect.DeepEqual(&c1, c2) { t.Errorf("clone failed to copy a field") } } // changeImplConn is a net.Conn which can change its Write and Close // methods. type changeImplConn struct { net.Conn writeFunc func([]byte) (int, error) closeFunc func() error } func (w *changeImplConn) Write(p []byte) (n int, err error) { if w.writeFunc != nil { return w.writeFunc(p) } return w.Conn.Write(p) } func (w *changeImplConn) Close() error { if w.closeFunc != nil { return w.closeFunc() } return w.Conn.Close() } func throughput(b *testing.B, totalBytes int64, dynamicRecordSizingDisabled bool) { ln := newLocalListener(b) defer ln.Close() N := b.N // Less than 64KB because Windows appears to use a TCP rwin < 64KB. // See Issue #15899. const bufsize = 32 << 10 go func() { buf := make([]byte, bufsize) for i := 0; i < N; i++ { sconn, err := ln.Accept() if err != nil { // panic rather than synchronize to avoid benchmark overhead // (cannot call b.Fatal in goroutine) panic(fmt.Errorf("accept: %v", err)) } serverConfig := testConfig.Clone() serverConfig.DynamicRecordSizingDisabled = dynamicRecordSizingDisabled srv := Server(sconn, serverConfig) if err := srv.Handshake(); err != nil { panic(fmt.Errorf("handshake: %v", err)) } if _, err := io.CopyBuffer(srv, srv, buf); err != nil { panic(fmt.Errorf("copy buffer: %v", err)) } } }() b.SetBytes(totalBytes) clientConfig := testConfig.Clone() clientConfig.DynamicRecordSizingDisabled = dynamicRecordSizingDisabled buf := make([]byte, bufsize) chunks := int(math.Ceil(float64(totalBytes) / float64(len(buf)))) for i := 0; i < N; i++ { conn, err := Dial("tcp", ln.Addr().String(), clientConfig) if err != nil { b.Fatal(err) } for j := 0; j < chunks; j++ { _, err := conn.Write(buf) if err != nil { b.Fatal(err) } _, err = io.ReadFull(conn, buf) if err != nil { b.Fatal(err) } } conn.Close() } } func BenchmarkThroughput(b *testing.B) { for _, mode := range []string{"Max", "Dynamic"} { for size := 1; size <= 64; size <<= 1 { name := fmt.Sprintf("%sPacket/%dMB", mode, size) b.Run(name, func(b *testing.B) { throughput(b, int64(size<<20), mode == "Max") }) } } } type slowConn struct { net.Conn bps int } func (c *slowConn) Write(p []byte) (int, error) { if c.bps == 0 { panic("too slow") } t0 := time.Now() wrote := 0 for wrote < len(p) { time.Sleep(100 * time.Microsecond) allowed := int(time.Since(t0).Seconds()*float64(c.bps)) / 8 if allowed > len(p) { allowed = len(p) } if wrote < allowed { n, err := c.Conn.Write(p[wrote:allowed]) wrote += n if err != nil { return wrote, err } } } return len(p), nil } func latency(b *testing.B, bps int, dynamicRecordSizingDisabled bool) { ln := newLocalListener(b) defer ln.Close() N := b.N go func() { for i := 0; i < N; i++ { sconn, err := ln.Accept() if err != nil { // panic rather than synchronize to avoid benchmark overhead // (cannot call b.Fatal in goroutine) panic(fmt.Errorf("accept: %v", err)) } serverConfig := testConfig.Clone() serverConfig.DynamicRecordSizingDisabled = dynamicRecordSizingDisabled srv := Server(&slowConn{sconn, bps}, serverConfig) if err := srv.Handshake(); err != nil { panic(fmt.Errorf("handshake: %v", err)) } io.Copy(srv, srv) } }() clientConfig := testConfig.Clone() clientConfig.DynamicRecordSizingDisabled = dynamicRecordSizingDisabled buf := make([]byte, 16384) peek := make([]byte, 1) for i := 0; i < N; i++ { conn, err := Dial("tcp", ln.Addr().String(), clientConfig) if err != nil { b.Fatal(err) } // make sure we're connected and previous connection has stopped if _, err := conn.Write(buf[:1]); err != nil { b.Fatal(err) } if _, err := io.ReadFull(conn, peek); err != nil { b.Fatal(err) } if _, err := conn.Write(buf); err != nil { b.Fatal(err) } if _, err = io.ReadFull(conn, peek); err != nil { b.Fatal(err) } conn.Close() } } func BenchmarkLatency(b *testing.B) { for _, mode := range []string{"Max", "Dynamic"} { for _, kbps := range []int{200, 500, 1000, 2000, 5000} { name := fmt.Sprintf("%sPacket/%dkbps", mode, kbps) b.Run(name, func(b *testing.B) { latency(b, kbps*1000, mode == "Max") }) } } }