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// Copyright 2018 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.
//go:build linux
package net
import (
"io"
"log"
"os"
"os/exec"
"strconv"
"sync"
"testing"
"time"
)
func TestSplice(t *testing.T) {
t.Run("tcp-to-tcp", func(t *testing.T) { testSplice(t, "tcp", "tcp") })
if !testableNetwork("unixgram") {
t.Skip("skipping unix-to-tcp tests")
}
t.Run("unix-to-tcp", func(t *testing.T) { testSplice(t, "unix", "tcp") })
t.Run("no-unixpacket", testSpliceNoUnixpacket)
t.Run("no-unixgram", testSpliceNoUnixgram)
}
func testSplice(t *testing.T, upNet, downNet string) {
t.Run("simple", spliceTestCase{upNet, downNet, 128, 128, 0}.test)
t.Run("multipleWrite", spliceTestCase{upNet, downNet, 4096, 1 << 20, 0}.test)
t.Run("big", spliceTestCase{upNet, downNet, 5 << 20, 1 << 30, 0}.test)
t.Run("honorsLimitedReader", spliceTestCase{upNet, downNet, 4096, 1 << 20, 1 << 10}.test)
t.Run("updatesLimitedReaderN", spliceTestCase{upNet, downNet, 1024, 4096, 4096 + 100}.test)
t.Run("limitedReaderAtLimit", spliceTestCase{upNet, downNet, 32, 128, 128}.test)
t.Run("readerAtEOF", func(t *testing.T) { testSpliceReaderAtEOF(t, upNet, downNet) })
t.Run("issue25985", func(t *testing.T) { testSpliceIssue25985(t, upNet, downNet) })
}
type spliceTestCase struct {
upNet, downNet string
chunkSize, totalSize int
limitReadSize int
}
func (tc spliceTestCase) test(t *testing.T) {
clientUp, serverUp := spliceTestSocketPair(t, tc.upNet)
defer serverUp.Close()
cleanup, err := startSpliceClient(clientUp, "w", tc.chunkSize, tc.totalSize)
if err != nil {
t.Fatal(err)
}
defer cleanup()
clientDown, serverDown := spliceTestSocketPair(t, tc.downNet)
defer serverDown.Close()
cleanup, err = startSpliceClient(clientDown, "r", tc.chunkSize, tc.totalSize)
if err != nil {
t.Fatal(err)
}
defer cleanup()
var (
r io.Reader = serverUp
size = tc.totalSize
)
if tc.limitReadSize > 0 {
if tc.limitReadSize < size {
size = tc.limitReadSize
}
r = &io.LimitedReader{
N: int64(tc.limitReadSize),
R: serverUp,
}
defer serverUp.Close()
}
n, err := io.Copy(serverDown, r)
serverDown.Close()
if err != nil {
t.Fatal(err)
}
if want := int64(size); want != n {
t.Errorf("want %d bytes spliced, got %d", want, n)
}
if tc.limitReadSize > 0 {
wantN := 0
if tc.limitReadSize > size {
wantN = tc.limitReadSize - size
}
if n := r.(*io.LimitedReader).N; n != int64(wantN) {
t.Errorf("r.N = %d, want %d", n, wantN)
}
}
}
func testSpliceReaderAtEOF(t *testing.T, upNet, downNet string) {
clientUp, serverUp := spliceTestSocketPair(t, upNet)
defer clientUp.Close()
clientDown, serverDown := spliceTestSocketPair(t, downNet)
defer clientDown.Close()
serverUp.Close()
// We'd like to call net.splice here and check the handled return
// value, but we disable splice on old Linux kernels.
//
// In that case, poll.Splice and net.splice return a non-nil error
// and handled == false. We'd ideally like to see handled == true
// because the source reader is at EOF, but if we're running on an old
// kernel, and splice is disabled, we won't see EOF from net.splice,
// because we won't touch the reader at all.
//
// Trying to untangle the errors from net.splice and match them
// against the errors created by the poll package would be brittle,
// so this is a higher level test.
//
// The following ReadFrom should return immediately, regardless of
// whether splice is disabled or not. The other side should then
// get a goodbye signal. Test for the goodbye signal.
msg := "bye"
go func() {
serverDown.(io.ReaderFrom).ReadFrom(serverUp)
io.WriteString(serverDown, msg)
serverDown.Close()
}()
buf := make([]byte, 3)
_, err := io.ReadFull(clientDown, buf)
if err != nil {
t.Errorf("clientDown: %v", err)
}
if string(buf) != msg {
t.Errorf("clientDown got %q, want %q", buf, msg)
}
}
func testSpliceIssue25985(t *testing.T, upNet, downNet string) {
front := newLocalListener(t, upNet)
defer front.Close()
back := newLocalListener(t, downNet)
defer back.Close()
var wg sync.WaitGroup
wg.Add(2)
proxy := func() {
src, err := front.Accept()
if err != nil {
return
}
dst, err := Dial(downNet, back.Addr().String())
if err != nil {
return
}
defer dst.Close()
defer src.Close()
go func() {
io.Copy(src, dst)
wg.Done()
}()
go func() {
io.Copy(dst, src)
wg.Done()
}()
}
go proxy()
toFront, err := Dial(upNet, front.Addr().String())
if err != nil {
t.Fatal(err)
}
io.WriteString(toFront, "foo")
toFront.Close()
fromProxy, err := back.Accept()
if err != nil {
t.Fatal(err)
}
defer fromProxy.Close()
_, err = io.ReadAll(fromProxy)
if err != nil {
t.Fatal(err)
}
wg.Wait()
}
func testSpliceNoUnixpacket(t *testing.T) {
clientUp, serverUp := spliceTestSocketPair(t, "unixpacket")
defer clientUp.Close()
defer serverUp.Close()
clientDown, serverDown := spliceTestSocketPair(t, "tcp")
defer clientDown.Close()
defer serverDown.Close()
// If splice called poll.Splice here, we'd get err == syscall.EINVAL
// and handled == false. If poll.Splice gets an EINVAL on the first
// try, it assumes the kernel it's running on doesn't support splice
// for unix sockets and returns handled == false. This works for our
// purposes by somewhat of an accident, but is not entirely correct.
//
// What we want is err == nil and handled == false, i.e. we never
// called poll.Splice, because we know the unix socket's network.
_, err, handled := splice(serverDown.(*TCPConn).fd, serverUp)
if err != nil || handled != false {
t.Fatalf("got err = %v, handled = %t, want nil error, handled == false", err, handled)
}
}
func testSpliceNoUnixgram(t *testing.T) {
addr, err := ResolveUnixAddr("unixgram", testUnixAddr(t))
if err != nil {
t.Fatal(err)
}
defer os.Remove(addr.Name)
up, err := ListenUnixgram("unixgram", addr)
if err != nil {
t.Fatal(err)
}
defer up.Close()
clientDown, serverDown := spliceTestSocketPair(t, "tcp")
defer clientDown.Close()
defer serverDown.Close()
// Analogous to testSpliceNoUnixpacket.
_, err, handled := splice(serverDown.(*TCPConn).fd, up)
if err != nil || handled != false {
t.Fatalf("got err = %v, handled = %t, want nil error, handled == false", err, handled)
}
}
func BenchmarkSplice(b *testing.B) {
testHookUninstaller.Do(uninstallTestHooks)
b.Run("tcp-to-tcp", func(b *testing.B) { benchSplice(b, "tcp", "tcp") })
b.Run("unix-to-tcp", func(b *testing.B) { benchSplice(b, "unix", "tcp") })
}
func benchSplice(b *testing.B, upNet, downNet string) {
for i := 0; i <= 10; i++ {
chunkSize := 1 << uint(i+10)
tc := spliceTestCase{
upNet: upNet,
downNet: downNet,
chunkSize: chunkSize,
}
b.Run(strconv.Itoa(chunkSize), tc.bench)
}
}
func (tc spliceTestCase) bench(b *testing.B) {
// To benchmark the genericReadFrom code path, set this to false.
useSplice := true
clientUp, serverUp := spliceTestSocketPair(b, tc.upNet)
defer serverUp.Close()
cleanup, err := startSpliceClient(clientUp, "w", tc.chunkSize, tc.chunkSize*b.N)
if err != nil {
b.Fatal(err)
}
defer cleanup()
clientDown, serverDown := spliceTestSocketPair(b, tc.downNet)
defer serverDown.Close()
cleanup, err = startSpliceClient(clientDown, "r", tc.chunkSize, tc.chunkSize*b.N)
if err != nil {
b.Fatal(err)
}
defer cleanup()
b.SetBytes(int64(tc.chunkSize))
b.ResetTimer()
if useSplice {
_, err := io.Copy(serverDown, serverUp)
if err != nil {
b.Fatal(err)
}
} else {
type onlyReader struct {
io.Reader
}
_, err := io.Copy(serverDown, onlyReader{serverUp})
if err != nil {
b.Fatal(err)
}
}
}
func spliceTestSocketPair(t testing.TB, net string) (client, server Conn) {
t.Helper()
ln := newLocalListener(t, net)
defer ln.Close()
var cerr, serr error
acceptDone := make(chan struct{})
go func() {
server, serr = ln.Accept()
acceptDone <- struct{}{}
}()
client, cerr = Dial(ln.Addr().Network(), ln.Addr().String())
<-acceptDone
if cerr != nil {
if server != nil {
server.Close()
}
t.Fatal(cerr)
}
if serr != nil {
if client != nil {
client.Close()
}
t.Fatal(serr)
}
return client, server
}
func startSpliceClient(conn Conn, op string, chunkSize, totalSize int) (func(), error) {
f, err := conn.(interface{ File() (*os.File, error) }).File()
if err != nil {
return nil, err
}
cmd := exec.Command(os.Args[0], os.Args[1:]...)
cmd.Env = []string{
"GO_NET_TEST_SPLICE=1",
"GO_NET_TEST_SPLICE_OP=" + op,
"GO_NET_TEST_SPLICE_CHUNK_SIZE=" + strconv.Itoa(chunkSize),
"GO_NET_TEST_SPLICE_TOTAL_SIZE=" + strconv.Itoa(totalSize),
"TMPDIR=" + os.Getenv("TMPDIR"),
}
cmd.ExtraFiles = append(cmd.ExtraFiles, f)
cmd.Stdout = os.Stdout
cmd.Stderr = os.Stderr
if err := cmd.Start(); err != nil {
return nil, err
}
donec := make(chan struct{})
go func() {
cmd.Wait()
conn.Close()
f.Close()
close(donec)
}()
return func() {
select {
case <-donec:
case <-time.After(5 * time.Second):
log.Printf("killing splice client after 5 second shutdown timeout")
cmd.Process.Kill()
select {
case <-donec:
case <-time.After(5 * time.Second):
log.Printf("splice client didn't die after 10 seconds")
}
}
}, nil
}
func init() {
if os.Getenv("GO_NET_TEST_SPLICE") == "" {
return
}
defer os.Exit(0)
f := os.NewFile(uintptr(3), "splice-test-conn")
defer f.Close()
conn, err := FileConn(f)
if err != nil {
log.Fatal(err)
}
var chunkSize int
if chunkSize, err = strconv.Atoi(os.Getenv("GO_NET_TEST_SPLICE_CHUNK_SIZE")); err != nil {
log.Fatal(err)
}
buf := make([]byte, chunkSize)
var totalSize int
if totalSize, err = strconv.Atoi(os.Getenv("GO_NET_TEST_SPLICE_TOTAL_SIZE")); err != nil {
log.Fatal(err)
}
var fn func([]byte) (int, error)
switch op := os.Getenv("GO_NET_TEST_SPLICE_OP"); op {
case "r":
fn = conn.Read
case "w":
defer conn.Close()
fn = conn.Write
default:
log.Fatalf("unknown op %q", op)
}
var n int
for count := 0; count < totalSize; count += n {
if count+chunkSize > totalSize {
buf = buf[:totalSize-count]
}
var err error
if n, err = fn(buf); err != nil {
return
}
}
}