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| 1 | +// Copyright 2021 The Go Authors. All rights reserved. |
| 2 | +// Use of this source code is governed by a BSD-style |
| 3 | +// license that can be found in the LICENSE file. |
| 4 | + |
| 5 | +//go:build darwin || dragonfly || freebsd || linux || netbsd || openbsd || solaris |
| 6 | +// +build darwin dragonfly freebsd linux netbsd openbsd solaris |
| 7 | + |
| 8 | +package socket_test |
| 9 | + |
| 10 | +import ( |
| 11 | + "bytes" |
| 12 | + "errors" |
| 13 | + "net" |
| 14 | + "runtime" |
| 15 | + "syscall" |
| 16 | + "testing" |
| 17 | + |
| 18 | + "golang.org/x/net/internal/socket" |
| 19 | + "golang.org/x/net/nettest" |
| 20 | +) |
| 21 | + |
| 22 | +func TestUDPDontwait(t *testing.T) { |
| 23 | + c, err := nettest.NewLocalPacketListener("udp") |
| 24 | + if err != nil { |
| 25 | + t.Skipf("not supported on %s/%s: %v", runtime.GOOS, runtime.GOARCH, err) |
| 26 | + } |
| 27 | + defer c.Close() |
| 28 | + cc, err := socket.NewConn(c.(*net.UDPConn)) |
| 29 | + if err != nil { |
| 30 | + t.Fatal(err) |
| 31 | + } |
| 32 | + isErrWouldblock := func(err error) bool { |
| 33 | + var errno syscall.Errno |
| 34 | + return errors.As(err, &errno) && (errno == syscall.EAGAIN || errno == syscall.EWOULDBLOCK) |
| 35 | + } |
| 36 | + |
| 37 | + t.Run("Message-dontwait", func(t *testing.T) { |
| 38 | + // Read before something was sent; expect EWOULDBLOCK |
| 39 | + b := make([]byte, 32) |
| 40 | + rm := socket.Message{ |
| 41 | + Buffers: [][]byte{b}, |
| 42 | + } |
| 43 | + if err := cc.RecvMsg(&rm, syscall.MSG_DONTWAIT); !isErrWouldblock(err) { |
| 44 | + t.Fatal(err) |
| 45 | + } |
| 46 | + // To trigger EWOULDBLOCK by SendMsg, we have to send faster than what the |
| 47 | + // system/network is able to process. Whether or not we can trigger this |
| 48 | + // depends on the system, specifically on write buffer sizes and the speed |
| 49 | + // of the network interface. |
| 50 | + // We cannot expect to quickly and reliably trigger this, especially not |
| 51 | + // because this test sends data over a (fast) loopback. Consequently, we |
| 52 | + // only check that sending with MSG_DONTWAIT works at all and don't attempt |
| 53 | + // testing that we would eventually get EWOULDBLOCK here. |
| 54 | + data := []byte("HELLO-R-U-THERE") |
| 55 | + wm := socket.Message{ |
| 56 | + Buffers: [][]byte{data}, |
| 57 | + Addr: c.LocalAddr(), |
| 58 | + } |
| 59 | + // Send one message, repeat until we don't get EWOULDBLOCK. This will likely succeed at the first attempt. |
| 60 | + for { |
| 61 | + err := cc.SendMsg(&wm, syscall.MSG_DONTWAIT) |
| 62 | + if err == nil { |
| 63 | + break |
| 64 | + } else if !isErrWouldblock(err) { |
| 65 | + t.Fatal(err) |
| 66 | + } |
| 67 | + } |
| 68 | + // Read the message now available; again, this will likely succeed at the first attempt. |
| 69 | + for { |
| 70 | + err := cc.RecvMsg(&rm, syscall.MSG_DONTWAIT) |
| 71 | + if err == nil { |
| 72 | + break |
| 73 | + } else if !isErrWouldblock(err) { |
| 74 | + t.Fatal(err) |
| 75 | + } |
| 76 | + } |
| 77 | + if !bytes.Equal(b[:rm.N], data) { |
| 78 | + t.Fatalf("got %#v; want %#v", b[:rm.N], data) |
| 79 | + } |
| 80 | + }) |
| 81 | + switch runtime.GOOS { |
| 82 | + case "android", "linux": |
| 83 | + t.Run("Messages", func(t *testing.T) { |
| 84 | + data := []byte("HELLO-R-U-THERE") |
| 85 | + wmbs := bytes.SplitAfter(data, []byte("-")) |
| 86 | + wms := []socket.Message{ |
| 87 | + {Buffers: wmbs[:1], Addr: c.LocalAddr()}, |
| 88 | + {Buffers: wmbs[1:], Addr: c.LocalAddr()}, |
| 89 | + } |
| 90 | + b := make([]byte, 32) |
| 91 | + rmbs := [][][]byte{{b[:len(wmbs[0])]}, {b[len(wmbs[0]):]}} |
| 92 | + rms := []socket.Message{ |
| 93 | + {Buffers: rmbs[0]}, |
| 94 | + {Buffers: rmbs[1]}, |
| 95 | + } |
| 96 | + _, err := cc.RecvMsgs(rms, syscall.MSG_DONTWAIT) |
| 97 | + if !isErrWouldblock(err) { |
| 98 | + t.Fatal(err) |
| 99 | + } |
| 100 | + for ntot := 0; ntot < len(wms); { |
| 101 | + n, err := cc.SendMsgs(wms[ntot:], syscall.MSG_DONTWAIT) |
| 102 | + if err == nil { |
| 103 | + ntot += n |
| 104 | + } else if !isErrWouldblock(err) { |
| 105 | + t.Fatal(err) |
| 106 | + } |
| 107 | + } |
| 108 | + for ntot := 0; ntot < len(rms); { |
| 109 | + n, err := cc.RecvMsgs(rms[ntot:], syscall.MSG_DONTWAIT) |
| 110 | + if err == nil { |
| 111 | + ntot += n |
| 112 | + } else if !isErrWouldblock(err) { |
| 113 | + t.Fatal(err) |
| 114 | + } |
| 115 | + } |
| 116 | + nn := 0 |
| 117 | + for i := 0; i < len(rms); i++ { |
| 118 | + nn += rms[i].N |
| 119 | + } |
| 120 | + if !bytes.Equal(b[:nn], data) { |
| 121 | + t.Fatalf("got %#v; want %#v", b[:nn], data) |
| 122 | + } |
| 123 | + }) |
| 124 | + } |
| 125 | +} |
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