git » go-net » commit 6c89f96

diff --git a/internal/netreflect/socket.go b/internal/netreflect/socket.go
new file mode 100644
index 0000000..e82e51c
--- /dev/null
+++ b/internal/netreflect/socket.go
@@ -0,0 +1,37 @@
+// 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 netreflect implements run-time reflection for the
+// facilities of net package.
+package netreflect
+
+import (
+	"errors"
+	"net"
+)
+
+var (
+	errInvalidType = errors.New("invalid type")
+	errOpNoSupport = errors.New("operation not supported")
+)
+
+// SocketOf returns the socket descriptor of c.
+func SocketOf(c net.Conn) (uintptr, error) {
+	switch c.(type) {
+	case *net.TCPConn, *net.UDPConn, *net.IPConn, *net.UnixConn:
+		return socketOf(c)
+	default:
+		return 0, errInvalidType
+	}
+}
+
+// PacketSocketOf returns the socket descriptor of c.
+func PacketSocketOf(c net.PacketConn) (uintptr, error) {
+	switch c.(type) {
+	case *net.UDPConn, *net.IPConn, *net.UnixConn:
+		return socketOf(c.(net.Conn))
+	default:
+		return 0, errInvalidType
+	}
+}
diff --git a/internal/netreflect/socket_posix.go b/internal/netreflect/socket_posix.go
new file mode 100644
index 0000000..df475a2
--- /dev/null
+++ b/internal/netreflect/socket_posix.go
@@ -0,0 +1,30 @@
+// 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.
+
+// +build darwin dragonfly freebsd linux netbsd openbsd solaris windows
+
+package netreflect
+
+import (
+	"net"
+	"reflect"
+	"runtime"
+)
+
+func socketOf(c net.Conn) (uintptr, error) {
+	v := reflect.ValueOf(c)
+	switch e := v.Elem(); e.Kind() {
+	case reflect.Struct:
+		fd := e.FieldByName("conn").FieldByName("fd")
+		switch e := fd.Elem(); e.Kind() {
+		case reflect.Struct:
+			sysfd := e.FieldByName("sysfd")
+			if runtime.GOOS == "windows" {
+				return uintptr(sysfd.Uint()), nil
+			}
+			return uintptr(sysfd.Int()), nil
+		}
+	}
+	return 0, errInvalidType
+}
diff --git a/internal/netreflect/socket_stub.go b/internal/netreflect/socket_stub.go
new file mode 100644
index 0000000..85adb4b
--- /dev/null
+++ b/internal/netreflect/socket_stub.go
@@ -0,0 +1,11 @@
+// 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.
+
+// +build !darwin,!dragonfly,!freebsd,!linux,!netbsd,!openbsd,!solaris,!windows
+
+package netreflect
+
+import "net"
+
+func socketOf(c net.Conn) (uintptr, error) { return 0, errOpNoSupport }
diff --git a/internal/netreflect/socket_test.go b/internal/netreflect/socket_test.go
new file mode 100644
index 0000000..cf814e2
--- /dev/null
+++ b/internal/netreflect/socket_test.go
@@ -0,0 +1,122 @@
+// 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 netreflect_test
+
+import (
+	"fmt"
+	"io/ioutil"
+	"net"
+	"os"
+	"runtime"
+	"testing"
+
+	"golang.org/x/net/internal/netreflect"
+)
+
+func localPath() string {
+	f, err := ioutil.TempFile("", "netreflect")
+	if err != nil {
+		panic(err)
+	}
+	path := f.Name()
+	f.Close()
+	os.Remove(path)
+	return path
+}
+
+func newLocalListener(network string) (net.Listener, error) {
+	switch network {
+	case "tcp":
+		if ln, err := net.Listen("tcp4", "127.0.0.1:0"); err == nil {
+			return ln, nil
+		}
+		return net.Listen("tcp6", "[::1]:0")
+	case "tcp4":
+		return net.Listen("tcp4", "127.0.0.1:0")
+	case "tcp6":
+		return net.Listen("tcp6", "[::1]:0")
+	case "unix", "unixpacket":
+		return net.Listen(network, localPath())
+	}
+	return nil, fmt.Errorf("%s is not supported", network)
+}
+
+func newLocalPacketListener(network string) (net.PacketConn, error) {
+	switch network {
+	case "udp":
+		if c, err := net.ListenPacket("udp4", "127.0.0.1:0"); err == nil {
+			return c, nil
+		}
+		return net.ListenPacket("udp6", "[::1]:0")
+	case "udp4":
+		return net.ListenPacket("udp4", "127.0.0.1:0")
+	case "udp6":
+		return net.ListenPacket("udp6", "[::1]:0")
+	case "unixgram":
+		return net.ListenPacket(network, localPath())
+	}
+	return nil, fmt.Errorf("%s is not supported", network)
+}
+
+func TestSocketOf(t *testing.T) {
+	for _, network := range []string{"tcp", "unix", "unixpacket"} {
+		switch network {
+		case "unix":
+			switch runtime.GOOS {
+			case "nacl", "plan9", "windows":
+				continue
+			}
+		case "unixpacket":
+			switch runtime.GOOS {
+			case "darwin", "nacl", "plan9", "windows":
+				continue
+			}
+		}
+		ln, err := newLocalListener(network)
+		if err != nil {
+			t.Error(err)
+			continue
+		}
+		defer func() {
+			path := ln.Addr().String()
+			ln.Close()
+			if network == "unix" || network == "unixpacket" {
+				os.Remove(path)
+			}
+		}()
+		c, err := net.Dial(ln.Addr().Network(), ln.Addr().String())
+		if err != nil {
+			t.Error(err)
+			continue
+		}
+		defer c.Close()
+		if _, err := netreflect.SocketOf(c); err != nil {
+			t.Error(err)
+			continue
+		}
+	}
+}
+
+func TestPacketSocketOf(t *testing.T) {
+	for _, network := range []string{"udp", "unixgram"} {
+		switch network {
+		case "unixgram":
+			switch runtime.GOOS {
+			case "nacl", "plan9", "windows":
+				continue
+			}
+		}
+		c, err := newLocalPacketListener(network)
+		if err != nil {
+			t.Error(err)
+			continue
+		}
+		defer c.Close()
+		if _, err := netreflect.PacketSocketOf(c); err != nil {
+			t.Error(err)
+			continue
+		}
+	}
+}