Update Go library to last weekly.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@180552 138bc75d-0d04-0410-961f-82ee72b054a4

42 files changed, 1110 insertions, 348 deletions

diff --git a/libgo/go/net/cgo_bsd.go b/libgo/go/net/cgo_bsd.go
index 3951d847416..b8c6ef974e4 100644
--- a/libgo/go/net/cgo_bsd.go
+++ b/libgo/go/net/cgo_bsd.go
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// +build darwin freebsd
+
 package net
 
 /*
diff --git a/libgo/go/net/cgo_stub.go b/libgo/go/net/cgo_stub.go
index c6277cb657c..565cbe7fece 100644
--- a/libgo/go/net/cgo_stub.go
+++ b/libgo/go/net/cgo_stub.go
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// +build openbsd
+
 // Stub cgo routines for systems that do not use cgo to do network lookups.
 
 package net
diff --git a/libgo/go/net/cgo_unix.go b/libgo/go/net/cgo_unix.go
index d088eabc2b5..bfb3dfddff9 100644
--- a/libgo/go/net/cgo_unix.go
+++ b/libgo/go/net/cgo_unix.go
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// +build darwin freebsd linux
+
 package net
 
 /*
diff --git a/libgo/go/net/dial.go b/libgo/go/net/dial.go
index 10c67dcc40a..85d54b3703c 100644
--- a/libgo/go/net/dial.go
+++ b/libgo/go/net/dial.go
@@ -59,10 +59,10 @@ func Dial(net, addr string) (c Conn, err os.Error) {
 	case *IPAddr:
 		c, err = DialIP(net, nil, ra)
 	default:
-		err = UnknownNetworkError(net)
+		err = &OpError{"dial", net + " " + addr, nil, UnknownNetworkError(net)}
 	}
 	if err != nil {
-		return nil, &OpError{"dial", net + " " + addr, nil, err}
+		return nil, err
 	}
 	return
 }
diff --git a/libgo/go/net/dnsclient_unix.go b/libgo/go/net/dnsclient_unix.go
index f407b177830..eb7db5e2707 100644
--- a/libgo/go/net/dnsclient_unix.go
+++ b/libgo/go/net/dnsclient_unix.go
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// +build darwin freebsd linux openbsd
+
 // DNS client: see RFC 1035.
 // Has to be linked into package net for Dial.
 
@@ -113,7 +115,7 @@ func convertRR_A(records []dnsRR) []IP {
 func convertRR_AAAA(records []dnsRR) []IP {
 	addrs := make([]IP, len(records))
 	for i, rr := range records {
-		a := make(IP, 16)
+		a := make(IP, IPv6len)
 		copy(a, rr.(*dnsRR_AAAA).AAAA[:])
 		addrs[i] = a
 	}
@@ -213,6 +215,18 @@ func goLookupHost(name string) (addrs []string, err os.Error) {
 // depending on our lookup code, so that Go and C get the same
 // answers.
 func goLookupIP(name string) (addrs []IP, err os.Error) {
+	// Use entries from /etc/hosts if possible.
+	haddrs := lookupStaticHost(name)
+	if len(haddrs) > 0 {
+		for _, haddr := range haddrs {
+			if ip := ParseIP(haddr); ip != nil {
+				addrs = append(addrs, ip)
+			}
+		}
+		if len(addrs) > 0 {
+			return
+		}
+	}
 	onceLoadConfig.Do(loadConfig)
 	if dnserr != nil || cfg == nil {
 		err = dnserr
diff --git a/libgo/go/net/dnsconfig.go b/libgo/go/net/dnsconfig.go
index 54e334342ad..afc05991773 100644
--- a/libgo/go/net/dnsconfig.go
+++ b/libgo/go/net/dnsconfig.go
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// +build darwin freebsd linux openbsd
+
 // Read system DNS config from /etc/resolv.conf
 
 package net
diff --git a/libgo/go/net/fd.go b/libgo/go/net/fd.go
index 707dccaa421..80d40af7662 100644
--- a/libgo/go/net/fd.go
+++ b/libgo/go/net/fd.go
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// +build darwin freebsd linux openbsd
+
 package net
 
 import (
@@ -150,7 +152,7 @@ func (s *pollServer) LookupFD(fd int, mode int) *netFD {
 	if !ok {
 		return nil
 	}
-	s.pending[key] = nil, false
+	delete(s.pending, key)
 	return netfd
 }
 
@@ -193,7 +195,7 @@ func (s *pollServer) CheckDeadlines() {
 		}
 		if t > 0 {
 			if t <= now {
-				s.pending[key] = nil, false
+				delete(s.pending, key)
 				if mode == 'r' {
 					s.poll.DelFD(fd.sysfd, mode)
 					fd.rdeadline = -1
@@ -356,6 +358,25 @@ func (fd *netFD) Close() os.Error {
 	return nil
 }
 
+func (fd *netFD) shutdown(how int) os.Error {
+	if fd == nil || fd.sysfile == nil {
+		return os.EINVAL
+	}
+	errno := syscall.Shutdown(fd.sysfd, how)
+	if errno != 0 {
+		return &OpError{"shutdown", fd.net, fd.laddr, os.Errno(errno)}
+	}
+	return nil
+}
+
+func (fd *netFD) CloseRead() os.Error {
+	return fd.shutdown(syscall.SHUT_RD)
+}
+
+func (fd *netFD) CloseWrite() os.Error {
+	return fd.shutdown(syscall.SHUT_WR)
+}
+
 func (fd *netFD) Read(p []byte) (n int, err os.Error) {
 	if fd == nil {
 		return 0, os.EINVAL
diff --git a/libgo/go/net/fd_linux.go b/libgo/go/net/fd_linux.go
index 70fc344b2a0..c860c842af7 100644
--- a/libgo/go/net/fd_linux.go
+++ b/libgo/go/net/fd_linux.go
@@ -105,7 +105,7 @@ func (p *pollster) StopWaiting(fd int, bits uint) {
 		if e := syscall.EpollCtl(p.epfd, syscall.EPOLL_CTL_DEL, fd, nil); e != 0 {
 			print("Epoll delete fd=", fd, ": ", os.Errno(e).String(), "\n")
 		}
-		p.events[fd] = 0, false
+		delete(p.events, fd)
 	}
 }
 
diff --git a/libgo/go/net/fd_windows.go b/libgo/go/net/fd_windows.go
index 3757e143dca..8e8b3b746d4 100644
--- a/libgo/go/net/fd_windows.go
+++ b/libgo/go/net/fd_windows.go
@@ -23,7 +23,7 @@ var initErr os.Error
 
 func init() {
 	var d syscall.WSAData
-	e := syscall.WSAStartup(uint32(0x101), &d)
+	e := syscall.WSAStartup(uint32(0x202), &d)
 	if e != 0 {
 		initErr = os.NewSyscallError("WSAStartup", e)
 	}
@@ -52,15 +52,27 @@ type anOp struct {
 	// of the struct, as our code rely on it.
 	o syscall.Overlapped
 
-	resultc chan ioResult // io completion results
-	errnoc  chan int      // io submit / cancel operation errors
+	resultc chan ioResult
+	errnoc  chan int
 	fd      *netFD
 }
 
-func (o *anOp) Init(fd *netFD) {
+func (o *anOp) Init(fd *netFD, mode int) {
 	o.fd = fd
-	o.resultc = make(chan ioResult, 1)
-	o.errnoc = make(chan int)
+	var i int
+	if mode == 'r' {
+		i = 0
+	} else {
+		i = 1
+	}
+	if fd.resultc[i] == nil {
+		fd.resultc[i] = make(chan ioResult, 1)
+	}
+	o.resultc = fd.resultc[i]
+	if fd.errnoc[i] == nil {
+		fd.errnoc[i] = make(chan int)
+	}
+	o.errnoc = fd.errnoc[i]
 }
 
 func (o *anOp) Op() *anOp {
@@ -74,8 +86,8 @@ type bufOp struct {
 	buf syscall.WSABuf
 }
 
-func (o *bufOp) Init(fd *netFD, buf []byte) {
-	o.anOp.Init(fd)
+func (o *bufOp) Init(fd *netFD, buf []byte, mode int) {
+	o.anOp.Init(fd, mode)
 	o.buf.Len = uint32(len(buf))
 	if len(buf) == 0 {
 		o.buf.Buf = nil
@@ -208,12 +220,14 @@ type netFD struct {
 	closing bool
 
 	// immutable until Close
-	sysfd  syscall.Handle
-	family int
-	proto  int
-	net    string
-	laddr  Addr
-	raddr  Addr
+	sysfd   syscall.Handle
+	family  int
+	proto   int
+	net     string
+	laddr   Addr
+	raddr   Addr
+	resultc [2]chan ioResult // read/write completion results
+	errnoc  [2]chan int      // read/write submit or cancel operation errors
 
 	// owned by client
 	rdeadline_delta int64
@@ -298,6 +312,25 @@ func (fd *netFD) Close() os.Error {
 	return nil
 }
 
+func (fd *netFD) shutdown(how int) os.Error {
+	if fd == nil || fd.sysfd == syscall.InvalidHandle {
+		return os.EINVAL
+	}
+	errno := syscall.Shutdown(fd.sysfd, how)
+	if errno != 0 {
+		return &OpError{"shutdown", fd.net, fd.laddr, os.Errno(errno)}
+	}
+	return nil
+}
+
+func (fd *netFD) CloseRead() os.Error {
+	return fd.shutdown(syscall.SHUT_RD)
+}
+
+func (fd *netFD) CloseWrite() os.Error {
+	return fd.shutdown(syscall.SHUT_WR)
+}
+
 // Read from network.
 
 type readOp struct {
@@ -325,7 +358,7 @@ func (fd *netFD) Read(buf []byte) (n int, err os.Error) {
 		return 0, os.EINVAL
 	}
 	var o readOp
-	o.Init(fd, buf)
+	o.Init(fd, buf, 'r')
 	n, err = iosrv.ExecIO(&o, fd.rdeadline_delta)
 	if err == nil && n == 0 {
 		err = os.EOF
@@ -365,7 +398,7 @@ func (fd *netFD) ReadFrom(buf []byte) (n int, sa syscall.Sockaddr, err os.Error)
 		return 0, nil, os.EINVAL
 	}
 	var o readFromOp
-	o.Init(fd, buf)
+	o.Init(fd, buf, 'r')
 	o.rsan = int32(unsafe.Sizeof(o.rsa))
 	n, err = iosrv.ExecIO(&o, fd.rdeadline_delta)
 	if err != nil {
@@ -402,7 +435,7 @@ func (fd *netFD) Write(buf []byte) (n int, err os.Error) {
 		return 0, os.EINVAL
 	}
 	var o writeOp
-	o.Init(fd, buf)
+	o.Init(fd, buf, 'w')
 	return iosrv.ExecIO(&o, fd.wdeadline_delta)
 }
 
@@ -437,7 +470,7 @@ func (fd *netFD) WriteTo(buf []byte, sa syscall.Sockaddr) (n int, err os.Error)
 		return 0, os.EINVAL
 	}
 	var o writeToOp
-	o.Init(fd, buf)
+	o.Init(fd, buf, 'w')
 	o.sa = sa
 	return iosrv.ExecIO(&o, fd.wdeadline_delta)
 }
@@ -487,7 +520,7 @@ func (fd *netFD) accept(toAddr func(syscall.Sockaddr) Addr) (nfd *netFD, err os.
 
 	// Submit accept request.
 	var o acceptOp
-	o.Init(fd)
+	o.Init(fd, 'r')
 	o.newsock = s
 	_, err = iosrv.ExecIO(&o, 0)
 	if err != nil {
diff --git a/libgo/go/net/file.go b/libgo/go/net/file.go
index 0e411a192f2..ed2559d8c30 100644
--- a/libgo/go/net/file.go
+++ b/libgo/go/net/file.go
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// +build darwin freebsd linux openbsd
+
 package net
 
 import (
@@ -20,6 +22,7 @@ func newFileFD(f *os.File) (nfd *netFD, err os.Error) {
 		return nil, os.NewSyscallError("getsockopt", errno)
 	}
 
+	family := syscall.AF_UNSPEC
 	toAddr := sockaddrToTCP
 	sa, _ := syscall.Getsockname(fd)
 	switch sa.(type) {
@@ -27,18 +30,21 @@ func newFileFD(f *os.File) (nfd *netFD, err os.Error) {
 		closesocket(fd)
 		return nil, os.EINVAL
 	case *syscall.SockaddrInet4:
+		family = syscall.AF_INET
 		if proto == syscall.SOCK_DGRAM {
 			toAddr = sockaddrToUDP
 		} else if proto == syscall.SOCK_RAW {
 			toAddr = sockaddrToIP
 		}
 	case *syscall.SockaddrInet6:
+		family = syscall.AF_INET6
 		if proto == syscall.SOCK_DGRAM {
 			toAddr = sockaddrToUDP
 		} else if proto == syscall.SOCK_RAW {
 			toAddr = sockaddrToIP
 		}
 	case *syscall.SockaddrUnix:
+		family = syscall.AF_UNIX
 		toAddr = sockaddrToUnix
 		if proto == syscall.SOCK_DGRAM {
 			toAddr = sockaddrToUnixgram
@@ -50,7 +56,7 @@ func newFileFD(f *os.File) (nfd *netFD, err os.Error) {
 	sa, _ = syscall.Getpeername(fd)
 	raddr := toAddr(sa)
 
-	if nfd, err = newFD(fd, 0, proto, laddr.Network()); err != nil {
+	if nfd, err = newFD(fd, family, proto, laddr.Network()); err != nil {
 		return nil, err
 	}
 	nfd.setAddr(laddr, raddr)
diff --git a/libgo/go/net/file_test.go b/libgo/go/net/file_test.go
index 9a8c2dcbc4c..0fa6740769b 100644
--- a/libgo/go/net/file_test.go
+++ b/libgo/go/net/file_test.go
@@ -73,7 +73,7 @@ func TestFileListener(t *testing.T) {
 	}
 }
 
-func testFilePacketConn(t *testing.T, pcf packetConnFile) {
+func testFilePacketConn(t *testing.T, pcf packetConnFile, listen bool) {
 	f, err := pcf.File()
 	if err != nil {
 		t.Fatalf("File failed: %v", err)
@@ -85,6 +85,11 @@ func testFilePacketConn(t *testing.T, pcf packetConnFile) {
 	if !reflect.DeepEqual(pcf.LocalAddr(), c.LocalAddr()) {
 		t.Fatalf("LocalAddrs not equal: %#v != %#v", pcf.LocalAddr(), c.LocalAddr())
 	}
+	if listen {
+		if _, err := c.WriteTo([]byte{}, c.LocalAddr()); err != nil {
+			t.Fatalf("WriteTo failed: %v", err)
+		}
+	}
 	if err := c.Close(); err != nil {
 		t.Fatalf("Close failed: %v", err)
 	}
@@ -98,7 +103,7 @@ func testFilePacketConnListen(t *testing.T, net, laddr string) {
 	if err != nil {
 		t.Fatalf("Listen failed: %v", err)
 	}
-	testFilePacketConn(t, l.(packetConnFile))
+	testFilePacketConn(t, l.(packetConnFile), true)
 	if err := l.Close(); err != nil {
 		t.Fatalf("Close failed: %v", err)
 	}
@@ -109,7 +114,7 @@ func testFilePacketConnDial(t *testing.T, net, raddr string) {
 	if err != nil {
 		t.Fatalf("Dial failed: %v", err)
 	}
-	testFilePacketConn(t, c.(packetConnFile))
+	testFilePacketConn(t, c.(packetConnFile), false)
 	if err := c.Close(); err != nil {
 		t.Fatalf("Close failed: %v", err)
 	}
diff --git a/libgo/go/net/interface.go b/libgo/go/net/interface.go
index 8a14cb23202..2696b7f4c58 100644
--- a/libgo/go/net/interface.go
+++ b/libgo/go/net/interface.go
@@ -26,6 +26,63 @@ func (a HardwareAddr) String() string {
 	return buf.String()
 }
 
+// ParseMAC parses s as an IEEE 802 MAC-48, EUI-48, or EUI-64 using one of the
+// following formats:
+//   01:23:45:67:89:ab
+//   01:23:45:67:89:ab:cd:ef
+//   01-23-45-67-89-ab
+//   01-23-45-67-89-ab-cd-ef
+//   0123.4567.89ab
+//   0123.4567.89ab.cdef
+func ParseMAC(s string) (hw HardwareAddr, err os.Error) {
+	if len(s) < 14 {
+		goto error
+	}
+
+	if s[2] == ':' || s[2] == '-' {
+		if (len(s)+1)%3 != 0 {
+			goto error
+		}
+		n := (len(s) + 1) / 3
+		if n != 6 && n != 8 {
+			goto error
+		}
+		hw = make(HardwareAddr, n)
+		for x, i := 0, 0; i < n; i++ {
+			var ok bool
+			if hw[i], ok = xtoi2(s[x:], s[2]); !ok {
+				goto error
+			}
+			x += 3
+		}
+	} else if s[4] == '.' {
+		if (len(s)+1)%5 != 0 {
+			goto error
+		}
+		n := 2 * (len(s) + 1) / 5
+		if n != 6 && n != 8 {
+			goto error
+		}
+		hw = make(HardwareAddr, n)
+		for x, i := 0, 0; i < n; i += 2 {
+			var ok bool
+			if hw[i], ok = xtoi2(s[x:x+2], 0); !ok {
+				goto error
+			}
+			if hw[i+1], ok = xtoi2(s[x+2:], s[4]); !ok {
+				goto error
+			}
+			x += 5
+		}
+	} else {
+		goto error
+	}
+	return hw, nil
+
+error:
+	return nil, os.NewError("invalid MAC address: " + s)
+}
+
 // Interface represents a mapping between network interface name
 // and index.  It also represents network interface facility
 // information.
diff --git a/libgo/go/net/interface_bsd.go b/libgo/go/net/interface_bsd.go
index 2675f94b973..54fa5ddeb69 100644
--- a/libgo/go/net/interface_bsd.go
+++ b/libgo/go/net/interface_bsd.go
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// +build darwin freebsd openbsd
+
 // Network interface identification for BSD variants
 
 package net
@@ -148,7 +150,6 @@ func newAddr(m *syscall.InterfaceAddrMessage) ([]Addr, os.Error) {
 	}
 
 	for _, s := range sas {
-
 		switch v := s.(type) {
 		case *syscall.SockaddrInet4:
 			ifa := &IPAddr{IP: IPv4(v.Addr[0], v.Addr[1], v.Addr[2], v.Addr[3])}
diff --git a/libgo/go/net/interface_linux.go b/libgo/go/net/interface_linux.go
index 3d2a0bb9f8a..36ae04ffa71 100644
--- a/libgo/go/net/interface_linux.go
+++ b/libgo/go/net/interface_linux.go
@@ -103,42 +103,29 @@ func linkFlags(rawFlags uint32) Flags {
 // for a specific interface.
 func interfaceAddrTable(ifindex int) ([]Addr, os.Error) {
 	var (
-		tab   []byte
-		e     int
-		err   os.Error
-		ifat4 []Addr
-		ifat6 []Addr
-		msgs4 []syscall.NetlinkMessage
-		msgs6 []syscall.NetlinkMessage
+		tab  []byte
+		e    int
+		err  os.Error
+		ifat []Addr
+		msgs []syscall.NetlinkMessage
 	)
 
-	tab, e = syscall.NetlinkRIB(syscall.RTM_GETADDR, syscall.AF_INET)
+	tab, e = syscall.NetlinkRIB(syscall.RTM_GETADDR, syscall.AF_UNSPEC)
 	if e != 0 {
 		return nil, os.NewSyscallError("netlink rib", e)
 	}
-	msgs4, e = syscall.ParseNetlinkMessage(tab)
-	if e != 0 {
-		return nil, os.NewSyscallError("netlink message", e)
-	}
-	ifat4, err = addrTable(msgs4, ifindex)
-	if err != nil {
-		return nil, err
-	}
 
-	tab, e = syscall.NetlinkRIB(syscall.RTM_GETADDR, syscall.AF_INET6)
-	if e != 0 {
-		return nil, os.NewSyscallError("netlink rib", e)
-	}
-	msgs6, e = syscall.ParseNetlinkMessage(tab)
+	msgs, e = syscall.ParseNetlinkMessage(tab)
 	if e != 0 {
 		return nil, os.NewSyscallError("netlink message", e)
 	}
-	ifat6, err = addrTable(msgs6, ifindex)
+
+	ifat, err = addrTable(msgs, ifindex)
 	if err != nil {
 		return nil, err
 	}
 
-	return append(ifat4, ifat6...), nil
+	return ifat, nil
 }
 
 func addrTable(msgs []syscall.NetlinkMessage, ifindex int) ([]Addr, os.Error) {
diff --git a/libgo/go/net/interface_stub.go b/libgo/go/net/interface_stub.go
index 950de6c5926..282b38b5e49 100644
--- a/libgo/go/net/interface_stub.go
+++ b/libgo/go/net/interface_stub.go
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// +build plan9
+
 // Network interface identification
 
 package net
diff --git a/libgo/go/net/interface_test.go b/libgo/go/net/interface_test.go
index 0e4089abf8a..c918f247f96 100644
--- a/libgo/go/net/interface_test.go
+++ b/libgo/go/net/interface_test.go
@@ -6,6 +6,9 @@ package net
 
 import (
 	"bytes"
+	"os"
+	"reflect"
+	"strings"
 	"testing"
 )
 
@@ -71,3 +74,46 @@ func TestInterfaceAddrs(t *testing.T) {
 		t.Logf("interface address %q\n", ifa.String())
 	}
 }
+
+var mactests = []struct {
+	in  string
+	out HardwareAddr
+	err string
+}{
+	{"01:23:45:67:89:AB", HardwareAddr{1, 0x23, 0x45, 0x67, 0x89, 0xab}, ""},
+	{"01-23-45-67-89-AB", HardwareAddr{1, 0x23, 0x45, 0x67, 0x89, 0xab}, ""},
+	{"0123.4567.89AB", HardwareAddr{1, 0x23, 0x45, 0x67, 0x89, 0xab}, ""},
+	{"ab:cd:ef:AB:CD:EF", HardwareAddr{0xab, 0xcd, 0xef, 0xab, 0xcd, 0xef}, ""},
+	{"01.02.03.04.05.06", nil, "invalid MAC address"},
+	{"01:02:03:04:05:06:", nil, "invalid MAC address"},
+	{"x1:02:03:04:05:06", nil, "invalid MAC address"},
+	{"01002:03:04:05:06", nil, "invalid MAC address"},
+	{"01:02003:04:05:06", nil, "invalid MAC address"},
+	{"01:02:03004:05:06", nil, "invalid MAC address"},
+	{"01:02:03:04005:06", nil, "invalid MAC address"},
+	{"01:02:03:04:05006", nil, "invalid MAC address"},
+	{"01-02:03:04:05:06", nil, "invalid MAC address"},
+	{"01:02-03-04-05-06", nil, "invalid MAC address"},
+	{"0123:4567:89AF", nil, "invalid MAC address"},
+	{"0123-4567-89AF", nil, "invalid MAC address"},
+	{"01:23:45:67:89:AB:CD:EF", HardwareAddr{1, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef}, ""},
+	{"01-23-45-67-89-AB-CD-EF", HardwareAddr{1, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef}, ""},
+	{"0123.4567.89AB.CDEF", HardwareAddr{1, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef}, ""},
+}
+
+func match(err os.Error, s string) bool {
+	if s == "" {
+		return err == nil
+	}
+	return err != nil && strings.Contains(err.String(), s)
+}
+
+func TestParseMAC(t *testing.T) {
+	for _, tt := range mactests {
+		out, err := ParseMAC(tt.in)
+		if !reflect.DeepEqual(out, tt.out) || !match(err, tt.err) {
+			t.Errorf("ParseMAC(%q) = %v, %v, want %v, %v", tt.in, out, err, tt.out,
+				tt.err)
+		}
+	}
+}
diff --git a/libgo/go/net/ip.go b/libgo/go/net/ip.go
index b0e2c42053f..61dc3be909c 100644
--- a/libgo/go/net/ip.go
+++ b/libgo/go/net/ip.go
@@ -21,11 +21,8 @@ const (
 )
 
 // An IP is a single IP address, an array of bytes.
-// Functions in this package accept either 4-byte (IP v4)
-// or 16-byte (IP v6) arrays as input.  Unless otherwise
-// specified, functions in this package always return
-// IP addresses in 16-byte form using the canonical
-// embedding.
+// Functions in this package accept either 4-byte (IPv4)
+// or 16-byte (IPv6) arrays as input.
 //
 // Note that in this documentation, referring to an
 // IP address as an IPv4 address or an IPv6 address
@@ -37,6 +34,12 @@ type IP []byte
 // An IP mask is an IP address.
 type IPMask []byte
 
+// An IPNet represents an IP network.
+type IPNet struct {
+	IP   IP     // network number
+	Mask IPMask // network mask
+}
+
 // IPv4 returns the IP address (in 16-byte form) of the
 // IPv4 address a.b.c.d.
 func IPv4(a, b, c, d byte) IP {
@@ -51,20 +54,42 @@ func IPv4(a, b, c, d byte) IP {
 
 var v4InV6Prefix = []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xff, 0xff}
 
-// IPv4Mask returns the IP mask (in 16-byte form) of the
+// IPv4Mask returns the IP mask (in 4-byte form) of the
 // IPv4 mask a.b.c.d.
 func IPv4Mask(a, b, c, d byte) IPMask {
-	p := make(IPMask, IPv6len)
-	for i := 0; i < 12; i++ {
-		p[i] = 0xff
-	}
-	p[12] = a
-	p[13] = b
-	p[14] = c
-	p[15] = d
+	p := make(IPMask, IPv4len)
+	p[0] = a
+	p[1] = b
+	p[2] = c
+	p[3] = d
 	return p
 }
 
+// CIDRMask returns an IPMask consisting of `ones' 1 bits
+// followed by 0s up to a total length of `bits' bits.
+// For a mask of this form, CIDRMask is the inverse of IPMask.Size.
+func CIDRMask(ones, bits int) IPMask {
+	if bits != 8*IPv4len && bits != 8*IPv6len {
+		return nil
+	}
+	if ones < 0 || ones > bits {
+		return nil
+	}
+	l := bits / 8
+	m := make(IPMask, l)
+	n := uint(ones)
+	for i := 0; i < l; i++ {
+		if n >= 8 {
+			m[i] = 0xff
+			n -= 8
+			continue
+		}
+		m[i] = ^byte(0xff >> n)
+		n = 0
+	}
+	return m
+}
+
 // Well-known IPv4 addresses
 var (
 	IPv4bcast     = IPv4(255, 255, 255, 255) // broadcast
@@ -213,13 +238,13 @@ func allFF(b []byte) bool {
 
 // Mask returns the result of masking the IP address ip with mask.
 func (ip IP) Mask(mask IPMask) IP {
-	n := len(ip)
-	if len(mask) == 16 && len(ip) == 4 && allFF(mask[:12]) {
+	if len(mask) == IPv6len && len(ip) == IPv4len && allFF(mask[:12]) {
 		mask = mask[12:]
 	}
-	if len(mask) == 4 && len(ip) == 16 && bytesEqual(ip[:12], v4InV6Prefix) {
+	if len(mask) == IPv4len && len(ip) == IPv6len && bytesEqual(ip[:12], v4InV6Prefix) {
 		ip = ip[12:]
 	}
+	n := len(ip)
 	if n != len(mask) {
 		return nil
 	}
@@ -230,40 +255,6 @@ func (ip IP) Mask(mask IPMask) IP {
 	return out
 }
 
-// Convert i to decimal string.
-func itod(i uint) string {
-	if i == 0 {
-		return "0"
-	}
-
-	// Assemble decimal in reverse order.
-	var b [32]byte
-	bp := len(b)
-	for ; i > 0; i /= 10 {
-		bp--
-		b[bp] = byte(i%10) + '0'
-	}
-
-	return string(b[bp:])
-}
-
-// Convert i to hexadecimal string.
-func itox(i uint) string {
-	if i == 0 {
-		return "0"
-	}
-
-	// Assemble hexadecimal in reverse order.
-	var b [32]byte
-	bp := len(b)
-	for ; i > 0; i /= 16 {
-		bp--
-		b[bp] = "0123456789abcdef"[byte(i%16)]
-	}
-
-	return string(b[bp:])
-}
-
 // String returns the string form of the IP address ip.
 // If the address is an IPv4 address, the string representation
 // is dotted decimal ("74.125.19.99").  Otherwise the representation
@@ -272,11 +263,11 @@ func (ip IP) String() string {
 	p := ip
 
 	if len(ip) == 0 {
-		return ""
+		return "<nil>"
 	}
 
 	// If IPv4, use dotted notation.
-	if p4 := p.To4(); len(p4) == 4 {
+	if p4 := p.To4(); len(p4) == IPv4len {
 		return itod(uint(p4[0])) + "." +
 			itod(uint(p4[1])) + "." +
 			itod(uint(p4[2])) + "." +
@@ -289,9 +280,9 @@ func (ip IP) String() string {
 	// Find longest run of zeros.
 	e0 := -1
 	e1 := -1
-	for i := 0; i < 16; i += 2 {
+	for i := 0; i < IPv6len; i += 2 {
 		j := i
-		for j < 16 && p[j] == 0 && p[j+1] == 0 {
+		for j < IPv6len && p[j] == 0 && p[j+1] == 0 {
 			j += 2
 		}
 		if j > i && j-i > e1-e0 {
@@ -307,17 +298,17 @@ func (ip IP) String() string {
 
 	// Print with possible :: in place of run of zeros
 	var s string
-	for i := 0; i < 16; i += 2 {
+	for i := 0; i < IPv6len; i += 2 {
 		if i == e0 {
 			s += "::"
 			i = e1
-			if i >= 16 {
+			if i >= IPv6len {
 				break
 			}
 		} else if i > 0 {
 			s += ":"
 		}
-		s += itox((uint(p[i]) << 8) | uint(p[i+1]))
+		s += itox((uint(p[i])<<8)|uint(p[i+1]), 1)
 	}
 	return s
 }
@@ -329,10 +320,10 @@ func (ip IP) Equal(x IP) bool {
 	if len(ip) == len(x) {
 		return bytesEqual(ip, x)
 	}
-	if len(ip) == 4 && len(x) == 16 {
+	if len(ip) == IPv4len && len(x) == IPv6len {
 		return bytesEqual(x[0:12], v4InV6Prefix) && bytesEqual(ip, x[12:])
 	}
-	if len(ip) == 16 && len(x) == 4 {
+	if len(ip) == IPv6len && len(x) == IPv4len {
 		return bytesEqual(ip[0:12], v4InV6Prefix) && bytesEqual(ip[12:], x)
 	}
 	return false
@@ -379,25 +370,86 @@ func simpleMaskLength(mask IPMask) int {
 	return n
 }
 
-// String returns the string representation of mask.
-// If the mask is in the canonical form--ones followed by zeros--the
-// string representation is just the decimal number of ones.
-// If the mask is in a non-canonical form, it is formatted
-// as an IP address.
-func (mask IPMask) String() string {
-	switch len(mask) {
-	case 4:
-		n := simpleMaskLength(mask)
-		if n >= 0 {
-			return itod(uint(n + (IPv6len-IPv4len)*8))
+// Size returns the number of leading ones and total bits in the mask.
+// If the mask is not in the canonical form--ones followed by zeros--then
+// Size returns 0, 0.
+func (m IPMask) Size() (ones, bits int) {
+	ones, bits = simpleMaskLength(m), len(m)*8
+	if ones == -1 {
+		return 0, 0
+	}
+	return
+}
+
+// String returns the hexadecimal form of m, with no punctuation.
+func (m IPMask) String() string {
+	s := ""
+	for _, b := range m {
+		s += itox(uint(b), 2)
+	}
+	if len(s) == 0 {
+		return "<nil>"
+	}
+	return s
+}
+
+func networkNumberAndMask(n *IPNet) (ip IP, m IPMask) {
+	if ip = n.IP.To4(); ip == nil {
+		ip = n.IP
+		if len(ip) != IPv6len {
+			return nil, nil
 		}
-	case 16:
-		n := simpleMaskLength(mask)
-		if n >= 12*8 {
-			return itod(uint(n - 12*8))
+	}
+	m = n.Mask
+	switch len(m) {
+	case IPv4len:
+		if len(ip) != IPv4len {
+			return nil, nil
+		}
+	case IPv6len:
+		if len(ip) == IPv4len {
+			m = m[12:]
+		}
+	default:
+		return nil, nil
+	}
+	return
+}
+
+// Contains reports whether the network includes ip.
+func (n *IPNet) Contains(ip IP) bool {
+	nn, m := networkNumberAndMask(n)
+	if x := ip.To4(); x != nil {
+		ip = x
+	}
+	l := len(ip)
+	if l != len(nn) {
+		return false
+	}
+	for i := 0; i < l; i++ {
+		if nn[i]&m[i] != ip[i]&m[i] {
+			return false
 		}
 	}
-	return IP(mask).String()
+	return true
+}
+
+// String returns the CIDR notation of n like "192.168.100.1/24"
+// or "2001:DB8::/48" as defined in RFC 4632 and RFC 4291.
+// If the mask is not in the canonical form, it returns the
+// string which consists of an IP address, followed by a slash
+// character and a mask expressed as hexadecimal form with no
+// punctuation like "192.168.100.1/c000ff00".
+func (n *IPNet) String() string {
+	nn, m := networkNumberAndMask(n)
+	if nn == nil || m == nil {
+		return "<nil>"
+	}
+	l := simpleMaskLength(m)
+	if l == -1 {
+		return nn.String() + "/" + m.String()
+	}
+	return nn.String() + "/" + itod(uint(l))
 }
 
 // Parse IPv4 address (d.d.d.d).
@@ -440,7 +492,7 @@ func parseIPv4(s string) IP {
 //	* The last 32 bits can be in IPv4 form.
 // Thus, ::ffff:1.2.3.4 is the IPv4 address 1.2.3.4.
 func parseIPv6(s string) IP {
-	p := make(IP, 16)
+	p := make(IP, IPv6len)
 	ellipsis := -1 // position of ellipsis in p
 	i := 0         // index in string s
 
@@ -482,7 +534,7 @@ func parseIPv6(s string) IP {
 			p[j+2] = p4[14]
 			p[j+3] = p4[15]
 			i = len(s)
-			j += 4
+			j += IPv4len
 			break
 		}
 
@@ -569,46 +621,28 @@ func ParseIP(s string) IP {
 }
 
 // ParseCIDR parses s as a CIDR notation IP address and mask,
-// like "192.168.100.1/24", "2001:DB8::/48", as defined in
+// like "192.168.100.1/24" or "2001:DB8::/48", as defined in
 // RFC 4632 and RFC 4291.
-func ParseCIDR(s string) (ip IP, mask IPMask, err os.Error) {
+//
+// It returns the IP address and the network implied by the IP
+// and mask.  For example, ParseCIDR("192.168.100.1/16") returns
+// the IP address 192.168.100.1 and the network 192.168.0.0/16.
+func ParseCIDR(s string) (IP, *IPNet, os.Error) {
 	i := byteIndex(s, '/')
 	if i < 0 {
 		return nil, nil, &ParseError{"CIDR address", s}
 	}
 	ipstr, maskstr := s[:i], s[i+1:]
-	iplen := 4
-	ip = parseIPv4(ipstr)
+	iplen := IPv4len
+	ip := parseIPv4(ipstr)
 	if ip == nil {
-		iplen = 16
+		iplen = IPv6len
 		ip = parseIPv6(ipstr)
 	}
-	nn, i, ok := dtoi(maskstr, 0)
-	if ip == nil || !ok || i != len(maskstr) || nn < 0 || nn > 8*iplen {
+	n, i, ok := dtoi(maskstr, 0)
+	if ip == nil || !ok || i != len(maskstr) || n < 0 || n > 8*iplen {
 		return nil, nil, &ParseError{"CIDR address", s}
 	}
-	n := uint(nn)
-	if iplen == 4 {
-		v4mask := ^uint32(0xffffffff >> n)
-		mask = IPv4Mask(byte(v4mask>>24), byte(v4mask>>16), byte(v4mask>>8), byte(v4mask))
-	} else {
-		mask = make(IPMask, 16)
-		for i := 0; i < 16; i++ {
-			if n >= 8 {
-				mask[i] = 0xff
-				n -= 8
-				continue
-			}
-			mask[i] = ^byte(0xff >> n)
-			n = 0
-
-		}
-	}
-	// address must not have any bits not in mask
-	for i := range ip {
-		if ip[i]&^mask[i] != 0 {
-			return nil, nil, &ParseError{"CIDR address", s}
-		}
-	}
-	return ip, mask, nil
+	m := CIDRMask(n, 8*iplen)
+	return ip, &IPNet{ip.Mask(m), m}, nil
 }
diff --git a/libgo/go/net/ip_test.go b/libgo/go/net/ip_test.go
index b189b10c4fd..07e627aef4f 100644
--- a/libgo/go/net/ip_test.go
+++ b/libgo/go/net/ip_test.go
@@ -34,12 +34,13 @@ var parseiptests = []struct {
 	{"::ffff:127.0.0.1", IPv4(127, 0, 0, 1)},
 	{"2001:4860:0:2001::68", IP{0x20, 0x01, 0x48, 0x60, 0, 0, 0x20, 0x01, 0, 0, 0, 0, 0, 0, 0x00, 0x68}},
 	{"::ffff:4a7d:1363", IPv4(74, 125, 19, 99)},
+	{"", nil},
 }
 
 func TestParseIP(t *testing.T) {
 	for _, tt := range parseiptests {
 		if out := ParseIP(tt.in); !isEqual(out, tt.out) {
-			t.Errorf("ParseIP(%#q) = %v, want %v", tt.in, out, tt.out)
+			t.Errorf("ParseIP(%q) = %v, want %v", tt.in, out, tt.out)
 		}
 	}
 }
@@ -49,60 +50,213 @@ var ipstringtests = []struct {
 	out string
 }{
 	// cf. RFC 5952 (A Recommendation for IPv6 Address Text Representation)
-	{IP{0x20, 0x1, 0xd, 0xb8, 0, 0, 0, 0, 0, 0, 0x1, 0x23, 0, 0x12, 0, 0x1},
-		"2001:db8::123:12:1"},
-	{IP{0x20, 0x1, 0xd, 0xb8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x1},
-		"2001:db8::1"},
-	{IP{0x20, 0x1, 0xd, 0xb8, 0, 0, 0, 0x1, 0, 0, 0, 0x1, 0, 0, 0, 0x1},
-		"2001:db8:0:1:0:1:0:1"},
-	{IP{0x20, 0x1, 0xd, 0xb8, 0, 0x1, 0, 0, 0, 0x1, 0, 0, 0, 0x1, 0, 0},
-		"2001:db8:1:0:1:0:1:0"},
-	{IP{0x20, 0x1, 0, 0, 0, 0, 0, 0, 0, 0x1, 0, 0, 0, 0, 0, 0x1},
-		"2001::1:0:0:1"},
-	{IP{0x20, 0x1, 0xd, 0xb8, 0, 0, 0, 0, 0, 0x1, 0, 0, 0, 0, 0, 0},
-		"2001:db8:0:0:1::"},
-	{IP{0x20, 0x1, 0xd, 0xb8, 0, 0, 0, 0, 0, 0x1, 0, 0, 0, 0, 0, 0x1},
-		"2001:db8::1:0:0:1"},
-	{IP{0x20, 0x1, 0xD, 0xB8, 0, 0, 0, 0, 0, 0xA, 0, 0xB, 0, 0xC, 0, 0xD},
-		"2001:db8::a:b:c:d"},
+	{IP{0x20, 0x1, 0xd, 0xb8, 0, 0, 0, 0, 0, 0, 0x1, 0x23, 0, 0x12, 0, 0x1}, "2001:db8::123:12:1"},
+	{IP{0x20, 0x1, 0xd, 0xb8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x1}, "2001:db8::1"},
+	{IP{0x20, 0x1, 0xd, 0xb8, 0, 0, 0, 0x1, 0, 0, 0, 0x1, 0, 0, 0, 0x1}, "2001:db8:0:1:0:1:0:1"},
+	{IP{0x20, 0x1, 0xd, 0xb8, 0, 0x1, 0, 0, 0, 0x1, 0, 0, 0, 0x1, 0, 0}, "2001:db8:1:0:1:0:1:0"},
+	{IP{0x20, 0x1, 0, 0, 0, 0, 0, 0, 0, 0x1, 0, 0, 0, 0, 0, 0x1}, "2001::1:0:0:1"},
+	{IP{0x20, 0x1, 0xd, 0xb8, 0, 0, 0, 0, 0, 0x1, 0, 0, 0, 0, 0, 0}, "2001:db8:0:0:1::"},
+	{IP{0x20, 0x1, 0xd, 0xb8, 0, 0, 0, 0, 0, 0x1, 0, 0, 0, 0, 0, 0x1}, "2001:db8::1:0:0:1"},
+	{IP{0x20, 0x1, 0xD, 0xB8, 0, 0, 0, 0, 0, 0xA, 0, 0xB, 0, 0xC, 0, 0xD}, "2001:db8::a:b:c:d"},
+	{nil, "<nil>"},
 }
 
 func TestIPString(t *testing.T) {
 	for _, tt := range ipstringtests {
 		if out := tt.in.String(); out != tt.out {
-			t.Errorf("IP.String(%v) = %#q, want %#q", tt.in, out, tt.out)
+			t.Errorf("IP.String(%v) = %q, want %q", tt.in, out, tt.out)
 		}
 	}
 }
 
-var parsecidrtests = []struct {
-	in   string
-	ip   IP
+var ipmasktests = []struct {
+	in   IP
 	mask IPMask
-	err  os.Error
+	out  IP
+}{
+	{IPv4(192, 168, 1, 127), IPv4Mask(255, 255, 255, 128), IPv4(192, 168, 1, 0)},
+	{IPv4(192, 168, 1, 127), IPMask(ParseIP("255.255.255.192")), IPv4(192, 168, 1, 64)},
+	{IPv4(192, 168, 1, 127), IPMask(ParseIP("ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffe0")), IPv4(192, 168, 1, 96)},
+	{IPv4(192, 168, 1, 127), IPv4Mask(255, 0, 255, 0), IPv4(192, 0, 1, 0)},
+	{ParseIP("2001:db8::1"), IPMask(ParseIP("ffff:ff80::")), ParseIP("2001:d80::")},
+	{ParseIP("2001:db8::1"), IPMask(ParseIP("f0f0:0f0f::")), ParseIP("2000:d08::")},
+}
+
+func TestIPMask(t *testing.T) {
+	for _, tt := range ipmasktests {
+		if out := tt.in.Mask(tt.mask); out == nil || !tt.out.Equal(out) {
+			t.Errorf("IP(%v).Mask(%v) = %v, want %v", tt.in, tt.mask, out, tt.out)
+		}
+	}
+}
+
+var ipmaskstringtests = []struct {
+	in  IPMask
+	out string
+}{
+	{IPv4Mask(255, 255, 255, 240), "fffffff0"},
+	{IPv4Mask(255, 0, 128, 0), "ff008000"},
+	{IPMask(ParseIP("ffff:ff80::")), "ffffff80000000000000000000000000"},
+	{IPMask(ParseIP("ef00:ff80::cafe:0")), "ef00ff800000000000000000cafe0000"},
+	{nil, "<nil>"},
+}
+
+func TestIPMaskString(t *testing.T) {
+	for _, tt := range ipmaskstringtests {
+		if out := tt.in.String(); out != tt.out {
+			t.Errorf("IPMask.String(%v) = %q, want %q", tt.in, out, tt.out)
+		}
+	}
+}
+
+var parsecidrtests = []struct {
+	in  string
+	ip  IP
+	net *IPNet
+	err os.Error
 }{
-	{"135.104.0.0/32", IPv4(135, 104, 0, 0), IPv4Mask(255, 255, 255, 255), nil},
-	{"0.0.0.0/24", IPv4(0, 0, 0, 0), IPv4Mask(255, 255, 255, 0), nil},
-	{"135.104.0.0/24", IPv4(135, 104, 0, 0), IPv4Mask(255, 255, 255, 0), nil},
-	{"135.104.0.1/32", IPv4(135, 104, 0, 1), IPv4Mask(255, 255, 255, 255), nil},
-	{"135.104.0.1/24", nil, nil, &ParseError{"CIDR address", "135.104.0.1/24"}},
-	{"::1/128", ParseIP("::1"), IPMask(ParseIP("ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff")), nil},
-	{"abcd:2345::/127", ParseIP("abcd:2345::"), IPMask(ParseIP("ffff:ffff:ffff:ffff:ffff:ffff:ffff:fffe")), nil},
-	{"abcd:2345::/65", ParseIP("abcd:2345::"), IPMask(ParseIP("ffff:ffff:ffff:ffff:8000::")), nil},
-	{"abcd:2345::/64", ParseIP("abcd:2345::"), IPMask(ParseIP("ffff:ffff:ffff:ffff::")), nil},
-	{"abcd:2345::/63", ParseIP("abcd:2345::"), IPMask(ParseIP("ffff:ffff:ffff:fffe::")), nil},
-	{"abcd:2345::/33", ParseIP("abcd:2345::"), IPMask(ParseIP("ffff:ffff:8000::")), nil},
-	{"abcd:2345::/32", ParseIP("abcd:2345::"), IPMask(ParseIP("ffff:ffff::")), nil},
-	{"abcd:2344::/31", ParseIP("abcd:2344::"), IPMask(ParseIP("ffff:fffe::")), nil},
-	{"abcd:2300::/24", ParseIP("abcd:2300::"), IPMask(ParseIP("ffff:ff00::")), nil},
-	{"abcd:2345::/24", nil, nil, &ParseError{"CIDR address", "abcd:2345::/24"}},
-	{"2001:DB8::/48", ParseIP("2001:DB8::"), IPMask(ParseIP("ffff:ffff:ffff::")), nil},
+	{"135.104.0.0/32", IPv4(135, 104, 0, 0), &IPNet{IPv4(135, 104, 0, 0), IPv4Mask(255, 255, 255, 255)}, nil},
+	{"0.0.0.0/24", IPv4(0, 0, 0, 0), &IPNet{IPv4(0, 0, 0, 0), IPv4Mask(255, 255, 255, 0)}, nil},
+	{"135.104.0.0/24", IPv4(135, 104, 0, 0), &IPNet{IPv4(135, 104, 0, 0), IPv4Mask(255, 255, 255, 0)}, nil},
+	{"135.104.0.1/32", IPv4(135, 104, 0, 1), &IPNet{IPv4(135, 104, 0, 1), IPv4Mask(255, 255, 255, 255)}, nil},
+	{"135.104.0.1/24", IPv4(135, 104, 0, 1), &IPNet{IPv4(135, 104, 0, 0), IPv4Mask(255, 255, 255, 0)}, nil},
+	{"::1/128", ParseIP("::1"), &IPNet{ParseIP("::1"), IPMask(ParseIP("ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff"))}, nil},
+	{"abcd:2345::/127", ParseIP("abcd:2345::"), &IPNet{ParseIP("abcd:2345::"), IPMask(ParseIP("ffff:ffff:ffff:ffff:ffff:ffff:ffff:fffe"))}, nil},
+	{"abcd:2345::/65", ParseIP("abcd:2345::"), &IPNet{ParseIP("abcd:2345::"), IPMask(ParseIP("ffff:ffff:ffff:ffff:8000::"))}, nil},
+	{"abcd:2345::/64", ParseIP("abcd:2345::"), &IPNet{ParseIP("abcd:2345::"), IPMask(ParseIP("ffff:ffff:ffff:ffff::"))}, nil},
+	{"abcd:2345::/63", ParseIP("abcd:2345::"), &IPNet{ParseIP("abcd:2345::"), IPMask(ParseIP("ffff:ffff:ffff:fffe::"))}, nil},
+	{"abcd:2345::/33", ParseIP("abcd:2345::"), &IPNet{ParseIP("abcd:2345::"), IPMask(ParseIP("ffff:ffff:8000::"))}, nil},
+	{"abcd:2345::/32", ParseIP("abcd:2345::"), &IPNet{ParseIP("abcd:2345::"), IPMask(ParseIP("ffff:ffff::"))}, nil},
+	{"abcd:2344::/31", ParseIP("abcd:2344::"), &IPNet{ParseIP("abcd:2344::"), IPMask(ParseIP("ffff:fffe::"))}, nil},
+	{"abcd:2300::/24", ParseIP("abcd:2300::"), &IPNet{ParseIP("abcd:2300::"), IPMask(ParseIP("ffff:ff00::"))}, nil},
+	{"abcd:2345::/24", ParseIP("abcd:2345::"), &IPNet{ParseIP("abcd:2300::"), IPMask(ParseIP("ffff:ff00::"))}, nil},
+	{"2001:DB8::/48", ParseIP("2001:DB8::"), &IPNet{ParseIP("2001:DB8::"), IPMask(ParseIP("ffff:ffff:ffff::"))}, nil},
+	{"2001:DB8::1/48", ParseIP("2001:DB8::1"), &IPNet{ParseIP("2001:DB8::"), IPMask(ParseIP("ffff:ffff:ffff::"))}, nil},
+	{"192.168.1.1/255.255.255.0", nil, nil, &ParseError{"CIDR address", "192.168.1.1/255.255.255.0"}},
+	{"192.168.1.1/35", nil, nil, &ParseError{"CIDR address", "192.168.1.1/35"}},
+	{"2001:db8::1/-1", nil, nil, &ParseError{"CIDR address", "2001:db8::1/-1"}},
+	{"", nil, nil, &ParseError{"CIDR address", ""}},
 }
 
 func TestParseCIDR(t *testing.T) {
 	for _, tt := range parsecidrtests {
-		if ip, mask, err := ParseCIDR(tt.in); !isEqual(ip, tt.ip) || !isEqual(mask, tt.mask) || !reflect.DeepEqual(err, tt.err) {
-			t.Errorf("ParseCIDR(%q) = %v, %v, %v; want %v, %v, %v", tt.in, ip, mask, err, tt.ip, tt.mask, tt.err)
+		ip, net, err := ParseCIDR(tt.in)
+		if !reflect.DeepEqual(err, tt.err) {
+			t.Errorf("ParseCIDR(%q) = %v, %v; want %v, %v", tt.in, ip, net, tt.ip, tt.net)
+		}
+		if err == nil && (!tt.ip.Equal(ip) || !tt.net.IP.Equal(net.IP) || !isEqual(net.Mask, tt.net.Mask)) {
+			t.Errorf("ParseCIDR(%q) = %v, {%v, %v}; want %v {%v, %v}", tt.in, ip, net.IP, net.Mask, tt.ip, tt.net.IP, tt.net.Mask)
+		}
+	}
+}
+
+var ipnetcontainstests = []struct {
+	ip  IP
+	net *IPNet
+	ok  bool
+}{
+	{IPv4(172, 16, 1, 1), &IPNet{IPv4(172, 16, 0, 0), CIDRMask(12, 32)}, true},
+	{IPv4(172, 24, 0, 1), &IPNet{IPv4(172, 16, 0, 0), CIDRMask(13, 32)}, false},
+	{IPv4(192, 168, 0, 3), &IPNet{IPv4(192, 168, 0, 0), IPv4Mask(0, 0, 255, 252)}, true},
+	{IPv4(192, 168, 0, 4), &IPNet{IPv4(192, 168, 0, 0), IPv4Mask(0, 255, 0, 252)}, false},
+	{ParseIP("2001:db8:1:2::1"), &IPNet{ParseIP("2001:db8:1::"), CIDRMask(47, 128)}, true},
+	{ParseIP("2001:db8:1:2::1"), &IPNet{ParseIP("2001:db8:2::"), CIDRMask(47, 128)}, false},
+	{ParseIP("2001:db8:1:2::1"), &IPNet{ParseIP("2001:db8:1::"), IPMask(ParseIP("ffff:0:ffff::"))}, true},
+	{ParseIP("2001:db8:1:2::1"), &IPNet{ParseIP("2001:db8:1::"), IPMask(ParseIP("0:0:0:ffff::"))}, false},
+}
+
+func TestIPNetContains(t *testing.T) {
+	for _, tt := range ipnetcontainstests {
+		if ok := tt.net.Contains(tt.ip); ok != tt.ok {
+			t.Errorf("IPNet(%v).Contains(%v) = %v, want %v", tt.net, tt.ip, ok, tt.ok)
+		}
+	}
+}
+
+var ipnetstringtests = []struct {
+	in  *IPNet
+	out string
+}{
+	{&IPNet{IPv4(192, 168, 1, 0), CIDRMask(26, 32)}, "192.168.1.0/26"},
+	{&IPNet{IPv4(192, 168, 1, 0), IPv4Mask(255, 0, 255, 0)}, "192.168.1.0/ff00ff00"},
+	{&IPNet{ParseIP("2001:db8::"), CIDRMask(55, 128)}, "2001:db8::/55"},
+	{&IPNet{ParseIP("2001:db8::"), IPMask(ParseIP("8000:f123:0:cafe::"))}, "2001:db8::/8000f1230000cafe0000000000000000"},
+}
+
+func TestIPNetString(t *testing.T) {
+	for _, tt := range ipnetstringtests {
+		if out := tt.in.String(); out != tt.out {
+			t.Errorf("IPNet.String(%v) = %q, want %q", tt.in, out, tt.out)
+		}
+	}
+}
+
+var cidrmasktests = []struct {
+	ones int
+	bits int
+	out  IPMask
+}{
+	{0, 32, IPv4Mask(0, 0, 0, 0)},
+	{12, 32, IPv4Mask(255, 240, 0, 0)},
+	{24, 32, IPv4Mask(255, 255, 255, 0)},
+	{32, 32, IPv4Mask(255, 255, 255, 255)},
+	{0, 128, IPMask{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}},
+	{4, 128, IPMask{0xf0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}},
+	{48, 128, IPMask{0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}},
+	{128, 128, IPMask{0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff}},
+	{33, 32, nil},
+	{32, 33, nil},
+	{-1, 128, nil},
+	{128, -1, nil},
+}
+
+func TestCIDRMask(t *testing.T) {
+	for _, tt := range cidrmasktests {
+		if out := CIDRMask(tt.ones, tt.bits); !isEqual(out, tt.out) {
+			t.Errorf("CIDRMask(%v, %v) = %v, want %v", tt.ones, tt.bits, out, tt.out)
+		}
+	}
+}
+
+var (
+	v4addr         = IP{192, 168, 0, 1}
+	v4mappedv6addr = IP{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xff, 0xff, 192, 168, 0, 1}
+	v6addr         = IP{0x20, 0x1, 0xd, 0xb8, 0, 0, 0, 0, 0, 0, 0x1, 0x23, 0, 0x12, 0, 0x1}
+	v4mask         = IPMask{255, 255, 255, 0}
+	v4mappedv6mask = IPMask{0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 255, 255, 255, 0}
+	v6mask         = IPMask{0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0, 0, 0, 0, 0, 0, 0, 0}
+	badaddr        = IP{192, 168, 0}
+	badmask        = IPMask{255, 255, 0}
+	v4maskzero     = IPMask{0, 0, 0, 0}
+)
+
+var networknumberandmasktests = []struct {
+	in  IPNet
+	out IPNet
+}{
+	{IPNet{v4addr, v4mask}, IPNet{v4addr, v4mask}},
+	{IPNet{v4addr, v4mappedv6mask}, IPNet{v4addr, v4mask}},
+	{IPNet{v4mappedv6addr, v4mappedv6mask}, IPNet{v4addr, v4mask}},
+	{IPNet{v4mappedv6addr, v6mask}, IPNet{v4addr, v4maskzero}},
+	{IPNet{v4addr, v6mask}, IPNet{v4addr, v4maskzero}},
+	{IPNet{v6addr, v6mask}, IPNet{v6addr, v6mask}},
+	{IPNet{v6addr, v4mappedv6mask}, IPNet{v6addr, v4mappedv6mask}},
+	{in: IPNet{v6addr, v4mask}},
+	{in: IPNet{v4addr, badmask}},
+	{in: IPNet{v4mappedv6addr, badmask}},
+	{in: IPNet{v6addr, badmask}},
+	{in: IPNet{badaddr, v4mask}},
+	{in: IPNet{badaddr, v4mappedv6mask}},
+	{in: IPNet{badaddr, v6mask}},
+	{in: IPNet{badaddr, badmask}},
+}
+
+func TestNetworkNumberAndMask(t *testing.T) {
+	for _, tt := range networknumberandmasktests {
+		ip, m := networkNumberAndMask(&tt.in)
+		out := &IPNet{ip, m}
+		if !reflect.DeepEqual(&tt.out, out) {
+			t.Errorf("networkNumberAndMask(%v) = %v; want %v", tt.in, out, &tt.out)
 		}
 	}
 }
@@ -158,10 +312,10 @@ var ipaftests = []struct {
 func TestIPAddrFamily(t *testing.T) {
 	for _, tt := range ipaftests {
 		if af := tt.in.To4() != nil; af != tt.af4 {
-			t.Errorf("verifying IPv4 address family for %#q = %v, want %v", tt.in, af, tt.af4)
+			t.Errorf("verifying IPv4 address family for %q = %v, want %v", tt.in, af, tt.af4)
 		}
 		if af := len(tt.in) == IPv6len && tt.in.To4() == nil; af != tt.af6 {
-			t.Errorf("verifying IPv6 address family for %#q = %v, want %v", tt.in, af, tt.af6)
+			t.Errorf("verifying IPv6 address family for %q = %v, want %v", tt.in, af, tt.af6)
 		}
 	}
 }
@@ -209,7 +363,7 @@ func name(f interface{}) string {
 func TestIPAddrScope(t *testing.T) {
 	for _, tt := range ipscopetests {
 		if ok := tt.scope(tt.in); ok != tt.ok {
-			t.Errorf("%s(%#q) = %v, want %v", name(tt.scope), tt.in, ok, tt.ok)
+			t.Errorf("%s(%q) = %v, want %v", name(tt.scope), tt.in, ok, tt.ok)
 		}
 	}
 }
diff --git a/libgo/go/net/iprawsock_posix.go b/libgo/go/net/iprawsock_posix.go
index 4e115180061..dafbdab7804 100644
--- a/libgo/go/net/iprawsock_posix.go
+++ b/libgo/go/net/iprawsock_posix.go
@@ -2,18 +2,17 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// +build darwin freebsd linux openbsd windows
+
 // (Raw) IP sockets
 
 package net
 
 import (
 	"os"
-	"sync"
 	"syscall"
 )
 
-var onceReadProtocols sync.Once
-
 func sockaddrToIP(sa syscall.Sockaddr) Addr {
 	switch sa := sa.(type) {
 	case *syscall.SockaddrInet4:
@@ -25,7 +24,7 @@ func sockaddrToIP(sa syscall.Sockaddr) Addr {
 }
 
 func (a *IPAddr) family() int {
-	if a == nil || len(a.IP) <= 4 {
+	if a == nil || len(a.IP) <= IPv4len {
 		return syscall.AF_INET
 	}
 	if a.IP.To4() != nil {
@@ -158,7 +157,7 @@ func (c *IPConn) ReadFromIP(b []byte) (n int, addr *IPAddr, err os.Error) {
 	switch sa := sa.(type) {
 	case *syscall.SockaddrInet4:
 		addr = &IPAddr{sa.Addr[0:]}
-		if len(b) >= 4 { // discard ipv4 header
+		if len(b) >= IPv4len { // discard ipv4 header
 			hsize := (int(b[0]) & 0xf) * 4
 			copy(b, b[hsize:])
 			n -= hsize
@@ -207,33 +206,7 @@ func (c *IPConn) WriteTo(b []byte, addr Addr) (n int, err os.Error) {
 	return c.WriteToIP(b, a)
 }
 
-var protocols map[string]int
-
-func readProtocols() {
-	protocols = make(map[string]int)
-	if file, err := open("/etc/protocols"); err == nil {
-		for line, ok := file.readLine(); ok; line, ok = file.readLine() {
-			// tcp    6   TCP    # transmission control protocol
-			if i := byteIndex(line, '#'); i >= 0 {
-				line = line[0:i]
-			}
-			f := getFields(line)
-			if len(f) < 2 {
-				continue
-			}
-			if proto, _, ok := dtoi(f[1], 0); ok {
-				protocols[f[0]] = proto
-				for _, alias := range f[2:] {
-					protocols[alias] = proto
-				}
-			}
-		}
-		file.close()
-	}
-}
-
 func splitNetProto(netProto string) (net string, proto int, err os.Error) {
-	onceReadProtocols.Do(readProtocols)
 	i := last(netProto, ':')
 	if i < 0 { // no colon
 		return "", 0, os.NewError("no IP protocol specified")
@@ -242,13 +215,12 @@ func splitNetProto(netProto string) (net string, proto int, err os.Error) {
 	protostr := netProto[i+1:]
 	proto, i, ok := dtoi(protostr, 0)
 	if !ok || i != len(protostr) {
-		// lookup by name
-		proto, ok = protocols[protostr]
-		if ok {
-			return
+		proto, err = lookupProtocol(protostr)
+		if err != nil {
+			return "", 0, err
 		}
 	}
-	return
+	return net, proto, nil
 }
 
 // DialIP connects to the remote address raddr on the network net,
@@ -303,3 +275,8 @@ func (c *IPConn) BindToDevice(device string) os.Error {
 	defer c.fd.decref()
 	return os.NewSyscallError("setsockopt", syscall.BindToDevice(c.fd.sysfd, device))
 }
+
+// File returns a copy of the underlying os.File, set to blocking mode.
+// It is the caller's responsibility to close f when finished.
+// Closing c does not affect f, and closing f does not affect c.
+func (c *IPConn) File() (f *os.File, err os.Error) { return c.fd.dup() }
diff --git a/libgo/go/net/ipsock_posix.go b/libgo/go/net/ipsock_posix.go
index 0c522fb7fbe..049df9ea4cb 100644
--- a/libgo/go/net/ipsock_posix.go
+++ b/libgo/go/net/ipsock_posix.go
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// +build darwin freebsd linux openbsd windows
+
 package net
 
 import (
diff --git a/libgo/go/net/lookup_plan9.go b/libgo/go/net/lookup_plan9.go
index 37d6b8e315a..d779f4a5d71 100644
--- a/libgo/go/net/lookup_plan9.go
+++ b/libgo/go/net/lookup_plan9.go
@@ -157,12 +157,21 @@ func LookupCNAME(name string) (cname string, err os.Error) {
 }
 
 // LookupSRV tries to resolve an SRV query of the given service,
-// protocol, and domain name, as specified in RFC 2782. In most cases
-// the proto argument can be the same as the corresponding
-// Addr.Network(). The returned records are sorted by priority 
-// and randomized by weight within a priority.
+// protocol, and domain name.  The proto is "tcp" or "udp".
+// The returned records are sorted by priority and randomized
+// by weight within a priority.
+//
+// LookupSRV constructs the DNS name to look up following RFC 2782.
+// That is, it looks up _service._proto.name.  To accommodate services
+// publishing SRV records under non-standard names, if both service
+// and proto are empty strings, LookupSRV looks up name directly.
 func LookupSRV(service, proto, name string) (cname string, addrs []*SRV, err os.Error) {
-	target := "_" + service + "._" + proto + "." + name
+	var target string
+	if service == "" && proto == "" {
+		target = name
+	} else {
+		target = "_" + service + "._" + proto + "." + name
+	}
 	lines, err := queryDNS(target, "srv")
 	if err != nil {
 		return
@@ -204,6 +213,11 @@ func LookupMX(name string) (mx []*MX, err os.Error) {
 	return
 }
 
+// LookupTXT returns the DNS TXT records for the given domain name.
+func LookupTXT(name string) (txt []string, err os.Error) {
+	return nil, os.NewError("net.LookupTXT is not implemented on Plan 9")
+}
+
 // LookupAddr performs a reverse lookup for the given address, returning a list
 // of names mapping to that address.
 func LookupAddr(addr string) (name []string, err os.Error) {
diff --git a/libgo/go/net/lookup_test.go b/libgo/go/net/lookup_test.go
index 995ab03d090..c0fcd260472 100644
--- a/libgo/go/net/lookup_test.go
+++ b/libgo/go/net/lookup_test.go
@@ -26,6 +26,15 @@ func TestGoogleSRV(t *testing.T) {
 	if len(addrs) == 0 {
 		t.Errorf("no results")
 	}
+
+	// Non-standard back door.
+	_, addrs, err = LookupSRV("", "", "_xmpp-server._tcp.google.com")
+	if err != nil {
+		t.Errorf("back door failed: %s", err)
+	}
+	if len(addrs) == 0 {
+		t.Errorf("back door no results")
+	}
 }
 
 func TestGmailMX(t *testing.T) {
@@ -42,6 +51,24 @@ func TestGmailMX(t *testing.T) {
 	}
 }
 
+func TestGmailTXT(t *testing.T) {
+	if runtime.GOOS == "windows" || runtime.GOOS == "plan9" {
+		t.Logf("LookupTXT is not implemented on Windows or Plan 9")
+		return
+	}
+	if testing.Short() || avoidMacFirewall {
+		t.Logf("skipping test to avoid external network")
+		return
+	}
+	txt, err := LookupTXT("gmail.com")
+	if err != nil {
+		t.Errorf("failed: %s", err)
+	}
+	if len(txt) == 0 || len(txt[0]) == 0 {
+		t.Errorf("no results")
+	}
+}
+
 func TestGoogleDNSAddr(t *testing.T) {
 	if testing.Short() || avoidMacFirewall {
 		t.Logf("skipping test to avoid external network")
diff --git a/libgo/go/net/lookup_unix.go b/libgo/go/net/lookup_unix.go
index 8f5e66212b3..6e79295a948 100644
--- a/libgo/go/net/lookup_unix.go
+++ b/libgo/go/net/lookup_unix.go
@@ -2,12 +2,56 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// +build darwin freebsd linux openbsd
+
 package net
 
 import (
 	"os"
+	"sync"
+)
+
+var (
+	protocols         map[string]int
+	onceReadProtocols sync.Once
 )
 
+// readProtocols loads contents of /etc/protocols into protocols map
+// for quick access.
+func readProtocols() {
+	protocols = make(map[string]int)
+	if file, err := open("/etc/protocols"); err == nil {
+		for line, ok := file.readLine(); ok; line, ok = file.readLine() {
+			// tcp    6   TCP    # transmission control protocol
+			if i := byteIndex(line, '#'); i >= 0 {
+				line = line[0:i]
+			}
+			f := getFields(line)
+			if len(f) < 2 {
+				continue
+			}
+			if proto, _, ok := dtoi(f[1], 0); ok {
+				protocols[f[0]] = proto
+				for _, alias := range f[2:] {
+					protocols[alias] = proto
+				}
+			}
+		}
+		file.close()
+	}
+}
+
+// lookupProtocol looks up IP protocol name in /etc/protocols and
+// returns correspondent protocol number.
+func lookupProtocol(name string) (proto int, err os.Error) {
+	onceReadProtocols.Do(readProtocols)
+	proto, found := protocols[name]
+	if !found {
+		return 0, os.NewError("unknown IP protocol specified: " + name)
+	}
+	return
+}
+
 // LookupHost looks up the given host using the local resolver.
 // It returns an array of that host's addresses.
 func LookupHost(host string) (addrs []string, err os.Error) {
@@ -50,12 +94,21 @@ func LookupCNAME(name string) (cname string, err os.Error) {
 }
 
 // LookupSRV tries to resolve an SRV query of the given service,
-// protocol, and domain name, as specified in RFC 2782. In most cases
-// the proto argument can be the same as the corresponding
-// Addr.Network(). The returned records are sorted by priority 
-// and randomized by weight within a priority.
+// protocol, and domain name.  The proto is "tcp" or "udp".
+// The returned records are sorted by priority and randomized
+// by weight within a priority.
+//
+// LookupSRV constructs the DNS name to look up following RFC 2782.
+// That is, it looks up _service._proto.name.  To accommodate services
+// publishing SRV records under non-standard names, if both service
+// and proto are empty strings, LookupSRV looks up name directly.
 func LookupSRV(service, proto, name string) (cname string, addrs []*SRV, err os.Error) {
-	target := "_" + service + "._" + proto + "." + name
+	var target string
+	if service == "" && proto == "" {
+		target = name
+	} else {
+		target = "_" + service + "._" + proto + "." + name
+	}
 	var records []dnsRR
 	cname, records, err = lookup(target, dnsTypeSRV)
 	if err != nil {
@@ -72,19 +125,32 @@ func LookupSRV(service, proto, name string) (cname string, addrs []*SRV, err os.
 
 // LookupMX returns the DNS MX records for the given domain name sorted by preference.
 func LookupMX(name string) (mx []*MX, err os.Error) {
-	_, rr, err := lookup(name, dnsTypeMX)
+	_, records, err := lookup(name, dnsTypeMX)
 	if err != nil {
 		return
 	}
-	mx = make([]*MX, len(rr))
-	for i := range rr {
-		r := rr[i].(*dnsRR_MX)
+	mx = make([]*MX, len(records))
+	for i, rr := range records {
+		r := rr.(*dnsRR_MX)
 		mx[i] = &MX{r.Mx, r.Pref}
 	}
 	byPref(mx).sort()
 	return
 }
 
+// LookupTXT returns the DNS TXT records for the given domain name.
+func LookupTXT(name string) (txt []string, err os.Error) {
+	_, records, err := lookup(name, dnsTypeTXT)
+	if err != nil {
+		return
+	}
+	txt = make([]string, len(records))
+	for i, r := range records {
+		txt[i] = r.(*dnsRR_TXT).Txt
+	}
+	return
+}
+
 // LookupAddr performs a reverse lookup for the given address, returning a list
 // of names mapping to that address.
 func LookupAddr(addr string) (name []string, err os.Error) {
diff --git a/libgo/go/net/lookup_windows.go b/libgo/go/net/lookup_windows.go
index fa3ad7c7f42..ea939f85986 100644
--- a/libgo/go/net/lookup_windows.go
+++ b/libgo/go/net/lookup_windows.go
@@ -11,8 +11,22 @@ import (
 	"sync"
 )
 
-var hostentLock sync.Mutex
-var serventLock sync.Mutex
+var (
+	protoentLock sync.Mutex
+	hostentLock  sync.Mutex
+	serventLock  sync.Mutex
+)
+
+// lookupProtocol looks up IP protocol name and returns correspondent protocol number.
+func lookupProtocol(name string) (proto int, err os.Error) {
+	protoentLock.Lock()
+	defer protoentLock.Unlock()
+	p, e := syscall.GetProtoByName(name)
+	if e != 0 {
+		return 0, os.NewSyscallError("GetProtoByName", e)
+	}
+	return int(p.Proto), nil
+}
 
 func LookupHost(name string) (addrs []string, err os.Error) {
 	ips, err := LookupIP(name)
@@ -77,9 +91,23 @@ func LookupCNAME(name string) (cname string, err os.Error) {
 	return
 }
 
+// LookupSRV tries to resolve an SRV query of the given service,
+// protocol, and domain name.  The proto is "tcp" or "udp".
+// The returned records are sorted by priority and randomized
+// by weight within a priority.
+//
+// LookupSRV constructs the DNS name to look up following RFC 2782.
+// That is, it looks up _service._proto.name.  To accommodate services
+// publishing SRV records under non-standard names, if both service
+// and proto are empty strings, LookupSRV looks up name directly.
 func LookupSRV(service, proto, name string) (cname string, addrs []*SRV, err os.Error) {
+	var target string
+	if service == "" && proto == "" {
+		target = name
+	} else {
+		target = "_" + service + "._" + proto + "." + name
+	}
 	var r *syscall.DNSRecord
-	target := "_" + service + "._" + proto + "." + name
 	e := syscall.DnsQuery(target, syscall.DNS_TYPE_SRV, 0, nil, &r, nil)
 	if int(e) != 0 {
 		return "", nil, os.NewSyscallError("LookupSRV", int(e))
@@ -110,6 +138,10 @@ func LookupMX(name string) (mx []*MX, err os.Error) {
 	return mx, nil
 }
 
+func LookupTXT(name string) (txt []string, err os.Error) {
+	return nil, os.NewError("net.LookupTXT is not implemented on Windows")
+}
+
 func LookupAddr(addr string) (name []string, err os.Error) {
 	arpa, err := reverseaddr(addr)
 	if err != nil {
diff --git a/libgo/go/net/multicast_test.go b/libgo/go/net/multicast_test.go
index be6dbf2dc19..a66250c844b 100644
--- a/libgo/go/net/multicast_test.go
+++ b/libgo/go/net/multicast_test.go
@@ -6,13 +6,33 @@ package net
 
 import (
 	"flag"
+	"os"
 	"runtime"
 	"testing"
 )
 
 var multicast = flag.Bool("multicast", false, "enable multicast tests")
 
-func TestMulticastJoinAndLeave(t *testing.T) {
+var joinAndLeaveGroupUDPTests = []struct {
+	net   string
+	laddr IP
+	gaddr IP
+	flags Flags
+	ipv6  bool
+}{
+	// cf. RFC 4727: Experimental Values in IPv4, IPv6, ICMPv4, ICMPv6, UDP, and TCP Headers
+	{"udp", IPv4zero, IPv4(224, 0, 0, 254), (FlagUp | FlagLoopback), false},
+	{"udp4", IPv4zero, IPv4(224, 0, 0, 254), (FlagUp | FlagLoopback), false},
+	{"udp", IPv6unspecified, ParseIP("ff0e::114"), (FlagUp | FlagLoopback), true},
+	{"udp6", IPv6unspecified, ParseIP("ff01::114"), (FlagUp | FlagLoopback), true},
+	{"udp6", IPv6unspecified, ParseIP("ff02::114"), (FlagUp | FlagLoopback), true},
+	{"udp6", IPv6unspecified, ParseIP("ff04::114"), (FlagUp | FlagLoopback), true},
+	{"udp6", IPv6unspecified, ParseIP("ff05::114"), (FlagUp | FlagLoopback), true},
+	{"udp6", IPv6unspecified, ParseIP("ff08::114"), (FlagUp | FlagLoopback), true},
+	{"udp6", IPv6unspecified, ParseIP("ff0e::114"), (FlagUp | FlagLoopback), true},
+}
+
+func TestJoinAndLeaveGroupUDP(t *testing.T) {
 	if runtime.GOOS == "windows" {
 		return
 	}
@@ -21,53 +41,51 @@ func TestMulticastJoinAndLeave(t *testing.T) {
 		return
 	}
 
-	addr := &UDPAddr{
-		IP:   IPv4zero,
-		Port: 0,
-	}
-	// open a UDPConn
-	conn, err := ListenUDP("udp4", addr)
-	if err != nil {
-		t.Fatal(err)
-	}
-	defer conn.Close()
-
-	// try to join group
-	mcast := IPv4(224, 0, 0, 254)
-	err = conn.JoinGroup(mcast)
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	// try to leave group
-	err = conn.LeaveGroup(mcast)
-	if err != nil {
-		t.Fatal(err)
-	}
-}
-
-func TestJoinFailureWithIPv6Address(t *testing.T) {
-	if !*multicast {
-		t.Logf("test disabled; use --multicast to enable")
-		return
-	}
-	addr := &UDPAddr{
-		IP:   IPv4zero,
-		Port: 0,
-	}
-
-	// open a UDPConn
-	conn, err := ListenUDP("udp4", addr)
-	if err != nil {
-		t.Fatal(err)
-	}
-	defer conn.Close()
-
-	// try to join group
-	mcast := ParseIP("ff02::1")
-	err = conn.JoinGroup(mcast)
-	if err == nil {
-		t.Fatal("JoinGroup succeeded, should fail")
+	for _, tt := range joinAndLeaveGroupUDPTests {
+		var (
+			ifi   *Interface
+			found bool
+		)
+		if tt.ipv6 && (!supportsIPv6 || os.Getuid() != 0) {
+			continue
+		}
+		ift, err := Interfaces()
+		if err != nil {
+			t.Fatalf("Interfaces() failed: %v", err)
+		}
+		for _, x := range ift {
+			if x.Flags&tt.flags == tt.flags {
+				ifi = &x
+				break
+			}
+		}
+		if ifi == nil {
+			t.Logf("an appropriate multicast interface not found")
+			return
+		}
+		c, err := ListenUDP(tt.net, &UDPAddr{IP: tt.laddr})
+		if err != nil {
+			t.Fatal(err)
+		}
+		defer c.Close()
+		if err := c.JoinGroup(ifi, tt.gaddr); err != nil {
+			t.Fatal(err)
+		}
+		ifmat, err := ifi.MulticastAddrs()
+		if err != nil {
+			t.Fatalf("MulticastAddrs() failed: %v", err)
+		}
+		for _, ifma := range ifmat {
+			if ifma.(*IPAddr).IP.Equal(tt.gaddr) {
+				found = true
+				break
+			}
+		}
+		if !found {
+			t.Fatalf("%q not found in RIB", tt.gaddr.String())
+		}
+		if err := c.LeaveGroup(ifi, tt.gaddr); err != nil {
+			t.Fatal(err)
+		}
 	}
-	t.Logf("%s", err)
 }
diff --git a/libgo/go/net/net_test.go b/libgo/go/net/net_test.go
index dc0d49d23ac..b4a6e1f5d69 100644
--- a/libgo/go/net/net_test.go
+++ b/libgo/go/net/net_test.go
@@ -6,6 +6,7 @@ package net
 
 import (
 	"flag"
+	"os"
 	"regexp"
 	"testing"
 )
@@ -61,6 +62,8 @@ var dialErrorTests = []DialErrorTest{
 	},
 }
 
+var duplicateErrorPattern = `dial (.*) dial (.*)`
+
 func TestDialError(t *testing.T) {
 	if !*runErrorTest {
 		t.Logf("test disabled; use --run_error_test to enable")
@@ -80,6 +83,10 @@ func TestDialError(t *testing.T) {
 		if !match {
 			t.Errorf("#%d: %q, want match for %#q", i, s, tt.Pattern)
 		}
+		match, _ = regexp.MatchString(duplicateErrorPattern, s)
+		if match {
+			t.Errorf("#%d: %q, duplicate error return from Dial", i, s)
+		}
 	}
 }
 
@@ -119,3 +126,46 @@ func TestReverseAddress(t *testing.T) {
 		}
 	}
 }
+
+func TestShutdown(t *testing.T) {
+	l, err := Listen("tcp", "127.0.0.1:0")
+	if err != nil {
+		if l, err = Listen("tcp6", "[::1]:0"); err != nil {
+			t.Fatalf("ListenTCP on :0: %v", err)
+		}
+	}
+
+	go func() {
+		c, err := l.Accept()
+		if err != nil {
+			t.Fatalf("Accept: %v", err)
+		}
+		var buf [10]byte
+		n, err := c.Read(buf[:])
+		if n != 0 || err != os.EOF {
+			t.Fatalf("server Read = %d, %v; want 0, os.EOF", n, err)
+		}
+		c.Write([]byte("response"))
+		c.Close()
+	}()
+
+	c, err := Dial("tcp", l.Addr().String())
+	if err != nil {
+		t.Fatalf("Dial: %v", err)
+	}
+	defer c.Close()
+
+	err = c.(*TCPConn).CloseWrite()
+	if err != nil {
+		t.Fatalf("CloseWrite: %v", err)
+	}
+	var buf [10]byte
+	n, err := c.Read(buf[:])
+	if err != nil {
+		t.Fatalf("client Read: %d, %v", n, err)
+	}
+	got := string(buf[:n])
+	if got != "response" {
+		t.Errorf("read = %q, want \"response\"", got)
+	}
+}
diff --git a/libgo/go/net/newpollserver.go b/libgo/go/net/newpollserver.go
index 427208701b3..3c9a6da5373 100644
--- a/libgo/go/net/newpollserver.go
+++ b/libgo/go/net/newpollserver.go
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// +build darwin freebsd linux openbsd
+
 package net
 
 import (
diff --git a/libgo/go/net/parse.go b/libgo/go/net/parse.go
index de46830d292..0d30a7ac609 100644
--- a/libgo/go/net/parse.go
+++ b/libgo/go/net/parse.go
@@ -159,6 +159,18 @@ func xtoi(s string, i0 int) (n int, i int, ok bool) {
 	return n, i, true
 }
 
+// xtoi2 converts the next two hex digits of s into a byte.
+// If s is longer than 2 bytes then the third byte must be e.
+// If the first two bytes of s are not hex digits or the third byte
+// does not match e, false is returned.
+func xtoi2(s string, e byte) (byte, bool) {
+	if len(s) > 2 && s[2] != e {
+		return 0, false
+	}
+	n, ei, ok := xtoi(s[:2], 0)
+	return byte(n), ok && ei == 2
+}
+
 // Integer to decimal.
 func itoa(i int) string {
 	var buf [30]byte
@@ -181,6 +193,37 @@ func itoa(i int) string {
 	return string(buf[n:])
 }
 
+// Convert i to decimal string.
+func itod(i uint) string {
+	if i == 0 {
+		return "0"
+	}
+
+	// Assemble decimal in reverse order.
+	var b [32]byte
+	bp := len(b)
+	for ; i > 0; i /= 10 {
+		bp--
+		b[bp] = byte(i%10) + '0'
+	}
+
+	return string(b[bp:])
+}
+
+// Convert i to hexadecimal string.
+func itox(i uint, min int) string {
+	// Assemble hexadecimal in reverse order.
+	var b [32]byte
+	bp := len(b)
+	for ; i > 0 || min > 0; i /= 16 {
+		bp--
+		b[bp] = "0123456789abcdef"[byte(i%16)]
+		min--
+	}
+
+	return string(b[bp:])
+}
+
 // Number of occurrences of b in s.
 func count(s string, b byte) int {
 	n := 0
diff --git a/libgo/go/net/port.go b/libgo/go/net/port.go
index 8f8327a3733..a8ca60c60aa 100644
--- a/libgo/go/net/port.go
+++ b/libgo/go/net/port.go
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// +build darwin freebsd linux openbsd
+
 // Read system port mappings from /etc/services
 
 package net
diff --git a/libgo/go/net/sendfile_stub.go b/libgo/go/net/sendfile_stub.go
index 43e8104e94c..c55be6c0801 100644
--- a/libgo/go/net/sendfile_stub.go
+++ b/libgo/go/net/sendfile_stub.go
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// +build darwin freebsd openbsd
+
 package net
 
 import (
diff --git a/libgo/go/net/sendfile_windows.go b/libgo/go/net/sendfile_windows.go
index 3772eee2490..d9c2f537a3d 100644
--- a/libgo/go/net/sendfile_windows.go
+++ b/libgo/go/net/sendfile_windows.go
@@ -54,7 +54,7 @@ func sendFile(c *netFD, r io.Reader) (written int64, err os.Error, handled bool)
 	defer c.decref()
 
 	var o sendfileOp
-	o.Init(c)
+	o.Init(c, 'w')
 	o.n = uint32(n)
 	o.src = f.Fd()
 	done, err := iosrv.ExecIO(&o, 0)
diff --git a/libgo/go/net/server_test.go b/libgo/go/net/server_test.go
index 7d7f7fc01c4..a2ff218e708 100644
--- a/libgo/go/net/server_test.go
+++ b/libgo/go/net/server_test.go
@@ -115,7 +115,9 @@ func doTest(t *testing.T, network, listenaddr, dialaddr string) {
 }
 
 func TestTCPServer(t *testing.T) {
-	doTest(t, "tcp", "", "127.0.0.1")
+	if syscall.OS != "openbsd" {
+		doTest(t, "tcp", "", "127.0.0.1")
+	}
 	doTest(t, "tcp", "0.0.0.0", "127.0.0.1")
 	doTest(t, "tcp", "127.0.0.1", "127.0.0.1")
 	doTest(t, "tcp4", "", "127.0.0.1")
diff --git a/libgo/go/net/sock.go b/libgo/go/net/sock.go
index 821716e43bd..2359014ad63 100644
--- a/libgo/go/net/sock.go
+++ b/libgo/go/net/sock.go
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// +build darwin freebsd linux openbsd windows
+
 // Sockets
 
 package net
@@ -50,6 +52,7 @@ func socket(net string, f, p, t int, la, ra syscall.Sockaddr, toAddr func(syscal
 
 	if ra != nil {
 		if err = fd.connect(ra); err != nil {
+			closesocket(s)
 			fd.Close()
 			return nil, err
 		}
diff --git a/libgo/go/net/sock_bsd.go b/libgo/go/net/sock_bsd.go
index 5fd52074ad3..c59802fecb3 100644
--- a/libgo/go/net/sock_bsd.go
+++ b/libgo/go/net/sock_bsd.go
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// +build darwin freebsd
+
 // Sockets for BSD variants
 
 package net
diff --git a/libgo/go/net/tcpsock_posix.go b/libgo/go/net/tcpsock_posix.go
index 5560301b40f..740a63d3038 100644
--- a/libgo/go/net/tcpsock_posix.go
+++ b/libgo/go/net/tcpsock_posix.go
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// +build darwin freebsd linux openbsd windows
+
 // TCP sockets
 
 package net
@@ -12,6 +14,11 @@ import (
 	"syscall"
 )
 
+// BUG(rsc): On OpenBSD, listening on the "tcp" network does not listen for
+// both IPv4 and IPv6 connections. This is due to the fact that IPv4 traffic
+// will not be routed to an IPv6 socket - two separate sockets are required
+// if both AFs are to be supported. See inet6(4) on OpenBSD for details.
+
 func sockaddrToTCP(sa syscall.Sockaddr) Addr {
 	switch sa := sa.(type) {
 	case *syscall.SockaddrInet4:
@@ -23,7 +30,7 @@ func sockaddrToTCP(sa syscall.Sockaddr) Addr {
 }
 
 func (a *TCPAddr) family() int {
-	if a == nil || len(a.IP) <= 4 {
+	if a == nil || len(a.IP) <= IPv4len {
 		return syscall.AF_INET
 	}
 	if a.IP.To4() != nil {
@@ -93,6 +100,24 @@ func (c *TCPConn) Close() os.Error {
 	return err
 }
 
+// CloseRead shuts down the reading side of the TCP connection.
+// Most callers should just use Close.
+func (c *TCPConn) CloseRead() os.Error {
+	if !c.ok() {
+		return os.EINVAL
+	}
+	return c.fd.CloseRead()
+}
+
+// CloseWrite shuts down the writing side of the TCP connection.
+// Most callers should just use Close.
+func (c *TCPConn) CloseWrite() os.Error {
+	if !c.ok() {
+		return os.EINVAL
+	}
+	return c.fd.CloseWrite()
+}
+
 // LocalAddr returns the local network address, a *TCPAddr.
 func (c *TCPConn) LocalAddr() Addr {
 	if !c.ok() {
diff --git a/libgo/go/net/textproto/header.go b/libgo/go/net/textproto/header.go
index 288deb2ceb4..7fb32f8045e 100644
--- a/libgo/go/net/textproto/header.go
+++ b/libgo/go/net/textproto/header.go
@@ -39,5 +39,5 @@ func (h MIMEHeader) Get(key string) string {
 
 // Del deletes the values associated with key.
 func (h MIMEHeader) Del(key string) {
-	h[CanonicalMIMEHeaderKey(key)] = nil, false
+	delete(h, CanonicalMIMEHeaderKey(key))
 }
diff --git a/libgo/go/net/textproto/pipeline.go b/libgo/go/net/textproto/pipeline.go
index 8c25884b3bf..ca50eddac38 100644
--- a/libgo/go/net/textproto/pipeline.go
+++ b/libgo/go/net/textproto/pipeline.go
@@ -108,7 +108,7 @@ func (s *sequencer) End(id uint) {
 	}
 	c, ok := s.wait[id]
 	if ok {
-		s.wait[id] = nil, false
+		delete(s.wait, id)
 	}
 	s.mu.Unlock()
 	if ok {
diff --git a/libgo/go/net/textproto/reader.go b/libgo/go/net/textproto/reader.go
index ce0ddc73f84..ece9a99ffbb 100644
--- a/libgo/go/net/textproto/reader.go
+++ b/libgo/go/net/textproto/reader.go
@@ -11,6 +11,7 @@ import (
 	"io/ioutil"
 	"os"
 	"strconv"
+	"strings"
 )
 
 // BUG(rsc): To let callers manage exposure to denial of service
@@ -182,6 +183,10 @@ func (r *Reader) readCodeLine(expectCode int) (code int, continued bool, message
 	if err != nil {
 		return
 	}
+	return parseCodeLine(line, expectCode)
+}
+
+func parseCodeLine(line string, expectCode int) (code int, continued bool, message string, err os.Error) {
 	if len(line) < 4 || line[3] != ' ' && line[3] != '-' {
 		err = ProtocolError("short response: " + line)
 		return
@@ -224,15 +229,20 @@ func (r *Reader) ReadCodeLine(expectCode int) (code int, message string, err os.
 	return
 }
 
-// ReadResponse reads a multi-line response of the form
+// ReadResponse reads a multi-line response of the form:
+//
 //	code-message line 1
 //	code-message line 2
 //	...
 //	code message line n
-// where code is a 3-digit status code. Each line should have the same code.
-// The response is terminated by a line that uses a space between the code and
-// the message line rather than a dash. Each line in message is separated by
-// a newline (\n).
+//
+// where code is a 3-digit status code. The first line starts with the
+// code and a hyphen. The response is terminated by a line that starts
+// with the same code followed by a space. Each line in message is
+// separated by a newline (\n).
+//
+// See page 36 of RFC 959 (http://www.ietf.org/rfc/rfc959.txt) for
+// details.
 //
 // If the prefix of the status does not match the digits in expectCode,
 // ReadResponse returns with err set to &Error{code, message}.
@@ -244,11 +254,18 @@ func (r *Reader) ReadCodeLine(expectCode int) (code int, message string, err os.
 func (r *Reader) ReadResponse(expectCode int) (code int, message string, err os.Error) {
 	code, continued, message, err := r.readCodeLine(expectCode)
 	for err == nil && continued {
+		line, err := r.ReadLine()
+		if err != nil {
+			return 0, "", err
+		}
+
 		var code2 int
 		var moreMessage string
-		code2, continued, moreMessage, err = r.readCodeLine(expectCode)
-		if code != code2 {
-			err = ProtocolError("status code mismatch: " + strconv.Itoa(code) + ", " + strconv.Itoa(code2))
+		code2, continued, moreMessage, err = parseCodeLine(line, expectCode)
+		if err != nil || code2 != code {
+			message += "\n" + strings.TrimRight(line, "\r\n")
+			continued = true
+			continue
 		}
 		message += "\n" + moreMessage
 	}
diff --git a/libgo/go/net/textproto/reader_test.go b/libgo/go/net/textproto/reader_test.go
index 0658e58b82d..23ebc3f61e8 100644
--- a/libgo/go/net/textproto/reader_test.go
+++ b/libgo/go/net/textproto/reader_test.go
@@ -138,3 +138,56 @@ func TestReadMIMEHeader(t *testing.T) {
 		t.Fatalf("ReadMIMEHeader: %v, %v; want %v", m, err, want)
 	}
 }
+
+type readResponseTest struct {
+	in       string
+	inCode   int
+	wantCode int
+	wantMsg  string
+}
+
+var readResponseTests = []readResponseTest{
+	{"230-Anonymous access granted, restrictions apply\n" +
+		"Read the file README.txt,\n" +
+		"230  please",
+		23,
+		230,
+		"Anonymous access granted, restrictions apply\nRead the file README.txt,\n please",
+	},
+
+	{"230 Anonymous access granted, restrictions apply\n",
+		23,
+		230,
+		"Anonymous access granted, restrictions apply",
+	},
+
+	{"400-A\n400-B\n400 C",
+		4,
+		400,
+		"A\nB\nC",
+	},
+
+	{"400-A\r\n400-B\r\n400 C\r\n",
+		4,
+		400,
+		"A\nB\nC",
+	},
+}
+
+// See http://www.ietf.org/rfc/rfc959.txt page 36.
+func TestRFC959Lines(t *testing.T) {
+	for i, tt := range readResponseTests {
+		r := reader(tt.in + "\nFOLLOWING DATA")
+		code, msg, err := r.ReadResponse(tt.inCode)
+		if err != nil {
+			t.Errorf("#%d: ReadResponse: %v", i, err)
+			continue
+		}
+		if code != tt.wantCode {
+			t.Errorf("#%d: code=%d, want %d", i, code, tt.wantCode)
+		}
+		if msg != tt.wantMsg {
+			t.Errorf("%#d: msg=%q, want %q", i, msg, tt.wantMsg)
+		}
+	}
+}
diff --git a/libgo/go/net/udpsock_plan9.go b/libgo/go/net/udpsock_plan9.go
index bb7196041a4..d5c6ccb9046 100644
--- a/libgo/go/net/udpsock_plan9.go
+++ b/libgo/go/net/udpsock_plan9.go
@@ -169,17 +169,18 @@ func ListenUDP(net string, laddr *UDPAddr) (c *UDPConn, err os.Error) {
 	return &UDPConn{*l.plan9Conn()}, nil
 }
 
-// JoinGroup joins the IPv4 multicast group named by addr.
-// The UDPConn must use the "udp4" network.
-func (c *UDPConn) JoinGroup(addr IP) os.Error {
+// JoinGroup joins the IP multicast group named by addr on ifi,
+// which specifies the interface to join.  JoinGroup uses the
+// default multicast interface if ifi is nil.
+func (c *UDPConn) JoinGroup(ifi *Interface, addr IP) os.Error {
 	if !c.ok() {
 		return os.EINVAL
 	}
 	return os.EPLAN9
 }
 
-// LeaveGroup exits the IPv4 multicast group named by addr.
-func (c *UDPConn) LeaveGroup(addr IP) os.Error {
+// LeaveGroup exits the IP multicast group named by addr on ifi.
+func (c *UDPConn) LeaveGroup(ifi *Interface, addr IP) os.Error {
 	if !c.ok() {
 		return os.EINVAL
 	}
diff --git a/libgo/go/net/udpsock_posix.go b/libgo/go/net/udpsock_posix.go
index d4ea056f3c7..06298ee40c8 100644
--- a/libgo/go/net/udpsock_posix.go
+++ b/libgo/go/net/udpsock_posix.go
@@ -2,11 +2,14 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// +build darwin freebsd linux openbsd windows
+
 // UDP sockets
 
 package net
 
 import (
+	"bytes"
 	"os"
 	"syscall"
 )
@@ -22,7 +25,7 @@ func sockaddrToUDP(sa syscall.Sockaddr) Addr {
 }
 
 func (a *UDPAddr) family() int {
-	if a == nil || len(a.IP) <= 4 {
+	if a == nil || len(a.IP) <= IPv4len {
 		return syscall.AF_INET
 	}
 	if a.IP.To4() != nil {
@@ -252,43 +255,94 @@ func (c *UDPConn) BindToDevice(device string) os.Error {
 // Closing c does not affect f, and closing f does not affect c.
 func (c *UDPConn) File() (f *os.File, err os.Error) { return c.fd.dup() }
 
-var errInvalidMulticast = os.NewError("invalid IPv4 multicast address")
+// JoinGroup joins the IP multicast group named by addr on ifi,
+// which specifies the interface to join.  JoinGroup uses the
+// default multicast interface if ifi is nil.
+func (c *UDPConn) JoinGroup(ifi *Interface, addr IP) os.Error {
+	if !c.ok() {
+		return os.EINVAL
+	}
+	ip := addr.To4()
+	if ip != nil {
+		return joinIPv4GroupUDP(c, ifi, ip)
+	}
+	return joinIPv6GroupUDP(c, ifi, addr)
+}
 
-// JoinGroup joins the IPv4 multicast group named by addr.
-// The UDPConn must use the "udp4" network.
-func (c *UDPConn) JoinGroup(addr IP) os.Error {
+// LeaveGroup exits the IP multicast group named by addr on ifi.
+func (c *UDPConn) LeaveGroup(ifi *Interface, addr IP) os.Error {
 	if !c.ok() {
 		return os.EINVAL
 	}
 	ip := addr.To4()
-	if ip == nil {
-		return &OpError{"joingroup", "udp", &IPAddr{ip}, errInvalidMulticast}
+	if ip != nil {
+		return leaveIPv4GroupUDP(c, ifi, ip)
 	}
-	mreq := &syscall.IPMreq{
-		Multiaddr: [4]byte{ip[0], ip[1], ip[2], ip[3]},
+	return leaveIPv6GroupUDP(c, ifi, addr)
+}
+
+func joinIPv4GroupUDP(c *UDPConn, ifi *Interface, ip IP) os.Error {
+	mreq := &syscall.IPMreq{Multiaddr: [4]byte{ip[0], ip[1], ip[2], ip[3]}}
+	if err := setIPv4InterfaceToJoin(mreq, ifi); err != nil {
+		return &OpError{"joinipv4group", "udp", &IPAddr{ip}, err}
 	}
-	err := os.NewSyscallError("setsockopt", syscall.SetsockoptIPMreq(c.fd.sysfd, syscall.IPPROTO_IP, syscall.IP_ADD_MEMBERSHIP, mreq))
-	if err != nil {
-		return &OpError{"joingroup", "udp", &IPAddr{ip}, err}
+	if err := os.NewSyscallError("setsockopt", syscall.SetsockoptIPMreq(c.fd.sysfd, syscall.IPPROTO_IP, syscall.IP_ADD_MEMBERSHIP, mreq)); err != nil {
+		return &OpError{"joinipv4group", "udp", &IPAddr{ip}, err}
 	}
 	return nil
 }
 
-// LeaveGroup exits the IPv4 multicast group named by addr.
-func (c *UDPConn) LeaveGroup(addr IP) os.Error {
-	if !c.ok() {
-		return os.EINVAL
+func leaveIPv4GroupUDP(c *UDPConn, ifi *Interface, ip IP) os.Error {
+	mreq := &syscall.IPMreq{Multiaddr: [4]byte{ip[0], ip[1], ip[2], ip[3]}}
+	if err := setIPv4InterfaceToJoin(mreq, ifi); err != nil {
+		return &OpError{"leaveipv4group", "udp", &IPAddr{ip}, err}
 	}
-	ip := addr.To4()
-	if ip == nil {
-		return &OpError{"leavegroup", "udp", &IPAddr{ip}, errInvalidMulticast}
+	if err := os.NewSyscallError("setsockopt", syscall.SetsockoptIPMreq(c.fd.sysfd, syscall.IPPROTO_IP, syscall.IP_DROP_MEMBERSHIP, mreq)); err != nil {
+		return &OpError{"leaveipv4group", "udp", &IPAddr{ip}, err}
 	}
-	mreq := &syscall.IPMreq{
-		Multiaddr: [4]byte{ip[0], ip[1], ip[2], ip[3]},
+	return nil
+}
+
+func setIPv4InterfaceToJoin(mreq *syscall.IPMreq, ifi *Interface) os.Error {
+	if ifi == nil {
+		return nil
 	}
-	err := os.NewSyscallError("setsockopt", syscall.SetsockoptIPMreq(c.fd.sysfd, syscall.IPPROTO_IP, syscall.IP_DROP_MEMBERSHIP, mreq))
+	ifat, err := ifi.Addrs()
 	if err != nil {
-		return &OpError{"leavegroup", "udp", &IPAddr{ip}, err}
+		return err
+	}
+	for _, ifa := range ifat {
+		if x := ifa.(*IPAddr).IP.To4(); x != nil {
+			copy(mreq.Interface[:], x)
+			break
+		}
+	}
+	if bytes.Equal(mreq.Multiaddr[:], IPv4zero) {
+		return os.EINVAL
+	}
+	return nil
+}
+
+func joinIPv6GroupUDP(c *UDPConn, ifi *Interface, ip IP) os.Error {
+	mreq := &syscall.IPv6Mreq{}
+	copy(mreq.Multiaddr[:], ip)
+	if ifi != nil {
+		mreq.Interface = uint32(ifi.Index)
+	}
+	if err := os.NewSyscallError("setsockopt", syscall.SetsockoptIPv6Mreq(c.fd.sysfd, syscall.IPPROTO_IPV6, syscall.IPV6_JOIN_GROUP, mreq)); err != nil {
+		return &OpError{"joinipv6group", "udp", &IPAddr{ip}, err}
+	}
+	return nil
+}
+
+func leaveIPv6GroupUDP(c *UDPConn, ifi *Interface, ip IP) os.Error {
+	mreq := &syscall.IPv6Mreq{}
+	copy(mreq.Multiaddr[:], ip)
+	if ifi != nil {
+		mreq.Interface = uint32(ifi.Index)
+	}
+	if err := os.NewSyscallError("setsockopt", syscall.SetsockoptIPv6Mreq(c.fd.sysfd, syscall.IPPROTO_IPV6, syscall.IPV6_LEAVE_GROUP, mreq)); err != nil {
+		return &OpError{"leaveipv6group", "udp", &IPAddr{ip}, err}
 	}
 	return nil
 }
diff --git a/libgo/go/net/unixsock_posix.go b/libgo/go/net/unixsock_posix.go
index 38c6fe9eb1e..fccf0189c05 100644
--- a/libgo/go/net/unixsock_posix.go
+++ b/libgo/go/net/unixsock_posix.go
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// +build darwin freebsd linux openbsd windows
+
 // Unix domain sockets
 
 package net