ipv4: implement control messages on windows

Fixes golang/go#7175

Change-Id: I583c5713bedf073cf5abe25976275fc6b9193379

internal/socket/cmsghdr.go

@@ -2,7 +2,7 @@
 // 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
+// +build darwin dragonfly freebsd linux netbsd openbsd solaris windows
 
 package socket
 

internal/socket/cmsghdr_stub.go

@@ -2,7 +2,7 @@
 // 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
+// +build !darwin,!dragonfly,!freebsd,!linux,!netbsd,!openbsd,!solaris,!windows
 
 package socket
 

internal/socket/cmsghdr_windows.go

@@ -0,0 +1,20 @@
+// Copyright 2017 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 socket
+
+// WSACMSGHDR
+type cmsghdr struct {
+	Len   uintptr
+	Level int32
+	Type  int32
+}
+
+const sizeofCmsghdr = 0xc
+
+func (h *cmsghdr) set(l, lvl, typ int) {
+	h.Len = uintptr(l)
+	h.Level = int32(lvl)
+	h.Type = int32(typ)
+}

internal/socket/iovec_stub.go

@@ -2,7 +2,7 @@
 // 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
+// +build !darwin,!dragonfly,!freebsd,!linux,!netbsd,!openbsd,!solaris,!windows
 
 package socket
 

internal/socket/iovec_windows.go

@@ -0,0 +1,21 @@
+// Copyright 2017 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 socket
+
+import (
+	"syscall"
+	"unsafe"
+)
+
+type iovec syscall.WSABuf
+
+func (v *iovec) set(b []byte) {
+	l := len(b)
+	if l == 0 {
+		return
+	}
+	v.Buf = (*byte)(unsafe.Pointer(&b[0]))
+	v.Len = uint32(l)
+}

internal/socket/msghdr_stub.go

@@ -2,7 +2,7 @@
 // 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
+// +build !darwin,!dragonfly,!freebsd,!linux,!netbsd,!openbsd,!solaris,!windows
 
 package socket
 

internal/socket/msghdr_windows.go

@@ -0,0 +1,51 @@
+// Copyright 2017 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 socket
+
+import (
+	"syscall"
+	"unsafe"
+)
+
+type msghdr syscall.WSAMsg
+
+func (h *msghdr) pack(vs []iovec, bs [][]byte, oob []byte, sa []byte) {
+	for i := range vs {
+		vs[i].set(bs[i])
+	}
+	h.setIov(vs)
+	if len(oob) > 0 {
+		h.Control.Buf = (*byte)(unsafe.Pointer(&oob[0]))
+		h.Control.Len = uint32(len(oob))
+	}
+	if sa != nil {
+		h.Name = uintptr(unsafe.Pointer(&sa[0]))
+		h.Namelen = int32(len(sa))
+	}
+}
+
+func (h *msghdr) name() []byte {
+	if h.Name != 0 && h.Namelen > 0 {
+		return (*[sizeofSockaddrInet6]byte)(unsafe.Pointer(h.Name))[:h.Namelen]
+	}
+	return nil
+}
+
+func (h *msghdr) controllen() int {
+	return int(h.Control.Len)
+}
+
+func (h *msghdr) flags() int {
+	return int(h.Flags)
+}
+
+func (h *msghdr) setIov(vs []iovec) {
+	l := len(vs)
+	if l == 0 {
+		return
+	}
+	h.Buffers = (*syscall.WSABuf)(unsafe.Pointer(&vs[0]))
+	h.Bufferslen = uint32(l)
+}

internal/socket/sys_windows.go

@@ -54,11 +54,17 @@ func setsockopt(s uintptr, level, name int, b []byte) error {
 }
 
 func recvmsg(s uintptr, h *msghdr, flags int) (int, error) {
-	return 0, errors.New("not implemented")
+	var bytesReceived uint32
+	msg := (*syscall.WSAMsg)(h)
+	msg.Flags = uint32(flags)
+	err := syscall.WSARecvMsg(syscall.Handle(s), msg, &bytesReceived, nil, 0)
+	return int(bytesReceived), err
 }
 
 func sendmsg(s uintptr, h *msghdr, flags int) (int, error) {
-	return 0, errors.New("not implemented")
+	var bytesSent uint32
+	err := syscall.WSASendMsg(syscall.Handle(s), (*syscall.WSAMsg)(h), uint32(flags), &bytesSent, nil, 0)
+	return int(bytesSent), err
 }
 
 func recvmmsg(s uintptr, hs []mmsghdr, flags int) (int, error) {

ipv4/control_windows.go

@@ -5,12 +5,54 @@
 package ipv4
 
 import (
-	"syscall"
-
 	"golang.org/x/net/internal/socket"
 )
 
 func setControlMessage(c *socket.Conn, opt *rawOpt, cf ControlFlags, on bool) error {
-	// TODO(mikio): implement this
-	return syscall.EWINDOWS
+	opt.Lock()
+	defer opt.Unlock()
+	if so, ok := sockOpts[ssoReceiveTTL]; ok && cf&FlagTTL != 0 {
+		if err := so.SetInt(c, boolint(on)); err != nil {
+			return err
+		}
+		if on {
+			opt.set(FlagTTL)
+		} else {
+			opt.clear(FlagTTL)
+		}
+	}
+	if so, ok := sockOpts[ssoPacketInfo]; ok {
+		if cf&(FlagSrc|FlagDst|FlagInterface) != 0 {
+			if err := so.SetInt(c, boolint(on)); err != nil {
+				return err
+			}
+			if on {
+				opt.set(cf & (FlagSrc | FlagDst | FlagInterface))
+			} else {
+				opt.clear(cf & (FlagSrc | FlagDst | FlagInterface))
+			}
+		}
+	} else {
+		if so, ok := sockOpts[ssoReceiveDst]; ok && cf&FlagDst != 0 {
+			if err := so.SetInt(c, boolint(on)); err != nil {
+				return err
+			}
+			if on {
+				opt.set(FlagDst)
+			} else {
+				opt.clear(FlagDst)
+			}
+		}
+		if so, ok := sockOpts[ssoReceiveInterface]; ok && cf&FlagInterface != 0 {
+			if err := so.SetInt(c, boolint(on)); err != nil {
+				return err
+			}
+			if on {
+				opt.set(FlagInterface)
+			} else {
+				opt.clear(FlagInterface)
+			}
+		}
+	}
+	return nil
 }

ipv4/packet.go

@@ -11,9 +11,6 @@ import (
 	"golang.org/x/net/internal/socket"
 )
 
-// BUG(mikio): On Windows, the ReadFrom and WriteTo methods of RawConn
-// are not implemented.
-
 // A packetHandler represents the IPv4 datagram handler.
 type packetHandler struct {
 	*net.IPConn

ipv4/payload.go

@@ -10,9 +10,6 @@ import (
 	"golang.org/x/net/internal/socket"
 )
 
-// BUG(mikio): On Windows, the ControlMessage for ReadFrom and WriteTo
-// methods of PacketConn is not implemented.
-
 // A payloadHandler represents the IPv4 datagram payload handler.
 type payloadHandler struct {
 	net.PacketConn

ipv4/payload_cmsg.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build !nacl,!plan9,!windows
+// +build !nacl,!plan9
 
 package ipv4
 

ipv4/payload_cmsg_go1_9.go

@@ -3,7 +3,7 @@
 // license that can be found in the LICENSE file.
 
 // +build go1.9
-// +build !nacl,!plan9,!windows
+// +build !nacl,!plan9
 
 package ipv4
 

ipv4/payload_nocmsg.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build nacl plan9 windows
+// +build nacl plan9
 
 package ipv4
 

ipv4/sockopt.go

@@ -16,7 +16,7 @@ const (
 	ssoReceiveTTL                // header field on received packet
 	ssoReceiveDst                // header field on received packet
 	ssoReceiveInterface          // inbound interface on received packet
-	ssoPacketInfo                // incbound or outbound packet path
+	ssoPacketInfo                // inbound or outbound packet path
 	ssoHeaderPrepend             // ipv4 header prepend
 	ssoStripHeader               // strip ipv4 header
 	ssoICMPFilter                // icmp filter

ipv4/sys_windows.go

@@ -5,6 +5,9 @@
 package ipv4
 
 import (
+	"net"
+	"unsafe"
+
 	"golang.org/x/net/internal/iana"
 	"golang.org/x/net/internal/socket"
 )
@@ -48,7 +51,9 @@ type ipMreqSource struct {
 
 // See http://msdn.microsoft.com/en-us/library/windows/desktop/ms738586(v=vs.85).aspx
 var (
-	ctlOpts = [ctlMax]ctlOpt{}
+	ctlOpts = [ctlMax]ctlOpt{
+		ctlPacketInfo: {sysIP_PKTINFO, sizeofInetPktinfo, marshalPacketInfo, parsePacketInfo},
+	}
 
 	sockOpts = map[int]*sockOpt{
 		ssoTOS:                {Option: socket.Option{Level: iana.ProtocolIP, Name: sysIP_TOS, Len: 4}},
@@ -59,9 +64,34 @@ var (
 		ssoHeaderPrepend:      {Option: socket.Option{Level: iana.ProtocolIP, Name: sysIP_HDRINCL, Len: 4}},
 		ssoJoinGroup:          {Option: socket.Option{Level: iana.ProtocolIP, Name: sysIP_ADD_MEMBERSHIP, Len: sizeofIPMreq}, typ: ssoTypeIPMreq},
 		ssoLeaveGroup:         {Option: socket.Option{Level: iana.ProtocolIP, Name: sysIP_DROP_MEMBERSHIP, Len: sizeofIPMreq}, typ: ssoTypeIPMreq},
+		ssoPacketInfo:         {Option: socket.Option{Level: iana.ProtocolIP, Name: sysIP_PKTINFO, Len: 4}},
 	}
 )
 
 func (pi *inetPktinfo) setIfindex(i int) {
 	pi.Ifindex = int32(i)
 }
+
+func marshalPacketInfo(b []byte, cm *ControlMessage) []byte {
+	m := socket.ControlMessage(b)
+	m.MarshalHeader(iana.ProtocolIP, sysIP_PKTINFO, sizeofInetPktinfo)
+	if cm != nil {
+		pi := (*inetPktinfo)(unsafe.Pointer(&m.Data(sizeofInetPktinfo)[0]))
+		if ip := cm.Src.To4(); ip != nil {
+			copy(pi.Addr[:], ip)
+		}
+		if cm.IfIndex > 0 {
+			pi.setIfindex(cm.IfIndex)
+		}
+	}
+	return m.Next(sizeofInetPktinfo)
+}
+
+func parsePacketInfo(cm *ControlMessage, b []byte) {
+	pi := (*inetPktinfo)(unsafe.Pointer(&b[0]))
+	cm.IfIndex = int(pi.Ifindex)
+	if len(cm.Dst) < net.IPv4len {
+		cm.Dst = make(net.IP, net.IPv4len)
+	}
+	copy(cm.Dst, pi.Addr[:])
+}