diff --git a/unum/vendor/golang.org/x/net/ipv6/payload_cmsg_go1_9.go b/unum/vendor/golang.org/x/net/ipv6/payload_cmsg_go1_9.go
new file mode 100644
index 0000000..8f6d02e
--- /dev/null
+++ b/unum/vendor/golang.org/x/net/ipv6/payload_cmsg_go1_9.go
@@ -0,0 +1,57 @@
+// 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.
+
+// +build go1.9
+// +build !nacl,!plan9,!windows
+
+package ipv6
+
+import (
+	"net"
+
+	"golang.org/x/net/internal/socket"
+)
+
+func (c *payloadHandler) readFrom(b []byte) (int, *ControlMessage, net.Addr, error) {
+	c.rawOpt.RLock()
+	m := socket.Message{
+		Buffers: [][]byte{b},
+		OOB:     NewControlMessage(c.rawOpt.cflags),
+	}
+	c.rawOpt.RUnlock()
+	switch c.PacketConn.(type) {
+	case *net.UDPConn:
+		if err := c.RecvMsg(&m, 0); err != nil {
+			return 0, nil, nil, &net.OpError{Op: "read", Net: c.PacketConn.LocalAddr().Network(), Source: c.PacketConn.LocalAddr(), Err: err}
+		}
+	case *net.IPConn:
+		if err := c.RecvMsg(&m, 0); err != nil {
+			return 0, nil, nil, &net.OpError{Op: "read", Net: c.PacketConn.LocalAddr().Network(), Source: c.PacketConn.LocalAddr(), Err: err}
+		}
+	default:
+		return 0, nil, nil, &net.OpError{Op: "read", Net: c.PacketConn.LocalAddr().Network(), Source: c.PacketConn.LocalAddr(), Err: errInvalidConnType}
+	}
+	var cm *ControlMessage
+	if m.NN > 0 {
+		cm = new(ControlMessage)
+		if err := cm.Parse(m.OOB[:m.NN]); err != nil {
+			return 0, nil, nil, &net.OpError{Op: "read", Net: c.PacketConn.LocalAddr().Network(), Source: c.PacketConn.LocalAddr(), Err: err}
+		}
+		cm.Src = netAddrToIP16(m.Addr)
+	}
+	return m.N, cm, m.Addr, nil
+}
+
+func (c *payloadHandler) writeTo(b []byte, cm *ControlMessage, dst net.Addr) (int, error) {
+	m := socket.Message{
+		Buffers: [][]byte{b},
+		OOB:     cm.Marshal(),
+		Addr:    dst,
+	}
+	err := c.SendMsg(&m, 0)
+	if err != nil {
+		err = &net.OpError{Op: "write", Net: c.PacketConn.LocalAddr().Network(), Source: c.PacketConn.LocalAddr(), Addr: opAddr(dst), Err: err}
+	}
+	return m.N, err
+}