diff --git a/unum/vendor/golang.org/x/net/ipv4/packet_go1_8.go b/unum/vendor/golang.org/x/net/ipv4/packet_go1_8.go
new file mode 100644
index 0000000..b47d186
--- /dev/null
+++ b/unum/vendor/golang.org/x/net/ipv4/packet_go1_8.go
@@ -0,0 +1,56 @@
+// Copyright 2012 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
+
+package ipv4
+
+import "net"
+
+func (c *packetHandler) readFrom(b []byte) (h *Header, p []byte, cm *ControlMessage, err error) {
+	c.rawOpt.RLock()
+	oob := NewControlMessage(c.rawOpt.cflags)
+	c.rawOpt.RUnlock()
+	n, nn, _, src, err := c.ReadMsgIP(b, oob)
+	if err != nil {
+		return nil, nil, nil, err
+	}
+	var hs []byte
+	if hs, p, err = slicePacket(b[:n]); err != nil {
+		return nil, nil, nil, err
+	}
+	if h, err = ParseHeader(hs); err != nil {
+		return nil, nil, nil, err
+	}
+	if nn > 0 {
+		cm = new(ControlMessage)
+		if err := cm.Parse(oob[:nn]); err != nil {
+			return nil, nil, nil, err
+		}
+	}
+	if src != nil && cm != nil {
+		cm.Src = src.IP
+	}
+	return
+}
+
+func (c *packetHandler) writeTo(h *Header, p []byte, cm *ControlMessage) error {
+	oob := cm.Marshal()
+	wh, err := h.Marshal()
+	if err != nil {
+		return err
+	}
+	dst := new(net.IPAddr)
+	if cm != nil {
+		if ip := cm.Dst.To4(); ip != nil {
+			dst.IP = ip
+		}
+	}
+	if dst.IP == nil {
+		dst.IP = h.Dst
+	}
+	wh = append(wh, p...)
+	_, _, err = c.WriteMsgIP(wh, oob, dst)
+	return err
+}