diff --git a/ipv6/sys.go b/ipv6/sys.go
new file mode 100644
index 0000000..18b1aca
--- /dev/null
+++ b/ipv6/sys.go
@@ -0,0 +1,23 @@
+// Copyright 2013 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 ipv6
+
+type sysSockoptLen uint32
+
+const (
+	sysSizeofPacketInfo   = 0x14
+	sysSizeofMulticastReq = 0x14
+	sysSizeofICMPFilter   = 0x20
+)
+
+type sysPacketInfo struct {
+	IP      [16]byte
+	IfIndex uint32
+}
+
+type sysMulticastReq struct {
+	IP      [16]byte
+	IfIndex uint32
+}