diff --git a/route/empty.s b/route/empty.s
new file mode 100644
index 0000000..bff0231
--- /dev/null
+++ b/route/empty.s
@@ -0,0 +1,7 @@
+// Copyright 2018 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 darwin,go1.12
+
+// This exists solely so we can linkname in symbols from syscall.
diff --git a/route/syscall.go b/route/syscall.go
index 5f69ea6..72431b0 100644
--- a/route/syscall.go
+++ b/route/syscall.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 netbsd openbsd
+// +build dragonfly freebsd netbsd openbsd
 
 package route
 
diff --git a/route/syscall_go1_11_darwin.go b/route/syscall_go1_11_darwin.go
new file mode 100644
index 0000000..7228e44
--- /dev/null
+++ b/route/syscall_go1_11_darwin.go
@@ -0,0 +1,28 @@
+// Copyright 2018 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 !go1.12
+
+package route
+
+import (
+	"syscall"
+	"unsafe"
+)
+
+var zero uintptr
+
+func sysctl(mib []int32, old *byte, oldlen *uintptr, new *byte, newlen uintptr) error {
+	var p unsafe.Pointer
+	if len(mib) > 0 {
+		p = unsafe.Pointer(&mib[0])
+	} else {
+		p = unsafe.Pointer(&zero)
+	}
+	_, _, errno := syscall.Syscall6(syscall.SYS___SYSCTL, uintptr(p), uintptr(len(mib)), uintptr(unsafe.Pointer(old)), uintptr(unsafe.Pointer(oldlen)), uintptr(unsafe.Pointer(new)), newlen)
+	if errno != 0 {
+		return error(errno)
+	}
+	return nil
+}
diff --git a/route/syscall_go1_12_darwin.go b/route/syscall_go1_12_darwin.go
new file mode 100644
index 0000000..7922a68
--- /dev/null
+++ b/route/syscall_go1_12_darwin.go
@@ -0,0 +1,12 @@
+// Copyright 2018 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 go1.12
+
+package route
+
+import _ "unsafe" // for linkname
+
+//go:linkname sysctl syscall.sysctl
+func sysctl(mib []int32, old *byte, oldlen *uintptr, new *byte, newlen uintptr) error