diff --git a/internal/socket/sys_go1_11_darwin.go b/internal/socket/sys_go1_11_darwin.go
deleted file mode 100644
index 02d2b3cc..00000000
--- a/internal/socket/sys_go1_11_darwin.go
+++ /dev/null
@@ -1,33 +0,0 @@
-// 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 socket
-
-import (
-	"syscall"
-	"unsafe"
-)
-
-func getsockopt(s uintptr, level, name int, b []byte) (int, error) {
-	l := uint32(len(b))
-	_, _, errno := syscall.Syscall6(syscall.SYS_GETSOCKOPT, s, uintptr(level), uintptr(name), uintptr(unsafe.Pointer(&b[0])), uintptr(unsafe.Pointer(&l)), 0)
-	return int(l), errnoErr(errno)
-}
-
-func setsockopt(s uintptr, level, name int, b []byte) error {
-	_, _, errno := syscall.Syscall6(syscall.SYS_SETSOCKOPT, s, uintptr(level), uintptr(name), uintptr(unsafe.Pointer(&b[0])), uintptr(len(b)), 0)
-	return errnoErr(errno)
-}
-
-func recvmsg(s uintptr, h *msghdr, flags int) (int, error) {
-	n, _, errno := syscall.Syscall(syscall.SYS_RECVMSG, s, uintptr(unsafe.Pointer(h)), uintptr(flags))
-	return int(n), errnoErr(errno)
-}
-
-func sendmsg(s uintptr, h *msghdr, flags int) (int, error) {
-	n, _, errno := syscall.Syscall(syscall.SYS_SENDMSG, s, uintptr(unsafe.Pointer(h)), uintptr(flags))
-	return int(n), errnoErr(errno)
-}
diff --git a/route/syscall_go1_11_darwin.go b/route/syscall_go1_11_darwin.go
deleted file mode 100644
index 7228e443..00000000
--- a/route/syscall_go1_11_darwin.go
+++ /dev/null
@@ -1,28 +0,0 @@
-// 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
-}