91 lines
1.9 KiB
Go
91 lines
1.9 KiB
Go
/* SPDX-License-Identifier: GPL-2.0
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*
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* Copyright (C) 2018 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
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*/
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package tun
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// #include <sys/types.h>
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// static ssize_t callFnWithCtx(const void *func, const void *ctx, const void *buffer, size_t len)
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// {
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// return ((ssize_t(*)(const void *, const unsigned char *, size_t))func)(ctx, buffer, len);
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// }
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import "C"
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import (
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"os"
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"syscall"
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"unsafe"
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)
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type nativeTun struct {
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events chan TUNEvent
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mtu int
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readFn unsafe.Pointer
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writeFn unsafe.Pointer
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ctx unsafe.Pointer
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}
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func CreateTUN(mtu uint16, readFn unsafe.Pointer, writeFn unsafe.Pointer, ctx unsafe.Pointer) TUNDevice {
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if mtu == 0 {
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/* 0 means automatic MTU, which iOS makes outerMTU-80-15. The 80 is for
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* WireGuard and the 15 ensures our padding will work. Therefore, it's
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* safe to have this code assume a massive MTU.
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*/
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mtu = ^mtu
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}
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tun := &nativeTun{
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events: make(chan TUNEvent, 10),
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mtu: int(mtu),
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readFn: readFn,
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writeFn: writeFn,
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ctx: ctx,
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}
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tun.events <- TUNEventUp
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return tun
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}
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func (tun *nativeTun) Name() (string, error) {
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return "tun", nil
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}
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func (tun *nativeTun) File() *os.File {
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return nil
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}
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func (tun *nativeTun) Events() chan TUNEvent {
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return tun.events
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}
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func (tun *nativeTun) Read(buff []byte, offset int) (int, error) {
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ret := C.callFnWithCtx(tun.readFn, tun.ctx, unsafe.Pointer(&buff[offset]), C.size_t(len(buff) - offset))
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if ret < 0 {
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return 0, syscall.Errno(-ret)
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}
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return int(ret), nil
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}
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func (tun *nativeTun) Write(buff []byte, offset int) (int, error) {
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ret := C.callFnWithCtx(tun.writeFn, tun.ctx, unsafe.Pointer(&buff[offset]), C.size_t(len(buff) - offset))
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if ret < 0 {
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return 0, syscall.Errno(-ret)
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}
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return int(ret), nil
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}
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func (tun *nativeTun) Close() error {
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if tun.events != nil {
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close(tun.events)
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}
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return nil
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}
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func (tun *nativeTun) setMTU(n int) error {
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tun.mtu = n
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return nil
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}
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func (tun *nativeTun) MTU() (int, error) {
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return tun.mtu, nil
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}
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