frp/pkg/vnet/tun.go
2025-04-27 15:22:28 +08:00

110 lines
2.3 KiB
Go

// Copyright 2025 The frp Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package vnet
import (
"context"
"io"
"github.com/fatedier/golib/pool"
"golang.zx2c4.com/wireguard/tun"
)
const (
offset = 16
defaultPacketSize = 1420
)
type TunDevice interface {
io.ReadWriteCloser
}
func OpenTun(ctx context.Context, addr string) (TunDevice, error) {
td, err := openTun(ctx, addr)
if err != nil {
return nil, err
}
mtu, err := td.MTU()
if err != nil {
mtu = defaultPacketSize
}
bufferSize := max(mtu, defaultPacketSize)
batchSize := td.BatchSize()
device := &tunDeviceWrapper{
dev: td,
bufferSize: bufferSize,
readBuffers: make([][]byte, batchSize),
sizeBuffer: make([]int, batchSize),
}
for i := range device.readBuffers {
device.readBuffers[i] = make([]byte, offset+bufferSize)
}
return device, nil
}
type tunDeviceWrapper struct {
dev tun.Device
bufferSize int
readBuffers [][]byte
packetBuffers [][]byte
sizeBuffer []int
}
func (d *tunDeviceWrapper) Read(p []byte) (int, error) {
if len(d.packetBuffers) > 0 {
n := copy(p, d.packetBuffers[0])
d.packetBuffers = d.packetBuffers[1:]
return n, nil
}
n, err := d.dev.Read(d.readBuffers, d.sizeBuffer, offset)
if err != nil {
return 0, err
}
if n == 0 {
return 0, io.EOF
}
for i := range n {
if d.sizeBuffer[i] <= 0 {
continue
}
d.packetBuffers = append(d.packetBuffers, d.readBuffers[i][offset:offset+d.sizeBuffer[i]])
}
dataSize := copy(p, d.packetBuffers[0])
d.packetBuffers = d.packetBuffers[1:]
return dataSize, nil
}
func (d *tunDeviceWrapper) Write(p []byte) (int, error) {
buf := pool.GetBuf(offset + d.bufferSize)
defer pool.PutBuf(buf)
n := copy(buf[offset:], p)
_, err := d.dev.Write([][]byte{buf[:offset+n]}, offset)
return n, err
}
func (d *tunDeviceWrapper) Close() error {
return d.dev.Close()
}