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//
// Copyright (c) 2017 anygone contributors (see AUTHORS file)
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// * Redistributions of source code must retain the above copyright notice, this
// list of conditions and the following disclaimer.
//
// * Redistributions in binary form must reproduce the above copyright notice,
// this list of conditions and the following disclaimer in the documentation
// and/or other materials provided with the distribution.
//
// * Neither the name of anygone nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
package tuntap
import (
"context"
"fmt"
"net"
"os/exec"
"strings"
"time"
extlib "github.com/lab11/go-tuntap/tuntap"
"github.com/vishvananda/netlink"
)
const (
EtherTypeIPv4 = 0x0800
EtherTypeIPv6 = 0x86DD
EtherTypeTransparentEthernetBridge = 0x6558
PostUpScriptTimeout = 10 * time.Second
)
type Device struct {
iface *extlib.Interface
iftype extlib.DevKind
nl netlink.Link
}
func (dev *Device) Name() string {
return dev.iface.Name()
}
func (dev *Device) AddAddress(addr net.IPNet) error {
// TODO: this only works on linux...
if err := netlink.AddrAdd(dev.nl, &netlink.Addr{IPNet: &addr}); err != nil {
return fmt.Errorf("netlink(addr add) failed: %v", err)
}
return nil
}
func (dev *Device) SetMTU(mtu int) error {
// TODO: this only works on linux...
if err := netlink.LinkSetMTU(dev.nl, mtu); err != nil {
return fmt.Errorf("netlink(link set mtu) failed: %v", err)
}
return nil
}
func (dev *Device) Up() error {
// TODO: this only works on linux...
if err := netlink.LinkSetUp(dev.nl); err != nil {
return fmt.Errorf("netlink(link set up) failed: %v", err)
}
return nil
}
func (dev *Device) Down() error {
// TODO: this only works on linux...
if err := netlink.LinkSetDown(dev.nl); err != nil {
return fmt.Errorf("netlink(link set down) failed: %v", err)
}
return nil
}
func (dev *Device) RunPostUp(script string) error {
ctx, cancel := context.WithTimeout(context.Background(), PostUpScriptTimeout)
defer cancel()
if err := exec.CommandContext(ctx, script, dev.iface.Name()).Run(); err != nil {
return err
}
return nil
}
func (dev *Device) ReadPacket() (pkt *extlib.Packet, err error) {
pkt, err = dev.iface.ReadPacket()
if dev.iftype == extlib.DevTap {
pkt.Protocol = EtherTypeTransparentEthernetBridge
}
return
}
func (dev *Device) WritePacket(pkt *extlib.Packet) error {
pkt.Protocol = 0
return dev.iface.WritePacket(pkt)
}
func NewTunDevice(name string) (dev *Device, err error) {
dev = &Device{iftype: extlib.DevTun}
if dev.iface, err = extlib.Open(name, extlib.DevTun, true); err != nil {
return
}
return
}
func NewTapDevice(name string) (dev *Device, err error) {
dev = &Device{iftype: extlib.DevTap}
if dev.iface, err = extlib.Open(name, extlib.DevTap, false); err != nil {
return
}
return
}
func NewDevice(iftype, name string) (dev *Device, err error) {
if iftype == "" {
if strings.HasPrefix(name, "tun") {
iftype = "tun"
} else if strings.HasPrefix(name, "tap") {
iftype = "tap"
} else {
return nil, fmt.Errorf("no device type is set and the given interface name(%s) doesn't start with 'tun' or 'tap'", name)
}
}
switch strings.ToLower(iftype) {
case "tun":
dev, err = NewTunDevice(name)
case "tap":
dev, err = NewTapDevice(name)
default:
return nil, fmt.Errorf("invalid interface type: %s", iftype)
}
if err != nil {
return nil, err
}
// TODO: this only works on linux...
if dev.nl, err = netlink.LinkByName(dev.iface.Name()); err != nil {
return nil, fmt.Errorf("netlink(open netlink by name) failed: %v", err)
}
return dev, nil
}
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