kilo/pkg/wireguard/wireguard.go

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// Copyright 2019 the Kilo 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 wireguard
import (
"bytes"
"fmt"
"os/exec"
"github.com/vishvananda/netlink"
)
type wgLink struct {
a netlink.LinkAttrs
t string
}
func (w wgLink) Attrs() *netlink.LinkAttrs {
return &w.a
}
func (w wgLink) Type() string {
return w.t
}
// New returns a WireGuard interface with the given name.
// If the interface exists, its index is returned.
// Otherwise, a new interface is created.
// The function also returns a boolean to indicate if the interface was created.
func New(name string) (int, bool, error) {
link, err := netlink.LinkByName(name)
if err == nil {
return link.Attrs().Index, false, nil
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}
if _, ok := err.(netlink.LinkNotFoundError); !ok {
return 0, false, fmt.Errorf("failed to get links: %v", err)
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}
wl := wgLink{a: netlink.NewLinkAttrs(), t: "wireguard"}
wl.a.Name = name
if err := netlink.LinkAdd(wl); err != nil {
return 0, false, fmt.Errorf("failed to create interface %s: %v", name, err)
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}
link, err = netlink.LinkByName(name)
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if err != nil {
return 0, false, fmt.Errorf("failed to get interface index: %v", err)
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}
return link.Attrs().Index, true, nil
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}
// Keys generates a WireGuard private and public key-pair.
func Keys() ([]byte, []byte, error) {
private, err := GenKey()
if err != nil {
return nil, nil, fmt.Errorf("failed to generate private key: %v", err)
}
public, err := PubKey(private)
return private, public, err
}
// GenKey generates a WireGuard private key.
func GenKey() ([]byte, error) {
key, err := exec.Command("wg", "genkey").Output()
return bytes.Trim(key, "\n"), err
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}
// PubKey generates a WireGuard public key for a given private key.
func PubKey(key []byte) ([]byte, error) {
cmd := exec.Command("wg", "pubkey")
stdin, err := cmd.StdinPipe()
if err != nil {
return nil, fmt.Errorf("failed to open pipe to stdin: %v", err)
}
go func() {
defer stdin.Close()
stdin.Write(key)
}()
public, err := cmd.Output()
if err != nil {
return nil, fmt.Errorf("failed to generate public key: %v", err)
}
return bytes.Trim(public, "\n"), nil
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}
// SetConf applies a WireGuard configuration file to the given interface.
func SetConf(iface string, path string) error {
cmd := exec.Command("wg", "setconf", iface, path)
var stderr bytes.Buffer
cmd.Stderr = &stderr
if err := cmd.Run(); err != nil {
return fmt.Errorf("failed to apply the WireGuard configuration: %s", stderr.String())
}
return nil
}
// ShowConf gets the WireGuard configuration for the given interface.
func ShowConf(iface string) ([]byte, error) {
cmd := exec.Command("wg", "showconf", iface)
var stderr, stdout bytes.Buffer
cmd.Stderr = &stderr
cmd.Stdout = &stdout
if err := cmd.Run(); err != nil {
return nil, fmt.Errorf("failed to read the WireGuard configuration: %s", stderr.String())
}
return stdout.Bytes(), nil
}