kilo/pkg/wireguard/wireguard.go
Lucas Serven e989f0a25f
init
2019-01-18 02:50:10 +01:00

184 lines
4.8 KiB
Go

// 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"
"regexp"
"sort"
"strconv"
"github.com/vishvananda/netlink"
"gopkg.in/ini.v1"
)
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 creates a new WireGuard interface.
func New(prefix string) (int, error) {
links, err := netlink.LinkList()
if err != nil {
return 0, fmt.Errorf("failed to list links: %v", err)
}
max := 0
re := regexp.MustCompile(fmt.Sprintf("^%s([0-9]+)$", prefix))
for _, link := range links {
if matches := re.FindStringSubmatch(link.Attrs().Name); len(matches) == 2 {
i, err := strconv.Atoi(matches[1])
if err != nil {
// This should never happen.
return 0, fmt.Errorf("failed to parse digits as an integer: %v", err)
}
if i >= max {
max = i + 1
}
}
}
name := fmt.Sprintf("%s%d", prefix, max)
wl := wgLink{a: netlink.NewLinkAttrs(), t: "wireguard"}
wl.a.Name = name
if err := netlink.LinkAdd(wl); err != nil {
return 0, fmt.Errorf("failed to create interface %s: %v", name, err)
}
link, err := netlink.LinkByName(name)
if err != nil {
return 0, fmt.Errorf("failed to get interface index: %v", err)
}
return link.Attrs().Index, nil
}
// 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) {
return exec.Command("wg", "genkey").Output()
}
// 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 public, nil
}
// 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
}
// CompareConf compares two WireGuard configurations.
// It returns true if they are equal, false if they are not,
// and any error that was encountered.
// Note: CompareConf only goes one level deep, as WireGuard
// configurations are not nested further than that.
func CompareConf(a, b []byte) (bool, error) {
iniA, err := ini.Load(a)
if err != nil {
return false, fmt.Errorf("failed to parse configuration: %v", err)
}
iniB, err := ini.Load(b)
if err != nil {
return false, fmt.Errorf("failed to parse configuration: %v", err)
}
secsA, secsB := iniA.SectionStrings(), iniB.SectionStrings()
if len(secsA) != len(secsB) {
return false, nil
}
sort.Strings(secsA)
sort.Strings(secsB)
var keysA, keysB []string
var valsA, valsB []string
for i := range secsA {
if secsA[i] != secsB[i] {
return false, nil
}
keysA, keysB = iniA.Section(secsA[i]).KeyStrings(), iniB.Section(secsB[i]).KeyStrings()
if len(keysA) != len(keysB) {
return false, nil
}
sort.Strings(keysA)
sort.Strings(keysB)
for j := range keysA {
if keysA[j] != keysB[j] {
return false, nil
}
valsA, valsB = iniA.Section(secsA[i]).Key(keysA[j]).Strings(","), iniB.Section(secsB[i]).Key(keysB[j]).Strings(",")
if len(valsA) != len(valsB) {
return false, nil
}
sort.Strings(valsA)
sort.Strings(valsB)
for k := range valsA {
if valsA[k] != valsB[k] {
return false, nil
}
}
}
}
return true, nil
}