/* SPDX-License-Identifier: GPL-2.0
*
* Copyright (C) 2017-2018 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
* Copyright (C) 2017-2018 Mathias N. Hall-Andersen <mathias@hall-andersen.dk>.
*/
package main
import (
"fmt"
"os"
"os/signal"
"runtime"
"strconv"
"syscall"
)
const (
ExitSetupSuccess = 0
ExitSetupFailed = 1
)
const (
ENV_WG_TUN_FD = "WG_TUN_FD"
ENV_WG_UAPI_FD = "WG_UAPI_FD"
ENV_WG_PROCESS_FOREGROUND = "WG_PROCESS_FOREGROUND"
)
func printUsage() {
fmt.Printf("usage:\n")
fmt.Printf("%s [-f/--foreground] INTERFACE-NAME\n", os.Args[0])
}
func warning() {
if os.Getenv(ENV_WG_PROCESS_FOREGROUND) == "1" {
return
}
shouldQuit := false
fmt.Fprintln(os.Stderr, "WARNING WARNING WARNING WARNING WARNING WARNING WARNING")
fmt.Fprintln(os.Stderr, "W G")
fmt.Fprintln(os.Stderr, "W This is alpha software. It will very likely not G")
fmt.Fprintln(os.Stderr, "W do what it is supposed to do, and things may go G")
fmt.Fprintln(os.Stderr, "W horribly wrong. You have been warned. Proceed G")
fmt.Fprintln(os.Stderr, "W at your own risk. G")
if runtime.GOOS == "linux" {
shouldQuit = os.Getenv("WG_I_PREFER_BUGGY_USERSPACE_TO_POLISHED_KMOD") != "1"
fmt.Fprintln(os.Stderr, "W G")
fmt.Fprintln(os.Stderr, "W Furthermore, you are running this software on a G")
fmt.Fprintln(os.Stderr, "W Linux kernel, which is probably unnecessary and G")
fmt.Fprintln(os.Stderr, "W foolish. This is because the Linux kernel has G")
fmt.Fprintln(os.Stderr, "W built-in first class support for WireGuard, and G")
fmt.Fprintln(os.Stderr, "W this support is much more refined than this G")
fmt.Fprintln(os.Stderr, "W program. For more information on installing the G")
fmt.Fprintln(os.Stderr, "W kernel module, please visit: G")
fmt.Fprintln(os.Stderr, "W https://www.wireguard.com/install G")
if shouldQuit {
fmt.Fprintln(os.Stderr, "W G")
fmt.Fprintln(os.Stderr, "W If you still want to use this program, against G")
fmt.Fprintln(os.Stderr, "W the sage advice here, please first export this G")
fmt.Fprintln(os.Stderr, "W environment variable: G")
fmt.Fprintln(os.Stderr, "W WG_I_PREFER_BUGGY_USERSPACE_TO_POLISHED_KMOD=1 G")
}
}
fmt.Fprintln(os.Stderr, "W G")
fmt.Fprintln(os.Stderr, "WARNING WARNING WARNING WARNING WARNING WARNING WARNING")
if shouldQuit {
os.Exit(1)
}
}
func main() {
warning()
// parse arguments
var foreground bool
var interfaceName string
if len(os.Args) < 2 || len(os.Args) > 3 {
printUsage()
return
}
switch os.Args[1] {
case "-f", "--foreground":
foreground = true
if len(os.Args) != 3 {
printUsage()
return
}
interfaceName = os.Args[2]
default:
foreground = false
if len(os.Args) != 2 {
printUsage()
return
}
interfaceName = os.Args[1]
}
if !foreground {
foreground = os.Getenv(ENV_WG_PROCESS_FOREGROUND) == "1"
}
// get log level (default: info)
logLevel := func() int {
switch os.Getenv("LOG_LEVEL") {
case "debug":
return LogLevelDebug
case "info":
return LogLevelInfo
case "error":
return LogLevelError
case "silent":
return LogLevelSilent
}
return LogLevelInfo
}()
// open TUN device (or use supplied fd)
tun, err := func() (TUNDevice, error) {
tunFdStr := os.Getenv(ENV_WG_TUN_FD)
if tunFdStr == "" {
return CreateTUN(interfaceName)
}
// construct tun device from supplied fd
fd, err := strconv.ParseUint(tunFdStr, 10, 32)
if err != nil {
return nil, err
}
file := os.NewFile(uintptr(fd), "")
return CreateTUNFromFile(file)
}()
if err == nil {
realInterfaceName, err2 := tun.Name()
if err2 == nil {
interfaceName = realInterfaceName
}
}
logger := NewLogger(
logLevel,
fmt.Sprintf("(%s) ", interfaceName),
)
logger.Debug.Println("Debug log enabled")
if err != nil {
logger.Error.Println("Failed to create TUN device:", err)
os.Exit(ExitSetupFailed)
}
// open UAPI file (or use supplied fd)
fileUAPI, err := func() (*os.File, error) {
uapiFdStr := os.Getenv(ENV_WG_UAPI_FD)
if uapiFdStr == "" {
return UAPIOpen(interfaceName)
}
// use supplied fd
fd, err := strconv.ParseUint(uapiFdStr, 10, 32)
if err != nil {
return nil, err
}
return os.NewFile(uintptr(fd), ""), nil
}()
if err != nil {
logger.Error.Println("UAPI listen error:", err)
os.Exit(ExitSetupFailed)
return
}
// daemonize the process
if !foreground {
env := os.Environ()
env = append(env, fmt.Sprintf("%s=3", ENV_WG_TUN_FD))
env = append(env, fmt.Sprintf("%s=4", ENV_WG_UAPI_FD))
env = append(env, fmt.Sprintf("%s=1", ENV_WG_PROCESS_FOREGROUND))
files := [3]*os.File{}
if os.Getenv("LOG_LEVEL") != "" && logLevel != LogLevelSilent {
files[0], _ = os.Open(os.DevNull)
files[1] = os.Stdout
files[2] = os.Stderr
} else {
files[0], _ = os.Open(os.DevNull)
files[1], _ = os.Open(os.DevNull)
files[2], _ = os.Open(os.DevNull)
}
attr := &os.ProcAttr{
Files: []*os.File{
files[0], // stdin
files[1], // stdout
files[2], // stderr
tun.File(),
fileUAPI,
},
Dir: ".",
Env: env,
}
path, err := os.Executable()
if err != nil {
logger.Error.Println("Failed to determine executable:", err)
os.Exit(ExitSetupFailed)
}
process, err := os.StartProcess(
path,
os.Args,
attr,
)
if err != nil {
logger.Error.Println("Failed to daemonize:", err)
os.Exit(ExitSetupFailed)
}
process.Release()
return
}
device := NewDevice(tun, logger)
logger.Info.Println("Device started")
errs := make(chan error)
term := make(chan os.Signal, 1)
uapi, err := UAPIListen(interfaceName, fileUAPI)
if err != nil {
logger.Error.Println("Failed to listen on uapi socket:", err)
os.Exit(ExitSetupFailed)
}
go func() {
for {
conn, err := uapi.Accept()
if err != nil {
errs <- err
return
}
go ipcHandle(device, conn)
}
}()
logger.Info.Println("UAPI listener started")
// wait for program to terminate
signal.Notify(term, syscall.SIGTERM)
signal.Notify(term, os.Interrupt)
select {
case <-term:
case <-errs:
case <-device.Wait():
}
// clean up
uapi.Close()
device.Close()
logger.Info.Println("Shutting down")
}