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/* SPDX-License-Identifier: GPL-2.0
*
* Copyright (C) 2017-2018 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
*/
package main
import (
"errors"
"fmt"
"golang.org/x/sys/unix"
"net"
"os"
"path"
)
const (
ipcErrorIO = -int64(unix.EIO)
ipcErrorProtocol = -int64(unix.EPROTO)
ipcErrorInvalid = -int64(unix.EINVAL)
ipcErrorPortInUse = -int64(unix.EADDRINUSE)
socketDirectory = "/var/run/wireguard"
socketName = "%s.sock"
)
type UAPIListener struct {
listener net.Listener // unix socket listener
connNew chan net.Conn
connErr chan error
kqueueFd int
keventFd int
}
func (l *UAPIListener) Accept() (net.Conn, error) {
for {
select {
case conn := <-l.connNew:
return conn, nil
case err := <-l.connErr:
return nil, err
}
}
}
func (l *UAPIListener) Close() error {
err1 := unix.Close(l.kqueueFd)
err2 := unix.Close(l.keventFd)
err3 := l.listener.Close()
if err1 != nil {
return err1
}
if err2 != nil {
return err2
}
return err3
}
func (l *UAPIListener) Addr() net.Addr {
return l.listener.Addr()
}
func UAPIListen(name string, file *os.File) (net.Listener, error) {
// wrap file in listener
listener, err := net.FileListener(file)
if err != nil {
return nil, err
}
uapi := &UAPIListener{
listener: listener,
connNew: make(chan net.Conn, 1),
connErr: make(chan error, 1),
}
if unixListener, ok := listener.(*net.UnixListener); ok {
unixListener.SetUnlinkOnClose(true)
}
socketPath := path.Join(
socketDirectory,
fmt.Sprintf(socketName, name),
)
// watch for deletion of socket
uapi.kqueueFd, err = unix.Kqueue()
if err != nil {
return nil, err
}
uapi.keventFd, err = unix.Open(socketDirectory, unix.O_EVTONLY, 0)
if err != nil {
unix.Close(uapi.kqueueFd)
return nil, err
}
go func(l *UAPIListener) {
event := unix.Kevent_t{
Ident: uint64(uapi.keventFd),
Filter: unix.EVFILT_VNODE,
Flags: unix.EV_ADD | unix.EV_ENABLE | unix.EV_ONESHOT,
Fflags: unix.NOTE_WRITE,
}
events := make([]unix.Kevent_t, 1)
n := 1
var kerr error
for {
// start with lstat to avoid race condition
if _, err := os.Lstat(socketPath); os.IsNotExist(err) {
l.connErr <- err
return
}
if kerr != nil || n != 1 {
if kerr != nil {
l.connErr <- kerr
} else {
l.connErr <- errors.New("kqueue returned empty")
}
return
}
n, kerr = unix.Kevent(uapi.kqueueFd, []unix.Kevent_t{event}, events, nil)
}
}(uapi)
// watch for new connections
go func(l *UAPIListener) {
for {
conn, err := l.listener.Accept()
if err != nil {
l.connErr <- err
break
}
l.connNew <- conn
}
}(uapi)
return uapi, nil
}
func UAPIOpen(name string) (*os.File, error) {
// check if path exist
err := os.MkdirAll(socketDirectory, 0600)
if err != nil && !os.IsExist(err) {
return nil, err
}
// open UNIX socket
socketPath := path.Join(
socketDirectory,
fmt.Sprintf(socketName, name),
)
addr, err := net.ResolveUnixAddr("unix", socketPath)
if err != nil {
return nil, err
}
listener, err := func() (*net.UnixListener, error) {
// initial connection attempt
listener, err := net.ListenUnix("unix", addr)
if err == nil {
return listener, nil
}
// check if socket already active
_, err = net.Dial("unix", socketPath)
if err == nil {
return nil, errors.New("unix socket in use")
}
// cleanup & attempt again
err = os.Remove(socketPath)
if err != nil {
return nil, err
}
return net.ListenUnix("unix", addr)
}()
if err != nil {
return nil, err
}
return listener.File()
}
|
