Rework freebsd support

README.md

@@ -40,7 +40,7 @@ It is currently a work in progress to strip out the beginnings of an experiment
 
 ### FreeBSD
 
-Work in progress, but nothing yet to share.
+This will run on FreeBSD.
 
 ## Building
 

conn_default.go

@@ -9,7 +9,9 @@
 package main
 
 import (
+	"golang.org/x/sys/unix"
 	"net"
+	"runtime"
 )
 
 /* This code is meant to be a temporary solution
@@ -138,6 +140,35 @@ func (bind *NativeBind) Send(buff []byte, endpoint Endpoint) error {
 	return err
 }
 
-func (bind *NativeBind) SetMark(_ uint32) error {
+func (bind *NativeBind) SetMark(mark uint32) error {
+	if runtime.GOOS == "freebsd" {
+		fd4, err1 := bind.ipv4.SyscallConn()
+		fd6, err2 := bind.ipv6.SyscallConn()
+		if err1 != nil {
+			return err1
+		}
+		if err2 != nil {
+			return err2
+		}
+		err3 := fd4.Control(func(fd uintptr) {
+			err1 = unix.SetsockoptInt(int(fd), unix.SOL_SOCKET, 0x1014 /* unix.SO_SETFIB */, int(mark))
+		})
+		err4 := fd6.Control(func(fd uintptr) {
+			err2 = unix.SetsockoptInt(int(fd), unix.SOL_SOCKET, 0x1014 /* unix.SO_SETFIB */, int(mark))
+		})
+		if err1 != nil {
+			return err1
+		}
+		if err2 != nil {
+			return err2
+		}
+		if err3 != nil {
+			return err3
+		}
+		if err4 != nil {
+			return err4
+		}
+		return nil
+	}
 	return nil
 }

rwcancel/select_default.go

@@ -1,10 +1,10 @@
+// +build !linux
+
 /* SPDX-License-Identifier: GPL-2.0
  *
  * Copyright (C) 2017-2018 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
  */
 
-// +build !linux
-
 package rwcancel
 
 import "golang.org/x/sys/unix"

tun_darwin.go

@@ -34,8 +34,6 @@ type sockaddrCtl struct {
 	scReserved [5]uint32
 }
 
-// NativeTun is a hack to work around the first 4 bytes "packet
-// information" because there doesn't seem to be an IFF_NO_PI for darwin.
 type NativeTun struct {
 	name        string
 	fd          *os.File
@@ -67,7 +65,7 @@ func (tun *NativeTun) RoutineRouteListener(tunIfindex int) {
 			continue
 		}
 
-		if data[3 /* type */] != 0xe /* RTM_IFINFO */ {
+		if data[3 /* type */] != unix.RTM_IFINFO {
 			continue
 		}
 		ifindex := int(*(*uint16)(unsafe.Pointer(&data[12 /* ifindex */])))
@@ -347,7 +345,7 @@ func (tun *NativeTun) setMTU(n int) error {
 	)
 
 	if errno != 0 {
-		return fmt.Errorf("Failed to set MTU on %s", tun.name)
+		return fmt.Errorf("failed to set MTU on %s", tun.name)
 	}
 
 	return nil
@@ -380,7 +378,7 @@ func (tun *NativeTun) MTU() (int, error) {
 		uintptr(unsafe.Pointer(&ifr[0])),
 	)
 	if errno != 0 {
-		return 0, fmt.Errorf("Failed to get MTU on %s", tun.name)
+		return 0, fmt.Errorf("failed to get MTU on %s", tun.name)
 	}
 
 	// convert result to signed 32-bit int

tun_freebsd.go

@@ -12,11 +12,8 @@ import (
 	"fmt"
 	"golang.org/x/net/ipv6"
 	"golang.org/x/sys/unix"
-	"io/ioutil"
 	"net"
 	"os"
-	"path/filepath"
-	"time"
 	"unsafe"
 )
 
@@ -29,38 +26,93 @@ const _TUNSIFPID = 0x2000745f
 // Iface status string max len
 const _IFSTATMAX = 800
 
+const SIZEOF_UINTPTR = 4 << (^uintptr(0) >> 32 & 1)
+
+// structure for iface requests with a pointer
+type ifreq_ptr struct {
+	Name [unix.IFNAMSIZ]byte
+	Data uintptr
+	Pad0 [24 - SIZEOF_UINTPTR]byte
+}
+
 // Structure for iface mtu get/set ioctls
 type ifreq_mtu struct {
-	Name [_IFNAMESIZ]byte
+	Name [unix.IFNAMSIZ]byte
 	MTU  uint32
 	Pad0 [12]byte
 }
 
 // Structure for interface status request ioctl
 type ifstat struct {
-	IfsName [_IFNAMESIZ]byte
+	IfsName [unix.IFNAMSIZ]byte
 	Ascii   [_IFSTATMAX]byte
 }
 
-// NativeTun is a hack to work around the first 4 bytes "packet
-// information" because there doesn't seem to be an IFF_NO_PI for darwin.
 type NativeTun struct {
 	name        string
 	fd          *os.File
 	rwcancel    *rwcancel.RWCancel
-	mtu                     int
 	events      chan TUNEvent
 	errors      chan error
-	statusListenersShutdown chan struct{}
+	routeSocket int
 }
 
-// Figure out the interface name for an open tun device file descriptor
+func (tun *NativeTun) RoutineRouteListener(tunIfindex int) {
-func TunIfaceName(f *os.File) (string, error) {
+	var (
+		statusUp  bool
+		statusMTU int
+	)
+
+	defer close(tun.events)
+
+	data := make([]byte, os.Getpagesize())
+	for {
+		n, err := unix.Read(tun.routeSocket, data)
+		if err != nil {
+			tun.errors <- err
+			return
+		}
+
+		if n < 14 {
+			continue
+		}
+
+		if data[3 /* type */] != unix.RTM_IFINFO {
+			continue
+		}
+		ifindex := int(*(*uint16)(unsafe.Pointer(&data[12 /* ifindex */])))
+		if ifindex != tunIfindex {
+			continue
+		}
+
+		iface, err := net.InterfaceByIndex(ifindex)
+		if err != nil {
+			tun.errors <- err
+			return
+		}
+
+		// Up / Down event
+		up := (iface.Flags & net.FlagUp) != 0
+		if up != statusUp && up {
+			tun.events <- TUNEventUp
+		}
+		if up != statusUp && !up {
+			tun.events <- TUNEventDown
+		}
+		statusUp = up
+
+		// MTU changes
+		if iface.MTU != statusMTU {
+			tun.events <- TUNEventMTUUpdate
+		}
+		statusMTU = iface.MTU
+	}
+}
+
+func tunName(fd uintptr) (string, error) {
 	//Terrible hack to make up for freebsd not having a TUNGIFNAME
 
-	fd := f.Fd()
 	//First, make sure the tun pid matches this proc's pid
-
 	_, _, errno := unix.Syscall(
 		unix.SYS_IOCTL,
 		uintptr(fd),
@@ -69,7 +121,7 @@ func TunIfaceName(f *os.File) (string, error) {
 	)
 
 	if errno != 0 {
-		return "", fmt.Errorf("Failed to set tun device PID: %s", errno.Error())
+		return "", fmt.Errorf("failed to set tun device PID: %s", errno.Error())
 	}
 
 	// Open iface control socket
@@ -80,12 +132,12 @@ func TunIfaceName(f *os.File) (string, error) {
 		0,
 	)
 
-	defer unix.Close(confd)
-
 	if err != nil {
 		return "", err
 	}
 
+	defer unix.Close(confd)
+
 	procPid := os.Getpid()
 
 	//Try to find interface with matching PID
@@ -97,8 +149,7 @@ func TunIfaceName(f *os.File) (string, error) {
 
 		// Structs for getting data in and out of SIOCGIFSTATUS ioctl
 		var ifstatus ifstat
-		ifname := iface.Name
+		copy(ifstatus.IfsName[:], iface.Name)
-		copy(ifstatus.IfsName[:], ifname)
 
 		// Make the syscall to get the status string
 		_, _, errno := unix.Syscall(
@@ -117,30 +168,26 @@ func TunIfaceName(f *os.File) (string, error) {
 		if i < 1 {
 			continue
 		}
-		if i != -1 {
+		statStr := string(nullStr[:i])
-			nullStr = nullStr[:i]
-		}
-		statStr := string(nullStr)
 		var pidNum int = 0
 
 		// Finally get the owning PID
 		// Format string taken from sys/net/if_tun.c
 		_, err := fmt.Sscanf(statStr, "\tOpened by PID %d\n", &pidNum)
 		if err != nil {
-			return "", err
+			continue
 		}
 
 		if pidNum == procPid {
-			return ifname, nil
+			return iface.Name, nil
 		}
-
 	}
 
 	return "", nil
 }
 
 // Destroy a named system interface
-func DestroyIface(name string) error {
+func tunDestroy(name string) error {
 	// open control socket
 	var fd int
 
@@ -168,21 +215,21 @@ func DestroyIface(name string) error {
 	)
 
 	if errno != 0 {
-		return fmt.Errorf("Failed to destroy interface %s: %s", name, errno.Error())
+		return fmt.Errorf("failed to destroy interface %s: %s", name, errno.Error())
 	}
 
 	return nil
 }
 
 func CreateTUN(name string) (TUNDevice, error) {
-	if len(name) > _IFNAMESIZ-1 {
+	if len(name) > unix.IFNAMSIZ-1 {
-		return nil, errors.New("Interface name too long")
+		return nil, errors.New("interface name too long")
 	}
 
 	// See if interface already exists
 	iface, _ := net.InterfaceByName(name)
 	if iface != nil {
-		return nil, fmt.Errorf("Interface %s already exists", name)
+		return nil, fmt.Errorf("interface %s already exists", name)
 	}
 
 	tunfile, err := os.OpenFile("/dev/tun", unix.O_RDWR, 0)
@@ -190,16 +237,13 @@ func CreateTUN(name string) (TUNDevice, error) {
 	if err != nil {
 		return nil, err
 	}
-
+	tunfd := tunfile.Fd()
-	nameif, err := TunIfaceName(tunfile)
+	assignedName, err := tunName(tunfd)
-
 	if err != nil {
 		tunfile.Close()
 		return nil, err
 	}
 
-	tunfd := tunfile.Fd()
-
 	// Enable ifhead mode, otherwise tun will complain if it gets a non-AF_INET packet
 	ifheadmode := 1
 	_, _, errno := unix.Syscall(
@@ -210,11 +254,10 @@ func CreateTUN(name string) (TUNDevice, error) {
 	)
 
 	if errno != 0 {
-		return nil, fmt.Errorf("Error %s", errno.Error())
+		return nil, fmt.Errorf("error %s", errno.Error())
 	}
 
-	/* Set TUN iface to broadcast mode. TUN inferfaces on freebsd come up
+	// Set TUN iface to broadcast mode. TUN inferfaces on freebsd come up in point to point by default
-	 * point to point by default */
 	ifmodemode := unix.IFF_BROADCAST
 	_, _, errno = unix.Syscall(
 		unix.SYS_IOCTL,
@@ -224,12 +267,13 @@ func CreateTUN(name string) (TUNDevice, error) {
 	)
 
 	if errno != 0 {
-		return nil, fmt.Errorf("Error %s", errno.Error())
+		return nil, fmt.Errorf("error %s", errno.Error())
 	}
 
 	// Rename tun interface
+
 	// Open control socket
-	ctfd, err := unix.Socket(
+	confd, err := unix.Socket(
 		unix.AF_INET,
 		unix.SOCK_DGRAM,
 		0,
@@ -239,27 +283,27 @@ func CreateTUN(name string) (TUNDevice, error) {
 		return nil, err
 	}
 
-	defer unix.Close(ctfd)
+	defer unix.Close(confd)
 
 	// set up struct for iface rename
-	var newnp [_IFNAMESIZ]byte
+	var newnp [unix.IFNAMSIZ]byte
 	copy(newnp[:], name)
 
 	var ifr ifreq_ptr
-	copy(ifr.Name[:], nameif)
+	copy(ifr.Name[:], assignedName)
 	ifr.Data = uintptr(unsafe.Pointer(&newnp[0]))
 
 	//do actual ioctl to rename iface
 	_, _, errno = unix.Syscall(
 		unix.SYS_IOCTL,
-		uintptr(ctfd),
+		uintptr(confd),
 		uintptr(unix.SIOCSIFNAME),
 		uintptr(unsafe.Pointer(&ifr)),
 	)
 	if errno != 0 {
 		tunfile.Close()
-		DestroyIface(name)
+		tunDestroy(name)
-		return nil, fmt.Errorf("Failed to rename %s to %s: %s", nameif, name, errno.Error())
+		return nil, fmt.Errorf("failed to rename %s to %s: %s", assignedName, name, errno.Error())
 	}
 
 	tun, err := CreateTUNFromFile(tunfile)
@@ -267,15 +311,6 @@ func CreateTUN(name string) (TUNDevice, error) {
 	if err != nil {
 		return nil, err
 	}
-
-	if err == nil && name == "tun" {
-		fname := os.Getenv("WG_FREEBSD_TUN_NAME_FILE")
-		if fname != "" {
-			os.MkdirAll(filepath.Dir(fname), 0700)
-			ioutil.WriteFile(fname, []byte(tun.(*NativeTun).name+"\n"), 0400)
-		}
-	}
-
 	return tun, err
 }
 
@@ -283,13 +318,27 @@ func CreateTUNFromFile(file *os.File) (TUNDevice, error) {
 
 	tun := &NativeTun{
 		fd:     file,
-		mtu:                     1500,
 		events: make(chan TUNEvent, 10),
 		errors: make(chan error, 1),
-		statusListenersShutdown: make(chan struct{}),
 	}
 
-	_, err := tun.Name()
+	name, err := tun.Name()
+	if err != nil {
+		tun.fd.Close()
+		return nil, err
+	}
+
+	tunIfindex, err := func() (int, error) {
+		iface, err := net.InterfaceByName(name)
+		if err != nil {
+			return -1, err
+		}
+		return iface.Index, nil
+	}()
+	if err != nil {
+		tun.fd.Close()
+		return nil, err
+	}
 
 	if err != nil {
 		tun.fd.Close()
@@ -302,43 +351,13 @@ func CreateTUNFromFile(file *os.File) (TUNDevice, error) {
 		return nil, err
 	}
 
-	// TODO: Fix this very naive implementation
+	tun.routeSocket, err = unix.Socket(unix.AF_ROUTE, unix.SOCK_RAW, unix.AF_UNSPEC)
-	go func(tun *NativeTun) {
-		var (
-			statusUp  bool
-			statusMTU int
-		)
-
-		for {
-			intr, err := net.InterfaceByName(tun.name)
 	if err != nil {
-				tun.errors <- err
+		tun.fd.Close()
-				return
+		return nil, err
 	}
 
-			// Up / Down event
+	go tun.RoutineRouteListener(tunIfindex)
-			up := (intr.Flags & net.FlagUp) != 0
-			if up != statusUp && up {
-				tun.events <- TUNEventUp
-			}
-			if up != statusUp && !up {
-				tun.events <- TUNEventDown
-			}
-			statusUp = up
-
-			// MTU changes
-			if intr.MTU != statusMTU {
-				tun.events <- TUNEventMTUUpdate
-			}
-			statusMTU = intr.MTU
-
-			select {
-			case <-time.After(time.Second / 10):
-			case <-tun.statusListenersShutdown:
-				return
-			}
-		}
-	}(tun)
 
 	// set default MTU
 	err = tun.setMTU(DefaultMTU)
@@ -351,7 +370,7 @@ func CreateTUNFromFile(file *os.File) (TUNDevice, error) {
 }
 
 func (tun *NativeTun) Name() (string, error) {
-	name, err := TunIfaceName(tun.fd)
+	name, err := tunName(tun.fd.Fd())
 	if err != nil {
 		return "", err
 	}
@@ -417,18 +436,28 @@ func (tun *NativeTun) Write(buff []byte, offset int) (int, error) {
 }
 
 func (tun *NativeTun) Close() error {
-	close(tun.statusListenersShutdown)
+	var err4 error
 	err1 := tun.rwcancel.Cancel()
 	err2 := tun.fd.Close()
-	err3 := DestroyIface(tun.name)
+	err3 := tunDestroy(tun.name)
+	if tun.routeSocket != -1 {
+		// Surprisingly, on FreeBSD, simply closing a route socket is enough to unblock it.
+		// We don't even need to call shutdown, or use a rwcancel. TODO: CONFIRM THIS CLAIM. IT WAS TRUE ON DARWIN BUT...
+		err4 = unix.Close(tun.routeSocket)
+		tun.routeSocket = -1
+	} else if tun.events != nil {
 		close(tun.events)
+	}
 	if err1 != nil {
 		return err1
 	}
 	if err2 != nil {
 		return err2
 	}
+	if err3 != nil {
 		return err3
+	}
+	return err4
 }
 
 func (tun *NativeTun) setMTU(n int) error {
@@ -462,7 +491,7 @@ func (tun *NativeTun) setMTU(n int) error {
 	)
 
 	if errno != 0 {
-		return fmt.Errorf("Failed to set MTU on %s", tun.name)
+		return fmt.Errorf("failed to set MTU on %s", tun.name)
 	}
 
 	return nil
@@ -494,7 +523,7 @@ func (tun *NativeTun) MTU() (int, error) {
 		uintptr(unsafe.Pointer(&ifr)),
 	)
 	if errno != 0 {
-		return 0, fmt.Errorf("Failed to get MTU on %s", tun.name)
+		return 0, fmt.Errorf("failed to get MTU on %s", tun.name)
 	}
 
 	// convert result to signed 32-bit int

tun_freebsd_386.go

@@ -1,18 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0
- *
- * Copyright (C) 2017-2018 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
- */
-
-/* Types to deal with FreeBSD fdiogname ioctl for determining tun device name */
-
-package main
-
-// Iface name max len
-const _IFNAMESIZ = 16
-
-// structure for iface requests with a pointer
-type ifreq_ptr struct {
-	Name [_IFNAMESIZ]byte
-	Data uintptr
-	Pad0 [20]byte
-}

tun_freebsd_amd64.go

@@ -1,18 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0
- *
- * Copyright (C) 2017-2018 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
- */
-
-/* Types to deal with FreeBSD fdiogname ioctl for determining tun device name */
-
-package main
-
-// Iface name max len
-const _IFNAMESIZ = 16
-
-// structure for iface requests with a pointer
-type ifreq_ptr struct {
-	Name [_IFNAMESIZ]byte
-	Data uintptr
-	Pad0 [16]byte
-}

tun_linux.go

@@ -227,7 +227,7 @@ func (tun *NativeTun) setMTU(n int) error {
 	)
 
 	if errno != 0 {
-		return errors.New("Failed to set MTU of TUN device")
+		return errors.New("failed to set MTU of TUN device")
 	}
 
 	return nil
@@ -260,7 +260,7 @@ func (tun *NativeTun) MTU() (int, error) {
 		uintptr(unsafe.Pointer(&ifr[0])),
 	)
 	if errno != 0 {
-		return 0, errors.New("Failed to get MTU of TUN device: " + strconv.FormatInt(int64(errno), 10))
+		return 0, errors.New("failed to get MTU of TUN device: " + strconv.FormatInt(int64(errno), 10))
 	}
 
 	// convert result to signed 32-bit int
@@ -282,7 +282,7 @@ func (tun *NativeTun) Name() (string, error) {
 		uintptr(unsafe.Pointer(&ifr[0])),
 	)
 	if errno != 0 {
-		return "", errors.New("Failed to get name of TUN device: " + strconv.FormatInt(int64(errno), 10))
+		return "", errors.New("failed to get name of TUN device: " + strconv.FormatInt(int64(errno), 10))
 	}
 	nullStr := ifr[:]
 	i := bytes.IndexByte(nullStr, 0)

uapi_bsd.go

@@ -1,3 +1,5 @@
+// +build darwin freebsd
+
 /* SPDX-License-Identifier: GPL-2.0
  *
  * Copyright (C) 2017-2018 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
@@ -91,7 +93,7 @@ func UAPIListen(name string, file *os.File) (net.Listener, error) {
 	if err != nil {
 		return nil, err
 	}
-	uapi.keventFd, err = unix.Open(socketDirectory, unix.O_EVTONLY, 0)
+	uapi.keventFd, err = unix.Open(socketDirectory, unix.O_RDONLY, 0)
 	if err != nil {
 		unix.Close(uapi.kqueueFd)
 		return nil, err

uapi_freebsd.go

@@ -1,195 +0,0 @@
-/* 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
-	}
-	// TODO: Double check socket deletion logic port from MacOS
-	uapi.keventFd, err = unix.Open(socketDirectory, unix.O_RDONLY, 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, 0700)
-	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()
-}