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Rework freebsd support

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This commit is contained in:
Jason A. Donenfeld
2018-05-21 17:27:18 +02:00
parent b962d7d791
commit ff3f2455e5
10 changed files with 182 additions and 353 deletions
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247
tun_freebsd.go
View File

@@ -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{}
name string
fd *os.File
rwcancel *rwcancel.RWCancel
events chan TUNEvent
errors chan error
routeSocket int
}
// Figure out the interface name for an open tun device file descriptor
func TunIfaceName(f *os.File) (string, error) {
func (tun *NativeTun) RoutineRouteListener(tunIfindex int) {
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[:], ifname)
copy(ifstatus.IfsName[:], iface.Name)
// 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 {
nullStr = nullStr[:i]
}
statStr := string(nullStr)
statStr := string(nullStr[:i])
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 {
return nil, errors.New("Interface name too long")
if len(name) > unix.IFNAMSIZ-1 {
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
}
nameif, err := TunIfaceName(tunfile)
tunfd := tunfile.Fd()
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
* point to point by default */
// Set TUN iface to broadcast mode. TUN inferfaces on freebsd come up in 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)
return nil, fmt.Errorf("Failed to rename %s to %s: %s", nameif, name, errno.Error())
tunDestroy(name)
return nil, fmt.Errorf("failed to rename %s to %s: %s", assignedName, name, errno.Error())
}
tun, err := CreateTUNFromFile(tunfile)
@@ -267,29 +311,34 @@ 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
}
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{}),
fd: file,
events: make(chan TUNEvent, 10),
errors: make(chan error, 1),
}
_, 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
go func(tun *NativeTun) {
var (
statusUp bool
statusMTU int
)
tun.routeSocket, err = unix.Socket(unix.AF_ROUTE, unix.SOCK_RAW, unix.AF_UNSPEC)
if err != nil {
tun.fd.Close()
return nil, err
}
for {
intr, err := net.InterfaceByName(tun.name)
if err != nil {
tun.errors <- err
return
}
// Up / Down event
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)
go tun.RoutineRouteListener(tunIfindex)
// 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)
close(tun.events)
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
}
return err3
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