nebula/overlay/tun_openbsd.go

175 lines
3.9 KiB
Go

//go:build !e2e_testing
// +build !e2e_testing
package overlay
import (
"fmt"
"io"
"net"
"os"
"os/exec"
"regexp"
"strconv"
"syscall"
"github.com/sirupsen/logrus"
"github.com/slackhq/nebula/cidr"
"github.com/slackhq/nebula/iputil"
)
type tun struct {
Device string
cidr *net.IPNet
MTU int
Routes []Route
routeTree *cidr.Tree4
l *logrus.Logger
io.ReadWriteCloser
// cache out buffer since we need to prepend 4 bytes for tun metadata
out []byte
}
func (t *tun) Close() error {
if t.ReadWriteCloser != nil {
return t.ReadWriteCloser.Close()
}
return nil
}
func newTunFromFd(_ *logrus.Logger, _ int, _ *net.IPNet, _ int, _ []Route, _ int, _ bool) (*tun, error) {
return nil, fmt.Errorf("newTunFromFd not supported in OpenBSD")
}
var deviceNameRE = regexp.MustCompile(`^tun[0-9]+$`)
func newTun(l *logrus.Logger, deviceName string, cidr *net.IPNet, defaultMTU int, routes []Route, _ int, _ bool, _ bool) (*tun, error) {
if deviceName == "" {
return nil, fmt.Errorf("a device name in the format of tunN must be specified")
}
if !deviceNameRE.MatchString(deviceName) {
return nil, fmt.Errorf("a device name in the format of tunN must be specified")
}
file, err := os.OpenFile("/dev/"+deviceName, os.O_RDWR, 0)
if err != nil {
return nil, err
}
routeTree, err := makeRouteTree(l, routes, false)
if err != nil {
return nil, err
}
return &tun{
ReadWriteCloser: file,
Device: deviceName,
cidr: cidr,
MTU: defaultMTU,
Routes: routes,
routeTree: routeTree,
l: l,
}, nil
}
func (t *tun) Activate() error {
var err error
// TODO use syscalls instead of exec.Command
cmd := exec.Command("/sbin/ifconfig", t.Device, t.cidr.String(), t.cidr.IP.String())
t.l.Debug("command: ", cmd.String())
if err = cmd.Run(); err != nil {
return fmt.Errorf("failed to run 'ifconfig': %s", err)
}
cmd = exec.Command("/sbin/ifconfig", t.Device, "mtu", strconv.Itoa(t.MTU))
t.l.Debug("command: ", cmd.String())
if err = cmd.Run(); err != nil {
return fmt.Errorf("failed to run 'ifconfig': %s", err)
}
cmd = exec.Command("/sbin/route", "-n", "add", "-inet", t.cidr.String(), t.cidr.IP.String())
t.l.Debug("command: ", cmd.String())
if err = cmd.Run(); err != nil {
return fmt.Errorf("failed to run 'route add': %s", err)
}
// Unsafe path routes
for _, r := range t.Routes {
if r.Via == nil || !r.Install {
// We don't allow route MTUs so only install routes with a via
continue
}
cmd = exec.Command("/sbin/route", "-n", "add", "-inet", r.Cidr.String(), t.cidr.IP.String())
t.l.Debug("command: ", cmd.String())
if err = cmd.Run(); err != nil {
return fmt.Errorf("failed to run 'route add' for unsafe_route %s: %s", r.Cidr.String(), err)
}
}
return nil
}
func (t *tun) RouteFor(ip iputil.VpnIp) iputil.VpnIp {
r := t.routeTree.MostSpecificContains(ip)
if r != nil {
return r.(iputil.VpnIp)
}
return 0
}
func (t *tun) Cidr() *net.IPNet {
return t.cidr
}
func (t *tun) Name() string {
return t.Device
}
func (t *tun) NewMultiQueueReader() (io.ReadWriteCloser, error) {
return nil, fmt.Errorf("TODO: multiqueue not implemented for freebsd")
}
func (t *tun) Read(to []byte) (int, error) {
buf := make([]byte, len(to)+4)
n, err := t.ReadWriteCloser.Read(buf)
copy(to, buf[4:])
return n - 4, err
}
// Write is only valid for single threaded use
func (t *tun) Write(from []byte) (int, error) {
buf := t.out
if cap(buf) < len(from)+4 {
buf = make([]byte, len(from)+4)
t.out = buf
}
buf = buf[:len(from)+4]
if len(from) == 0 {
return 0, syscall.EIO
}
// Determine the IP Family for the NULL L2 Header
ipVer := from[0] >> 4
if ipVer == 4 {
buf[3] = syscall.AF_INET
} else if ipVer == 6 {
buf[3] = syscall.AF_INET6
} else {
return 0, fmt.Errorf("unable to determine IP version from packet")
}
copy(buf[4:], from)
n, err := t.ReadWriteCloser.Write(buf)
return n - 4, err
}