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Original file line number | Diff line number | Diff line change |
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//go:build !e2e_testing | ||
// +build !e2e_testing | ||
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package overlay | ||
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import ( | ||
"fmt" | ||
"io" | ||
"net" | ||
"os" | ||
"os/exec" | ||
"regexp" | ||
"strconv" | ||
"syscall" | ||
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"github.com/sirupsen/logrus" | ||
"github.com/slackhq/nebula/cidr" | ||
"github.com/slackhq/nebula/iputil" | ||
) | ||
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type tun struct { | ||
Device string | ||
cidr *net.IPNet | ||
MTU int | ||
Routes []Route | ||
routeTree *cidr.Tree4 | ||
l *logrus.Logger | ||
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io.ReadWriteCloser | ||
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// cache out buffer since we need to prepend 4 bytes for tun metadata | ||
out []byte | ||
} | ||
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func (t *tun) Close() error { | ||
if t.ReadWriteCloser != nil { | ||
return t.ReadWriteCloser.Close() | ||
} | ||
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return nil | ||
} | ||
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func newTunFromFd(_ *logrus.Logger, _ int, _ *net.IPNet, _ int, _ []Route, _ int, _ bool) (*tun, error) { | ||
return nil, fmt.Errorf("newTunFromFd not supported in OpenBSD") | ||
} | ||
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var deviceNameRE = regexp.MustCompile(`^tun[0-9]+$`) | ||
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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") | ||
} | ||
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if !deviceNameRE.MatchString(deviceName) { | ||
return nil, fmt.Errorf("a device name in the format of tunN must be specified") | ||
} | ||
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file, err := os.OpenFile("/dev/"+deviceName, os.O_RDWR, 0) | ||
if err != nil { | ||
return nil, err | ||
} | ||
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routeTree, err := makeRouteTree(l, routes, false) | ||
if err != nil { | ||
return nil, err | ||
} | ||
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return &tun{ | ||
ReadWriteCloser: file, | ||
Device: deviceName, | ||
cidr: cidr, | ||
MTU: defaultMTU, | ||
Routes: routes, | ||
routeTree: routeTree, | ||
l: l, | ||
}, nil | ||
} | ||
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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) | ||
} | ||
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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) | ||
} | ||
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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) | ||
} | ||
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// 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 | ||
} | ||
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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) | ||
} | ||
} | ||
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return nil | ||
} | ||
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func (t *tun) RouteFor(ip iputil.VpnIp) iputil.VpnIp { | ||
r := t.routeTree.MostSpecificContains(ip) | ||
if r != nil { | ||
return r.(iputil.VpnIp) | ||
} | ||
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return 0 | ||
} | ||
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func (t *tun) Cidr() *net.IPNet { | ||
return t.cidr | ||
} | ||
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func (t *tun) Name() string { | ||
return t.Device | ||
} | ||
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func (t *tun) NewMultiQueueReader() (io.ReadWriteCloser, error) { | ||
return nil, fmt.Errorf("TODO: multiqueue not implemented for freebsd") | ||
} | ||
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func (t *tun) Read(to []byte) (int, error) { | ||
buf := make([]byte, len(to)+4) | ||
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n, err := t.ReadWriteCloser.Read(buf) | ||
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copy(to, buf[4:]) | ||
return n - 4, err | ||
} | ||
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// 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] | ||
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if len(from) == 0 { | ||
return 0, syscall.EIO | ||
} | ||
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// 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") | ||
} | ||
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copy(buf[4:], from) | ||
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n, err := t.ReadWriteCloser.Write(buf) | ||
return n - 4, err | ||
} |
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