104 lines
3.1 KiB
Go
104 lines
3.1 KiB
Go
// Copyright (c) Tailscale Inc & AUTHORS
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// SPDX-License-Identifier: BSD-3-Clause
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package tstun
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import (
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"bytes"
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"errors"
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"os"
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"os/exec"
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"strings"
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"syscall"
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"tailscale.com/types/logger"
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"tailscale.com/version/distro"
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)
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func init() {
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tunDiagnoseFailure = diagnoseLinuxTUNFailure
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}
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func diagnoseLinuxTUNFailure(tunName string, logf logger.Logf, createErr error) {
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if errors.Is(createErr, syscall.EBUSY) {
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logf("TUN device %s is busy; another process probably still has it open (from old version of Tailscale that had a bug)", tunName)
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logf("To fix, kill the process that has it open. Find with:\n\n$ sudo lsof -n /dev/net/tun\n\n")
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logf("... and then kill those PID(s)")
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return
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}
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var un syscall.Utsname
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err := syscall.Uname(&un)
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if err != nil {
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logf("no TUN, and failed to look up kernel version: %v", err)
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return
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}
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kernel := utsReleaseField(&un)
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logf("Linux kernel version: %s", kernel)
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modprobeOut, err := exec.Command("/sbin/modprobe", "tun").CombinedOutput()
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if err == nil {
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logf("'modprobe tun' successful")
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// Either tun is currently loaded, or it's statically
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// compiled into the kernel (which modprobe checks
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// with /lib/modules/$(uname -r)/modules.builtin)
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//
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// So if there's a problem at this point, it's
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// probably because /dev/net/tun doesn't exist.
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const dev = "/dev/net/tun"
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if fi, err := os.Stat(dev); err != nil {
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logf("tun module loaded in kernel, but %s does not exist", dev)
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} else {
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logf("%s: %v", dev, fi.Mode())
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}
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// We failed to find why it failed. Just let our
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// caller report the error it got from wireguard-go.
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return
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}
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logf("is CONFIG_TUN enabled in your kernel? `modprobe tun` failed with: %s", modprobeOut)
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switch distro.Get() {
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case distro.Debian:
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dpkgOut, err := exec.Command("dpkg", "-S", "kernel/drivers/net/tun.ko").CombinedOutput()
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if len(bytes.TrimSpace(dpkgOut)) == 0 || err != nil {
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logf("tun module not loaded nor found on disk")
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return
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}
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if !bytes.Contains(dpkgOut, []byte(kernel)) {
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logf("kernel/drivers/net/tun.ko found on disk, but not for current kernel; are you in middle of a system update and haven't rebooted? found: %s", dpkgOut)
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}
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case distro.Arch:
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findOut, err := exec.Command("find", "/lib/modules/", "-path", "*/net/tun.ko*").CombinedOutput()
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if len(bytes.TrimSpace(findOut)) == 0 || err != nil {
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logf("tun module not loaded nor found on disk")
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return
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}
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if !bytes.Contains(findOut, []byte(kernel)) {
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logf("kernel/drivers/net/tun.ko found on disk, but not for current kernel; are you in middle of a system update and haven't rebooted? found: %s", findOut)
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}
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case distro.OpenWrt:
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out, err := exec.Command("opkg", "list-installed").CombinedOutput()
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if err != nil {
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logf("error querying OpenWrt installed packages: %s", out)
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return
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}
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for _, pkg := range []string{"kmod-tun", "ca-bundle"} {
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if !bytes.Contains(out, []byte(pkg+" - ")) {
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logf("Missing required package %s; run: opkg install %s", pkg, pkg)
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}
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}
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}
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}
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func utsReleaseField(u *syscall.Utsname) string {
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var sb strings.Builder
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for _, v := range u.Release {
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if v == 0 {
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break
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}
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sb.WriteByte(byte(v))
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}
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return strings.TrimSpace(sb.String())
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}
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