tailscale/wgengine/router/router_userspace_bsd.go

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// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
//go:build darwin || freebsd
// +build darwin freebsd
package router
import (
"fmt"
"log"
"os/exec"
"runtime"
"golang.zx2c4.com/wireguard/tun"
"inet.af/netaddr"
"tailscale.com/net/tsaddr"
"tailscale.com/types/logger"
"tailscale.com/version"
"tailscale.com/wgengine/monitor"
)
type userspaceBSDRouter struct {
logf logger.Logf
linkMon *monitor.Mon
tunname string
local []netaddr.IPPrefix
routes map[netaddr.IPPrefix]struct{}
}
func newUserspaceBSDRouter(logf logger.Logf, tundev tun.Device, linkMon *monitor.Mon) (Router, error) {
tunname, err := tundev.Name()
if err != nil {
return nil, err
}
return &userspaceBSDRouter{
logf: logf,
linkMon: linkMon,
tunname: tunname,
}, nil
}
func (r *userspaceBSDRouter) addrsToRemove(newLocalAddrs []netaddr.IPPrefix) (remove []netaddr.IPPrefix) {
for _, cur := range r.local {
found := false
for _, v := range newLocalAddrs {
found = (v == cur)
if found {
break
}
}
if !found {
remove = append(remove, cur)
}
}
return
}
func (r *userspaceBSDRouter) addrsToAdd(newLocalAddrs []netaddr.IPPrefix) (add []netaddr.IPPrefix) {
for _, cur := range newLocalAddrs {
found := false
for _, v := range r.local {
found = (v == cur)
if found {
break
}
}
if !found {
add = append(add, cur)
}
}
return
}
func cmd(args ...string) *exec.Cmd {
if len(args) == 0 {
log.Fatalf("exec.Cmd(%#v) invalid; need argv[0]", args)
}
return exec.Command(args[0], args[1:]...)
}
func (r *userspaceBSDRouter) Up() error {
ifup := []string{"ifconfig", r.tunname, "up"}
if out, err := cmd(ifup...).CombinedOutput(); err != nil {
r.logf("running ifconfig failed: %v\n%s", err, out)
return err
}
return nil
}
func inet(p netaddr.IPPrefix) string {
if p.IP().Is6() {
return "inet6"
}
return "inet"
}
func (r *userspaceBSDRouter) Set(cfg *Config) (reterr error) {
if cfg == nil {
cfg = &shutdownConfig
}
var errq error
setErr := func(err error) {
if errq == nil {
errq = err
}
}
// Update the addresses.
for _, addr := range r.addrsToRemove(cfg.LocalAddrs) {
arg := []string{"ifconfig", r.tunname, inet(addr), addr.String(), "-alias"}
out, err := cmd(arg...).CombinedOutput()
if err != nil {
r.logf("addr del failed: %v => %v\n%s", arg, err, out)
setErr(err)
}
}
for _, addr := range r.addrsToAdd(cfg.LocalAddrs) {
var arg []string
if runtime.GOOS == "freebsd" && addr.IP().Is6() && addr.Bits() == 128 {
// FreeBSD rejects tun addresses of the form fc00::1/128 -> fc00::1,
// https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=218508
// Instead add our whole /48, which works because we use a /48 route.
// Full history: https://github.com/tailscale/tailscale/issues/1307
tmp := netaddr.IPPrefixFrom(addr.IP(), 48)
arg = []string{"ifconfig", r.tunname, inet(tmp), tmp.String()}
} else {
arg = []string{"ifconfig", r.tunname, inet(addr), addr.String(), addr.IP().String()}
}
out, err := cmd(arg...).CombinedOutput()
if err != nil {
r.logf("addr add failed: %v => %v\n%s", arg, err, out)
setErr(err)
}
}
newRoutes := make(map[netaddr.IPPrefix]struct{})
for _, route := range cfg.Routes {
if runtime.GOOS != "darwin" && route == tsaddr.TailscaleULARange() {
// Because we added the interface address as a /48 above,
// the kernel already created the Tailscale ULA route
// implicitly. We mustn't try to add/delete it ourselves.
continue
}
newRoutes[route] = struct{}{}
}
// Delete any pre-existing routes.
for route := range r.routes {
if _, keep := newRoutes[route]; !keep {
net := route.IPNet()
nip := net.IP.Mask(net.Mask)
nstr := fmt.Sprintf("%v/%d", nip, route.Bits())
del := "del"
if version.OS() == "macOS" {
del = "delete"
}
routedel := []string{"route", "-q", "-n",
del, "-" + inet(route), nstr,
"-iface", r.tunname}
out, err := cmd(routedel...).CombinedOutput()
if err != nil {
r.logf("route del failed: %v: %v\n%s", routedel, err, out)
setErr(err)
}
}
}
// Add the routes.
for route := range newRoutes {
if _, exists := r.routes[route]; !exists {
net := route.IPNet()
nip := net.IP.Mask(net.Mask)
nstr := fmt.Sprintf("%v/%d", nip, route.Bits())
routeadd := []string{"route", "-q", "-n",
"add", "-" + inet(route), nstr,
"-iface", r.tunname}
out, err := cmd(routeadd...).CombinedOutput()
if err != nil {
r.logf("addr add failed: %v: %v\n%s", routeadd, err, out)
setErr(err)
}
}
}
// Store the interface and routes so we know what to change on an update.
if errq == nil {
r.local = append([]netaddr.IPPrefix{}, cfg.LocalAddrs...)
}
r.routes = newRoutes
return errq
}
func (r *userspaceBSDRouter) Close() error {
return nil
}