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tailscale/wgengine/router_bsd.go

179 lines
4.7 KiB
Go

// 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.
// +build openbsd freebsd
package wgengine
import (
"fmt"
"log"
"net"
"os/exec"
"github.com/tailscale/wireguard-go/device"
"github.com/tailscale/wireguard-go/tun"
"github.com/tailscale/wireguard-go/wgcfg"
"tailscale.com/logger"
)
// For now this router only supports the userspace WireGuard implementations.
//
// There is an experimental kernel version in the works:
// https://git.zx2c4.com/wireguard-openbsd.
//
// TODO(mbaillie): netlink-style monitoring might be possible through
// `ifstated(8)`/`devd(8)`, or become possible with the OpenBSD kernel
// implementation. This merits further investigation.
type bsdRouter struct {
logf logger.Logf
tunname string
local wgcfg.CIDR
routes map[wgcfg.CIDR]struct{}
}
func NewUserspaceRouter(logf logger.Logf, tunname string, _ *device.Device, tuntap tun.Device, _ func()) Router {
r := bsdRouter{
logf: logf,
tunname: tunname,
}
return &r
}
// TODO(mbaillie): extract as identical to linux version
func cmd(args ...string) *exec.Cmd {
if len(args) == 0 {
log.Fatalf("exec.Cmd(%#v) invalid; need argv[0]\n", args)
}
return exec.Command(args[0], args[1:]...)
}
func (r *bsdRouter) 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 (r *bsdRouter) SetRoutes(rs RouteSettings) error {
var errq error
if rs.LocalAddr != r.local {
if r.local != (wgcfg.CIDR{}) {
addrdel := []string{"ifconfig", r.tunname,
"inet", r.local.String(), "-alias"}
out, err := cmd(addrdel...).CombinedOutput()
if err != nil {
r.logf("addr del failed: %v: %v\n%s", addrdel, err, out)
if errq == nil {
errq = err
}
}
routedel := []string{"route", "-q", "-n",
"del", "-inet", r.local.String(),
"-iface", r.local.IP.String()}
if out, err := cmd(routedel...).CombinedOutput(); err != nil {
r.logf("route del failed: %v: %v\n%s", routedel, err, out)
if errq == nil {
errq = err
}
}
}
addradd := []string{"ifconfig", r.tunname,
"inet", rs.LocalAddr.String(), "alias"}
out, err := cmd(addradd...).CombinedOutput()
if err != nil {
r.logf("addr add failed: %v: %v\n%s", addradd, err, out)
if errq == nil {
errq = err
}
}
routeadd := []string{"route", "-q", "-n",
"add", "-inet", rs.LocalAddr.String(),
"-iface", rs.LocalAddr.IP.String()}
if out, err := cmd(routeadd...).CombinedOutput(); err != nil {
r.logf("route add failed: %v: %v\n%s", routeadd, err, out)
if errq == nil {
errq = err
}
}
}
newRoutes := make(map[wgcfg.CIDR]struct{})
for _, peer := range rs.Cfg.Peers {
for _, route := range peer.AllowedIPs {
newRoutes[route] = struct{}{}
}
}
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.Mask)
routedel := []string{"route", "-q", "-n",
"del", "-inet", nstr,
"-iface", rs.LocalAddr.IP.String()}
out, err := cmd(routedel...).CombinedOutput()
if err != nil {
r.logf("route del failed: %v: %v\n%s", routedel, err, out)
if errq == nil {
errq = err
}
}
}
}
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.Mask)
routeadd := []string{"route", "-q", "-n",
"add", "-inet", nstr,
"-iface", rs.LocalAddr.IP.String()}
out, err := cmd(routeadd...).CombinedOutput()
if err != nil {
r.logf("addr add failed: %v: %v\n%s", routeadd, err, out)
if errq == nil {
errq = err
}
}
}
}
r.local = rs.LocalAddr
r.routes = newRoutes
if err := r.replaceResolvConf(rs.DNS, rs.DNSDomains); err != nil {
errq = fmt.Errorf("replacing resolv.conf failed: %v", err)
}
return errq
}
func (r *bsdRouter) Close() error {
out, err := cmd("ifconfig", r.tunname, "down").CombinedOutput()
if err != nil {
r.logf("running ifconfig failed: %v\n%s", err, out)
}
if err := r.restoreResolvConf(); err != nil {
r.logf("failed to restore system resolv.conf: %v", err)
}
// TODO(mbaillie): wipe routes
return nil
}
// TODO(mbaillie): these are no-ops for now. They could re-use the Linux funcs
// (sans systemd parts), but I note Linux DNS is disabled(?) so leaving for now.
func (r *bsdRouter) replaceResolvConf(_ []net.IP, _ []string) error { return nil }
func (r *bsdRouter) restoreResolvConf() error { return nil }