tailscale/ipn/prefs.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.
package ipn
import (
"encoding/json"
"fmt"
"io/ioutil"
"log"
"os"
"path/filepath"
"github.com/tailscale/wireguard-go/wgcfg"
"tailscale.com/atomicfile"
"tailscale.com/control/controlclient"
)
// Prefs are the user modifiable settings of the Tailscale node agent.
type Prefs struct {
// ControlURL is the URL of the control server to use.
ControlURL string
// RouteAll specifies whether to accept subnet and default routes
// advertised by other nodes on the Tailscale network.
RouteAll bool
// AllowSingleHosts specifies whether to install routes for each
// node IP on the tailscale network, in addition to a route for
// the whole network.
//
// TODO(danderson): why do we have this? It dumps a lot of stuff
// into the routing table, and a single network route _should_ be
// all that we need. But when I turn this off in my tailscaled,
// packets stop flowing. What's up with that?
AllowSingleHosts bool
// CorpDNS specifies whether to install the Tailscale network's
// DNS configuration, if it exists.
CorpDNS bool
// WantRunning indicates whether networking should be active on
// this node.
WantRunning bool
// UsePacketFilter indicates whether to enforce centralized ACLs
// on this node. If false, all traffic in and out of this node is
// allowed.
UsePacketFilter bool
// AdvertiseRoutes specifies CIDR prefixes to advertise into the
// Tailscale network as reachable through the current node.
AdvertiseRoutes []wgcfg.CIDR
// NotepadURLs is a debugging setting that opens OAuth URLs in
// notepad.exe on Windows, rather than loading them in a browser.
//
// TODO(danderson): remove?
NotepadURLs bool
// The Persist field is named 'Config' in the file for backward
// compatibility with earlier versions.
// TODO(apenwarr): We should move this out of here, it's not a pref.
// We can maybe do that once we're sure which module should persist
// it (backend or frontend?)
Persist *controlclient.Persist `json:"Config"`
}
// IsEmpty reports whether p is nil or pointing to a Prefs zero value.
func (p *Prefs) IsEmpty() bool { return p == nil || p.Equals(&Prefs{}) }
func (p *Prefs) Pretty() string {
var pp string
if p.Persist != nil {
pp = p.Persist.Pretty()
} else {
pp = "Persist=nil"
}
return fmt.Sprintf("Prefs{ra=%v mesh=%v dns=%v want=%v notepad=%v pf=%v routes=%v %v}",
p.RouteAll, p.AllowSingleHosts, p.CorpDNS, p.WantRunning,
p.NotepadURLs, p.UsePacketFilter, p.AdvertiseRoutes, pp)
}
func (p *Prefs) ToBytes() []byte {
data, err := json.MarshalIndent(p, "", "\t")
if err != nil {
log.Fatalf("Prefs marshal: %v\n", err)
}
return data
}
func (p *Prefs) Equals(p2 *Prefs) bool {
if p == nil && p2 == nil {
return true
}
if p == nil || p2 == nil {
return false
}
return p != nil && p2 != nil &&
p.ControlURL == p2.ControlURL &&
p.RouteAll == p2.RouteAll &&
p.AllowSingleHosts == p2.AllowSingleHosts &&
p.CorpDNS == p2.CorpDNS &&
p.WantRunning == p2.WantRunning &&
p.NotepadURLs == p2.NotepadURLs &&
p.UsePacketFilter == p2.UsePacketFilter &&
compareIPNets(p.AdvertiseRoutes, p2.AdvertiseRoutes) &&
p.Persist.Equals(p2.Persist)
}
func compareIPNets(a, b []wgcfg.CIDR) bool {
if len(a) != len(b) {
return false
}
for i := range a {
if !a[i].IP.Equal(&b[i].IP) || a[i].Mask != b[i].Mask {
return false
}
}
return true
}
func NewPrefs() *Prefs {
return &Prefs{
// Provide default values for options which might be missing
// from the json data for any reason. The json can still
// override them to false.
ControlURL: "https://login.tailscale.com",
RouteAll: true,
AllowSingleHosts: true,
CorpDNS: true,
WantRunning: true,
UsePacketFilter: true,
}
}
// PrefsFromBytes deserializes Prefs from a JSON blob. If
// enforceDefaults is true, Prefs.RouteAll and Prefs.AllowSingleHosts
// are forced on.
func PrefsFromBytes(b []byte, enforceDefaults bool) (*Prefs, error) {
p := NewPrefs()
if len(b) == 0 {
return p, nil
}
persist := &controlclient.Persist{}
err := json.Unmarshal(b, persist)
if err == nil && (persist.Provider != "" || persist.LoginName != "") {
// old-style relaynode config; import it
p.Persist = persist
} else {
err = json.Unmarshal(b, &p)
if err != nil {
log.Printf("Prefs parse: %v: %v\n", err, b)
}
}
if enforceDefaults {
p.RouteAll = true
p.AllowSingleHosts = true
}
return p, err
}
// Clone returns a deep copy of p.
func (p *Prefs) Clone() *Prefs {
// TODO: write a faster/non-Fatal-y Clone implementation?
p2, err := PrefsFromBytes(p.ToBytes(), false)
if err != nil {
log.Fatalf("Prefs was uncopyable: %v\n", err)
}
return p2
}
// LoadLegacyPrefs loads a legacy relaynode config file into Prefs
// with sensible migration defaults set. If enforceDefaults is true,
// Prefs.RouteAll and Prefs.AllowSingleHosts are forced on.
func LoadPrefs(filename string, enforceDefaults bool) (*Prefs, error) {
data, err := ioutil.ReadFile(filename)
if err != nil {
return nil, fmt.Errorf("loading prefs from %q: %v", filename, err)
}
p, err := PrefsFromBytes(data, false)
if err != nil {
return nil, fmt.Errorf("decoding prefs in %q: %v", filename, err)
}
return p, nil
}
func SavePrefs(filename string, p *Prefs) {
log.Printf("Saving prefs %v %v\n", filename, p.Pretty())
data := p.ToBytes()
os.MkdirAll(filepath.Dir(filename), 0700)
if err := atomicfile.WriteFile(filename, data, 0666); err != nil {
log.Printf("SavePrefs: %v\n", err)
}
}