types/persist: split controlclient.Persist into a small leaf package

This one alone doesn't modify the global dependency map much
(depaware.txt if anything looks slightly worse), but it leave
controlclient as only containing NetworkMap:

bradfitz@tsdev:~/src/tailscale.com/ipn$ grep -F "controlclient." *.go
backend.go:     NetMap        *controlclient.NetworkMap // new netmap received
fake_test.go:   b.notify(Notify{NetMap: &controlclient.NetworkMap{}})
fake_test.go:   b.notify(Notify{NetMap: &controlclient.NetworkMap{}})
handle.go:      netmapCache       *controlclient.NetworkMap
handle.go:func (h *Handle) NetMap() *controlclient.NetworkMap {

Once that goes into a leaf package, then ipn doesn't depend on
controlclient at all, and then the client gets smaller.

Updates #1278

types/persist/persist.go

@@ -0,0 +1,73 @@
+// Copyright (c) 2021 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 persist contains the Persist type.
+package persist
+
+import (
+	"fmt"
+
+	"tailscale.com/types/structs"
+	"tailscale.com/types/wgkey"
+)
+
+//go:generate go run tailscale.com/cmd/cloner -type=Persist -output=persist_clone.go
+
+// Persist is the JSON type stored on disk on nodes to remember their
+// settings between runs.
+type Persist struct {
+	_ structs.Incomparable
+
+	// LegacyFrontendPrivateMachineKey is here temporarily
+	// (starting 2020-09-28) during migration of Windows users'
+	// machine keys from frontend storage to the backend. On the
+	// first LocalBackend.Start call, the backend will initialize
+	// the real (backend-owned) machine key from the frontend's
+	// provided value (if non-zero), picking a new random one if
+	// needed. This field should be considered read-only from GUI
+	// frontends. The real value should not be written back in
+	// this field, lest the frontend persist it to disk.
+	LegacyFrontendPrivateMachineKey wgkey.Private `json:"PrivateMachineKey"`
+
+	PrivateNodeKey    wgkey.Private
+	OldPrivateNodeKey wgkey.Private // needed to request key rotation
+	Provider          string
+	LoginName         string
+}
+
+func (p *Persist) Equals(p2 *Persist) bool {
+	if p == nil && p2 == nil {
+		return true
+	}
+	if p == nil || p2 == nil {
+		return false
+	}
+
+	return p.LegacyFrontendPrivateMachineKey.Equal(p2.LegacyFrontendPrivateMachineKey) &&
+		p.PrivateNodeKey.Equal(p2.PrivateNodeKey) &&
+		p.OldPrivateNodeKey.Equal(p2.OldPrivateNodeKey) &&
+		p.Provider == p2.Provider &&
+		p.LoginName == p2.LoginName
+}
+
+func (p *Persist) Pretty() string {
+	var mk, ok, nk wgkey.Key
+	if !p.LegacyFrontendPrivateMachineKey.IsZero() {
+		mk = p.LegacyFrontendPrivateMachineKey.Public()
+	}
+	if !p.OldPrivateNodeKey.IsZero() {
+		ok = p.OldPrivateNodeKey.Public()
+	}
+	if !p.PrivateNodeKey.IsZero() {
+		nk = p.PrivateNodeKey.Public()
+	}
+	ss := func(k wgkey.Key) string {
+		if k.IsZero() {
+			return ""
+		}
+		return k.ShortString()
+	}
+	return fmt.Sprintf("Persist{lm=%v, o=%v, n=%v u=%#v}",
+		ss(mk), ss(ok), ss(nk), p.LoginName)
+}

types/persist/persist_clone.go

@@ -0,0 +1,34 @@
+// 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.
+
+// Code generated by tailscale.com/cmd/cloner -type Persist; DO NOT EDIT.
+
+package persist
+
+import (
+	"tailscale.com/types/structs"
+	"tailscale.com/types/wgkey"
+)
+
+// Clone makes a deep copy of Persist.
+// The result aliases no memory with the original.
+func (src *Persist) Clone() *Persist {
+	if src == nil {
+		return nil
+	}
+	dst := new(Persist)
+	*dst = *src
+	return dst
+}
+
+// A compilation failure here means this code must be regenerated, with command:
+//   tailscale.com/cmd/cloner -type Persist
+var _PersistNeedsRegeneration = Persist(struct {
+	_                               structs.Incomparable
+	LegacyFrontendPrivateMachineKey wgkey.Private
+	PrivateNodeKey                  wgkey.Private
+	OldPrivateNodeKey               wgkey.Private
+	Provider                        string
+	LoginName                       string
+}{})

types/persist/persist_test.go

@@ -0,0 +1,107 @@
+// 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 persist
+
+import (
+	"reflect"
+	"testing"
+
+	"tailscale.com/types/wgkey"
+)
+
+func fieldsOf(t reflect.Type) (fields []string) {
+	for i := 0; i < t.NumField(); i++ {
+		if name := t.Field(i).Name; name != "_" {
+			fields = append(fields, name)
+		}
+	}
+	return
+}
+
+func TestPersistEqual(t *testing.T) {
+	persistHandles := []string{"LegacyFrontendPrivateMachineKey", "PrivateNodeKey", "OldPrivateNodeKey", "Provider", "LoginName"}
+	if have := fieldsOf(reflect.TypeOf(Persist{})); !reflect.DeepEqual(have, persistHandles) {
+		t.Errorf("Persist.Equal check might be out of sync\nfields: %q\nhandled: %q\n",
+			have, persistHandles)
+	}
+
+	newPrivate := func() wgkey.Private {
+		k, err := wgkey.NewPrivate()
+		if err != nil {
+			panic(err)
+		}
+		return k
+	}
+	k1 := newPrivate()
+	tests := []struct {
+		a, b *Persist
+		want bool
+	}{
+		{nil, nil, true},
+		{nil, &Persist{}, false},
+		{&Persist{}, nil, false},
+		{&Persist{}, &Persist{}, true},
+
+		{
+			&Persist{LegacyFrontendPrivateMachineKey: k1},
+			&Persist{LegacyFrontendPrivateMachineKey: newPrivate()},
+			false,
+		},
+		{
+			&Persist{LegacyFrontendPrivateMachineKey: k1},
+			&Persist{LegacyFrontendPrivateMachineKey: k1},
+			true,
+		},
+
+		{
+			&Persist{PrivateNodeKey: k1},
+			&Persist{PrivateNodeKey: newPrivate()},
+			false,
+		},
+		{
+			&Persist{PrivateNodeKey: k1},
+			&Persist{PrivateNodeKey: k1},
+			true,
+		},
+
+		{
+			&Persist{OldPrivateNodeKey: k1},
+			&Persist{OldPrivateNodeKey: newPrivate()},
+			false,
+		},
+		{
+			&Persist{OldPrivateNodeKey: k1},
+			&Persist{OldPrivateNodeKey: k1},
+			true,
+		},
+
+		{
+			&Persist{Provider: "google"},
+			&Persist{Provider: "o365"},
+			false,
+		},
+		{
+			&Persist{Provider: "google"},
+			&Persist{Provider: "google"},
+			true,
+		},
+
+		{
+			&Persist{LoginName: "foo@tailscale.com"},
+			&Persist{LoginName: "bar@tailscale.com"},
+			false,
+		},
+		{
+			&Persist{LoginName: "foo@tailscale.com"},
+			&Persist{LoginName: "foo@tailscale.com"},
+			true,
+		},
+	}
+	for i, test := range tests {
+		if got := test.a.Equals(test.b); got != test.want {
+			t.Errorf("%d. Equals = %v; want %v", i, got, test.want)
+		}
+	}
+}