1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
|
// Copyright (c) Tailscale Inc & contributors
// SPDX-License-Identifier: BSD-3-Clause
package dns
import (
"context"
"errors"
"fmt"
"io/fs"
"net/netip"
"os"
"path/filepath"
"strings"
"syscall"
"testing"
qt "github.com/frankban/quicktest"
"tailscale.com/util/dnsname"
)
func TestDirectManager(t *testing.T) {
tmp := t.TempDir()
if err := os.MkdirAll(filepath.Join(tmp, "etc"), 0700); err != nil {
t.Fatal(err)
}
testDirect(t, directFS{prefix: tmp})
}
type boundResolvConfFS struct {
directFS
}
func (fs boundResolvConfFS) Rename(old, new string) error {
if old == "/etc/resolv.conf" || new == "/etc/resolv.conf" {
return errors.New("cannot move to/from /etc/resolv.conf")
}
return fs.directFS.Rename(old, new)
}
func (fs boundResolvConfFS) Remove(name string) error {
if name == "/etc/resolv.conf" {
return errors.New("cannot remove /etc/resolv.conf")
}
return fs.directFS.Remove(name)
}
func TestDirectBrokenRename(t *testing.T) {
tmp := t.TempDir()
if err := os.MkdirAll(filepath.Join(tmp, "etc"), 0700); err != nil {
t.Fatal(err)
}
testDirect(t, boundResolvConfFS{directFS{prefix: tmp}})
}
func testDirect(t *testing.T, fs wholeFileFS) {
const orig = "nameserver 9.9.9.9 # orig"
resolvPath := "/etc/resolv.conf"
backupPath := "/etc/resolv.pre-tailscale-backup.conf"
if err := fs.WriteFile(resolvPath, []byte(orig), 0644); err != nil {
t.Fatal(err)
}
readFile := func(t *testing.T, path string) string {
t.Helper()
b, err := fs.ReadFile(path)
if err != nil {
t.Fatal(err)
}
return string(b)
}
assertBaseState := func(t *testing.T) {
if got := readFile(t, resolvPath); got != orig {
t.Fatalf("resolv.conf:\n%s, want:\n%s", got, orig)
}
if _, err := fs.Stat(backupPath); !os.IsNotExist(err) {
t.Fatalf("resolv.conf backup: want it to be gone but: %v", err)
}
}
ctx, cancel := context.WithCancel(context.Background())
defer cancel()
m := directManager{logf: t.Logf, fs: fs, ctx: ctx, ctxClose: cancel}
if err := m.SetDNS(OSConfig{
Nameservers: []netip.Addr{netip.MustParseAddr("8.8.8.8"), netip.MustParseAddr("8.8.4.4")},
SearchDomains: []dnsname.FQDN{"ts.net.", "ts-dns.test."},
MatchDomains: []dnsname.FQDN{"ignored."},
}); err != nil {
t.Fatal(err)
}
want := `# resolv.conf(5) file generated by tailscale
# For more info, see https://tailscale.com/s/resolvconf-overwrite
# DO NOT EDIT THIS FILE BY HAND -- CHANGES WILL BE OVERWRITTEN
nameserver 8.8.8.8
nameserver 8.8.4.4
search ts.net ts-dns.test
`
if got := readFile(t, resolvPath); got != want {
t.Fatalf("resolv.conf:\n%s, want:\n%s", got, want)
}
if got := readFile(t, backupPath); got != orig {
t.Fatalf("resolv.conf backup:\n%s, want:\n%s", got, orig)
}
// Test that a nil OSConfig cleans up resolv.conf.
if err := m.SetDNS(OSConfig{}); err != nil {
t.Fatal(err)
}
assertBaseState(t)
// Test that Close cleans up resolv.conf.
if err := m.SetDNS(OSConfig{Nameservers: []netip.Addr{netip.MustParseAddr("8.8.8.8")}}); err != nil {
t.Fatal(err)
}
if err := m.Close(); err != nil {
t.Fatal(err)
}
assertBaseState(t)
}
type brokenRemoveFS struct {
directFS
}
func (b brokenRemoveFS) Rename(old, new string) error {
return errors.New("nyaaah I'm a silly container!")
}
func (b brokenRemoveFS) Remove(name string) error {
if strings.Contains(name, "/etc/resolv.conf") {
return fmt.Errorf("Faking remove failure: %q", &fs.PathError{Err: syscall.EBUSY})
}
return b.directFS.Remove(name)
}
func TestDirectBrokenRemove(t *testing.T) {
tmp := t.TempDir()
if err := os.MkdirAll(filepath.Join(tmp, "etc"), 0700); err != nil {
t.Fatal(err)
}
testDirect(t, brokenRemoveFS{directFS{prefix: tmp}})
}
func TestReadResolve(t *testing.T) {
c := qt.New(t)
tests := []struct {
in string
want OSConfig
wantErr bool
}{
{in: `nameserver 192.168.0.100`,
want: OSConfig{
Nameservers: []netip.Addr{
netip.MustParseAddr("192.168.0.100"),
},
},
},
{in: `nameserver 192.168.0.100 # comment`,
want: OSConfig{
Nameservers: []netip.Addr{
netip.MustParseAddr("192.168.0.100"),
},
},
},
{in: `nameserver 192.168.0.100#`,
want: OSConfig{
Nameservers: []netip.Addr{
netip.MustParseAddr("192.168.0.100"),
},
},
},
{in: `nameserver #192.168.0.100`, wantErr: true},
{in: `nameserver`, wantErr: true},
{in: `# nameserver 192.168.0.100`, want: OSConfig{}},
{in: `nameserver192.168.0.100`, wantErr: true},
{in: `search tailscale.com`,
want: OSConfig{
SearchDomains: []dnsname.FQDN{"tailscale.com."},
},
},
{in: `search tailscale.com # comment`,
want: OSConfig{
SearchDomains: []dnsname.FQDN{"tailscale.com."},
},
},
{in: `searchtailscale.com`, wantErr: true},
{in: `search`, wantErr: true},
}
for _, test := range tests {
cfg, err := readResolv(strings.NewReader(test.in))
if test.wantErr {
c.Assert(err, qt.IsNotNil)
} else {
c.Assert(err, qt.IsNil)
}
c.Assert(cfg, qt.DeepEquals, test.want)
}
}
|
