/
stream_dialer.go
333 lines (303 loc) · 10.6 KB
/
stream_dialer.go
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
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
// Copyright 2023 Jigsaw Operations LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package smart
import (
"context"
"crypto/tls"
"encoding/json"
"errors"
"fmt"
"io"
"net"
"net/url"
"sync"
"time"
"github.com/Jigsaw-Code/outline-sdk/dns"
"github.com/Jigsaw-Code/outline-sdk/transport"
"github.com/Jigsaw-Code/outline-sdk/x/config"
)
// To test one strategy:
// go run ./x/examples/smart-proxy -v -localAddr=localhost:1080 --transport="" --domain www.rferl.org --config=<(echo '{"dns": [{"https": {"name": "doh.sb"}}]}')
type StrategyFinder struct {
TestTimeout time.Duration
LogWriter io.Writer
StreamDialer transport.StreamDialer
PacketDialer transport.PacketDialer
logMu sync.Mutex
}
func (f *StrategyFinder) log(format string, a ...any) {
if f.LogWriter != nil {
f.logMu.Lock()
defer f.logMu.Unlock()
fmt.Fprintf(f.LogWriter, format, a...)
}
}
// Only log if context is not done
func (f *StrategyFinder) logCtx(ctx context.Context, format string, a ...any) {
if ctx != nil {
select {
case <-ctx.Done():
return
default:
}
}
f.log(format, a...)
}
type httpsEntryJSON struct {
// Domain name of the host.
Name string `json:"name,omitempty"`
// Host:port. Defaults to Name:443.
Address string `json:"address,omitempty"`
}
type tlsEntryJSON struct {
// Domain name of the host.
Name string `json:"name,omitempty"`
// Host:port. Defaults to Name:853.
Address string `json:"address,omitempty"`
}
type udpEntryJSON struct {
// Host:port.
Address string `json:"address,omitempty"`
}
type tcpEntryJSON struct {
// Host:port.
Address string `json:"address,omitempty"`
}
type dnsEntryJSON struct {
System *struct{} `json:"system,omitempty"`
HTTPS *httpsEntryJSON `json:"https,omitempty"`
TLS *tlsEntryJSON `json:"tls,omitempty"`
UDP *udpEntryJSON `json:"udp,omitempty"`
TCP *tcpEntryJSON `json:"tcp,omitempty"`
}
type configJSON struct {
DNS []dnsEntryJSON `json:"dns,omitempty"`
TLS []string `json:"tls,omitempty"`
}
// newDNSResolverFromEntry creates a [dns.Resolver] based on the config, returning the resolver and
// a boolean indicating whether the resolver is secure (TLS, HTTPS) and a possible error.
func (f *StrategyFinder) newDNSResolverFromEntry(entry dnsEntryJSON) (dns.Resolver, bool, error) {
if entry.System != nil {
return nil, false, nil
} else if cfg := entry.HTTPS; cfg != nil {
if cfg.Name == "" {
return nil, true, errors.New("https entry has empty server name")
}
serverAddr := cfg.Address
if serverAddr == "" {
serverAddr = cfg.Name
}
_, port, err := net.SplitHostPort(serverAddr)
if err != nil {
serverAddr = net.JoinHostPort(serverAddr, "443")
port = "443"
}
dohURL := url.URL{Scheme: "https", Host: net.JoinHostPort(cfg.Name, port), Path: "/dns-query"}
return dns.NewHTTPSResolver(f.StreamDialer, serverAddr, dohURL.String()), true, nil
} else if cfg := entry.TLS; cfg != nil {
if cfg.Name == "" {
return nil, true, errors.New("tls entry has empty server name")
}
serverAddr := cfg.Address
if serverAddr == "" {
serverAddr = cfg.Name
}
_, _, err := net.SplitHostPort(serverAddr)
if err != nil {
serverAddr = net.JoinHostPort(serverAddr, "853")
}
return dns.NewTLSResolver(f.StreamDialer, serverAddr, cfg.Name), true, nil
} else if cfg := entry.TCP; cfg != nil {
if cfg.Address == "" {
return nil, false, errors.New("tcp entry has empty server address")
}
host, port, err := net.SplitHostPort(cfg.Address)
if err != nil {
host = cfg.Address
port = "53"
}
serverAddr := net.JoinHostPort(host, port)
return dns.NewTCPResolver(f.StreamDialer, serverAddr), false, nil
} else if cfg := entry.UDP; cfg != nil {
if cfg.Address == "" {
return nil, false, errors.New("udp entry has empty server address")
}
host, port, err := net.SplitHostPort(cfg.Address)
if err != nil {
host = cfg.Address
port = "53"
}
serverAddr := net.JoinHostPort(host, port)
return dns.NewUDPResolver(f.PacketDialer, serverAddr), false, nil
} else {
return nil, false, errors.New("invalid DNS entry")
}
}
type smartResolver struct {
dns.Resolver
ID string
Secure bool
}
func (f *StrategyFinder) dnsConfigToResolver(dnsConfig []dnsEntryJSON) ([]*smartResolver, error) {
if len(dnsConfig) == 0 {
return nil, errors.New("no DNS config entry")
}
rts := make([]*smartResolver, 0, len(dnsConfig))
for ei, entry := range dnsConfig {
idBytes, err := json.Marshal(entry)
if err != nil {
return nil, fmt.Errorf("cannot serialize entry %v: %w", ei, err)
}
id := string(idBytes)
resolver, isSecure, err := f.newDNSResolverFromEntry(entry)
if err != nil {
return nil, fmt.Errorf("failed to process entry %v: %w", ei, err)
}
rts = append(rts, &smartResolver{Resolver: resolver, ID: id, Secure: isSecure})
}
return rts, nil
}
func (f *StrategyFinder) findDNS(ctx context.Context, testDomains []string, dnsConfig []dnsEntryJSON) (dns.Resolver, error) {
resolvers, err := f.dnsConfigToResolver(dnsConfig)
if err != nil {
return nil, err
}
ctx, searchDone := context.WithCancel(ctx)
defer searchDone()
raceStart := time.Now()
resolver, err := raceTests(ctx, 250*time.Millisecond, resolvers, func(resolver *smartResolver) (*smartResolver, error) {
for _, testDomain := range testDomains {
select {
case <-ctx.Done():
return nil, ctx.Err()
default:
}
f.logCtx(ctx, "🏃 run DNS: %v (domain: %v)\n", resolver.ID, testDomain)
startTime := time.Now()
ips, err := testDNSResolver(ctx, f.TestTimeout, resolver, testDomain)
duration := time.Since(startTime)
status := "ok ✅"
if err != nil {
status = fmt.Sprintf("%v ❌", err)
}
// Only output log if the search is not done yet.
f.logCtx(ctx, "🏁 got DNS: %v (domain: %v), duration=%v, ips=%v, status=%v\n", resolver.ID, testDomain, duration, ips, status)
if err != nil {
return nil, err
}
}
return resolver, nil
})
if err != nil {
return nil, fmt.Errorf("could not find working resolver: %w", err)
}
f.log("🏆 selected DNS resolver %v in %0.2fs\n\n", resolver.ID, time.Since(raceStart).Seconds())
return resolver.Resolver, nil
}
var configParser = config.NewDefaultConfigParser()
func (f *StrategyFinder) findTLS(ctx context.Context, testDomains []string, baseDialer transport.StreamDialer, tlsConfig []string) (transport.StreamDialer, error) {
if len(tlsConfig) == 0 {
return nil, errors.New("config for TLS is empty. Please specify at least one transport")
}
ctx, searchDone := context.WithCancel(ctx)
defer searchDone()
raceStart := time.Now()
type SearchResult struct {
Dialer transport.StreamDialer
Config string
}
result, err := raceTests(ctx, 250*time.Millisecond, tlsConfig, func(transportCfg string) (*SearchResult, error) {
tlsDialer, err := configParser.WrapStreamDialer(baseDialer, transportCfg)
if err != nil {
return nil, fmt.Errorf("WrapStreamDialer failed: %w", err)
}
for _, testDomain := range testDomains {
startTime := time.Now()
testAddr := net.JoinHostPort(testDomain, "443")
f.logCtx(ctx, "🏃 run TLS: '%v' (domain: %v)\n", transportCfg, testDomain)
ctx, cancel := context.WithTimeout(ctx, f.TestTimeout)
defer cancel()
testConn, err := tlsDialer.DialStream(ctx, testAddr)
if err != nil {
f.logCtx(ctx, "🏁 got TLS: '%v' (domain: %v), duration=%v, dial_error=%v ❌\n", transportCfg, testDomain, time.Since(startTime), err)
return nil, err
}
tlsConn := tls.Client(testConn, &tls.Config{ServerName: testDomain})
err = tlsConn.HandshakeContext(ctx)
tlsConn.Close()
if err != nil {
f.logCtx(ctx, "🏁 got TLS: '%v' (domain: %v), duration=%v, handshake=%v ❌\n", transportCfg, testDomain, time.Since(startTime), err)
return nil, err
}
f.logCtx(ctx, "🏁 got TLS: '%v' (domain: %v), duration=%v, status=ok ✅\n", transportCfg, testDomain, time.Since(startTime))
}
return &SearchResult{tlsDialer, transportCfg}, nil
})
if err != nil {
return nil, fmt.Errorf("could not find TLS strategy: %w", err)
}
f.log("🏆 selected TLS strategy '%v' in %0.2fs\n\n", result.Config, time.Since(raceStart).Seconds())
tlsDialer := result.Dialer
return transport.FuncStreamDialer(func(ctx context.Context, raddr string) (transport.StreamConn, error) {
_, portStr, err := net.SplitHostPort(raddr)
if err != nil {
return nil, fmt.Errorf("failed to parse address: %w", err)
}
portNum, err := net.DefaultResolver.LookupPort(ctx, "tcp", portStr)
if err != nil {
return nil, fmt.Errorf("could not resolve port: %w", err)
}
selectedDialer := baseDialer
if portNum == 443 || portNum == 853 {
selectedDialer = tlsDialer
}
return selectedDialer.DialStream(ctx, raddr)
}), nil
}
// NewDialer uses the config in configBytes to search for a strategy that unblocks DNS and TLS for all of the testDomains, returning a dialer with the found strategy.
// It returns an error if no strategy was found that unblocks the testDomains.
// The testDomains must be domains with a TLS service running on port 443.
func (f *StrategyFinder) NewDialer(ctx context.Context, testDomains []string, configBytes []byte) (transport.StreamDialer, error) {
var parsedConfig configJSON
err := json.Unmarshal(configBytes, &parsedConfig)
if err != nil {
return nil, fmt.Errorf("failed to parse config: %v", err)
}
// Make domain fully-qualified to prevent confusing domain search.
testDomains = append(make([]string, 0, len(testDomains)), testDomains...)
for di, domain := range testDomains {
testDomains[di] = makeFullyQualified(domain)
}
resolver, err := f.findDNS(ctx, testDomains, parsedConfig.DNS)
if err != nil {
return nil, err
}
var dnsDialer transport.StreamDialer
if resolver == nil {
if _, ok := f.StreamDialer.(*transport.TCPDialer); !ok {
return nil, fmt.Errorf("cannot use system resolver with base dialer of type %T", f.StreamDialer)
}
dnsDialer = f.StreamDialer
} else {
resolver = newSimpleLRUCacheResolver(resolver, 100)
dnsDialer, err = dns.NewStreamDialer(resolver, f.StreamDialer)
if err != nil {
return nil, fmt.Errorf("dns.NewStreamDialer failed: %w", err)
}
}
if len(parsedConfig.TLS) == 0 {
return dnsDialer, nil
}
return f.findTLS(ctx, testDomains, dnsDialer, parsedConfig.TLS)
}