-
Notifications
You must be signed in to change notification settings - Fork 1.3k
/
tsweb.go
575 lines (523 loc) · 17.4 KB
/
tsweb.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
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
// 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 tsweb contains code used in various Tailscale webservers.
package tsweb
import (
"bufio"
"bytes"
"context"
"errors"
"expvar"
"fmt"
"io"
"io/ioutil"
"net"
"net/http"
_ "net/http/pprof"
"os"
"path/filepath"
"reflect"
"runtime"
"strings"
"time"
"inet.af/netaddr"
"tailscale.com/envknob"
"tailscale.com/metrics"
"tailscale.com/net/tsaddr"
"tailscale.com/types/logger"
"tailscale.com/version"
)
func init() {
expvar.Publish("process_start_unix_time", expvar.Func(func() interface{} { return timeStart.Unix() }))
expvar.Publish("version", expvar.Func(func() interface{} { return version.Long }))
expvar.Publish("counter_uptime_sec", expvar.Func(func() interface{} { return int64(Uptime().Seconds()) }))
expvar.Publish("gauge_goroutines", expvar.Func(func() interface{} { return runtime.NumGoroutine() }))
}
// DevMode controls whether extra output in shown, for when the binary is being run in dev mode.
var DevMode bool
func DefaultCertDir(leafDir string) string {
cacheDir, err := os.UserCacheDir()
if err == nil {
return filepath.Join(cacheDir, "tailscale", leafDir)
}
return ""
}
// IsProd443 reports whether addr is a Go listen address for port 443.
func IsProd443(addr string) bool {
_, port, _ := net.SplitHostPort(addr)
return port == "443" || port == "https"
}
// AllowDebugAccess reports whether r should be permitted to access
// various debug endpoints.
func AllowDebugAccess(r *http.Request) bool {
if r.Header.Get("X-Forwarded-For") != "" {
// TODO if/when needed. For now, conservative:
return false
}
ipStr, _, err := net.SplitHostPort(r.RemoteAddr)
if err != nil {
return false
}
ip, err := netaddr.ParseIP(ipStr)
if err != nil {
return false
}
if tsaddr.IsTailscaleIP(ip) || ip.IsLoopback() || ipStr == envknob.String("TS_ALLOW_DEBUG_IP") {
return true
}
if r.Method == "GET" {
urlKey := r.FormValue("debugkey")
keyPath := envknob.String("TS_DEBUG_KEY_PATH")
if urlKey != "" && keyPath != "" {
slurp, err := ioutil.ReadFile(keyPath)
if err == nil && string(bytes.TrimSpace(slurp)) == urlKey {
return true
}
}
}
return false
}
// Protected wraps a provided debug handler, h, returning a Handler
// that enforces AllowDebugAccess and returns forbidden replies for
// unauthorized requests.
func Protected(h http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
if !AllowDebugAccess(r) {
msg := "debug access denied"
if DevMode {
ipStr, _, _ := net.SplitHostPort(r.RemoteAddr)
msg += fmt.Sprintf("; to permit access, set TS_ALLOW_DEBUG_IP=%v", ipStr)
}
http.Error(w, msg, http.StatusForbidden)
return
}
h.ServeHTTP(w, r)
})
}
var timeStart = time.Now()
func Uptime() time.Duration { return time.Since(timeStart).Round(time.Second) }
// Port80Handler is the handler to be given to
// autocert.Manager.HTTPHandler. The inner handler is the mux
// returned by NewMux containing registered /debug handlers.
type Port80Handler struct{ Main http.Handler }
func (h Port80Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
path := r.RequestURI
if path == "/debug" || strings.HasPrefix(path, "/debug") {
h.Main.ServeHTTP(w, r)
return
}
if r.Method != "GET" && r.Method != "HEAD" {
http.Error(w, "Use HTTPS", http.StatusBadRequest)
return
}
if path == "/" && AllowDebugAccess(r) {
// Redirect authorized user to the debug handler.
path = "/debug/"
}
target := "https://" + stripPort(r.Host) + path
http.Redirect(w, r, target, http.StatusFound)
}
func stripPort(hostport string) string {
host, _, err := net.SplitHostPort(hostport)
if err != nil {
return hostport
}
return net.JoinHostPort(host, "443")
}
// ReturnHandler is like net/http.Handler, but the handler can return an
// error instead of writing to its ResponseWriter.
type ReturnHandler interface {
// ServeHTTPReturn is like http.Handler.ServeHTTP, except that
// it can choose to return an error instead of writing to its
// http.ResponseWriter.
//
// If ServeHTTPReturn returns an error, it caller should handle
// an error by serving an HTTP 500 response to the user. The
// error details should not be sent to the client, as they may
// contain sensitive information. If the error is an
// HTTPError, though, callers should use the HTTP response
// code and message as the response to the client.
ServeHTTPReturn(http.ResponseWriter, *http.Request) error
}
type HandlerOptions struct {
Quiet200s bool // if set, do not log successfully handled HTTP requests
Logf logger.Logf
Now func() time.Time // if nil, defaults to time.Now
// If non-nil, StatusCodeCounters maintains counters
// of status codes for handled responses.
// The keys are "1xx", "2xx", "3xx", "4xx", and "5xx".
StatusCodeCounters *expvar.Map
}
// ReturnHandlerFunc is an adapter to allow the use of ordinary
// functions as ReturnHandlers. If f is a function with the
// appropriate signature, ReturnHandlerFunc(f) is a ReturnHandler that
// calls f.
type ReturnHandlerFunc func(http.ResponseWriter, *http.Request) error
// ServeHTTPReturn calls f(w, r).
func (f ReturnHandlerFunc) ServeHTTPReturn(w http.ResponseWriter, r *http.Request) error {
return f(w, r)
}
// StdHandler converts a ReturnHandler into a standard http.Handler.
// Handled requests are logged using opts.Logf, as are any errors.
// Errors are handled as specified by the Handler interface.
func StdHandler(h ReturnHandler, opts HandlerOptions) http.Handler {
if opts.Now == nil {
opts.Now = time.Now
}
if opts.Logf == nil {
opts.Logf = logger.Discard
}
return retHandler{h, opts}
}
// retHandler is an http.Handler that wraps a Handler and handles errors.
type retHandler struct {
rh ReturnHandler
opts HandlerOptions
}
// ServeHTTP implements the http.Handler interface.
func (h retHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
msg := AccessLogRecord{
When: h.opts.Now(),
RemoteAddr: r.RemoteAddr,
Proto: r.Proto,
TLS: r.TLS != nil,
Host: r.Host,
Method: r.Method,
RequestURI: r.URL.RequestURI(),
UserAgent: r.UserAgent(),
Referer: r.Referer(),
}
lw := &loggingResponseWriter{ResponseWriter: w, logf: h.opts.Logf}
err := h.rh.ServeHTTPReturn(lw, r)
hErr, hErrOK := err.(HTTPError)
if lw.code == 0 && err == nil && !lw.hijacked {
// If the handler didn't write and didn't send a header, that still means 200.
// (See https://play.golang.org/p/4P7nx_Tap7p)
lw.code = 200
}
msg.Seconds = h.opts.Now().Sub(msg.When).Seconds()
msg.Code = lw.code
msg.Bytes = lw.bytes
switch {
case lw.hijacked:
// Connection no longer belongs to us, just log that we
// switched protocols away from HTTP.
if msg.Code == 0 {
msg.Code = http.StatusSwitchingProtocols
}
case err != nil && r.Context().Err() == context.Canceled:
msg.Code = 499 // nginx convention: Client Closed Request
msg.Err = context.Canceled.Error()
case hErrOK:
// Handler asked us to send an error. Do so, if we haven't
// already sent a response.
msg.Err = hErr.Msg
if hErr.Err != nil {
if msg.Err == "" {
msg.Err = hErr.Err.Error()
} else {
msg.Err = msg.Err + ": " + hErr.Err.Error()
}
}
if lw.code != 0 {
h.opts.Logf("[unexpected] handler returned HTTPError %v, but already sent a response with code %d", hErr, lw.code)
break
}
msg.Code = hErr.Code
if msg.Code == 0 {
h.opts.Logf("[unexpected] HTTPError %v did not contain an HTTP status code, sending internal server error", hErr)
msg.Code = http.StatusInternalServerError
}
http.Error(lw, hErr.Msg, msg.Code)
case err != nil:
// Handler returned a generic error. Serve an internal server
// error, if necessary.
msg.Err = err.Error()
if lw.code == 0 {
msg.Code = http.StatusInternalServerError
http.Error(lw, "internal server error", msg.Code)
}
}
if msg.Code != 200 || !h.opts.Quiet200s {
h.opts.Logf("%s", msg)
}
if h.opts.StatusCodeCounters != nil {
key := fmt.Sprintf("%dxx", msg.Code/100)
h.opts.StatusCodeCounters.Add(key, 1)
}
}
// loggingResponseWriter wraps a ResponseWriter and record the HTTP
// response code that gets sent, if any.
type loggingResponseWriter struct {
http.ResponseWriter
code int
bytes int
hijacked bool
logf logger.Logf
}
// WriteHeader implements http.Handler.
func (l *loggingResponseWriter) WriteHeader(statusCode int) {
if l.code != 0 {
l.logf("[unexpected] HTTP handler set statusCode twice (%d and %d)", l.code, statusCode)
return
}
l.code = statusCode
l.ResponseWriter.WriteHeader(statusCode)
}
// Write implements http.Handler.
func (l *loggingResponseWriter) Write(bs []byte) (int, error) {
if l.code == 0 {
l.code = 200
}
n, err := l.ResponseWriter.Write(bs)
l.bytes += n
return n, err
}
// Hijack implements http.Hijacker. Note that hijacking can still fail
// because the wrapped ResponseWriter is not required to implement
// Hijacker, as this breaks HTTP/2.
func (l *loggingResponseWriter) Hijack() (net.Conn, *bufio.ReadWriter, error) {
h, ok := l.ResponseWriter.(http.Hijacker)
if !ok {
return nil, nil, errors.New("ResponseWriter is not a Hijacker")
}
conn, buf, err := h.Hijack()
if err == nil {
l.hijacked = true
}
return conn, buf, err
}
func (l loggingResponseWriter) Flush() {
f, _ := l.ResponseWriter.(http.Flusher)
if f == nil {
l.logf("[unexpected] tried to Flush a ResponseWriter that can't flush")
return
}
f.Flush()
}
// HTTPError is an error with embedded HTTP response information.
//
// It is the error type to be (optionally) used by Handler.ServeHTTPReturn.
type HTTPError struct {
Code int // HTTP response code to send to client; 0 means means 500
Msg string // Response body to send to client
Err error // Detailed error to log on the server
}
// Error implements the error interface.
func (e HTTPError) Error() string { return fmt.Sprintf("httperror{%d, %q, %v}", e.Code, e.Msg, e.Err) }
// Error returns an HTTPError containing the given information.
func Error(code int, msg string, err error) HTTPError {
return HTTPError{Code: code, Msg: msg, Err: err}
}
// WritePrometheusExpvar writes kv to w in Prometheus metrics format.
//
// See VarzHandler for conventions. This is exported primarily for
// people to test their varz.
func WritePrometheusExpvar(w io.Writer, kv expvar.KeyValue) {
writePromExpVar(w, "", kv)
}
func writePromExpVar(w io.Writer, prefix string, kv expvar.KeyValue) {
key := kv.Key
var typ string
var label string
switch {
case strings.HasPrefix(kv.Key, "gauge_"):
typ = "gauge"
key = strings.TrimPrefix(kv.Key, "gauge_")
case strings.HasPrefix(kv.Key, "counter_"):
typ = "counter"
key = strings.TrimPrefix(kv.Key, "counter_")
}
if strings.HasPrefix(key, "labelmap_") {
key = strings.TrimPrefix(key, "labelmap_")
if i := strings.Index(key, "_"); i != -1 {
label, key = key[:i], key[i+1:]
}
}
name := prefix + key
switch v := kv.Value.(type) {
case *expvar.Int:
if typ == "" {
typ = "counter"
}
fmt.Fprintf(w, "# TYPE %s %s\n%s %v\n", name, typ, name, v.Value())
return
case *metrics.Set:
v.Do(func(kv expvar.KeyValue) {
writePromExpVar(w, name+"_", kv)
})
return
case PrometheusMetricsReflectRooter:
root := v.PrometheusMetricsReflectRoot()
rv := reflect.ValueOf(root)
if rv.Type().Kind() == reflect.Ptr {
if rv.IsNil() {
return
}
rv = rv.Elem()
}
if rv.Type().Kind() != reflect.Struct {
fmt.Fprintf(w, "# skipping expvar %q; unknown root type\n", name)
return
}
foreachExportedStructField(rv, func(fieldOrJSONName, metricType string, rv reflect.Value) {
mname := name + "_" + fieldOrJSONName
switch rv.Kind() {
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
fmt.Fprintf(w, "# TYPE %s %s\n%s %v\n", mname, metricType, mname, rv.Int())
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
fmt.Fprintf(w, "# TYPE %s %s\n%s %v\n", mname, metricType, mname, rv.Uint())
case reflect.Float32, reflect.Float64:
fmt.Fprintf(w, "# TYPE %s %s\n%s %v\n", mname, metricType, mname, rv.Float())
case reflect.Struct:
if rv.CanAddr() {
// Slight optimization, not copying big structs if they're addressable:
writePromExpVar(w, name+"_", expvar.KeyValue{Key: fieldOrJSONName, Value: expVarPromStructRoot{rv.Addr().Interface()}})
} else {
writePromExpVar(w, name+"_", expvar.KeyValue{Key: fieldOrJSONName, Value: expVarPromStructRoot{rv.Interface()}})
}
}
return
})
return
}
if typ == "" {
var funcRet string
if f, ok := kv.Value.(expvar.Func); ok {
v := f()
if ms, ok := v.(runtime.MemStats); ok && name == "memstats" {
writeMemstats(w, &ms)
return
}
switch v := v.(type) {
case int, int8, int16, int32, int64, uint, uint8, uint16, uint32, uint64, uintptr, float32, float64:
fmt.Fprintf(w, "%s %v\n", name, v)
return
}
funcRet = fmt.Sprintf(" returning %T", v)
}
switch kv.Value.(type) {
default:
fmt.Fprintf(w, "# skipping expvar %q (Go type %T%s) with undeclared Prometheus type\n", name, kv.Value, funcRet)
return
case *metrics.LabelMap, *expvar.Map:
// Permit typeless LabelMap and expvar.Map for
// compatibility with old expvar-registered
// metrics.LabelMap.
}
}
switch v := kv.Value.(type) {
case expvar.Func:
val := v()
switch val.(type) {
case float64, int64, int:
fmt.Fprintf(w, "# TYPE %s %s\n%s %v\n", name, typ, name, val)
default:
fmt.Fprintf(w, "# skipping expvar func %q returning unknown type %T\n", name, val)
}
case *metrics.LabelMap:
if typ != "" {
fmt.Fprintf(w, "# TYPE %s %s\n", name, typ)
}
// IntMap uses expvar.Map on the inside, which presorts
// keys. The output ordering is deterministic.
v.Do(func(kv expvar.KeyValue) {
fmt.Fprintf(w, "%s{%s=%q} %v\n", name, v.Label, kv.Key, kv.Value)
})
case *expvar.Map:
if label != "" && typ != "" {
fmt.Fprintf(w, "# TYPE %s %s\n", name, typ)
v.Do(func(kv expvar.KeyValue) {
fmt.Fprintf(w, "%s{%s=%q} %v\n", name, label, kv.Key, kv.Value)
})
} else {
v.Do(func(kv expvar.KeyValue) {
fmt.Fprintf(w, "%s_%s %v\n", name, kv.Key, kv.Value)
})
}
}
}
// VarzHandler is an HTTP handler to write expvar values into the
// prometheus export format:
//
// https://github.com/prometheus/docs/blob/master/content/docs/instrumenting/exposition_formats.md
//
// It makes the following assumptions:
//
// * *expvar.Int are counters (unless marked as a gauge_; see below)
// * a *tailscale/metrics.Set is descended into, joining keys with
// underscores. So use underscores as your metric names.
// * an expvar named starting with "gauge_" or "counter_" is of that
// Prometheus type, and has that prefix stripped.
// * anything else is untyped and thus not exported.
// * expvar.Func can return an int or int64 (for now) and anything else
// is not exported.
//
// This will evolve over time, or perhaps be replaced.
func VarzHandler(w http.ResponseWriter, r *http.Request) {
w.Header().Set("Content-Type", "text/plain; version=0.0.4")
expvarDo(func(kv expvar.KeyValue) {
writePromExpVar(w, "", kv)
})
}
// PrometheusMetricsReflectRooter is an optional interface that expvar.Var implementations
// can implement to indicate that they should be walked recursively with reflect to find
// sets of fields to export.
type PrometheusMetricsReflectRooter interface {
expvar.Var
// PrometheusMetricsReflectRoot returns the struct or struct pointer to walk.
PrometheusMetricsReflectRoot() interface{}
}
var expvarDo = expvar.Do // pulled out for tests
func writeMemstats(w io.Writer, ms *runtime.MemStats) {
out := func(name, typ string, v uint64, help string) {
if help != "" {
fmt.Fprintf(w, "# HELP memstats_%s %s\n", name, help)
}
fmt.Fprintf(w, "# TYPE memstats_%s %s\nmemstats_%s %v\n", name, typ, name, v)
}
g := func(name string, v uint64, help string) { out(name, "gauge", v, help) }
c := func(name string, v uint64, help string) { out(name, "counter", v, help) }
g("heap_alloc", ms.HeapAlloc, "current bytes of allocated heap objects (up/down smoothly)")
c("total_alloc", ms.TotalAlloc, "cumulative bytes allocated for heap objects")
g("sys", ms.Sys, "total bytes of memory obtained from the OS")
c("mallocs", ms.Mallocs, "cumulative count of heap objects allocated")
c("frees", ms.Frees, "cumulative count of heap objects freed")
c("num_gc", uint64(ms.NumGC), "number of completed GC cycles")
}
func foreachExportedStructField(rv reflect.Value, f func(fieldOrJSONName, metricType string, rv reflect.Value)) {
t := rv.Type()
for i, n := 0, t.NumField(); i < n; i++ {
sf := t.Field(i)
name := sf.Name
if v := sf.Tag.Get("json"); v != "" {
if i := strings.Index(v, ","); i != -1 {
v = v[:i]
}
if v == "-" {
// Skip it, regardless of its metrictype.
continue
}
if v != "" {
name = v
}
}
metricType := sf.Tag.Get("metrictype")
if metricType != "" || sf.Type.Kind() == reflect.Struct {
f(name, metricType, rv.Field(i))
} else if sf.Type.Kind() == reflect.Ptr && sf.Type.Elem().Kind() == reflect.Struct {
fv := rv.Field(i)
if !fv.IsNil() {
f(name, metricType, fv.Elem())
}
}
}
}
type expVarPromStructRoot struct{ v interface{} }
func (r expVarPromStructRoot) PrometheusMetricsReflectRoot() interface{} { return r.v }
func (r expVarPromStructRoot) String() string { panic("unused") }
var (
_ PrometheusMetricsReflectRooter = expVarPromStructRoot{}
_ expvar.Var = expVarPromStructRoot{}
)