src/chrome/browser/captive_portal/captive_portal_service.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "chrome/browser/captive_portal/captive_portal_service.h"
   6
   7 #include "base/bind.h"
   8 #include "base/bind_helpers.h"
   9 #include "base/logging.h"
  10 #include "base/message_loop/message_loop.h"
  11 #include "base/metrics/histogram.h"
  12 #include "base/prefs/pref_service.h"
  13 #include "chrome/browser/chrome_notification_types.h"
  14 #include "chrome/browser/profiles/profile.h"
  15 #include "chrome/common/pref_names.h"
  16 #include "components/captive_portal/captive_portal_types.h"
  17 #include "content/public/browser/notification_service.h"
  18
  19 #if defined(OS_MACOSX)
  20 #include "base/mac/mac_util.h"
  21 #endif
  22
  23 #if defined(OS_WIN)
  24 #include "base/win/windows_version.h"
  25 #endif
  26
  27 using captive_portal::CaptivePortalResult;
  28
  29 namespace {
  30
  31 // Make sure this enum is in sync with CaptivePortalDetectionResult enum
  32 // in histograms.xml. This enum is append-only, don't modify existing values.
  33 enum CaptivePortalDetectionResult {
  34   // There's a confirmed connection to the Internet.
  35   DETECTION_RESULT_INTERNET_CONNECTED,
  36   // Received a network or HTTP error, or a non-HTTP response.
  37   DETECTION_RESULT_NO_RESPONSE,
  38   // Encountered a captive portal with a non-HTTPS landing URL.
  39   DETECTION_RESULT_BEHIND_CAPTIVE_PORTAL,
  40   // Received a network or HTTP error with an HTTPS landing URL.
  41   DETECTION_RESULT_NO_RESPONSE_HTTPS_LANDING_URL,
  42   // Encountered a captive portal with an HTTPS landing URL.
  43   DETECTION_RESULT_BEHIND_CAPTIVE_PORTAL_HTTPS_LANDING_URL,
  44   DETECTION_RESULT_COUNT
  45 };
  46
  47 // Records histograms relating to how often captive portal detection attempts
  48 // ended with |result| in a row, and for how long |result| was the last result
  49 // of a detection attempt.  Recorded both on quit and on a new Result.
  50 //
  51 // |repeat_count| may be 0 if there were no captive portal checks during
  52 // a session.
  53 //
  54 // |result_duration| is the time between when a captive portal check first
  55 // returned |result| and when a check returned a different result, or when the
  56 // CaptivePortalService was shut down.
  57 void RecordRepeatHistograms(CaptivePortalResult result,
  58                             int repeat_count,
  59                             base::TimeDelta result_duration) {
  60   // Histogram macros can't be used with variable names, since they cache
  61   // pointers, so have to use the histogram functions directly.
  62
  63   // Record number of times the last result was received in a row.
  64   base::HistogramBase* result_repeated_histogram =
  65       base::Histogram::FactoryGet(
  66           "CaptivePortal.ResultRepeated." + CaptivePortalResultToString(result),
  67           1,  // min
  68           100,  // max
  69           100,  // bucket_count
  70           base::Histogram::kUmaTargetedHistogramFlag);
  71   result_repeated_histogram->Add(repeat_count);
  72
  73   if (repeat_count == 0)
  74     return;
  75
  76   // Time between first request that returned |result| and now.
  77   base::HistogramBase* result_duration_histogram =
  78       base::Histogram::FactoryTimeGet(
  79           "CaptivePortal.ResultDuration." + CaptivePortalResultToString(result),
  80           base::TimeDelta::FromSeconds(1),  // min
  81           base::TimeDelta::FromHours(1),  // max
  82           50,  // bucket_count
  83           base::Histogram::kUmaTargetedHistogramFlag);
  84   result_duration_histogram->AddTime(result_duration);
  85 }
  86
  87 int GetHistogramEntryForDetectionResult(
  88     const captive_portal::CaptivePortalDetector::Results& results) {
  89   bool is_https = results.landing_url.SchemeIs("https");
  90   switch (results.result) {
  91     case captive_portal::RESULT_INTERNET_CONNECTED:
  92       return DETECTION_RESULT_INTERNET_CONNECTED;
  93     case captive_portal::RESULT_NO_RESPONSE:
  94       return is_https ?
  95           DETECTION_RESULT_NO_RESPONSE_HTTPS_LANDING_URL :
  96           DETECTION_RESULT_NO_RESPONSE;
  97     case captive_portal::RESULT_BEHIND_CAPTIVE_PORTAL:
  98       return is_https ?
  99           DETECTION_RESULT_BEHIND_CAPTIVE_PORTAL_HTTPS_LANDING_URL :
 100           DETECTION_RESULT_BEHIND_CAPTIVE_PORTAL;
 101     default:
 102       NOTREACHED();
 103       return -1;
 104   }
 105 }
 106
 107 bool ShouldDeferToNativeCaptivePortalDetection() {
 108   // On Windows 8, defer to the native captive portal detection.  OSX Lion and
 109   // later also have captive portal detection, but experimentally, this code
 110   // works in cases its does not.
 111   //
 112   // TODO(mmenke): Investigate how well Windows 8's captive portal detection
 113   // works.
 114 #if defined(OS_WIN)
 115   return base::win::GetVersion() >= base::win::VERSION_WIN8;
 116 #else
 117   return false;
 118 #endif
 119 }
 120
 121 }  // namespace
 122
 123 CaptivePortalService::TestingState CaptivePortalService::testing_state_ =
 124     NOT_TESTING;
 125
 126 class CaptivePortalService::RecheckBackoffEntry : public net::BackoffEntry {
 127  public:
 128   explicit RecheckBackoffEntry(CaptivePortalService* captive_portal_service)
 129       : net::BackoffEntry(
 130             &captive_portal_service->recheck_policy().backoff_policy),
 131         captive_portal_service_(captive_portal_service) {
 132   }
 133
 134  private:
 135   virtual base::TimeTicks ImplGetTimeNow() const OVERRIDE {
 136     return captive_portal_service_->GetCurrentTimeTicks();
 137   }
 138
 139   CaptivePortalService* captive_portal_service_;
 140
 141   DISALLOW_COPY_AND_ASSIGN(RecheckBackoffEntry);
 142 };
 143
 144 CaptivePortalService::RecheckPolicy::RecheckPolicy()
 145     : initial_backoff_no_portal_ms(600 * 1000),
 146       initial_backoff_portal_ms(20 * 1000) {
 147   // Receiving a new Result is considered a success.  All subsequent requests
 148   // that get the same Result are considered "failures", so a value of N
 149   // means exponential backoff starts after getting a result N + 2 times:
 150   // +1 for the initial success, and +1 because N failures are ignored.
 151   //
 152   // A value of 6 means to start backoff on the 7th failure, which is the 8th
 153   // time the same result is received.
 154   backoff_policy.num_errors_to_ignore = 6;
 155
 156   // It doesn't matter what this is initialized to.  It will be overwritten
 157   // after the first captive portal detection request.
 158   backoff_policy.initial_delay_ms = initial_backoff_no_portal_ms;
 159
 160   backoff_policy.multiply_factor = 2.0;
 161   backoff_policy.jitter_factor = 0.3;
 162   backoff_policy.maximum_backoff_ms = 2 * 60 * 1000;
 163
 164   // -1 means the entry never expires.  This doesn't really matter, as the
 165   // service never checks for its expiration.
 166   backoff_policy.entry_lifetime_ms = -1;
 167
 168   backoff_policy.always_use_initial_delay = true;
 169 }
 170
 171 CaptivePortalService::CaptivePortalService(Profile* profile)
 172     : profile_(profile),
 173       state_(STATE_IDLE),
 174       captive_portal_detector_(profile->GetRequestContext()),
 175       enabled_(false),
 176       last_detection_result_(captive_portal::RESULT_INTERNET_CONNECTED),
 177       num_checks_with_same_result_(0),
 178       test_url_(captive_portal::CaptivePortalDetector::kDefaultURL) {
 179   // The order matters here:
 180   // |resolve_errors_with_web_service_| must be initialized and |backoff_entry_|
 181   // created before the call to UpdateEnabledState.
 182   resolve_errors_with_web_service_.Init(
 183       prefs::kAlternateErrorPagesEnabled,
 184       profile_->GetPrefs(),
 185       base::Bind(&CaptivePortalService::UpdateEnabledState,
 186                  base::Unretained(this)));
 187   ResetBackoffEntry(last_detection_result_);
 188
 189   UpdateEnabledState();
 190 }
 191
 192 CaptivePortalService::~CaptivePortalService() {
 193 }
 194
 195 void CaptivePortalService::DetectCaptivePortal() {
 196   DCHECK(CalledOnValidThread());
 197
 198   // If a request is pending or running, do nothing.
 199   if (state_ == STATE_CHECKING_FOR_PORTAL || state_ == STATE_TIMER_RUNNING)
 200     return;
 201
 202   base::TimeDelta time_until_next_check = backoff_entry_->GetTimeUntilRelease();
 203
 204   // Start asynchronously.
 205   state_ = STATE_TIMER_RUNNING;
 206   check_captive_portal_timer_.Start(
 207       FROM_HERE,
 208       time_until_next_check,
 209       this,
 210       &CaptivePortalService::DetectCaptivePortalInternal);
 211 }
 212
 213 void CaptivePortalService::DetectCaptivePortalInternal() {
 214   DCHECK(CalledOnValidThread());
 215   DCHECK(state_ == STATE_TIMER_RUNNING || state_ == STATE_IDLE);
 216   DCHECK(!TimerRunning());
 217
 218   state_ = STATE_CHECKING_FOR_PORTAL;
 219
 220   // When not enabled, just claim there's an Internet connection.
 221   if (!enabled_) {
 222     // Count this as a success, so the backoff entry won't apply exponential
 223     // backoff, but will apply the standard delay.
 224     backoff_entry_->InformOfRequest(true);
 225     OnResult(captive_portal::RESULT_INTERNET_CONNECTED);
 226     return;
 227   }
 228
 229   captive_portal_detector_.DetectCaptivePortal(
 230       test_url_, base::Bind(
 231           &CaptivePortalService::OnPortalDetectionCompleted,
 232           base::Unretained(this)));
 233 }
 234
 235 void CaptivePortalService::OnPortalDetectionCompleted(
 236     const captive_portal::CaptivePortalDetector::Results& results) {
 237   DCHECK(CalledOnValidThread());
 238   DCHECK_EQ(STATE_CHECKING_FOR_PORTAL, state_);
 239   DCHECK(!TimerRunning());
 240   DCHECK(enabled_);
 241
 242   CaptivePortalResult result = results.result;
 243   const base::TimeDelta& retry_after_delta = results.retry_after_delta;
 244   base::TimeTicks now = GetCurrentTimeTicks();
 245
 246   // Record histograms.
 247   UMA_HISTOGRAM_ENUMERATION("CaptivePortal.DetectResult",
 248                             GetHistogramEntryForDetectionResult(results),
 249                             DETECTION_RESULT_COUNT);
 250
 251   // If this isn't the first captive portal result, record stats.
 252   if (!last_check_time_.is_null()) {
 253     UMA_HISTOGRAM_LONG_TIMES("CaptivePortal.TimeBetweenChecks",
 254                              now - last_check_time_);
 255
 256     if (last_detection_result_ != result) {
 257       // If the last result was different from the result of the latest test,
 258       // record histograms about the previous period over which the result was
 259       // the same.
 260       RecordRepeatHistograms(last_detection_result_,
 261                              num_checks_with_same_result_,
 262                              now - first_check_time_with_same_result_);
 263     }
 264   }
 265
 266   if (last_check_time_.is_null() || result != last_detection_result_) {
 267     first_check_time_with_same_result_ = now;
 268     num_checks_with_same_result_ = 1;
 269
 270     // Reset the backoff entry both to update the default time and clear
 271     // previous failures.
 272     ResetBackoffEntry(result);
 273
 274     backoff_entry_->SetCustomReleaseTime(now + retry_after_delta);
 275     // The BackoffEntry is not informed of this request, so there's no delay
 276     // before the next request.  This allows for faster login when a captive
 277     // portal is first detected.  It can also help when moving between captive
 278     // portals.
 279   } else {
 280     DCHECK_LE(1, num_checks_with_same_result_);
 281     ++num_checks_with_same_result_;
 282
 283     // Requests that have the same Result as the last one are considered
 284     // "failures", to trigger backoff.
 285     backoff_entry_->SetCustomReleaseTime(now + retry_after_delta);
 286     backoff_entry_->InformOfRequest(false);
 287   }
 288
 289   last_check_time_ = now;
 290
 291   OnResult(result);
 292 }
 293
 294 void CaptivePortalService::Shutdown() {
 295   DCHECK(CalledOnValidThread());
 296   if (enabled_) {
 297     RecordRepeatHistograms(
 298         last_detection_result_,
 299         num_checks_with_same_result_,
 300         GetCurrentTimeTicks() - first_check_time_with_same_result_);
 301   }
 302 }
 303
 304 void CaptivePortalService::OnResult(CaptivePortalResult result) {
 305   DCHECK_EQ(STATE_CHECKING_FOR_PORTAL, state_);
 306   state_ = STATE_IDLE;
 307
 308   Results results;
 309   results.previous_result = last_detection_result_;
 310   results.result = result;
 311   last_detection_result_ = result;
 312
 313   content::NotificationService::current()->Notify(
 314       chrome::NOTIFICATION_CAPTIVE_PORTAL_CHECK_RESULT,
 315       content::Source<Profile>(profile_),
 316       content::Details<Results>(&results));
 317 }
 318
 319 void CaptivePortalService::ResetBackoffEntry(CaptivePortalResult result) {
 320   if (!enabled_ || result == captive_portal::RESULT_BEHIND_CAPTIVE_PORTAL) {
 321     // Use the shorter time when the captive portal service is not enabled, or
 322     // behind a captive portal.
 323     recheck_policy_.backoff_policy.initial_delay_ms =
 324         recheck_policy_.initial_backoff_portal_ms;
 325   } else {
 326     recheck_policy_.backoff_policy.initial_delay_ms =
 327         recheck_policy_.initial_backoff_no_portal_ms;
 328   }
 329
 330   backoff_entry_.reset(new RecheckBackoffEntry(this));
 331 }
 332
 333 void CaptivePortalService::UpdateEnabledState() {
 334   DCHECK(CalledOnValidThread());
 335   bool enabled_before = enabled_;
 336   enabled_ = testing_state_ != DISABLED_FOR_TESTING &&
 337              resolve_errors_with_web_service_.GetValue();
 338
 339   if (testing_state_ != SKIP_OS_CHECK_FOR_TESTING &&
 340       ShouldDeferToNativeCaptivePortalDetection()) {
 341     enabled_ = false;
 342   }
 343
 344   if (enabled_before == enabled_)
 345     return;
 346
 347   // Clear data used for histograms.
 348   num_checks_with_same_result_ = 0;
 349   first_check_time_with_same_result_ = base::TimeTicks();
 350   last_check_time_ = base::TimeTicks();
 351
 352   ResetBackoffEntry(last_detection_result_);
 353
 354   if (state_ == STATE_CHECKING_FOR_PORTAL || state_ == STATE_TIMER_RUNNING) {
 355     // If a captive portal check was running or pending, cancel check
 356     // and the timer.
 357     check_captive_portal_timer_.Stop();
 358     captive_portal_detector_.Cancel();
 359     state_ = STATE_IDLE;
 360
 361     // Since a captive portal request was queued or running, something may be
 362     // expecting to receive a captive portal result.
 363     DetectCaptivePortal();
 364   }
 365 }
 366
 367 base::TimeTicks CaptivePortalService::GetCurrentTimeTicks() const {
 368   if (time_ticks_for_testing_.is_null())
 369     return base::TimeTicks::Now();
 370   else
 371     return time_ticks_for_testing_;
 372 }
 373
 374 bool CaptivePortalService::DetectionInProgress() const {
 375   return state_ == STATE_CHECKING_FOR_PORTAL;
 376 }
 377
 378 bool CaptivePortalService::TimerRunning() const {
 379   return check_captive_portal_timer_.IsRunning();
 380 }