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