chrome/browser/safe_browsing/protocol_manager.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/safe_browsing/protocol_manager.h"
   6
   7 #include "base/environment.h"
   8 #include "base/logging.h"
   9 #include "base/memory/scoped_vector.h"
  10 #include "base/metrics/histogram.h"
  11 #include "base/profiler/scoped_tracker.h"
  12 #include "base/rand_util.h"
  13 #include "base/stl_util.h"
  14 #include "base/strings/string_util.h"
  15 #include "base/strings/stringprintf.h"
  16 #include "base/timer/timer.h"
  17 #include "chrome/browser/safe_browsing/protocol_parser.h"
  18 #include "chrome/common/env_vars.h"
  19 #include "google_apis/google_api_keys.h"
  20 #include "net/base/escape.h"
  21 #include "net/base/load_flags.h"
  22 #include "net/base/net_errors.h"
  23 #include "net/url_request/url_fetcher.h"
  24 #include "net/url_request/url_request_context_getter.h"
  25 #include "net/url_request/url_request_status.h"
  26
  27 #if defined(OS_ANDROID)
  28 #include "net/base/network_change_notifier.h"
  29 #endif
  30
  31 using base::Time;
  32 using base::TimeDelta;
  33
  34 namespace {
  35
  36 // UpdateResult indicates what happened with the primary and/or backup update
  37 // requests. The ordering of the values must stay the same for UMA consistency,
  38 // and is also ordered in this way to match ProtocolManager::BackupUpdateReason.
  39 enum UpdateResult {
  40   UPDATE_RESULT_FAIL,
  41   UPDATE_RESULT_SUCCESS,
  42   UPDATE_RESULT_BACKUP_CONNECT_FAIL,
  43   UPDATE_RESULT_BACKUP_CONNECT_SUCCESS,
  44   UPDATE_RESULT_BACKUP_HTTP_FAIL,
  45   UPDATE_RESULT_BACKUP_HTTP_SUCCESS,
  46   UPDATE_RESULT_BACKUP_NETWORK_FAIL,
  47   UPDATE_RESULT_BACKUP_NETWORK_SUCCESS,
  48   UPDATE_RESULT_MAX,
  49   UPDATE_RESULT_BACKUP_START = UPDATE_RESULT_BACKUP_CONNECT_FAIL,
  50 };
  51
  52 void RecordUpdateResult(UpdateResult result) {
  53   DCHECK(result >= 0 && result < UPDATE_RESULT_MAX);
  54   UMA_HISTOGRAM_ENUMERATION("SB2.UpdateResult", result, UPDATE_RESULT_MAX);
  55 }
  56
  57 }  // namespace
  58
  59 // Minimum time, in seconds, from start up before we must issue an update query.
  60 static const int kSbTimerStartIntervalSecMin = 60;
  61
  62 // Maximum time, in seconds, from start up before we must issue an update query.
  63 static const int kSbTimerStartIntervalSecMax = 300;
  64
  65 // The maximum time, in seconds, to wait for a response to an update request.
  66 static const int kSbMaxUpdateWaitSec = 30;
  67
  68 // Maximum back off multiplier.
  69 static const size_t kSbMaxBackOff = 8;
  70
  71 // The default SBProtocolManagerFactory.
  72 class SBProtocolManagerFactoryImpl : public SBProtocolManagerFactory {
  73  public:
  74   SBProtocolManagerFactoryImpl() { }
  75   ~SBProtocolManagerFactoryImpl() override {}
  76   SafeBrowsingProtocolManager* CreateProtocolManager(
  77       SafeBrowsingProtocolManagerDelegate* delegate,
  78       net::URLRequestContextGetter* request_context_getter,
  79       const SafeBrowsingProtocolConfig& config) override {
  80     return new SafeBrowsingProtocolManager(
  81         delegate, request_context_getter, config);
  82   }
  83  private:
  84   DISALLOW_COPY_AND_ASSIGN(SBProtocolManagerFactoryImpl);
  85 };
  86
  87 // SafeBrowsingProtocolManager implementation ----------------------------------
  88
  89 // static
  90 SBProtocolManagerFactory* SafeBrowsingProtocolManager::factory_ = NULL;
  91
  92 // static
  93 SafeBrowsingProtocolManager* SafeBrowsingProtocolManager::Create(
  94     SafeBrowsingProtocolManagerDelegate* delegate,
  95     net::URLRequestContextGetter* request_context_getter,
  96     const SafeBrowsingProtocolConfig& config) {
  97   // TODO(cbentzel): Remove ScopedTracker below once crbug.com/483689 is fixed.
  98   tracked_objects::ScopedTracker tracking_profile(
  99       FROM_HERE_WITH_EXPLICIT_FUNCTION(
 100           "483689 SafeBrowsingProtocolManager::Create"));
 101   if (!factory_)
 102     factory_ = new SBProtocolManagerFactoryImpl();
 103   return factory_->CreateProtocolManager(
 104       delegate, request_context_getter, config);
 105 }
 106
 107 SafeBrowsingProtocolManager::SafeBrowsingProtocolManager(
 108     SafeBrowsingProtocolManagerDelegate* delegate,
 109     net::URLRequestContextGetter* request_context_getter,
 110     const SafeBrowsingProtocolConfig& config)
 111     : delegate_(delegate),
 112       request_type_(NO_REQUEST),
 113       update_error_count_(0),
 114       gethash_error_count_(0),
 115       update_back_off_mult_(1),
 116       gethash_back_off_mult_(1),
 117       next_update_interval_(base::TimeDelta::FromSeconds(
 118           base::RandInt(kSbTimerStartIntervalSecMin,
 119                         kSbTimerStartIntervalSecMax))),
 120       update_state_(FIRST_REQUEST),
 121       chunk_pending_to_write_(false),
 122       version_(config.version),
 123       update_size_(0),
 124       client_name_(config.client_name),
 125       request_context_getter_(request_context_getter),
 126       url_prefix_(config.url_prefix),
 127       backup_update_reason_(BACKUP_UPDATE_REASON_MAX),
 128       disable_auto_update_(config.disable_auto_update),
 129 #if defined(OS_ANDROID)
 130       disable_connection_check_(config.disable_connection_check),
 131 #endif
 132       url_fetcher_id_(0),
 133       app_in_foreground_(true) {
 134   DCHECK(!url_prefix_.empty());
 135
 136   backup_url_prefixes_[BACKUP_UPDATE_REASON_CONNECT] =
 137       config.backup_connect_error_url_prefix;
 138   backup_url_prefixes_[BACKUP_UPDATE_REASON_HTTP] =
 139       config.backup_http_error_url_prefix;
 140   backup_url_prefixes_[BACKUP_UPDATE_REASON_NETWORK] =
 141       config.backup_network_error_url_prefix;
 142
 143   // Set the backoff multiplier fuzz to a random value between 0 and 1.
 144   back_off_fuzz_ = static_cast<float>(base::RandDouble());
 145   if (version_.empty())
 146     version_ = SafeBrowsingProtocolManagerHelper::Version();
 147 }
 148
 149 // static
 150 void SafeBrowsingProtocolManager::RecordGetHashResult(
 151     bool is_download, ResultType result_type) {
 152   if (is_download) {
 153     UMA_HISTOGRAM_ENUMERATION("SB2.GetHashResultDownload", result_type,
 154                               GET_HASH_RESULT_MAX);
 155   } else {
 156     UMA_HISTOGRAM_ENUMERATION("SB2.GetHashResult", result_type,
 157                               GET_HASH_RESULT_MAX);
 158   }
 159 }
 160
 161 bool SafeBrowsingProtocolManager::IsUpdateScheduled() const {
 162   return update_timer_.IsRunning();
 163 }
 164
 165 SafeBrowsingProtocolManager::~SafeBrowsingProtocolManager() {
 166   // Delete in-progress SafeBrowsing requests.
 167   STLDeleteContainerPairFirstPointers(hash_requests_.begin(),
 168                                       hash_requests_.end());
 169   hash_requests_.clear();
 170 }
 171
 172 // We can only have one update or chunk request outstanding, but there may be
 173 // multiple GetHash requests pending since we don't want to serialize them and
 174 // slow down the user.
 175 void SafeBrowsingProtocolManager::GetFullHash(
 176     const std::vector<SBPrefix>& prefixes,
 177     FullHashCallback callback,
 178     bool is_download,
 179     bool is_extended_reporting) {
 180   DCHECK(CalledOnValidThread());
 181   // If we are in GetHash backoff, we need to check if we're past the next
 182   // allowed time. If we are, we can proceed with the request. If not, we are
 183   // required to return empty results (i.e. treat the page as safe).
 184   if (gethash_error_count_ && Time::Now() <= next_gethash_time_) {
 185     RecordGetHashResult(is_download, GET_HASH_BACKOFF_ERROR);
 186     std::vector<SBFullHashResult> full_hashes;
 187     callback.Run(full_hashes, base::TimeDelta());
 188     return;
 189   }
 190   GURL gethash_url = GetHashUrl(is_extended_reporting);
 191   net::URLFetcher* fetcher =
 192       net::URLFetcher::Create(url_fetcher_id_++, gethash_url,
 193                               net::URLFetcher::POST, this).release();
 194   hash_requests_[fetcher] = FullHashDetails(callback, is_download);
 195
 196   const std::string get_hash = safe_browsing::FormatGetHash(prefixes);
 197
 198   fetcher->SetLoadFlags(net::LOAD_DISABLE_CACHE);
 199   fetcher->SetRequestContext(request_context_getter_.get());
 200   fetcher->SetUploadData("text/plain", get_hash);
 201   fetcher->Start();
 202 }
 203
 204 void SafeBrowsingProtocolManager::GetNextUpdate() {
 205   DCHECK(CalledOnValidThread());
 206   if (request_.get() || request_type_ != NO_REQUEST)
 207     return;
 208
 209 #if defined(OS_ANDROID)
 210   if (!disable_connection_check_) {
 211     net::NetworkChangeNotifier::ConnectionType type =
 212       net::NetworkChangeNotifier::GetConnectionType();
 213     if (type != net::NetworkChangeNotifier::CONNECTION_WIFI) {
 214       ScheduleNextUpdate(false /* no back off */);
 215       return;
 216     }
 217   }
 218 #endif
 219
 220   IssueUpdateRequest();
 221 }
 222
 223 // net::URLFetcherDelegate implementation ----------------------------------
 224
 225 // All SafeBrowsing request responses are handled here.
 226 // TODO(paulg): Clarify with the SafeBrowsing team whether a failed parse of a
 227 //              chunk should retry the download and parse of that chunk (and
 228 //              what back off / how many times to try), and if that effects the
 229 //              update back off. For now, a failed parse of the chunk means we
 230 //              drop it. This isn't so bad because the next UPDATE_REQUEST we
 231 //              do will report all the chunks we have. If that chunk is still
 232 //              required, the SafeBrowsing servers will tell us to get it again.
 233 void SafeBrowsingProtocolManager::OnURLFetchComplete(
 234     const net::URLFetcher* source) {
 235   DCHECK(CalledOnValidThread());
 236   scoped_ptr<const net::URLFetcher> fetcher;
 237
 238   HashRequests::iterator it = hash_requests_.find(source);
 239   if (it != hash_requests_.end()) {
 240     // GetHash response.
 241     fetcher.reset(it->first);
 242     const FullHashDetails& details = it->second;
 243     std::vector<SBFullHashResult> full_hashes;
 244     base::TimeDelta cache_lifetime;
 245     if (source->GetStatus().is_success() &&
 246         (source->GetResponseCode() == 200 ||
 247          source->GetResponseCode() == 204)) {
 248       // For tracking our GetHash false positive (204) rate, compared to real
 249       // (200) responses.
 250       if (source->GetResponseCode() == 200)
 251         RecordGetHashResult(details.is_download, GET_HASH_STATUS_200);
 252       else
 253         RecordGetHashResult(details.is_download, GET_HASH_STATUS_204);
 254
 255       gethash_error_count_ = 0;
 256       gethash_back_off_mult_ = 1;
 257       std::string data;
 258       source->GetResponseAsString(&data);
 259       if (!safe_browsing::ParseGetHash(
 260               data.data(), data.length(), &cache_lifetime, &full_hashes)) {
 261         full_hashes.clear();
 262         RecordGetHashResult(details.is_download, GET_HASH_PARSE_ERROR);
 263         // TODO(cbentzel): Should cache_lifetime be set to 0 here? (See
 264         // http://crbug.com/360232.)
 265       }
 266     } else {
 267       HandleGetHashError(Time::Now());
 268       if (source->GetStatus().status() == net::URLRequestStatus::FAILED) {
 269         RecordGetHashResult(details.is_download, GET_HASH_NETWORK_ERROR);
 270         DVLOG(1) << "SafeBrowsing GetHash request for: " << source->GetURL()
 271                  << " failed with error: " << source->GetStatus().error();
 272       } else {
 273         RecordGetHashResult(details.is_download, GET_HASH_HTTP_ERROR);
 274         DVLOG(1) << "SafeBrowsing GetHash request for: " << source->GetURL()
 275                  << " failed with error: " << source->GetResponseCode();
 276       }
 277     }
 278
 279     // Invoke the callback with full_hashes, even if there was a parse error or
 280     // an error response code (in which case full_hashes will be empty). The
 281     // caller can't be blocked indefinitely.
 282     details.callback.Run(full_hashes, cache_lifetime);
 283
 284     hash_requests_.erase(it);
 285   } else {
 286     // Update or chunk response.
 287     fetcher.reset(request_.release());
 288
 289     if (request_type_ == UPDATE_REQUEST ||
 290         request_type_ == BACKUP_UPDATE_REQUEST) {
 291       if (!fetcher.get()) {
 292         // We've timed out waiting for an update response, so we've cancelled
 293         // the update request and scheduled a new one. Ignore this response.
 294         return;
 295       }
 296
 297       // Cancel the update response timeout now that we have the response.
 298       timeout_timer_.Stop();
 299     }
 300
 301     net::URLRequestStatus status = source->GetStatus();
 302     if (status.is_success() && source->GetResponseCode() == 200) {
 303       // We have data from the SafeBrowsing service.
 304       std::string data;
 305       source->GetResponseAsString(&data);
 306
 307       // TODO(shess): Cleanup the flow of this code so that |parsed_ok| can be
 308       // removed or omitted.
 309       const bool parsed_ok = HandleServiceResponse(
 310           source->GetURL(), data.data(), data.length());
 311       if (!parsed_ok) {
 312         DVLOG(1) << "SafeBrowsing request for: " << source->GetURL()
 313                  << " failed parse.";
 314         chunk_request_urls_.clear();
 315         if (request_type_ == UPDATE_REQUEST &&
 316             IssueBackupUpdateRequest(BACKUP_UPDATE_REASON_HTTP)) {
 317           return;
 318         }
 319         UpdateFinished(false);
 320       }
 321
 322       switch (request_type_) {
 323         case CHUNK_REQUEST:
 324           if (parsed_ok) {
 325             chunk_request_urls_.pop_front();
 326             if (chunk_request_urls_.empty() && !chunk_pending_to_write_)
 327               UpdateFinished(true);
 328           }
 329           break;
 330         case UPDATE_REQUEST:
 331         case BACKUP_UPDATE_REQUEST:
 332           if (chunk_request_urls_.empty() && parsed_ok) {
 333             // We are up to date since the servers gave us nothing new, so we
 334             // are done with this update cycle.
 335             UpdateFinished(true);
 336           }
 337           break;
 338         case NO_REQUEST:
 339           // This can happen if HandleServiceResponse fails above.
 340           break;
 341         default:
 342           NOTREACHED();
 343           break;
 344       }
 345     } else {
 346       if (status.status() == net::URLRequestStatus::FAILED) {
 347         DVLOG(1) << "SafeBrowsing request for: " << source->GetURL()
 348                  << " failed with error: " << source->GetStatus().error();
 349       } else {
 350         DVLOG(1) << "SafeBrowsing request for: " << source->GetURL()
 351                  << " failed with error: " << source->GetResponseCode();
 352       }
 353       if (request_type_ == CHUNK_REQUEST) {
 354         // The SafeBrowsing service error, or very bad response code: back off.
 355         chunk_request_urls_.clear();
 356       } else if (request_type_ == UPDATE_REQUEST) {
 357         BackupUpdateReason backup_update_reason = BACKUP_UPDATE_REASON_MAX;
 358         if (status.is_success()) {
 359           backup_update_reason = BACKUP_UPDATE_REASON_HTTP;
 360         } else {
 361           switch (status.error()) {
 362             case net::ERR_INTERNET_DISCONNECTED:
 363             case net::ERR_NETWORK_CHANGED:
 364               backup_update_reason = BACKUP_UPDATE_REASON_NETWORK;
 365               break;
 366             default:
 367               backup_update_reason = BACKUP_UPDATE_REASON_CONNECT;
 368               break;
 369           }
 370         }
 371         if (backup_update_reason != BACKUP_UPDATE_REASON_MAX &&
 372             IssueBackupUpdateRequest(backup_update_reason)) {
 373           return;
 374         }
 375       }
 376       UpdateFinished(false);
 377     }
 378   }
 379
 380   // Get the next chunk if available.
 381   IssueChunkRequest();
 382 }
 383
 384 bool SafeBrowsingProtocolManager::HandleServiceResponse(
 385     const GURL& url, const char* data, size_t length) {
 386   DCHECK(CalledOnValidThread());
 387
 388   switch (request_type_) {
 389     case UPDATE_REQUEST:
 390     case BACKUP_UPDATE_REQUEST: {
 391       size_t next_update_sec = 0;
 392       bool reset = false;
 393       scoped_ptr<std::vector<SBChunkDelete> > chunk_deletes(
 394           new std::vector<SBChunkDelete>);
 395       std::vector<ChunkUrl> chunk_urls;
 396       if (!safe_browsing::ParseUpdate(data, length, &next_update_sec, &reset,
 397                                       chunk_deletes.get(), &chunk_urls)) {
 398         return false;
 399       }
 400
 401       base::TimeDelta next_update_interval =
 402           base::TimeDelta::FromSeconds(next_update_sec);
 403       last_update_ = Time::Now();
 404
 405       if (update_state_ == FIRST_REQUEST)
 406         update_state_ = SECOND_REQUEST;
 407       else if (update_state_ == SECOND_REQUEST)
 408         update_state_ = NORMAL_REQUEST;
 409
 410       // New time for the next update.
 411       if (next_update_interval > base::TimeDelta()) {
 412         next_update_interval_ = next_update_interval;
 413       } else if (update_state_ == SECOND_REQUEST) {
 414         next_update_interval_ = base::TimeDelta::FromSeconds(
 415             base::RandInt(15, 45));
 416       }
 417
 418       // New chunks to download.
 419       if (!chunk_urls.empty()) {
 420         UMA_HISTOGRAM_COUNTS("SB2.UpdateUrls", chunk_urls.size());
 421         for (size_t i = 0; i < chunk_urls.size(); ++i)
 422           chunk_request_urls_.push_back(chunk_urls[i]);
 423       }
 424
 425       // Handle the case were the SafeBrowsing service tells us to dump our
 426       // database.
 427       if (reset) {
 428         delegate_->ResetDatabase();
 429         return true;
 430       }
 431
 432       // Chunks to delete from our storage.
 433       if (!chunk_deletes->empty())
 434         delegate_->DeleteChunks(chunk_deletes.Pass());
 435
 436       break;
 437     }
 438     case CHUNK_REQUEST: {
 439       UMA_HISTOGRAM_TIMES("SB2.ChunkRequest",
 440                           base::Time::Now() - chunk_request_start_);
 441
 442       const ChunkUrl chunk_url = chunk_request_urls_.front();
 443       scoped_ptr<ScopedVector<SBChunkData> >
 444           chunks(new ScopedVector<SBChunkData>);
 445       UMA_HISTOGRAM_COUNTS("SB2.ChunkSize", length);
 446       update_size_ += length;
 447       if (!safe_browsing::ParseChunk(data, length, chunks.get()))
 448         return false;
 449
 450       // Chunks to add to storage.  Pass ownership of |chunks|.
 451       if (!chunks->empty()) {
 452         chunk_pending_to_write_ = true;
 453         delegate_->AddChunks(
 454             chunk_url.list_name, chunks.Pass(),
 455             base::Bind(&SafeBrowsingProtocolManager::OnAddChunksComplete,
 456                        base::Unretained(this)));
 457       }
 458
 459       break;
 460     }
 461
 462     default:
 463       return false;
 464   }
 465
 466   return true;
 467 }
 468
 469 void SafeBrowsingProtocolManager::Initialize() {
 470   DCHECK(CalledOnValidThread());
 471   // TODO(cbentzel): Remove ScopedTracker below once crbug.com/483689 is fixed.
 472   tracked_objects::ScopedTracker tracking_profile(
 473       FROM_HERE_WITH_EXPLICIT_FUNCTION(
 474           "483689 SafeBrowsingProtocolManager::Initialize"));
 475   // Don't want to hit the safe browsing servers on build/chrome bots.
 476   scoped_ptr<base::Environment> env(base::Environment::Create());
 477   if (env->HasVar(env_vars::kHeadless))
 478     return;
 479   ScheduleNextUpdate(false /* no back off */);
 480 }
 481
 482 void SafeBrowsingProtocolManager::ScheduleNextUpdate(bool back_off) {
 483   DCHECK(CalledOnValidThread());
 484   if (disable_auto_update_) {
 485     // Unschedule any current timer.
 486     update_timer_.Stop();
 487     return;
 488   }
 489   // Reschedule with the new update.
 490   base::TimeDelta next_update_interval = GetNextUpdateInterval(back_off);
 491   ForceScheduleNextUpdate(next_update_interval);
 492 }
 493
 494 void SafeBrowsingProtocolManager::ForceScheduleNextUpdate(
 495     base::TimeDelta interval) {
 496   DCHECK(CalledOnValidThread());
 497   DCHECK(interval >= base::TimeDelta());
 498   // Unschedule any current timer.
 499   update_timer_.Stop();
 500   update_timer_.Start(FROM_HERE, interval, this,
 501                       &SafeBrowsingProtocolManager::GetNextUpdate);
 502 }
 503
 504 // According to section 5 of the SafeBrowsing protocol specification, we must
 505 // back off after a certain number of errors. We only change |next_update_sec_|
 506 // when we receive a response from the SafeBrowsing service.
 507 base::TimeDelta SafeBrowsingProtocolManager::GetNextUpdateInterval(
 508     bool back_off) {
 509   DCHECK(CalledOnValidThread());
 510   DCHECK(next_update_interval_ > base::TimeDelta());
 511   base::TimeDelta next = next_update_interval_;
 512   if (back_off) {
 513     next = GetNextBackOffInterval(&update_error_count_, &update_back_off_mult_);
 514   } else {
 515     // Successful response means error reset.
 516     update_error_count_ = 0;
 517     update_back_off_mult_ = 1;
 518   }
 519   return next;
 520 }
 521
 522 base::TimeDelta SafeBrowsingProtocolManager::GetNextBackOffInterval(
 523     size_t* error_count, size_t* multiplier) const {
 524   DCHECK(CalledOnValidThread());
 525   DCHECK(multiplier && error_count);
 526   (*error_count)++;
 527   if (*error_count > 1 && *error_count < 6) {
 528     base::TimeDelta next = base::TimeDelta::FromMinutes(
 529         *multiplier * (1 + back_off_fuzz_) * 30);
 530     *multiplier *= 2;
 531     if (*multiplier > kSbMaxBackOff)
 532       *multiplier = kSbMaxBackOff;
 533     return next;
 534   }
 535   if (*error_count >= 6)
 536     return base::TimeDelta::FromHours(8);
 537   return base::TimeDelta::FromMinutes(1);
 538 }
 539
 540 // This request requires getting a list of all the chunks for each list from the
 541 // database asynchronously. The request will be issued when we're called back in
 542 // OnGetChunksComplete.
 543 // TODO(paulg): We should get this at start up and maintain a ChunkRange cache
 544 //              to avoid hitting the database with each update request. On the
 545 //              otherhand, this request will only occur ~20-30 minutes so there
 546 //              isn't that much overhead. Measure!
 547 void SafeBrowsingProtocolManager::IssueUpdateRequest() {
 548   DCHECK(CalledOnValidThread());
 549   request_type_ = UPDATE_REQUEST;
 550   delegate_->UpdateStarted();
 551   delegate_->GetChunks(
 552       base::Bind(&SafeBrowsingProtocolManager::OnGetChunksComplete,
 553                  base::Unretained(this)));
 554 }
 555
 556 // The backup request can run immediately since the chunks have already been
 557 // retrieved from the DB.
 558 bool SafeBrowsingProtocolManager::IssueBackupUpdateRequest(
 559     BackupUpdateReason backup_update_reason) {
 560   DCHECK(CalledOnValidThread());
 561   DCHECK_EQ(request_type_, UPDATE_REQUEST);
 562   DCHECK(backup_update_reason >= 0 &&
 563          backup_update_reason < BACKUP_UPDATE_REASON_MAX);
 564   if (backup_url_prefixes_[backup_update_reason].empty())
 565     return false;
 566   request_type_ = BACKUP_UPDATE_REQUEST;
 567   backup_update_reason_ = backup_update_reason;
 568
 569   GURL backup_update_url = BackupUpdateUrl(backup_update_reason);
 570   request_ = net::URLFetcher::Create(url_fetcher_id_++, backup_update_url,
 571                                      net::URLFetcher::POST, this);
 572   request_->SetLoadFlags(net::LOAD_DISABLE_CACHE);
 573   request_->SetRequestContext(request_context_getter_.get());
 574   request_->SetUploadData("text/plain", update_list_data_);
 575   request_->Start();
 576
 577   // Begin the update request timeout.
 578   timeout_timer_.Start(FROM_HERE, TimeDelta::FromSeconds(kSbMaxUpdateWaitSec),
 579                        this,
 580                        &SafeBrowsingProtocolManager::UpdateResponseTimeout);
 581
 582   return true;
 583 }
 584
 585 void SafeBrowsingProtocolManager::IssueChunkRequest() {
 586   DCHECK(CalledOnValidThread());
 587   // We are only allowed to have one request outstanding at any time.  Also,
 588   // don't get the next url until the previous one has been written to disk so
 589   // that we don't use too much memory.
 590   if (request_.get() || chunk_request_urls_.empty() || chunk_pending_to_write_)
 591     return;
 592
 593   ChunkUrl next_chunk = chunk_request_urls_.front();
 594   DCHECK(!next_chunk.url.empty());
 595   GURL chunk_url = NextChunkUrl(next_chunk.url);
 596   request_type_ = CHUNK_REQUEST;
 597   request_ = net::URLFetcher::Create(url_fetcher_id_++, chunk_url,
 598                                      net::URLFetcher::GET, this);
 599   request_->SetLoadFlags(net::LOAD_DISABLE_CACHE);
 600   request_->SetRequestContext(request_context_getter_.get());
 601   chunk_request_start_ = base::Time::Now();
 602   request_->Start();
 603 }
 604
 605 void SafeBrowsingProtocolManager::OnGetChunksComplete(
 606     const std::vector<SBListChunkRanges>& lists,
 607     bool database_error,
 608     bool is_extended_reporting) {
 609   DCHECK(CalledOnValidThread());
 610   DCHECK_EQ(request_type_, UPDATE_REQUEST);
 611   DCHECK(update_list_data_.empty());
 612   if (database_error) {
 613     // The update was not successful, but don't back off.
 614     UpdateFinished(false, false);
 615     return;
 616   }
 617
 618   // Format our stored chunks:
 619   bool found_malware = false;
 620   bool found_phishing = false;
 621   for (size_t i = 0; i < lists.size(); ++i) {
 622     update_list_data_.append(safe_browsing::FormatList(lists[i]));
 623     if (lists[i].name == safe_browsing_util::kPhishingList)
 624       found_phishing = true;
 625
 626     if (lists[i].name == safe_browsing_util::kMalwareList)
 627       found_malware = true;
 628   }
 629
 630   // If we have an empty database, let the server know we want data for these
 631   // lists.
 632   // TODO(shess): These cases never happen because the database fills in the
 633   // lists in GetChunks().  Refactor the unit tests so that this code can be
 634   // removed.
 635   if (!found_phishing) {
 636     update_list_data_.append(safe_browsing::FormatList(
 637         SBListChunkRanges(safe_browsing_util::kPhishingList)));
 638   }
 639   if (!found_malware) {
 640     update_list_data_.append(safe_browsing::FormatList(
 641         SBListChunkRanges(safe_browsing_util::kMalwareList)));
 642   }
 643
 644   // Large requests are (probably) a sign of database corruption.
 645   // Record stats to inform decisions about whether to automate
 646   // deletion of such databases.  http://crbug.com/120219
 647   UMA_HISTOGRAM_COUNTS("SB2.UpdateRequestSize", update_list_data_.size());
 648
 649   GURL update_url = UpdateUrl(is_extended_reporting);
 650   request_ = net::URLFetcher::Create(url_fetcher_id_++, update_url,
 651                                      net::URLFetcher::POST, this);
 652   request_->SetLoadFlags(net::LOAD_DISABLE_CACHE);
 653   request_->SetRequestContext(request_context_getter_.get());
 654   request_->SetUploadData("text/plain", update_list_data_);
 655   request_->Start();
 656
 657   // Begin the update request timeout.
 658   timeout_timer_.Start(FROM_HERE, TimeDelta::FromSeconds(kSbMaxUpdateWaitSec),
 659                        this,
 660                        &SafeBrowsingProtocolManager::UpdateResponseTimeout);
 661 }
 662
 663 // If we haven't heard back from the server with an update response, this method
 664 // will run. Close the current update session and schedule another update.
 665 void SafeBrowsingProtocolManager::UpdateResponseTimeout() {
 666   DCHECK(CalledOnValidThread());
 667   DCHECK(request_type_ == UPDATE_REQUEST ||
 668          request_type_ == BACKUP_UPDATE_REQUEST);
 669   request_.reset();
 670   if (request_type_ == UPDATE_REQUEST &&
 671       IssueBackupUpdateRequest(BACKUP_UPDATE_REASON_CONNECT)) {
 672     return;
 673   }
 674   UpdateFinished(false);
 675 }
 676
 677 void SafeBrowsingProtocolManager::OnAddChunksComplete() {
 678   DCHECK(CalledOnValidThread());
 679   chunk_pending_to_write_ = false;
 680
 681   if (chunk_request_urls_.empty()) {
 682     UMA_HISTOGRAM_LONG_TIMES("SB2.Update", Time::Now() - last_update_);
 683     UpdateFinished(true);
 684   } else {
 685     IssueChunkRequest();
 686   }
 687 }
 688
 689 void SafeBrowsingProtocolManager::HandleGetHashError(const Time& now) {
 690   DCHECK(CalledOnValidThread());
 691   base::TimeDelta next = GetNextBackOffInterval(
 692       &gethash_error_count_, &gethash_back_off_mult_);
 693   next_gethash_time_ = now + next;
 694 }
 695
 696 void SafeBrowsingProtocolManager::UpdateFinished(bool success) {
 697   UpdateFinished(success, !success);
 698 }
 699
 700 void SafeBrowsingProtocolManager::UpdateFinished(bool success, bool back_off) {
 701   DCHECK(CalledOnValidThread());
 702 #if defined(OS_ANDROID)
 703   if (app_in_foreground_)
 704     UMA_HISTOGRAM_COUNTS("SB2.UpdateSizeForeground", update_size_);
 705   else
 706     UMA_HISTOGRAM_COUNTS("SB2.UpdateSizeBackground", update_size_);
 707 #endif
 708   UMA_HISTOGRAM_COUNTS("SB2.UpdateSize", update_size_);
 709   update_size_ = 0;
 710   bool update_success = success || request_type_ == CHUNK_REQUEST;
 711   if (backup_update_reason_ == BACKUP_UPDATE_REASON_MAX) {
 712     RecordUpdateResult(
 713         update_success ? UPDATE_RESULT_SUCCESS : UPDATE_RESULT_FAIL);
 714   } else {
 715     UpdateResult update_result = static_cast<UpdateResult>(
 716           UPDATE_RESULT_BACKUP_START +
 717           (static_cast<int>(backup_update_reason_) * 2) +
 718           update_success);
 719     RecordUpdateResult(update_result);
 720   }
 721   backup_update_reason_ = BACKUP_UPDATE_REASON_MAX;
 722   request_type_ = NO_REQUEST;
 723   update_list_data_.clear();
 724   delegate_->UpdateFinished(success);
 725   ScheduleNextUpdate(back_off);
 726 }
 727
 728 GURL SafeBrowsingProtocolManager::UpdateUrl(bool is_extended_reporting) const {
 729   std::string url = SafeBrowsingProtocolManagerHelper::ComposeUrl(
 730       url_prefix_, "downloads", client_name_, version_, additional_query_,
 731       is_extended_reporting);
 732   return GURL(url);
 733 }
 734
 735 GURL SafeBrowsingProtocolManager::BackupUpdateUrl(
 736     BackupUpdateReason backup_update_reason) const {
 737   DCHECK(backup_update_reason >= 0 &&
 738          backup_update_reason < BACKUP_UPDATE_REASON_MAX);
 739   DCHECK(!backup_url_prefixes_[backup_update_reason].empty());
 740   std::string url = SafeBrowsingProtocolManagerHelper::ComposeUrl(
 741       backup_url_prefixes_[backup_update_reason], "downloads", client_name_,
 742       version_, additional_query_);
 743   return GURL(url);
 744 }
 745
 746 GURL SafeBrowsingProtocolManager::GetHashUrl(bool is_extended_reporting) const {
 747   std::string url = SafeBrowsingProtocolManagerHelper::ComposeUrl(
 748       url_prefix_, "gethash", client_name_, version_, additional_query_,
 749       is_extended_reporting);
 750   return GURL(url);
 751 }
 752
 753 GURL SafeBrowsingProtocolManager::NextChunkUrl(const std::string& url) const {
 754   DCHECK(CalledOnValidThread());
 755   std::string next_url;
 756   if (!base::StartsWith(url, "http://",
 757                         base::CompareCase::INSENSITIVE_ASCII) &&
 758       !base::StartsWith(url, "https://",
 759                         base::CompareCase::INSENSITIVE_ASCII)) {
 760     // Use https if we updated via https, otherwise http (useful for testing).
 761     if (base::StartsWith(url_prefix_, "https://",
 762                          base::CompareCase::INSENSITIVE_ASCII))
 763       next_url.append("https://");
 764     else
 765       next_url.append("http://");
 766     next_url.append(url);
 767   } else {
 768     next_url = url;
 769   }
 770   if (!additional_query_.empty()) {
 771     if (next_url.find("?") != std::string::npos) {
 772       next_url.append("&");
 773     } else {
 774       next_url.append("?");
 775     }
 776     next_url.append(additional_query_);
 777   }
 778   return GURL(next_url);
 779 }
 780
 781 SafeBrowsingProtocolManager::FullHashDetails::FullHashDetails()
 782     : callback(),
 783       is_download(false) {
 784 }
 785
 786 SafeBrowsingProtocolManager::FullHashDetails::FullHashDetails(
 787     FullHashCallback callback, bool is_download)
 788     : callback(callback),
 789       is_download(is_download) {
 790 }
 791
 792 SafeBrowsingProtocolManager::FullHashDetails::~FullHashDetails() {
 793 }
 794
 795 SafeBrowsingProtocolManagerDelegate::~SafeBrowsingProtocolManagerDelegate() {
 796 }