extensions/browser/extension_throttle_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 "extensions/browser/extension_throttle_manager.h"
   6
   7 #include "base/logging.h"
   8 #include "base/metrics/field_trial.h"
   9 #include "base/metrics/histogram.h"
  10 #include "base/strings/string_util.h"
  11 #include "extensions/browser/extension_request_limiting_throttle.h"
  12 #include "extensions/common/constants.h"
  13 #include "net/base/net_util.h"
  14 #include "net/log/net_log.h"
  15 #include "net/url_request/url_request.h"
  16
  17 namespace extensions {
  18
  19 const unsigned int ExtensionThrottleManager::kMaximumNumberOfEntries = 1500;
  20 const unsigned int ExtensionThrottleManager::kRequestsBetweenCollecting = 200;
  21
  22 ExtensionThrottleManager::ExtensionThrottleManager()
  23     : requests_since_last_gc_(0),
  24       enable_thread_checks_(false),
  25       logged_for_localhost_disabled_(false),
  26       registered_from_thread_(base::kInvalidThreadId),
  27       ignore_user_gesture_load_flag_for_tests_(false) {
  28   url_id_replacements_.ClearPassword();
  29   url_id_replacements_.ClearUsername();
  30   url_id_replacements_.ClearQuery();
  31   url_id_replacements_.ClearRef();
  32
  33   net::NetworkChangeNotifier::AddIPAddressObserver(this);
  34   net::NetworkChangeNotifier::AddConnectionTypeObserver(this);
  35 }
  36
  37 ExtensionThrottleManager::~ExtensionThrottleManager() {
  38   net::NetworkChangeNotifier::RemoveIPAddressObserver(this);
  39   net::NetworkChangeNotifier::RemoveConnectionTypeObserver(this);
  40
  41   // Since the manager object might conceivably go away before the
  42   // entries, detach the entries' back-pointer to the manager.
  43   UrlEntryMap::iterator i = url_entries_.begin();
  44   while (i != url_entries_.end()) {
  45     if (i->second.get() != NULL) {
  46       i->second->DetachManager();
  47     }
  48     ++i;
  49   }
  50
  51   // Delete all entries.
  52   url_entries_.clear();
  53 }
  54
  55 scoped_ptr<content::ResourceThrottle>
  56 ExtensionThrottleManager::MaybeCreateThrottle(const net::URLRequest* request) {
  57   if (request->first_party_for_cookies().scheme() !=
  58       extensions::kExtensionScheme) {
  59     return nullptr;
  60   }
  61   return make_scoped_ptr(
  62       new extensions::ExtensionRequestLimitingThrottle(request, this));
  63 }
  64
  65 scoped_refptr<ExtensionThrottleEntryInterface>
  66 ExtensionThrottleManager::RegisterRequestUrl(const GURL& url) {
  67   DCHECK(!enable_thread_checks_ || CalledOnValidThread());
  68
  69   // Normalize the url.
  70   std::string url_id = GetIdFromUrl(url);
  71
  72   // Periodically garbage collect old entries.
  73   GarbageCollectEntriesIfNecessary();
  74
  75   // Find the entry in the map or create a new NULL entry.
  76   scoped_refptr<ExtensionThrottleEntry>& entry = url_entries_[url_id];
  77
  78   // If the entry exists but could be garbage collected at this point, we
  79   // start with a fresh entry so that we possibly back off a bit less
  80   // aggressively (i.e. this resets the error count when the entry's URL
  81   // hasn't been requested in long enough).
  82   if (entry.get() && entry->IsEntryOutdated()) {
  83     entry = NULL;
  84   }
  85
  86   // Create the entry if needed.
  87   if (entry.get() == NULL) {
  88     if (backoff_policy_for_tests_) {
  89       entry = new ExtensionThrottleEntry(
  90           this, url_id, backoff_policy_for_tests_.get(),
  91           ignore_user_gesture_load_flag_for_tests_);
  92     } else {
  93       entry = new ExtensionThrottleEntry(
  94           this, url_id, ignore_user_gesture_load_flag_for_tests_);
  95     }
  96
  97     // We only disable back-off throttling on an entry that we have
  98     // just constructed.  This is to allow unit tests to explicitly override
  99     // the entry for localhost URLs.
 100     std::string host = url.host();
 101     if (net::IsLocalhost(host)) {
 102       if (!logged_for_localhost_disabled_ && net::IsLocalhost(host)) {
 103         logged_for_localhost_disabled_ = true;
 104         net_log_.AddEvent(net::NetLog::TYPE_THROTTLING_DISABLED_FOR_HOST,
 105                           net::NetLog::StringCallback("host", &host));
 106       }
 107
 108       // TODO(joi): Once sliding window is separate from back-off throttling,
 109       // we can simply return a dummy implementation of
 110       // ExtensionThrottleEntryInterface here that never blocks anything.
 111       entry->DisableBackoffThrottling();
 112     }
 113   }
 114
 115   return entry;
 116 }
 117
 118 void ExtensionThrottleManager::SetBackoffPolicyForTests(
 119     scoped_ptr<net::BackoffEntry::Policy> policy) {
 120   backoff_policy_for_tests_ = policy.Pass();
 121 }
 122
 123 void ExtensionThrottleManager::OverrideEntryForTests(
 124     const GURL& url,
 125     ExtensionThrottleEntry* entry) {
 126   // Normalize the url.
 127   std::string url_id = GetIdFromUrl(url);
 128
 129   // Periodically garbage collect old entries.
 130   GarbageCollectEntriesIfNecessary();
 131
 132   url_entries_[url_id] = entry;
 133 }
 134
 135 void ExtensionThrottleManager::EraseEntryForTests(const GURL& url) {
 136   // Normalize the url.
 137   std::string url_id = GetIdFromUrl(url);
 138   url_entries_.erase(url_id);
 139 }
 140
 141 void ExtensionThrottleManager::SetIgnoreUserGestureLoadFlagForTests(
 142     bool ignore_user_gesture_load_flag_for_tests) {
 143   ignore_user_gesture_load_flag_for_tests_ = true;
 144 }
 145
 146 void ExtensionThrottleManager::set_enable_thread_checks(bool enable) {
 147   enable_thread_checks_ = enable;
 148 }
 149
 150 bool ExtensionThrottleManager::enable_thread_checks() const {
 151   return enable_thread_checks_;
 152 }
 153
 154 void ExtensionThrottleManager::set_net_log(net::NetLog* net_log) {
 155   DCHECK(net_log);
 156   net_log_ = net::BoundNetLog::Make(
 157       net_log, net::NetLog::SOURCE_EXPONENTIAL_BACKOFF_THROTTLING);
 158 }
 159
 160 net::NetLog* ExtensionThrottleManager::net_log() const {
 161   return net_log_.net_log();
 162 }
 163
 164 void ExtensionThrottleManager::OnIPAddressChanged() {
 165   OnNetworkChange();
 166 }
 167
 168 void ExtensionThrottleManager::OnConnectionTypeChanged(
 169     net::NetworkChangeNotifier::ConnectionType type) {
 170   OnNetworkChange();
 171 }
 172
 173 std::string ExtensionThrottleManager::GetIdFromUrl(const GURL& url) const {
 174   if (!url.is_valid())
 175     return url.possibly_invalid_spec();
 176
 177   GURL id = url.ReplaceComponents(url_id_replacements_);
 178   return base::StringToLowerASCII(id.spec()).c_str();
 179 }
 180
 181 void ExtensionThrottleManager::GarbageCollectEntriesIfNecessary() {
 182   requests_since_last_gc_++;
 183   if (requests_since_last_gc_ < kRequestsBetweenCollecting)
 184     return;
 185   requests_since_last_gc_ = 0;
 186
 187   GarbageCollectEntries();
 188 }
 189
 190 void ExtensionThrottleManager::GarbageCollectEntries() {
 191   UrlEntryMap::iterator i = url_entries_.begin();
 192   while (i != url_entries_.end()) {
 193     if ((i->second)->IsEntryOutdated()) {
 194       url_entries_.erase(i++);
 195     } else {
 196       ++i;
 197     }
 198   }
 199
 200   // In case something broke we want to make sure not to grow indefinitely.
 201   while (url_entries_.size() > kMaximumNumberOfEntries) {
 202     url_entries_.erase(url_entries_.begin());
 203   }
 204 }
 205
 206 void ExtensionThrottleManager::OnNetworkChange() {
 207   // Remove all entries.  Any entries that in-flight requests have a reference
 208   // to will live until those requests end, and these entries may be
 209   // inconsistent with new entries for the same URLs, but since what we
 210   // want is a clean slate for the new connection type, this is OK.
 211   url_entries_.clear();
 212   requests_since_last_gc_ = 0;
 213 }
 214
 215 }  // namespace extensions