1 // Copyright 2012 The Chromium Authors
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 "net/url_request/url_request_throttler_manager.h"
6
7 #include "base/check_op.h"
8 #include "base/strings/string_util.h"
9 #include "net/base/url_util.h"
10 #include "net/log/net_log.h"
11 #include "net/log/net_log_event_type.h"
12 #include "net/log/net_log_source_type.h"
13
14 namespace net {
15
16 const unsigned int URLRequestThrottlerManager::kMaximumNumberOfEntries = 1500;
17 const unsigned int URLRequestThrottlerManager::kRequestsBetweenCollecting = 200;
18
URLRequestThrottlerManager()19 URLRequestThrottlerManager::URLRequestThrottlerManager() {
20 url_id_replacements_.ClearPassword();
21 url_id_replacements_.ClearUsername();
22 url_id_replacements_.ClearQuery();
23 url_id_replacements_.ClearRef();
24
25 NetworkChangeNotifier::AddIPAddressObserver(this);
26 NetworkChangeNotifier::AddConnectionTypeObserver(this);
27 }
28
~URLRequestThrottlerManager()29 URLRequestThrottlerManager::~URLRequestThrottlerManager() {
30 DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
31 NetworkChangeNotifier::RemoveIPAddressObserver(this);
32 NetworkChangeNotifier::RemoveConnectionTypeObserver(this);
33
34 // Since the manager object might conceivably go away before the
35 // entries, detach the entries' back-pointer to the manager.
36 auto i = url_entries_.begin();
37 while (i != url_entries_.end()) {
38 if (i->second.get() != nullptr) {
39 i->second->DetachManager();
40 }
41 ++i;
42 }
43
44 // Delete all entries.
45 url_entries_.clear();
46 }
47
48 scoped_refptr<URLRequestThrottlerEntryInterface>
RegisterRequestUrl(const GURL & url)49 URLRequestThrottlerManager::RegisterRequestUrl(const GURL &url) {
50 DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
51
52 // Normalize the url.
53 std::string url_id = GetIdFromUrl(url);
54
55 // Periodically garbage collect old entries.
56 GarbageCollectEntriesIfNecessary();
57
58 // Find the entry in the map or create a new NULL entry.
59 scoped_refptr<URLRequestThrottlerEntry>& entry = url_entries_[url_id];
60
61 // If the entry exists but could be garbage collected at this point, we
62 // start with a fresh entry so that we possibly back off a bit less
63 // aggressively (i.e. this resets the error count when the entry's URL
64 // hasn't been requested in long enough).
65 if (entry.get() && entry->IsEntryOutdated()) {
66 entry = nullptr;
67 }
68
69 // Create the entry if needed.
70 if (entry.get() == nullptr) {
71 entry = base::MakeRefCounted<URLRequestThrottlerEntry>(this, url_id);
72
73 // We only disable back-off throttling on an entry that we have
74 // just constructed. This is to allow unit tests to explicitly override
75 // the entry for localhost URLs.
76 if (IsLocalhost(url)) {
77 if (!logged_for_localhost_disabled_ && IsLocalhost(url)) {
78 logged_for_localhost_disabled_ = true;
79 net_log_.AddEventWithStringParams(
80 NetLogEventType::THROTTLING_DISABLED_FOR_HOST, "host", url.host());
81 }
82
83 // TODO(joi): Once sliding window is separate from back-off throttling,
84 // we can simply return a dummy implementation of
85 // URLRequestThrottlerEntryInterface here that never blocks anything.
86 entry->DisableBackoffThrottling();
87 }
88 }
89
90 return entry;
91 }
92
OverrideEntryForTests(const GURL & url,scoped_refptr<URLRequestThrottlerEntry> entry)93 void URLRequestThrottlerManager::OverrideEntryForTests(
94 const GURL& url,
95 scoped_refptr<URLRequestThrottlerEntry> entry) {
96 // Normalize the url.
97 std::string url_id = GetIdFromUrl(url);
98
99 // Periodically garbage collect old entries.
100 GarbageCollectEntriesIfNecessary();
101
102 url_entries_[url_id] = std::move(entry);
103 }
104
EraseEntryForTests(const GURL & url)105 void URLRequestThrottlerManager::EraseEntryForTests(const GURL& url) {
106 // Normalize the url.
107 std::string url_id = GetIdFromUrl(url);
108 url_entries_.erase(url_id);
109 }
110
set_net_log(NetLog * net_log)111 void URLRequestThrottlerManager::set_net_log(NetLog* net_log) {
112 DCHECK(net_log);
113 net_log_ = NetLogWithSource::Make(
114 net_log, NetLogSourceType::EXPONENTIAL_BACKOFF_THROTTLING);
115 }
116
net_log() const117 NetLog* URLRequestThrottlerManager::net_log() const {
118 return net_log_.net_log();
119 }
120
OnIPAddressChanged()121 void URLRequestThrottlerManager::OnIPAddressChanged() {
122 OnNetworkChange();
123 }
124
OnConnectionTypeChanged(NetworkChangeNotifier::ConnectionType type)125 void URLRequestThrottlerManager::OnConnectionTypeChanged(
126 NetworkChangeNotifier::ConnectionType type) {
127 OnNetworkChange();
128 }
129
GetIdFromUrl(const GURL & url) const130 std::string URLRequestThrottlerManager::GetIdFromUrl(const GURL& url) const {
131 if (!url.is_valid())
132 return url.possibly_invalid_spec();
133
134 GURL id = url.ReplaceComponents(url_id_replacements_);
135 return base::ToLowerASCII(id.spec());
136 }
137
GarbageCollectEntriesIfNecessary()138 void URLRequestThrottlerManager::GarbageCollectEntriesIfNecessary() {
139 requests_since_last_gc_++;
140 if (requests_since_last_gc_ < kRequestsBetweenCollecting)
141 return;
142 requests_since_last_gc_ = 0;
143
144 GarbageCollectEntries();
145 }
146
GarbageCollectEntries()147 void URLRequestThrottlerManager::GarbageCollectEntries() {
148 auto i = url_entries_.begin();
149 while (i != url_entries_.end()) {
150 if ((i->second)->IsEntryOutdated()) {
151 url_entries_.erase(i++);
152 } else {
153 ++i;
154 }
155 }
156
157 // In case something broke we want to make sure not to grow indefinitely.
158 while (url_entries_.size() > kMaximumNumberOfEntries) {
159 url_entries_.erase(url_entries_.begin());
160 }
161 }
162
OnNetworkChange()163 void URLRequestThrottlerManager::OnNetworkChange() {
164 // Remove all entries. Any entries that in-flight requests have a reference
165 // to will live until those requests end, and these entries may be
166 // inconsistent with new entries for the same URLs, but since what we
167 // want is a clean slate for the new connection type, this is OK.
168 url_entries_.clear();
169 requests_since_last_gc_ = 0;
170 }
171
172 } // namespace net
173