1 // Copyright (c) 2011 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 #ifndef NET_PROXY_RESOLUTION_PROXY_CONFIG_SERVICE_WIN_H_
6 #define NET_PROXY_RESOLUTION_PROXY_CONFIG_SERVICE_WIN_H_
7 
8 #include <windows.h>
9 #include <winhttp.h>
10 
11 #include <memory>
12 #include <vector>
13 
14 #include "base/compiler_specific.h"
15 #include "base/gtest_prod_util.h"
16 #include "base/strings/string16.h"
17 #include "net/base/net_export.h"
18 #include "net/proxy_resolution/polling_proxy_config_service.h"
19 #include "net/proxy_resolution/proxy_config_with_annotation.h"
20 
21 namespace base {
22 namespace win {
23 class RegKey;
24 }
25 }  // namespace base.
26 
27 namespace net {
28 
29 // Implementation of ProxyConfigService that retrieves the system proxy
30 // settings.
31 //
32 // It works by calling WinHttpGetIEProxyConfigForCurrentUser() to fetch the
33 // Internet Explorer proxy settings.
34 //
35 // We use two different strategies to notice when the configuration has
36 // changed:
37 //
38 // (1) Watch the internet explorer settings registry keys for changes. When
39 //     one of the registry keys pertaining to proxy settings has changed, we
40 //     call WinHttpGetIEProxyConfigForCurrentUser() again to read the
41 //     configuration's new value.
42 //
43 // (2) Do regular polling every 10 seconds during network activity to see if
44 //     WinHttpGetIEProxyConfigForCurrentUser() returns something different.
45 //
46 // Ideally strategy (1) should be sufficient to pick up all of the changes.
47 // However we still do the regular polling as a precaution in case the
48 // implementation details of  WinHttpGetIEProxyConfigForCurrentUser() ever
49 // change, or in case we got it wrong (and are not checking all possible
50 // registry dependencies).
51 class NET_EXPORT_PRIVATE ProxyConfigServiceWin
52     : public PollingProxyConfigService {
53  public:
54   ProxyConfigServiceWin(const NetworkTrafficAnnotationTag& traffic_annotation);
55   ~ProxyConfigServiceWin() override;
56 
57   // Overrides a function from PollingProxyConfigService.
58   void AddObserver(Observer* observer) override;
59 
60  private:
61   FRIEND_TEST_ALL_PREFIXES(ProxyConfigServiceWinTest, SetFromIEConfig);
62 
63   // Registers change observers on the registry keys relating to proxy settings.
64   void StartWatchingRegistryForChanges();
65 
66   // Creates a new key and appends it to |keys_to_watch_|. If the key fails to
67   // be created, it is not appended to the list and we return false.
68   bool AddKeyToWatchList(HKEY rootkey, const base::char16* subkey);
69 
70   // This is called whenever one of the registry keys we are watching change.
71   void OnObjectSignaled(base::win::RegKey* key);
72 
73   static void GetCurrentProxyConfig(
74       const NetworkTrafficAnnotationTag traffic_annotation,
75       ProxyConfigWithAnnotation* config);
76 
77   // Set |config| using the proxy configuration values of |ie_config|.
78   static void SetFromIEConfig(
79       ProxyConfig* config,
80       const WINHTTP_CURRENT_USER_IE_PROXY_CONFIG& ie_config);
81 
82   std::vector<std::unique_ptr<base::win::RegKey>> keys_to_watch_;
83 };
84 
85 }  // namespace net
86 
87 #endif  // NET_PROXY_RESOLUTION_PROXY_CONFIG_SERVICE_WIN_H_
88