intranet_redirect_detector.cc revision c2e0dbddbe15c98d52c4786dac06cb8952a8ae6d 
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/intranet_redirect_detector.h"
6
7#include "base/bind.h"
8#include "base/command_line.h"
9#include "base/prefs/pref_registry_simple.h"
10#include "base/prefs/pref_service.h"
11#include "base/rand_util.h"
12#include "base/stl_util.h"
13#include "base/utf_string_conversions.h"
14#include "chrome/browser/browser_process.h"
15#include "chrome/common/chrome_switches.h"
16#include "chrome/common/pref_names.h"
17#include "net/base/load_flags.h"
18#include "net/base/net_errors.h"
19#include "net/base/registry_controlled_domains/registry_controlled_domain.h"
20#include "net/url_request/url_fetcher.h"
21#include "net/url_request/url_request_context_getter.h"
22#include "net/url_request/url_request_status.h"
23
24const size_t IntranetRedirectDetector::kNumCharsInHostnames = 10;
25
26IntranetRedirectDetector::IntranetRedirectDetector()
27    : redirect_origin_(g_browser_process->local_state()->GetString(
28          prefs::kLastKnownIntranetRedirectOrigin)),
29      weak_factory_(this),
30      in_sleep_(true) {
31  // Because this function can be called during startup, when kicking off a URL
32  // fetch can eat up 20 ms of time, we delay seven seconds, which is hopefully
33  // long enough to be after startup, but still get results back quickly.
34  // Ideally, instead of this timer, we'd do something like "check if the
35  // browser is starting up, and if so, come back later", but there is currently
36  // no function to do this.
37  static const int kStartFetchDelaySeconds = 7;
38  MessageLoop::current()->PostDelayedTask(FROM_HERE,
39      base::Bind(&IntranetRedirectDetector::FinishSleep,
40                 weak_factory_.GetWeakPtr()),
41      base::TimeDelta::FromSeconds(kStartFetchDelaySeconds));
42
43  net::NetworkChangeNotifier::AddIPAddressObserver(this);
44}
45
46IntranetRedirectDetector::~IntranetRedirectDetector() {
47  net::NetworkChangeNotifier::RemoveIPAddressObserver(this);
48  STLDeleteElements(&fetchers_);
49}
50
51// static
52GURL IntranetRedirectDetector::RedirectOrigin() {
53  const IntranetRedirectDetector* const detector =
54      g_browser_process->intranet_redirect_detector();
55  return detector ? detector->redirect_origin_ : GURL();
56}
57
58// static
59void IntranetRedirectDetector::RegisterPrefs(PrefRegistrySimple* registry) {
60  registry->RegisterStringPref(prefs::kLastKnownIntranetRedirectOrigin,
61                               std::string());
62}
63
64void IntranetRedirectDetector::FinishSleep() {
65  in_sleep_ = false;
66
67  // If another fetch operation is still running, cancel it.
68  STLDeleteElements(&fetchers_);
69  resulting_origins_.clear();
70
71  // The detector is not needed in Chrome Frame since we have no omnibox there.
72  const CommandLine* cmd_line = CommandLine::ForCurrentProcess();
73  if (cmd_line->HasSwitch(switches::kDisableBackgroundNetworking) ||
74      cmd_line->HasSwitch(switches::kChromeFrame))
75    return;
76
77  DCHECK(fetchers_.empty() && resulting_origins_.empty());
78
79  // Start three fetchers on random hostnames.
80  for (size_t i = 0; i < 3; ++i) {
81    std::string url_string("http://");
82    for (size_t j = 0; j < kNumCharsInHostnames; ++j)
83      url_string += ('a' + base::RandInt(0, 'z' - 'a'));
84    GURL random_url(url_string + '/');
85    net::URLFetcher* fetcher = net::URLFetcher::Create(
86        random_url, net::URLFetcher::HEAD, this);
87    // We don't want these fetches to affect existing state in the profile.
88    fetcher->SetLoadFlags(net::LOAD_DISABLE_CACHE |
89                          net::LOAD_DO_NOT_SAVE_COOKIES |
90                          net::LOAD_DO_NOT_SEND_COOKIES);
91    fetcher->SetRequestContext(g_browser_process->system_request_context());
92    fetcher->Start();
93    fetchers_.insert(fetcher);
94  }
95}
96
97void IntranetRedirectDetector::OnURLFetchComplete(
98    const net::URLFetcher* source) {
99  // Delete the fetcher on this function's exit.
100  Fetchers::iterator fetcher = fetchers_.find(
101      const_cast<net::URLFetcher*>(source));
102  DCHECK(fetcher != fetchers_.end());
103  scoped_ptr<net::URLFetcher> clean_up_fetcher(*fetcher);
104  fetchers_.erase(fetcher);
105
106  // If any two fetches result in the same domain/host, we set the redirect
107  // origin to that; otherwise we set it to nothing.
108  if (!source->GetStatus().is_success() || (source->GetResponseCode() != 200)) {
109    if ((resulting_origins_.empty()) ||
110        ((resulting_origins_.size() == 1) &&
111         resulting_origins_.front().is_valid())) {
112      resulting_origins_.push_back(GURL());
113      return;
114    }
115    redirect_origin_ = GURL();
116  } else {
117    DCHECK(source->GetURL().is_valid());
118    GURL origin(source->GetURL().GetOrigin());
119    if (resulting_origins_.empty()) {
120      resulting_origins_.push_back(origin);
121      return;
122    }
123    if (net::RegistryControlledDomainService::SameDomainOrHost(
124        resulting_origins_.front(), origin)) {
125      redirect_origin_ = origin;
126      if (!fetchers_.empty()) {
127        // Cancel remaining fetch, we don't need it.
128        DCHECK(fetchers_.size() == 1);
129        delete (*fetchers_.begin());
130        fetchers_.clear();
131      }
132    }
133    if (resulting_origins_.size() == 1) {
134      resulting_origins_.push_back(origin);
135      return;
136    }
137    DCHECK(resulting_origins_.size() == 2);
138    redirect_origin_ = net::RegistryControlledDomainService::SameDomainOrHost(
139        resulting_origins_.back(), origin) ? origin : GURL();
140  }
141
142  g_browser_process->local_state()->SetString(
143      prefs::kLastKnownIntranetRedirectOrigin, redirect_origin_.is_valid() ?
144          redirect_origin_.spec() : std::string());
145}
146
147void IntranetRedirectDetector::OnIPAddressChanged() {
148  // If a request is already scheduled, do not scheduled yet another one.
149  if (in_sleep_)
150    return;
151
152  // Since presumably many programs open connections after network changes,
153  // delay this a little bit.
154  in_sleep_ = true;
155  static const int kNetworkSwitchDelayMS = 1000;
156  MessageLoop::current()->PostDelayedTask(FROM_HERE,
157      base::Bind(&IntranetRedirectDetector::FinishSleep,
158                 weak_factory_.GetWeakPtr()),
159      base::TimeDelta::FromMilliseconds(kNetworkSwitchDelayMS));
160}
161
162IntranetRedirectHostResolverProc::IntranetRedirectHostResolverProc(
163    net::HostResolverProc* previous)
164    : net::HostResolverProc(previous) {
165}
166
167int IntranetRedirectHostResolverProc::Resolve(
168    const std::string& host,
169    net::AddressFamily address_family,
170    net::HostResolverFlags host_resolver_flags,
171    net::AddressList* addrlist,
172    int* os_error) {
173  // We'd love to just ask the IntranetRedirectDetector, but we may not be on
174  // the same thread.  So just use the heuristic that any all-lowercase a-z
175  // hostname with the right number of characters is likely from the detector
176  // (and thus should be blocked).
177  return ((host.length() == IntranetRedirectDetector::kNumCharsInHostnames) &&
178      (host.find_first_not_of("abcdefghijklmnopqrstuvwxyz") ==
179          std::string::npos)) ?
180      net::ERR_NAME_NOT_RESOLVED :
181      ResolveUsingPrevious(host, address_family, host_resolver_flags, addrlist,
182                           os_error);
183}
184