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/net/preconnect.h"
6
7#include "base/bind.h"
8#include "base/logging.h"
9#include "base/metrics/histogram.h"
10#include "content/public/browser/browser_thread.h"
11#include "net/base/net_log.h"
12#include "net/http/http_network_session.h"
13#include "net/http/http_request_info.h"
14#include "net/http/http_stream_factory.h"
15#include "net/http/http_transaction_factory.h"
16#include "net/ssl/ssl_config_service.h"
17#include "net/url_request/http_user_agent_settings.h"
18#include "net/url_request/url_request_context.h"
19#include "net/url_request/url_request_context_getter.h"
20
21using content::BrowserThread;
22
23namespace chrome_browser_net {
24
25void PreconnectOnUIThread(
26    const GURL& url,
27    const GURL& first_party_for_cookies,
28    UrlInfo::ResolutionMotivation motivation,
29    int count,
30    net::URLRequestContextGetter* getter) {
31  // Prewarm connection to Search URL.
32  BrowserThread::PostTask(
33      BrowserThread::IO,
34      FROM_HERE,
35      base::Bind(&PreconnectOnIOThread, url, first_party_for_cookies,
36                 motivation, count, make_scoped_refptr(getter)));
37  return;
38}
39
40
41void PreconnectOnIOThread(
42    const GURL& url,
43    const GURL& first_party_for_cookies,
44    UrlInfo::ResolutionMotivation motivation,
45    int count,
46    net::URLRequestContextGetter* getter) {
47  if (!BrowserThread::CurrentlyOn(BrowserThread::IO)) {
48    LOG(DFATAL) << "This must be run only on the IO thread.";
49    return;
50  }
51  if (!getter)
52    return;
53  // We are now commited to doing the async preconnection call.
54  UMA_HISTOGRAM_ENUMERATION("Net.PreconnectMotivation", motivation,
55                            UrlInfo::MAX_MOTIVATED);
56
57  net::URLRequestContext* context = getter->GetURLRequestContext();
58  net::HttpTransactionFactory* factory = context->http_transaction_factory();
59  net::HttpNetworkSession* session = factory->GetSession();
60
61  std::string user_agent;
62  if (context->http_user_agent_settings())
63    user_agent = context->http_user_agent_settings()->GetUserAgent();
64  net::HttpRequestInfo request_info;
65  request_info.url = url;
66  request_info.method = "GET";
67  request_info.extra_headers.SetHeader(net::HttpRequestHeaders::kUserAgent,
68                                       user_agent);
69
70  net::NetworkDelegate* delegate = context->network_delegate();
71  if (delegate->CanEnablePrivacyMode(url, first_party_for_cookies))
72    request_info.privacy_mode = net::PRIVACY_MODE_ENABLED;
73
74  // It almost doesn't matter whether we use net::LOWEST or net::HIGHEST
75  // priority here, as we won't make a request, and will surrender the created
76  // socket to the pool as soon as we can.  However, we would like to mark the
77  // speculative socket as such, and IF we use a net::LOWEST priority, and if
78  // a navigation asked for a socket (after us) then it would get our socket,
79  // and we'd get its later-arriving socket, which might make us record that
80  // the speculation didn't help :-/.  By using net::HIGHEST, we ensure that
81  // a socket is given to us if "we asked first" and this allows us to mark it
82  // as speculative, and better detect stats (if it gets used).
83  // TODO(jar): histogram to see how often we accidentally use a previously-
84  // unused socket, when a previously used socket was available.
85  net::RequestPriority priority = net::HIGHEST;
86
87  // Translate the motivation from UrlRequest motivations to HttpRequest
88  // motivations.
89  switch (motivation) {
90    case UrlInfo::OMNIBOX_MOTIVATED:
91      request_info.motivation = net::HttpRequestInfo::OMNIBOX_MOTIVATED;
92      break;
93    case UrlInfo::LEARNED_REFERAL_MOTIVATED:
94      request_info.motivation = net::HttpRequestInfo::PRECONNECT_MOTIVATED;
95      break;
96    case UrlInfo::MOUSE_OVER_MOTIVATED:
97    case UrlInfo::SELF_REFERAL_MOTIVATED:
98    case UrlInfo::EARLY_LOAD_MOTIVATED:
99      request_info.motivation = net::HttpRequestInfo::EARLY_LOAD_MOTIVATED;
100      break;
101    default:
102      // Other motivations should never happen here.
103      NOTREACHED();
104      break;
105  }
106
107  // Setup the SSL Configuration.
108  net::SSLConfig ssl_config;
109  session->ssl_config_service()->GetSSLConfig(&ssl_config);
110  session->GetNextProtos(&ssl_config.next_protos);
111
112  // All preconnects should perform EV certificate verification.
113  ssl_config.verify_ev_cert = true;
114
115  net::HttpStreamFactory* http_stream_factory = session->http_stream_factory();
116  http_stream_factory->PreconnectStreams(count, request_info, priority,
117                                         ssl_config, ssl_config);
118}
119
120}  // namespace chrome_browser_net
121