net/proxy/proxy_script_decider.h

   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 #ifndef NET_PROXY_PROXY_SCRIPT_DECIDER_H_
   6 #define NET_PROXY_PROXY_SCRIPT_DECIDER_H_
   7
   8 #include <string>
   9 #include <vector>
  10
  11 #include "base/memory/ref_counted.h"
  12 #include "base/strings/string16.h"
  13 #include "base/time/time.h"
  14 #include "base/timer/timer.h"
  15 #include "net/base/address_list.h"
  16 #include "net/base/completion_callback.h"
  17 #include "net/base/net_export.h"
  18 #include "net/dns/host_resolver.h"
  19 #include "net/dns/single_request_host_resolver.h"
  20 #include "net/log/net_log.h"
  21 #include "net/proxy/proxy_config.h"
  22 #include "net/proxy/proxy_resolver.h"
  23 #include "url/gurl.h"
  24
  25 namespace net {
  26
  27 class DhcpProxyScriptFetcher;
  28 class NetLogParameter;
  29 class ProxyResolver;
  30 class ProxyScriptFetcher;
  31
  32 // ProxyScriptDecider is a helper class used by ProxyService to determine which
  33 // PAC script to use given our proxy configuration.
  34 //
  35 // This involves trying to use PAC scripts in this order:
  36 //
  37 //   (1) WPAD (DHCP) if auto-detect is on.
  38 //   (2) WPAD (DNS) if auto-detect is on.
  39 //   (3) Custom PAC script if a URL was given.
  40 //
  41 // If no PAC script was successfully selected, then it fails with either a
  42 // network error, or PAC_SCRIPT_FAILED (indicating it did not pass our
  43 // validation).
  44 //
  45 // On successful completion, the fetched PAC script data can be accessed using
  46 // script_data().
  47 //
  48 // Deleting ProxyScriptDecider while Init() is in progress, will
  49 // cancel the request.
  50 //
  51 class NET_EXPORT_PRIVATE ProxyScriptDecider {
  52  public:
  53   // |proxy_script_fetcher|, |dhcp_proxy_script_fetcher| and
  54   // |net_log| must remain valid for the lifespan of ProxyScriptDecider.
  55   ProxyScriptDecider(ProxyScriptFetcher* proxy_script_fetcher,
  56                      DhcpProxyScriptFetcher* dhcp_proxy_script_fetcher,
  57                      NetLog* net_log);
  58
  59   // Aborts any in-progress request.
  60   ~ProxyScriptDecider();
  61
  62   // Evaluates the effective proxy settings for |config|, and downloads the
  63   // associated PAC script.
  64   // If |wait_delay| is positive, the initialization will pause for this
  65   // amount of time before getting started.
  66   // On successful completion, the "effective" proxy settings we ended up
  67   // deciding on will be available vial the effective_settings() accessor.
  68   // Note that this may differ from |config| since we will have stripped any
  69   // manual settings, and decided whether to use auto-detect or the custom PAC
  70   // URL. Finally, if auto-detect was used we may now have resolved that to a
  71   // specific script URL.
  72   int Start(const ProxyConfig& config,
  73             const base::TimeDelta wait_delay,
  74             bool fetch_pac_bytes,
  75             const net::CompletionCallback& callback);
  76
  77   const ProxyConfig& effective_config() const;
  78
  79   // TODO(eroman): Return a const-pointer.
  80   ProxyResolverScriptData* script_data() const;
  81
  82   void set_quick_check_enabled(bool enabled) {
  83     quick_check_enabled_ = enabled;
  84   }
  85
  86   bool quick_check_enabled() const { return quick_check_enabled_; }
  87
  88  private:
  89   // Represents the sources from which we can get PAC files; two types of
  90   // auto-detect or a custom URL.
  91   struct PacSource {
  92     enum Type {
  93       WPAD_DHCP,
  94       WPAD_DNS,
  95       CUSTOM
  96     };
  97
  98     PacSource(Type type, const GURL& url)
  99         : type(type), url(url) {}
 100
 101     // Returns a Value representing the PacSource.  |effective_pac_url| must
 102     // be non-NULL and point to the URL derived from information contained in
 103     // |this|, if Type is not WPAD_DHCP.
 104     base::Value* NetLogCallback(const GURL* effective_pac_url,
 105                                 NetLogCaptureMode capture_mode) const;
 106
 107     Type type;
 108     GURL url;  // Empty unless |type == PAC_SOURCE_CUSTOM|.
 109   };
 110
 111   typedef std::vector<PacSource> PacSourceList;
 112
 113   enum State {
 114     STATE_NONE,
 115     STATE_WAIT,
 116     STATE_WAIT_COMPLETE,
 117     STATE_QUICK_CHECK,
 118     STATE_QUICK_CHECK_COMPLETE,
 119     STATE_FETCH_PAC_SCRIPT,
 120     STATE_FETCH_PAC_SCRIPT_COMPLETE,
 121     STATE_VERIFY_PAC_SCRIPT,
 122     STATE_VERIFY_PAC_SCRIPT_COMPLETE,
 123   };
 124
 125   // Returns ordered list of PAC urls to try for |config|.
 126   PacSourceList BuildPacSourcesFallbackList(const ProxyConfig& config) const;
 127
 128   void OnIOCompletion(int result);
 129   int DoLoop(int result);
 130   void DoCallback(int result);
 131
 132   int DoWait();
 133   int DoWaitComplete(int result);
 134
 135   int DoQuickCheck();
 136   int DoQuickCheckComplete(int result);
 137
 138   int DoFetchPacScript();
 139   int DoFetchPacScriptComplete(int result);
 140
 141   int DoVerifyPacScript();
 142   int DoVerifyPacScriptComplete(int result);
 143
 144   // Tries restarting using the next fallback PAC URL:
 145   // |pac_sources_[++current_pac_source_index]|.
 146   // Returns OK and rewinds the state machine when there
 147   // is something to try, otherwise returns |error|.
 148   int TryToFallbackPacSource(int error);
 149
 150   // Gets the initial state (we skip fetching when the
 151   // ProxyResolver doesn't |expect_pac_bytes()|.
 152   State GetStartState() const;
 153
 154   void DetermineURL(const PacSource& pac_source, GURL* effective_pac_url);
 155
 156   // Returns the current PAC URL we are fetching/testing.
 157   const PacSource& current_pac_source() const;
 158
 159   void OnWaitTimerFired();
 160   void DidComplete();
 161   void Cancel();
 162
 163   ProxyScriptFetcher* proxy_script_fetcher_;
 164   DhcpProxyScriptFetcher* dhcp_proxy_script_fetcher_;
 165
 166   net::CompletionCallback callback_;
 167
 168   size_t current_pac_source_index_;
 169
 170   // Filled when the PAC script fetch completes.
 171   base::string16 pac_script_;
 172
 173   // Flag indicating whether the caller requested a mandatory pac script
 174   // (i.e. fallback to direct connections are prohibited).
 175   bool pac_mandatory_;
 176
 177   // Whether we have an existing custom PAC URL.
 178   bool have_custom_pac_url_;
 179
 180   PacSourceList pac_sources_;
 181   State next_state_;
 182
 183   BoundNetLog net_log_;
 184
 185   bool fetch_pac_bytes_;
 186
 187   base::TimeDelta wait_delay_;
 188   base::OneShotTimer<ProxyScriptDecider> wait_timer_;
 189
 190   // Whether to do DNS quick check
 191   bool quick_check_enabled_;
 192
 193   // Results.
 194   ProxyConfig effective_config_;
 195   scoped_refptr<ProxyResolverScriptData> script_data_;
 196
 197   AddressList wpad_addresses_;
 198   base::OneShotTimer<ProxyScriptDecider> quick_check_timer_;
 199   scoped_ptr<SingleRequestHostResolver> host_resolver_;
 200   base::Time quick_check_start_time_;
 201
 202   DISALLOW_COPY_AND_ASSIGN(ProxyScriptDecider);
 203 };
 204
 205 }  // namespace net
 206
 207 #endif  // NET_PROXY_PROXY_SCRIPT_DECIDER_H_