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