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      1 // Copyright (c) 2010 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 // For OSX 10.5 we use the system API function WirelessScanSplit. This function
      6 // is not documented or included in the SDK, so we use a reverse-engineered
      7 // header, osx_wifi_.h. This file is taken from the iStumbler project
      8 // (http://www.istumbler.net).
      9 
     10 #include "content/browser/geolocation/wifi_data_provider_mac.h"
     11 
     12 #include <dlfcn.h>
     13 #include <stdio.h>
     14 
     15 #include "base/strings/utf_string_conversions.h"
     16 #include "content/browser/geolocation/osx_wifi.h"
     17 #include "content/browser/geolocation/wifi_data_provider_common.h"
     18 
     19 namespace content {
     20 namespace {
     21 // The time periods, in milliseconds, between successive polls of the wifi data.
     22 const int kDefaultPollingInterval = 120000;  // 2 mins
     23 const int kNoChangePollingInterval = 300000;  // 5 mins
     24 const int kTwoNoChangePollingInterval = 600000;  // 10 mins
     25 const int kNoWifiPollingIntervalMilliseconds = 20 * 1000; // 20s
     26 
     27 // Provides the wifi API binding for use when running on OSX 10.5 machines using
     28 // the Apple80211 framework.
     29 class Apple80211Api : public WifiDataProviderCommon::WlanApiInterface {
     30  public:
     31   Apple80211Api();
     32   virtual ~Apple80211Api();
     33 
     34   // Must be called before any other interface method. Will return false if the
     35   // Apple80211 framework cannot be initialized (e.g. running on post-10.5 OSX),
     36   // in which case no other method may be called.
     37   bool Init();
     38 
     39   // WlanApiInterface
     40   virtual bool GetAccessPointData(WifiData::AccessPointDataSet* data) OVERRIDE;
     41 
     42  private:
     43   // Handle, context and function pointers for Apple80211 library.
     44   void* apple_80211_library_;
     45   WirelessContext* wifi_context_;
     46   WirelessAttachFunction WirelessAttach_function_;
     47   WirelessScanSplitFunction WirelessScanSplit_function_;
     48   WirelessDetachFunction WirelessDetach_function_;
     49 
     50   WifiData wifi_data_;
     51 
     52   DISALLOW_COPY_AND_ASSIGN(Apple80211Api);
     53 };
     54 
     55 Apple80211Api::Apple80211Api()
     56     : apple_80211_library_(NULL), wifi_context_(NULL),
     57       WirelessAttach_function_(NULL), WirelessScanSplit_function_(NULL),
     58       WirelessDetach_function_(NULL) {
     59 }
     60 
     61 Apple80211Api::~Apple80211Api() {
     62   if (WirelessDetach_function_)
     63     (*WirelessDetach_function_)(wifi_context_);
     64   dlclose(apple_80211_library_);
     65 }
     66 
     67 bool Apple80211Api::Init() {
     68   DVLOG(1) << "Apple80211Api::Init";
     69   apple_80211_library_ = dlopen(
     70       "/System/Library/PrivateFrameworks/Apple80211.framework/Apple80211",
     71       RTLD_LAZY);
     72   if (!apple_80211_library_) {
     73     DLOG(WARNING) << "Could not open Apple80211 library";
     74     return false;
     75   }
     76   WirelessAttach_function_ = reinterpret_cast<WirelessAttachFunction>(
     77       dlsym(apple_80211_library_, "WirelessAttach"));
     78   WirelessScanSplit_function_ = reinterpret_cast<WirelessScanSplitFunction>(
     79       dlsym(apple_80211_library_, "WirelessScanSplit"));
     80   WirelessDetach_function_ = reinterpret_cast<WirelessDetachFunction>(
     81       dlsym(apple_80211_library_, "WirelessDetach"));
     82   DCHECK(WirelessAttach_function_);
     83   DCHECK(WirelessScanSplit_function_);
     84   DCHECK(WirelessDetach_function_);
     85 
     86   if (!WirelessAttach_function_ || !WirelessScanSplit_function_ ||
     87       !WirelessDetach_function_) {
     88     DLOG(WARNING) << "Symbol error. Attach: " << !!WirelessAttach_function_
     89         << " Split: " << !!WirelessScanSplit_function_
     90         << " Detach: " << !!WirelessDetach_function_;
     91     return false;
     92   }
     93 
     94   WIErr err = (*WirelessAttach_function_)(&wifi_context_, 0);
     95   if (err != noErr) {
     96     DLOG(WARNING) << "Error attaching: " << err;
     97     return false;
     98   }
     99   return true;
    100 }
    101 
    102 bool Apple80211Api::GetAccessPointData(WifiData::AccessPointDataSet* data) {
    103   DVLOG(1) << "Apple80211Api::GetAccessPointData";
    104   DCHECK(data);
    105   DCHECK(WirelessScanSplit_function_);
    106   CFArrayRef managed_access_points = NULL;
    107   CFArrayRef adhoc_access_points = NULL;
    108   // Arrays returned here are owned by the caller.
    109   WIErr err = (*WirelessScanSplit_function_)(wifi_context_,
    110                                              &managed_access_points,
    111                                              &adhoc_access_points,
    112                                              0);
    113   if (err != noErr) {
    114     DLOG(WARNING) << "Error spliting scan: " << err;
    115     return false;
    116   }
    117 
    118   if (managed_access_points == NULL) {
    119     DLOG(WARNING) << "managed_access_points == NULL";
    120     return false;
    121   }
    122 
    123   int num_access_points = CFArrayGetCount(managed_access_points);
    124   DVLOG(1) << "Found " << num_access_points << " managed access points";
    125   for (int i = 0; i < num_access_points; ++i) {
    126     const WirelessNetworkInfo* access_point_info =
    127         reinterpret_cast<const WirelessNetworkInfo*>(
    128         CFDataGetBytePtr(
    129         reinterpret_cast<const CFDataRef>(
    130         CFArrayGetValueAtIndex(managed_access_points, i))));
    131 
    132     // Currently we get only MAC address, signal strength, channel
    133     // signal-to-noise and SSID
    134     AccessPointData access_point_data;
    135     access_point_data.mac_address =
    136         MacAddressAsString16(access_point_info->macAddress);
    137     // WirelessNetworkInfo::signal appears to be signal strength in dBm.
    138     access_point_data.radio_signal_strength = access_point_info->signal;
    139     access_point_data.channel = access_point_info->channel;
    140     // WirelessNetworkInfo::noise appears to be noise floor in dBm.
    141     access_point_data.signal_to_noise = access_point_info->signal -
    142                                         access_point_info->noise;
    143     if (!base::UTF8ToUTF16(reinterpret_cast<const char*>(
    144                                access_point_info->name),
    145                            access_point_info->nameLen,
    146                            &access_point_data.ssid)) {
    147       access_point_data.ssid.clear();
    148     }
    149     data->insert(access_point_data);
    150   }
    151 
    152   if (managed_access_points)
    153     CFRelease(managed_access_points);
    154   if (adhoc_access_points)
    155     CFRelease(adhoc_access_points);
    156 
    157   return true;
    158 }
    159 }  // namespace
    160 
    161 // static
    162 WifiDataProviderImplBase* WifiDataProvider::DefaultFactoryFunction() {
    163   return new MacWifiDataProvider();
    164 }
    165 
    166 MacWifiDataProvider::MacWifiDataProvider() {
    167 }
    168 
    169 MacWifiDataProvider::~MacWifiDataProvider() {
    170 }
    171 
    172 MacWifiDataProvider::WlanApiInterface* MacWifiDataProvider::NewWlanApi() {
    173   // Try and find a API binding that works: first try the officially supported
    174   // CoreWLAN API, and if this fails (e.g. on OSX 10.5) fall back to the reverse
    175   // engineered Apple80211 API.
    176   MacWifiDataProvider::WlanApiInterface* core_wlan_api = NewCoreWlanApi();
    177   if (core_wlan_api)
    178     return core_wlan_api;
    179 
    180   scoped_ptr<Apple80211Api> wlan_api(new Apple80211Api);
    181   if (wlan_api->Init())
    182     return wlan_api.release();
    183 
    184   DVLOG(1) << "MacWifiDataProvider : failed to initialize any wlan api";
    185   return NULL;
    186 }
    187 
    188 WifiPollingPolicy* MacWifiDataProvider::NewPollingPolicy() {
    189   return new GenericWifiPollingPolicy<kDefaultPollingInterval,
    190                                       kNoChangePollingInterval,
    191                                       kTwoNoChangePollingInterval,
    192                                       kNoWifiPollingIntervalMilliseconds>;
    193 }
    194 
    195 }  // namespace content
    196