netwerk/wifi/win_wifiScanner.cpp

   1 /* This Source Code Form is subject to the terms of the Mozilla Public
   2  * License, v. 2.0. If a copy of the MPL was not distributed with this
   3  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   4
   5 #include "nsWifiAccessPoint.h"
   6 #include "win_wifiScanner.h"
   7
   8 // Moz headers (alphabetical)
   9 #include "win_wlanLibrary.h"
  10
  11 #define DOT11_BSS_TYPE_UNUSED static_cast<DOT11_BSS_TYPE>(0)
  12
  13 class InterfaceScanCallbackData {
  14 public:
  15   explicit InterfaceScanCallbackData(uint32_t numInterfaces)
  16     : mCurrentlyScanningInterfaces(numInterfaces)
  17   {
  18     mAllInterfacesDoneScanningEvent =
  19       ::CreateEvent(nullptr,  // null security
  20                     TRUE,     // manual reset event
  21                     FALSE,    // initially nonsignaled
  22                     nullptr); // not named
  23     MOZ_ASSERT(NULL != mAllInterfacesDoneScanningEvent);
  24   }
  25
  26   ~InterfaceScanCallbackData()
  27   {
  28     ::CloseHandle(mAllInterfacesDoneScanningEvent);
  29   }
  30
  31   void
  32   OnInterfaceScanComplete()
  33   {
  34     uint32_t val = ::InterlockedDecrement(&mCurrentlyScanningInterfaces);
  35     if (!val) {
  36       ::SetEvent(mAllInterfacesDoneScanningEvent);
  37     }
  38   }
  39
  40   void
  41   WaitForAllInterfacesToFinishScanning(uint32_t msToWait)
  42   {
  43     ::WaitForSingleObject(mAllInterfacesDoneScanningEvent,
  44                           msToWait);
  45   }
  46
  47 private:
  48   volatile uint32_t mCurrentlyScanningInterfaces;
  49   HANDLE mAllInterfacesDoneScanningEvent;
  50 };
  51
  52 static void
  53 OnScanComplete(PWLAN_NOTIFICATION_DATA data, PVOID context)
  54 {
  55   if (WLAN_NOTIFICATION_SOURCE_ACM != data->NotificationSource) {
  56     return;
  57   }
  58
  59   if (wlan_notification_acm_scan_complete != data->NotificationCode &&
  60       wlan_notification_acm_scan_fail != data->NotificationCode) {
  61     return;
  62   }
  63
  64   InterfaceScanCallbackData* cbData =
  65     reinterpret_cast<InterfaceScanCallbackData*>(context);
  66   cbData->OnInterfaceScanComplete();
  67 }
  68
  69 WinWifiScanner::WinWifiScanner()
  70 {
  71   // NOTE: We assume that, if we were unable to load the WLAN library when
  72   // we initially tried, we will not be able to load it in the future.
  73   // Technically, on Windows XP SP2, a user could install the redistributable
  74   // and make our assumption incorrect. We opt to avoid making a bunch of
  75   // spurious LoadLibrary calls in the common case rather than load the
  76   // WLAN API in the edge case.
  77   mWlanLibrary = WinWLANLibrary::Load();
  78   if (!mWlanLibrary) {
  79     NS_WARNING("Could not initialize Windows Wi-Fi scanner");
  80   }
  81 }
  82
  83 WinWifiScanner::~WinWifiScanner()
  84 {
  85 }
  86
  87 nsresult
  88 WinWifiScanner::GetAccessPointsFromWLAN(nsCOMArray<nsWifiAccessPoint> &accessPoints)
  89 {
  90   accessPoints.Clear();
  91
  92   // NOTE: We do not try to load the WLAN library if we previously failed
  93   // to load it. See the note in WinWifiScanner constructor
  94   if (!mWlanLibrary) {
  95     return NS_ERROR_NOT_AVAILABLE;
  96   }
  97
  98   // Get the list of interfaces. WlanEnumInterfaces allocates interface_list.
  99   WLAN_INTERFACE_INFO_LIST *interface_list = nullptr;
 100   if (ERROR_SUCCESS !=
 101       (*mWlanLibrary->GetWlanEnumInterfacesPtr())(mWlanLibrary->GetWLANHandle(),
 102                                                   nullptr,
 103                                                   &interface_list)) {
 104     return NS_ERROR_FAILURE;
 105   }
 106
 107   // This ensures we call WlanFreeMemory on interface_list
 108   ScopedWLANObject scopedInterfaceList(mWlanLibrary, interface_list);
 109
 110   if (!interface_list->dwNumberOfItems) {
 111     return NS_OK;
 112   }
 113
 114   InterfaceScanCallbackData cbData(interface_list->dwNumberOfItems);
 115
 116   DWORD wlanNotifySource;
 117   if (ERROR_SUCCESS !=
 118       (*mWlanLibrary->GetWlanRegisterNotificationPtr())(
 119                                   mWlanLibrary->GetWLANHandle(),
 120                                   WLAN_NOTIFICATION_SOURCE_ACM,
 121                                   TRUE,
 122                                   (WLAN_NOTIFICATION_CALLBACK)OnScanComplete,
 123                                   &cbData,
 124                                   NULL,
 125                                   &wlanNotifySource)) {
 126     return NS_ERROR_FAILURE;
 127   }
 128
 129   // Go through the list of interfaces and call `WlanScan` on each
 130   for (unsigned int i = 0; i < interface_list->dwNumberOfItems; ++i) {
 131     if (ERROR_SUCCESS !=
 132         (*mWlanLibrary->GetWlanScanPtr())(
 133                     mWlanLibrary->GetWLANHandle(),
 134                     &interface_list->InterfaceInfo[i].InterfaceGuid,
 135                     NULL,
 136                     NULL,
 137                     NULL)) {
 138       cbData.OnInterfaceScanComplete();
 139     }
 140   }
 141
 142   // From the MSDN documentation:
 143   //   "Wireless network drivers that meet Windows logo requirements are
 144   // required to complete a WlanScan function request in 4 seconds"
 145   cbData.WaitForAllInterfacesToFinishScanning(5000);
 146
 147   // Unregister for the notifications. The documentation mentions that,
 148   // if a callback is currently running, this will wait for the callback
 149   // to complete.
 150   (*mWlanLibrary->GetWlanRegisterNotificationPtr())(
 151                               mWlanLibrary->GetWLANHandle(),
 152                               WLAN_NOTIFICATION_SOURCE_NONE,
 153                               TRUE,
 154                               NULL,
 155                               NULL,
 156                               NULL,
 157                               &wlanNotifySource);
 158
 159   // Go through the list of interfaces and get the data for each.
 160   for (uint32_t i = 0; i < interface_list->dwNumberOfItems; ++i) {
 161     WLAN_BSS_LIST *bss_list;
 162     if (ERROR_SUCCESS !=
 163         (*mWlanLibrary->GetWlanGetNetworkBssListPtr())(
 164                            mWlanLibrary->GetWLANHandle(),
 165                            &interface_list->InterfaceInfo[i].InterfaceGuid,
 166                            nullptr,  // Use all SSIDs.
 167                            DOT11_BSS_TYPE_UNUSED,
 168                            false,    // bSecurityEnabled - unused
 169                            nullptr,  // reserved
 170                            &bss_list)) {
 171       continue;
 172     }
 173
 174     // This ensures we call WlanFreeMemory on bss_list
 175     ScopedWLANObject scopedBssList(mWlanLibrary, bss_list);
 176
 177     // Store each discovered access point in our outparam
 178     for (int j = 0; j < static_cast<int>(bss_list->dwNumberOfItems); ++j) {
 179       nsWifiAccessPoint* ap = new nsWifiAccessPoint();
 180       if (!ap) {
 181         continue;
 182       }
 183
 184       const WLAN_BSS_ENTRY bss_entry = bss_list->wlanBssEntries[j];
 185       ap->setMac(bss_entry.dot11Bssid);
 186       ap->setSignal(bss_entry.lRssi);
 187       ap->setSSID(reinterpret_cast<char const*>(bss_entry.dot11Ssid.ucSSID),
 188                   bss_entry.dot11Ssid.uSSIDLength);
 189
 190       accessPoints.AppendObject(ap);
 191     }
 192   }
 193
 194   return NS_OK;
 195 }