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   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   MOZ_ASSERT(mWlanLibrary);
  79 }
  80
  81 WinWifiScanner::~WinWifiScanner()
  82 {
  83 }
  84
  85 nsresult
  86 WinWifiScanner::GetAccessPointsFromWLAN(nsCOMArray<nsWifiAccessPoint> &accessPoints)
  87 {
  88   accessPoints.Clear();
  89
  90   // NOTE: We do not try to load the WLAN library if we previously failed
  91   // to load it. See the note in WinWifiScanner constructor
  92   if (!mWlanLibrary) {
  93     return NS_ERROR_NOT_AVAILABLE;
  94   }
  95
  96   // Get the list of interfaces. WlanEnumInterfaces allocates interface_list.
  97   WLAN_INTERFACE_INFO_LIST *interface_list = nullptr;
  98   if (ERROR_SUCCESS !=
  99       (*mWlanLibrary->GetWlanEnumInterfacesPtr())(mWlanLibrary->GetWLANHandle(),
 100                                                   nullptr,
 101                                                   &interface_list)) {
 102     return NS_ERROR_FAILURE;
 103   }
 104
 105   // This ensures we call WlanFreeMemory on interface_list
 106   ScopedWLANObject scopedInterfaceList(mWlanLibrary, interface_list);
 107
 108   if (!interface_list->dwNumberOfItems) {
 109     return NS_OK;
 110   }
 111
 112   InterfaceScanCallbackData cbData(interface_list->dwNumberOfItems);
 113
 114   DWORD wlanNotifySource;
 115   if (ERROR_SUCCESS !=
 116       (*mWlanLibrary->GetWlanRegisterNotificationPtr())(
 117                                   mWlanLibrary->GetWLANHandle(),
 118                                   WLAN_NOTIFICATION_SOURCE_ACM,
 119                                   TRUE,
 120                                   (WLAN_NOTIFICATION_CALLBACK)OnScanComplete,
 121                                   &cbData,
 122                                   NULL,
 123                                   &wlanNotifySource)) {
 124     return NS_ERROR_FAILURE;
 125   }
 126
 127   // Go through the list of interfaces and call `WlanScan` on each
 128   for (unsigned int i = 0; i < interface_list->dwNumberOfItems; ++i) {
 129     if (ERROR_SUCCESS !=
 130         (*mWlanLibrary->GetWlanScanPtr())(
 131                     mWlanLibrary->GetWLANHandle(),
 132                     &interface_list->InterfaceInfo[i].InterfaceGuid,
 133                     NULL,
 134                     NULL,
 135                     NULL)) {
 136       cbData.OnInterfaceScanComplete();
 137     }
 138   }
 139
 140   // From the MSDN documentation:
 141   //   "Wireless network drivers that meet Windows logo requirements are
 142   // required to complete a WlanScan function request in 4 seconds"
 143   cbData.WaitForAllInterfacesToFinishScanning(5000);
 144
 145   // Unregister for the notifications. The documentation mentions that,
 146   // if a callback is currently running, this will wait for the callback
 147   // to complete.
 148   (*mWlanLibrary->GetWlanRegisterNotificationPtr())(
 149                               mWlanLibrary->GetWLANHandle(),
 150                               WLAN_NOTIFICATION_SOURCE_NONE,
 151                               TRUE,
 152                               NULL,
 153                               NULL,
 154                               NULL,
 155                               &wlanNotifySource);
 156
 157   // Go through the list of interfaces and get the data for each.
 158   for (uint32_t i = 0; i < interface_list->dwNumberOfItems; ++i) {
 159     WLAN_BSS_LIST *bss_list;
 160     if (ERROR_SUCCESS !=
 161         (*mWlanLibrary->GetWlanGetNetworkBssListPtr())(
 162                            mWlanLibrary->GetWLANHandle(),
 163                            &interface_list->InterfaceInfo[i].InterfaceGuid,
 164                            nullptr,  // Use all SSIDs.
 165                            DOT11_BSS_TYPE_UNUSED,
 166                            false,    // bSecurityEnabled - unused
 167                            nullptr,  // reserved
 168                            &bss_list)) {
 169       continue;
 170     }
 171
 172     // This ensures we call WlanFreeMemory on bss_list
 173     ScopedWLANObject scopedBssList(mWlanLibrary, bss_list);
 174
 175     // Store each discovered access point in our outparam
 176     for (int j = 0; j < static_cast<int>(bss_list->dwNumberOfItems); ++j) {
 177       nsWifiAccessPoint* ap = new nsWifiAccessPoint();
 178       if (!ap) {
 179         continue;
 180       }
 181
 182       const WLAN_BSS_ENTRY bss_entry = bss_list->wlanBssEntries[j];
 183       ap->setMac(bss_entry.dot11Bssid);
 184       ap->setSignal(bss_entry.lRssi);
 185       ap->setSSID(reinterpret_cast<char const*>(bss_entry.dot11Ssid.ucSSID),
 186                   bss_entry.dot11Ssid.uSSIDLength);
 187
 188       accessPoints.AppendObject(ap);
 189     }
 190   }
 191
 192   return NS_OK;
 193 }