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