Source code

Revision control

Other Tools

Line Code
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "nsWifiAccessPoint.h"
#include "win_wifiScanner.h"

// Moz headers (alphabetical)
#include "win_wlanLibrary.h"

#define DOT11_BSS_TYPE_UNUSED static_cast<DOT11_BSS_TYPE>(0)

class InterfaceScanCallbackData {
 public:
  explicit InterfaceScanCallbackData(uint32_t numInterfaces)
      : mCurrentlyScanningInterfaces(numInterfaces) {
    mAllInterfacesDoneScanningEvent =
        ::CreateEvent(nullptr,   // null security
                      TRUE,      // manual reset event
                      FALSE,     // initially nonsignaled
                      nullptr);  // not named
    MOZ_ASSERT(NULL != mAllInterfacesDoneScanningEvent);
  }

  ~InterfaceScanCallbackData() {
    ::CloseHandle(mAllInterfacesDoneScanningEvent);
  }

  void OnInterfaceScanComplete() {
    uint32_t val = ::InterlockedDecrement(&mCurrentlyScanningInterfaces);
    if (!val) {
      ::SetEvent(mAllInterfacesDoneScanningEvent);
    }
  }

  void WaitForAllInterfacesToFinishScanning(uint32_t msToWait) {
    ::WaitForSingleObject(mAllInterfacesDoneScanningEvent, msToWait);
  }

 private:
  volatile uint32_t mCurrentlyScanningInterfaces;
  HANDLE mAllInterfacesDoneScanningEvent;
};

static void WINAPI OnScanComplete(PWLAN_NOTIFICATION_DATA data, PVOID context) {
  if (WLAN_NOTIFICATION_SOURCE_ACM != data->NotificationSource) {
    return;
  }

  if (wlan_notification_acm_scan_complete != data->NotificationCode &&
      wlan_notification_acm_scan_fail != data->NotificationCode) {
    return;
  }

  InterfaceScanCallbackData *cbData =
      reinterpret_cast<InterfaceScanCallbackData *>(context);
  cbData->OnInterfaceScanComplete();
}

WinWifiScanner::WinWifiScanner() {
  // NOTE: We assume that, if we were unable to load the WLAN library when
  // we initially tried, we will not be able to load it in the future.
  // Technically, on Windows XP SP2, a user could install the redistributable
  // and make our assumption incorrect. We opt to avoid making a bunch of
  // spurious LoadLibrary calls in the common case rather than load the
  // WLAN API in the edge case.
  mWlanLibrary = WinWLANLibrary::Load();
  if (!mWlanLibrary) {
    NS_WARNING("Could not initialize Windows Wi-Fi scanner");
  }
}

WinWifiScanner::~WinWifiScanner() {}

nsresult WinWifiScanner::GetAccessPointsFromWLAN(
    nsCOMArray<nsWifiAccessPoint> &accessPoints) {
  accessPoints.Clear();

  // NOTE: We do not try to load the WLAN library if we previously failed
  // to load it. See the note in WinWifiScanner constructor
  if (!mWlanLibrary) {
    return NS_ERROR_NOT_AVAILABLE;
  }

  // Get the list of interfaces. WlanEnumInterfaces allocates interface_list.
  WLAN_INTERFACE_INFO_LIST *interface_list = nullptr;
  if (ERROR_SUCCESS !=
      (*mWlanLibrary->GetWlanEnumInterfacesPtr())(mWlanLibrary->GetWLANHandle(),
                                                  nullptr, &interface_list)) {
    return NS_ERROR_FAILURE;
  }

  // This ensures we call WlanFreeMemory on interface_list
  ScopedWLANObject scopedInterfaceList(mWlanLibrary, interface_list);

  if (!interface_list->dwNumberOfItems) {
    return NS_OK;
  }

  InterfaceScanCallbackData cbData(interface_list->dwNumberOfItems);

  DWORD wlanNotifySource;
  if (ERROR_SUCCESS != (*mWlanLibrary->GetWlanRegisterNotificationPtr())(
                           mWlanLibrary->GetWLANHandle(),
                           WLAN_NOTIFICATION_SOURCE_ACM, TRUE,
                           (WLAN_NOTIFICATION_CALLBACK)OnScanComplete, &cbData,
                           NULL, &wlanNotifySource)) {
    return NS_ERROR_FAILURE;
  }

  // Go through the list of interfaces and call `WlanScan` on each
  for (unsigned int i = 0; i < interface_list->dwNumberOfItems; ++i) {
    if (ERROR_SUCCESS != (*mWlanLibrary->GetWlanScanPtr())(
                             mWlanLibrary->GetWLANHandle(),
                             &interface_list->InterfaceInfo[i].InterfaceGuid,
                             NULL, NULL, NULL)) {
      cbData.OnInterfaceScanComplete();
    }
  }

  // From the MSDN documentation:
  //   "Wireless network drivers that meet Windows logo requirements are
  // required to complete a WlanScan function request in 4 seconds"
  cbData.WaitForAllInterfacesToFinishScanning(5000);

  // Unregister for the notifications. The documentation mentions that,
  // if a callback is currently running, this will wait for the callback
  // to complete.
  (*mWlanLibrary->GetWlanRegisterNotificationPtr())(
      mWlanLibrary->GetWLANHandle(), WLAN_NOTIFICATION_SOURCE_NONE, TRUE, NULL,
      NULL, NULL, &wlanNotifySource);

  // Go through the list of interfaces and get the data for each.
  for (uint32_t i = 0; i < interface_list->dwNumberOfItems; ++i) {
    WLAN_BSS_LIST *bss_list;
    if (ERROR_SUCCESS != (*mWlanLibrary->GetWlanGetNetworkBssListPtr())(
                             mWlanLibrary->GetWLANHandle(),
                             &interface_list->InterfaceInfo[i].InterfaceGuid,
                             nullptr,  // Use all SSIDs.
                             DOT11_BSS_TYPE_UNUSED,
                             false,    // bSecurityEnabled - unused
                             nullptr,  // reserved
                             &bss_list)) {
      continue;
    }

    // This ensures we call WlanFreeMemory on bss_list
    ScopedWLANObject scopedBssList(mWlanLibrary, bss_list);

    // Store each discovered access point in our outparam
    for (int j = 0; j < static_cast<int>(bss_list->dwNumberOfItems); ++j) {
      nsWifiAccessPoint *ap = new nsWifiAccessPoint();
      if (!ap) {
        continue;
      }

      const WLAN_BSS_ENTRY bss_entry = bss_list->wlanBssEntries[j];
      ap->setMac(bss_entry.dot11Bssid);
      ap->setSignal(bss_entry.lRssi);
      ap->setSSID(reinterpret_cast<char const *>(bss_entry.dot11Ssid.ucSSID),
                  bss_entry.dot11Ssid.uSSIDLength);

      accessPoints.AppendObject(ap);
    }
  }

  return NS_OK;
}