Get WiFi SSID information for Windows

net/base/network_interfaces_win.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/base/net_util.h"
 
 #include <iphlpapi.h>
 #include <wlanapi.h>
 
 #include <algorithm>
@@ skipping 31 matching lines @@
       NetworkChangeNotifier::CONNECTION_UNKNOWN;
   if (ifType == IF_TYPE_ETHERNET_CSMACD) {
     type = NetworkChangeNotifier::CONNECTION_ETHERNET;
   } else if (ifType == IF_TYPE_IEEE80211) {
     type = NetworkChangeNotifier::CONNECTION_WIFI;
   }
   // TODO(mallinath) - Cellular?
   return type;
 }
 
+// Get unique |network_guid| string based on |dot11_ssid|.
+std::string GUIDFromSSID(const DOT11_SSID& dot11_ssid) {

[mef, 2015/07/28 16:26:30]

The GUID in this name is very WiFiService / networkingPrivate API specific. I'd
call it 'StringFromDot11SSID' or just inline where it is called.

[tbansal1, 2015/07/28 17:34:28]

Inlined.

+  return std::string(reinterpret_cast<const char*>(dot11_ssid.ucSSID),
+                     dot11_ssid.uSSIDLength);
+}
+
 }  // namespace
 
 namespace internal {
 
 base::LazyInstance<WlanApi>::Leaky lazy_wlanapi =
   LAZY_INSTANCE_INITIALIZER;
 
 WlanApi& WlanApi::GetInstance() {
   return lazy_wlanapi.Get();
 }
@@ skipping 131 matching lines @@
       reinterpret_cast<IP_ADAPTER_ADDRESSES*>(buf.get());
   result = GetAdaptersAddresses(AF_UNSPEC, flags, NULL, adapters, &len);
   if (result != NO_ERROR) {
     LOG(ERROR) << "GetAdaptersAddresses failed: " << result;
     return false;
   }
 
   return internal::GetNetworkListImpl(networks, policy, is_xp, adapters);
 }
 
-WifiPHYLayerProtocol GetWifiPHYLayerProtocol() {
+// Returns true if WLAN connection attributes are available and populates
+// |conn_info_ptr|.
+bool GetConnectionAttributesPtr(WLAN_CONNECTION_ATTRIBUTES** conn_info_ptr) {
   const internal::WlanApi& wlanapi = internal::WlanApi::GetInstance();
   if (!wlanapi.initialized)
-    return WIFI_PHY_LAYER_PROTOCOL_NONE;
+    return false;
 
   internal::WlanHandle client;
   DWORD cur_version = 0;
   const DWORD kMaxClientVersion = 2;
   {
     // TODO(rtenneti): Remove ScopedTracker below once crbug.com/422516 is
     // fixed.
     tracked_objects::ScopedTracker tracking_profile(
         FROM_HERE_WITH_EXPLICIT_FUNCTION("422516 OpenHandle()"));
     DWORD result = wlanapi.OpenHandle(kMaxClientVersion, &cur_version, &client);
     if (result != ERROR_SUCCESS)
-      return WIFI_PHY_LAYER_PROTOCOL_NONE;
+      return false;
   }
 
   WLAN_INTERFACE_INFO_LIST* interface_list_ptr = NULL;
   DWORD result =
       wlanapi.enum_interfaces_func(client.Get(), NULL, &interface_list_ptr);
   if (result != ERROR_SUCCESS)
-    return WIFI_PHY_LAYER_PROTOCOL_NONE;
+    return false;
   scoped_ptr<WLAN_INTERFACE_INFO_LIST, internal::WlanApiDeleter> interface_list(
       interface_list_ptr);
 
   // Assume at most one connected wifi interface.
   WLAN_INTERFACE_INFO* info = NULL;
   for (unsigned i = 0; i < interface_list->dwNumberOfItems; ++i) {
     if (interface_list->InterfaceInfo[i].isState ==
         wlan_interface_state_connected) {
       info = &interface_list->InterfaceInfo[i];
       break;
     }
   }
 
   if (info == NULL)
-    return WIFI_PHY_LAYER_PROTOCOL_NONE;
+    return false;
 
-  WLAN_CONNECTION_ATTRIBUTES* conn_info_ptr;
   DWORD conn_info_size = 0;
   WLAN_OPCODE_VALUE_TYPE op_code;
   result = wlanapi.query_interface_func(
       client.Get(), &info->InterfaceGuid, wlan_intf_opcode_current_connection,
-      NULL, &conn_info_size, reinterpret_cast<VOID**>(&conn_info_ptr),
-      &op_code);
+      NULL, &conn_info_size, reinterpret_cast<VOID**>(conn_info_ptr), &op_code);
   if (result != ERROR_SUCCESS)
-    return WIFI_PHY_LAYER_PROTOCOL_UNKNOWN;
+    return false;
+
+  return true;
+}
+
+WifiPHYLayerProtocol GetWifiPHYLayerProtocol() {
+  WLAN_CONNECTION_ATTRIBUTES* conn_info_ptr = NULL;
+  if (!GetConnectionAttributesPtr(&conn_info_ptr)) {
+    DCHECK(!conn_info_ptr);
+    return WIFI_PHY_LAYER_PROTOCOL_NONE;
+  }
+  DCHECK(conn_info_ptr);
+
   scoped_ptr<WLAN_CONNECTION_ATTRIBUTES, internal::WlanApiDeleter> conn_info(
       conn_info_ptr);
 
   switch (conn_info->wlanAssociationAttributes.dot11PhyType) {
     case dot11_phy_type_fhss:
       return WIFI_PHY_LAYER_PROTOCOL_ANCIENT;
     case dot11_phy_type_dsss:
       return WIFI_PHY_LAYER_PROTOCOL_B;
     case dot11_phy_type_irbaseband:
       return WIFI_PHY_LAYER_PROTOCOL_ANCIENT;
@@ skipping 60 matching lines @@
 
  private:
   internal::WlanHandle client_;
 };
 
 scoped_ptr<ScopedWifiOptions> SetWifiOptions(int options) {
   return scoped_ptr<ScopedWifiOptions>(new WifiOptionSetter(options));
 }
 
 std::string GetWifiSSID() {
-  NOTIMPLEMENTED();
-  return "";
+  WLAN_CONNECTION_ATTRIBUTES* conn_info_ptr = NULL;
+  if (!GetConnectionAttributesPtr(&conn_info_ptr)) {
+    DCHECK(!conn_info_ptr);
+    return "";
+  }
+  DCHECK(conn_info_ptr);
+
+  scoped_ptr<WLAN_CONNECTION_ATTRIBUTES, internal::WlanApiDeleter> conn_info(
+      conn_info_ptr);
+
+  return GUIDFromSSID(conn_info->wlanAssociationAttributes.dot11Ssid);

[mef, 2015/07/28 16:26:30]

I wouldn't be surprised that wlanAssociationAttributes is NULL if adapter is
disabled or disconnected.

Also, inline GUIDFromSSID here. 

[tbansal1, 2015/07/28 17:34:28]

I am confused. How can the |wlanAssociationAttributes| struct be
NULL since it is not a pointer.
https://msdn.microsoft.com/en-us/library/windows/desktop/ms706842(v=vs.85).aspx
Done.

[mef, 2015/07/28 17:45:09]

Oops, never mind.

 }
 
 }  // namespace net