Check for an active network connection when network adapter status changes....

chrome/browser/sync/notifier/base/win/async_network_alive_win32.cc

 // Copyright (c) 2009 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 "chrome/browser/sync/notifier/base/async_network_alive.h"
 
 #include <winsock2.h>
 
 #include "base/scoped_handle_win.h"
 #include "chrome/browser/sync/notifier/base/utils.h"
 #include "talk/base/common.h"
 #include "talk/base/criticalsection.h"
 #include "talk/base/logging.h"
+#include "talk/base/physicalsocketserver.h"
 #include "talk/base/scoped_ptr.h"
 
 namespace notifier {
 
 class PlatformNetworkInfo {
  public:
   PlatformNetworkInfo() : ws_handle_(NULL), event_handle_(NULL) {
   }
 
   ~PlatformNetworkInfo() {
@@ skipping 71 matching lines @@
         if (result == WSAEFAULT) {
           alive = true;
           flush_previous_result = true;
         } else {
           LOG(WARNING) << "failed:" << result;
           *error = true;
           break;
         }
       }
     } while (true);
+
     LOG(INFO) << "alive: " << alive;
     return alive;
   }
 
   bool WaitForChange() {
     //  IsAlive must be called first.
     int junk1 = 0, junk2 = 0;
     DWORD bytes_returned = 0;
     int result = SOCKET_ERROR;
     {
@@ skipping 93 matching lines @@
     } else {
       // Since network_info is set, it means that
       // we are suppose to wait for network state changes.
       if (!network_info_->WaitForChange()) {
         // The wait was aborted so we must be shutting down.
         alive_ = false;
         error_ = true;
         return;
       }
     }
-    alive_ = network_info_->IsAlive(&error_);
+
+    if (network_info_->IsAlive(&error_)) {
+      // If there is an active connection, check that www.google.com:80
+      // is reachable.
+      talk_base::PhysicalSocketServer physical;
+      scoped_ptr<talk_base::Socket> socket(physical.CreateSocket(SOCK_STREAM));
+      if (socket->Connect(talk_base::SocketAddress("talk.google.com", 5222))) {
+        alive_ = false;
+      } else {
+        alive_ = true;
+      }
+    } else {
+      // If there are no available connections, then we aren't alive.
+      alive_ = false;
+    }
   }
 
   virtual void OnWorkStop() {
     if (network_info_) {
       network_info_->Close();
     }
   }
 
  private:
   DISALLOW_COPY_AND_ASSIGN(AsyncNetworkAliveWin32);
 };
 
 AsyncNetworkAlive* AsyncNetworkAlive::Create() {
   return new AsyncNetworkAliveWin32();
 }
 
 }  // namespace notifier