Use Netlink instead of NetworkManager (via D-bus) to monitor network

net/base/address_tracker_linux.h

 // 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.
 
 #ifndef NET_BASE_ADDRESS_TRACKER_LINUX_H_
 #define NET_BASE_ADDRESS_TRACKER_LINUX_H_
 
 #include <sys/socket.h>  // Needed to include netlink.
 // Mask superfluous definition of |struct net|. This is fixed in Linux 2.6.38.
 #define net net_kernel
 #include <linux/rtnetlink.h>
 #undef net
 
 #include <map>
 
 #include "base/basictypes.h"
 #include "base/callback.h"
 #include "base/compiler_specific.h"
+#include "base/hash_tables.h"
 #include "base/message_loop.h"
 #include "base/synchronization/lock.h"
+#include "base/synchronization/waitable_event.h"
 #include "net/base/net_util.h"
+#include "net/base/network_change_notifier.h"
 
 namespace net {
 namespace internal {
 
 // Keeps track of network interface addresses using rtnetlink. Used by
 // NetworkChangeNotifier to provide signals to registered IPAddressObservers.
 class NET_EXPORT_PRIVATE AddressTrackerLinux
     : public MessageLoopForIO::Watcher {
  public:
   typedef std::map<IPAddressNumber, struct ifaddrmsg> AddressMap;
 
-  // Will run |callback| when the AddressMap changes.
-  explicit AddressTrackerLinux(const base::Closure& callback);
+  // Will run |address_callback| when the AddressMap changes and will run
+  // |link_callback| when the list of online links changes.
+  AddressTrackerLinux(const base::Closure& address_callback,
+                      const base::Closure& link_callback);
   virtual ~AddressTrackerLinux();
 
   // Starts watching system configuration for changes. The current thread must
   // have a MessageLoopForIO.
   void Init();
 
   AddressMap GetAddressMap() const;
 
+  // Implementation of NetworkChangeNotifierLinux::GetCurrentConnectionType().
+  // Safe to call from any thread, but will block until Init() has completed.
+  NetworkChangeNotifier::ConnectionType GetCurrentConnectionType();

[szym, 2012/11/11 16:21:55]

const?

[pauljensen, 2012/11/12 16:45:21]

This would require making is_offline_lock_ and offline_state_initialized_
mutable which isn't safe with multiple threads and this function is called from
multiple threads.  I'm just moving this from NetworkManagerApi.

+
  private:
   friend class AddressTrackerLinuxTest;
 
-  // Returns true if |map_| changed while reading messages from |netlink_fd_|.
-  bool ReadMessages();
+  // Sets |*address_changed| to indicate whether |address_map_| changed and
+  // sets |*link_changed| to indicate if |online_links_| changed while reading
+  // messages from |netlink_fd_|.
+  void ReadMessages(bool* address_changed, bool* link_changed);
 
-  // Returns true if |map_| changed while reading the message from |buffer|.
-  bool HandleMessage(const char* buffer, size_t length);
+  // Sets |*address_changed| to true if |address_map_| changed, sets
+  // |*link_changed| to true if |online_links_| changed while reading the
+  // message from |buffer|.
+  void HandleMessage(const char* buffer,
+                     size_t length,
+                     bool* address_changed,
+                     bool* link_changed);
+
+  // Populates |address_map_| and |online_links_|.
+  void GetInitialSettings();
 
   // MessageLoopForIO::Watcher:
   virtual void OnFileCanReadWithoutBlocking(int fd) OVERRIDE;
   virtual void OnFileCanWriteWithoutBlocking(int /* fd */) OVERRIDE;
 
-  base::Closure callback_;
+  base::Closure address_callback_;
+  base::Closure link_callback_;
 
   int netlink_fd_;
   MessageLoopForIO::FileDescriptorWatcher watcher_;
 
-  mutable base::Lock lock_;
-  AddressMap map_;
+  mutable base::Lock address_map_lock_;
+  AddressMap address_map_;
+  base::hash_set<int> online_links_;
+
+  bool is_offline_;
+  base::Lock is_offline_lock_;

[szym, 2012/11/11 16:21:55]

If you make GetCurrentConnectionType const, then this needs to be mutable. 

More prevalent style is putting lock as first in the group, followed by any
state and conditional variables protected by the lock.

[pauljensen, 2012/11/12 16:45:21]

I was just moving this from NetworkManagerApi.  I'll move the lock before the
bool.

+  base::WaitableEvent offline_state_initialized_;
 };
 
 }  // namespace internal
 }  // namespace net
 
 #endif  // NET_BASE_ADDRESS_TRACKER_LINUX_H_