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      1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #ifndef NET_BASE_ADDRESS_TRACKER_LINUX_H_
      6 #define NET_BASE_ADDRESS_TRACKER_LINUX_H_
      7 
      8 #include <sys/socket.h>  // Needed to include netlink.
      9 // Mask superfluous definition of |struct net|. This is fixed in Linux 2.6.38.
     10 #define net net_kernel
     11 #include <linux/rtnetlink.h>
     12 #undef net
     13 
     14 #include <map>
     15 
     16 #include "base/basictypes.h"
     17 #include "base/callback.h"
     18 #include "base/compiler_specific.h"
     19 #include "base/containers/hash_tables.h"
     20 #include "base/message_loop/message_loop.h"
     21 #include "base/synchronization/condition_variable.h"
     22 #include "base/synchronization/lock.h"
     23 #include "net/base/net_util.h"
     24 #include "net/base/network_change_notifier.h"
     25 
     26 namespace net {
     27 namespace internal {
     28 
     29 // Keeps track of network interface addresses using rtnetlink. Used by
     30 // NetworkChangeNotifier to provide signals to registered IPAddressObservers.
     31 class NET_EXPORT_PRIVATE AddressTrackerLinux :
     32     public base::MessageLoopForIO::Watcher {
     33  public:
     34   typedef std::map<IPAddressNumber, struct ifaddrmsg> AddressMap;
     35 
     36   // Will run |address_callback| when the AddressMap changes, |link_callback|
     37   // when the list of online links changes, and |tunnel_callback| when the list
     38   // of online tunnels changes.
     39   AddressTrackerLinux(const base::Closure& address_callback,
     40                       const base::Closure& link_callback,
     41                       const base::Closure& tunnel_callback);
     42   virtual ~AddressTrackerLinux();
     43 
     44   // Starts watching system configuration for changes. The current thread must
     45   // have a MessageLoopForIO.
     46   void Init();
     47 
     48   AddressMap GetAddressMap() const;
     49 
     50   // Implementation of NetworkChangeNotifierLinux::GetCurrentConnectionType().
     51   // Safe to call from any thread, but will block until Init() has completed.
     52   NetworkChangeNotifier::ConnectionType GetCurrentConnectionType();
     53 
     54  private:
     55   friend class AddressTrackerLinuxTest;
     56 
     57   // A function that returns the name of an interface given the interface index
     58   // in |interface_index|.
     59   typedef const char* (*GetInterfaceNameFunction)(int interface_index);
     60 
     61   // Sets |*address_changed| to indicate whether |address_map_| changed and
     62   // sets |*link_changed| to indicate if |online_links_| changed and sets
     63   // |*tunnel_changed| to indicate if |online_links_| changed with regards to a
     64   // tunnel interface while reading messages from |netlink_fd_|.
     65   void ReadMessages(bool* address_changed,
     66                     bool* link_changed,
     67                     bool* tunnel_changed);
     68 
     69   // Sets |*address_changed| to true if |address_map_| changed, sets
     70   // |*link_changed| to true if |online_links_| changed, sets |*tunnel_changed|
     71   // to true if |online_links_| changed with regards to a tunnel interface while
     72   // reading the message from |buffer|.
     73   void HandleMessage(char* buffer,
     74                      size_t length,
     75                      bool* address_changed,
     76                      bool* link_changed,
     77                      bool* tunnel_changed);
     78 
     79   // Call when some part of initialization failed; forces online and unblocks.
     80   void AbortAndForceOnline();
     81 
     82   // MessageLoopForIO::Watcher:
     83   virtual void OnFileCanReadWithoutBlocking(int fd) OVERRIDE;
     84   virtual void OnFileCanWriteWithoutBlocking(int /* fd */) OVERRIDE;
     85 
     86   // Close |netlink_fd_|
     87   void CloseSocket();
     88 
     89   // Does |msg| refer to a tunnel interface?
     90   bool IsTunnelInterface(const struct ifinfomsg* msg) const;
     91 
     92   // Gets the name of an interface given the interface index |interface_index|.
     93   // May return empty string if it fails but should not return NULL. This is
     94   // overridden by tests.
     95   GetInterfaceNameFunction get_interface_name_;
     96 
     97   base::Closure address_callback_;
     98   base::Closure link_callback_;
     99   base::Closure tunnel_callback_;
    100 
    101   int netlink_fd_;
    102   base::MessageLoopForIO::FileDescriptorWatcher watcher_;
    103 
    104   mutable base::Lock address_map_lock_;
    105   AddressMap address_map_;
    106 
    107   // Set of interface indices for links that are currently online.
    108   base::hash_set<int> online_links_;
    109 
    110   base::Lock is_offline_lock_;
    111   bool is_offline_;
    112   bool is_offline_initialized_;
    113   base::ConditionVariable is_offline_initialized_cv_;
    114 };
    115 
    116 }  // namespace internal
    117 }  // namespace net
    118 
    119 #endif  // NET_BASE_ADDRESS_TRACKER_LINUX_H_
    120