1 //
2 // Copyright (C) 2012 The Android Open Source Project
3 //
4 // Licensed under the Apache License, Version 2.0 (the "License");
5 // you may not use this file except in compliance with the License.
6 // You may obtain a copy of the License at
7 //
8 //      http://www.apache.org/licenses/LICENSE-2.0
9 //
10 // Unless required by applicable law or agreed to in writing, software
11 // distributed under the License is distributed on an "AS IS" BASIS,
12 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 // See the License for the specific language governing permissions and
14 // limitations under the License.
15 //
16 
17 #ifndef SHILL_LINK_MONITOR_H_
18 #define SHILL_LINK_MONITOR_H_
19 
20 #include <time.h>
21 
22 #include <memory>
23 #include <string>
24 
25 #include <base/callback.h>
26 #include <base/cancelable_callback.h>
27 
28 #include "shill/metrics.h"
29 #include "shill/net/byte_string.h"
30 #include "shill/refptr_types.h"
31 
32 namespace shill {
33 
34 class ActiveLinkMonitor;
35 class DeviceInfo;
36 class EventDispatcher;
37 class PassiveLinkMonitor;
38 class Time;
39 
40 class LinkMonitor {
41  public:
42   typedef base::Closure FailureCallback;
43   typedef base::Closure GatewayChangeCallback;
44 
45   // The default number of milliseconds between ARP requests used by
46   // ActiveLinkMonitor. Needed by Metrics.
47   static const int kDefaultTestPeriodMilliseconds;
48 
49   // The default list of technologies for which link monitoring is enabled.
50   // Needed by DefaultProfile.
51   static const char kDefaultLinkMonitorTechnologies[];
52 
53   // Failure threshold count used by ActiveLinkMonitor.  Needed by Metrics.
54   static const int kFailureThreshold;
55 
56   LinkMonitor(const ConnectionRefPtr& connection,
57               EventDispatcher* dispatcher,  // Owned by caller; can't be NULL.
58               Metrics* metrics,  // Owned by caller; must not be NULL.
59               DeviceInfo* device_info,
60               const FailureCallback& failure_callback,
61               const GatewayChangeCallback& gateway_change_callback);
62   virtual ~LinkMonitor();
63 
64   // Starts link-monitoring on the selected connection.  Returns
65   // true if successful, false otherwise.
66   virtual bool Start();
67   // Stop link-monitoring on the selected connection. Clears any
68   // accumulated statistics.
69   virtual void Stop();
70 
71   // Inform LinkMonitor that the system is resuming from sleep.
72   // LinkMonitor will immediately start the ActiveLinkMonitor, using a lower
73   // timeout than normal.
74   virtual void OnAfterResume();
75 
76   // Return modified cumulative average of the gateway ARP response
77   // time.  Returns zero if no samples are available.  For each
78   // missed ARP response, the sample is assumed to be the full
79   // test period.
80   virtual int GetResponseTimeMilliseconds() const;
81 
82   // Returns true if the LinkMonitor was ever able to find the default
83   // gateway via broadcast ARP.
84   virtual bool IsGatewayFound() const;
85 
gateway_mac_address()86   const ByteString& gateway_mac_address() const {
87     return gateway_mac_address_;
88   }
89 
90  private:
91   friend class LinkMonitorTest;
92 
93   void OnActiveLinkMonitorFailure(Metrics::LinkMonitorFailure failure,
94                                   int broadcast_failure_count,
95                                   int unicast_failure_count);
96   void OnActiveLinkMonitorSuccess();
97   void OnPassiveLinkMonitorResultCallback(bool status);
98 
99   // The connection on which to perform link monitoring.
100   ConnectionRefPtr connection_;
101   // Dispatcher on which to create delayed tasks.
102   EventDispatcher* dispatcher_;
103   // Metrics instance on which to post performance results.
104   Metrics* metrics_;
105   // Failure callback method to call if LinkMonitor fails.
106   FailureCallback failure_callback_;
107   // Callback method to call if gateway mac address changes.
108   GatewayChangeCallback gateway_change_callback_;
109   std::unique_ptr<ActiveLinkMonitor> active_link_monitor_;
110   std::unique_ptr<PassiveLinkMonitor> passive_link_monitor_;
111   // The MAC address of the default gateway.
112   ByteString gateway_mac_address_;
113   // The time at which the link monitor started.
114   struct timeval started_monitoring_at_;
115   // Time instance for performing GetTimeMonotonic().
116   Time* time_;
117 
118   DISALLOW_COPY_AND_ASSIGN(LinkMonitor);
119 };
120 
121 }  // namespace shill
122 
123 #endif  // SHILL_LINK_MONITOR_H_
124