1 // Copyright (c) 2010 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 #include "net/base/network_change_notifier_linux.h"
6
7 #include <errno.h>
8 #include <sys/socket.h>
9
10 #include "base/compiler_specific.h"
11 #include "base/eintr_wrapper.h"
12 #include "base/task.h"
13 #include "base/threading/thread.h"
14 #include "net/base/net_errors.h"
15 #include "net/base/network_change_notifier_netlink_linux.h"
16
17 namespace net {
18
19 namespace {
20
21 const int kInvalidSocket = -1;
22
23 } // namespace
24
25 class NetworkChangeNotifierLinux::Thread
26 : public base::Thread, public MessageLoopForIO::Watcher {
27 public:
28 Thread();
29 virtual ~Thread();
30
31 // MessageLoopForIO::Watcher:
32 virtual void OnFileCanReadWithoutBlocking(int fd);
33 virtual void OnFileCanWriteWithoutBlocking(int /* fd */);
34
35 protected:
36 // base::Thread
37 virtual void Init();
38 virtual void CleanUp();
39
40 private:
NotifyObserversOfIPAddressChange()41 void NotifyObserversOfIPAddressChange() {
42 NetworkChangeNotifier::NotifyObserversOfIPAddressChange();
43 }
44
45 // Starts listening for netlink messages. Also handles the messages if there
46 // are any available on the netlink socket.
47 void ListenForNotifications();
48
49 // Attempts to read from the netlink socket into |buf| of length |len|.
50 // Returns the bytes read on synchronous success and ERR_IO_PENDING if the
51 // recv() would block. Otherwise, it returns a net error code.
52 int ReadNotificationMessage(char* buf, size_t len);
53
54 // The netlink socket descriptor.
55 int netlink_fd_;
56 MessageLoopForIO::FileDescriptorWatcher netlink_watcher_;
57
58 // Technically only needed for ChromeOS, but it's ugly to #ifdef out.
59 ScopedRunnableMethodFactory<Thread> method_factory_;
60
61 DISALLOW_COPY_AND_ASSIGN(Thread);
62 };
63
Thread()64 NetworkChangeNotifierLinux::Thread::Thread()
65 : base::Thread("NetworkChangeNotifier"),
66 netlink_fd_(kInvalidSocket),
67 ALLOW_THIS_IN_INITIALIZER_LIST(method_factory_(this)) {}
68
~Thread()69 NetworkChangeNotifierLinux::Thread::~Thread() {}
70
Init()71 void NetworkChangeNotifierLinux::Thread::Init() {
72 netlink_fd_ = InitializeNetlinkSocket();
73 if (netlink_fd_ < 0) {
74 netlink_fd_ = kInvalidSocket;
75 return;
76 }
77 ListenForNotifications();
78 }
79
CleanUp()80 void NetworkChangeNotifierLinux::Thread::CleanUp() {
81 if (netlink_fd_ != kInvalidSocket) {
82 if (HANDLE_EINTR(close(netlink_fd_)) != 0)
83 PLOG(ERROR) << "Failed to close socket";
84 netlink_fd_ = kInvalidSocket;
85 netlink_watcher_.StopWatchingFileDescriptor();
86 }
87 }
88
OnFileCanReadWithoutBlocking(int fd)89 void NetworkChangeNotifierLinux::Thread::OnFileCanReadWithoutBlocking(int fd) {
90 DCHECK_EQ(fd, netlink_fd_);
91 ListenForNotifications();
92 }
93
OnFileCanWriteWithoutBlocking(int)94 void NetworkChangeNotifierLinux::Thread::OnFileCanWriteWithoutBlocking(
95 int /* fd */) {
96 NOTREACHED();
97 }
98
ListenForNotifications()99 void NetworkChangeNotifierLinux::Thread::ListenForNotifications() {
100 char buf[4096];
101 int rv = ReadNotificationMessage(buf, arraysize(buf));
102 while (rv > 0) {
103 if (HandleNetlinkMessage(buf, rv)) {
104 VLOG(1) << "Detected IP address changes.";
105 #if defined(OS_CHROMEOS)
106 // TODO(oshima): chromium-os:8285 - introduced artificial delay to
107 // work around the issue of network load issue after connection
108 // restored. See the bug for more details.
109 // This should be removed once this bug is properly fixed.
110 const int kObserverNotificationDelayMS = 200;
111 message_loop()->PostDelayedTask(
112 FROM_HERE,
113 method_factory_.NewRunnableMethod(
114 &Thread::NotifyObserversOfIPAddressChange),
115 kObserverNotificationDelayMS);
116 #else
117 NotifyObserversOfIPAddressChange();
118 #endif
119 }
120 rv = ReadNotificationMessage(buf, arraysize(buf));
121 }
122
123 if (rv == ERR_IO_PENDING) {
124 rv = MessageLoopForIO::current()->WatchFileDescriptor(netlink_fd_, false,
125 MessageLoopForIO::WATCH_READ, &netlink_watcher_, this);
126 LOG_IF(ERROR, !rv) << "Failed to watch netlink socket: " << netlink_fd_;
127 }
128 }
129
ReadNotificationMessage(char * buf,size_t len)130 int NetworkChangeNotifierLinux::Thread::ReadNotificationMessage(
131 char* buf,
132 size_t len) {
133 DCHECK_NE(len, 0u);
134 DCHECK(buf);
135 memset(buf, 0, sizeof(buf));
136 int rv = recv(netlink_fd_, buf, len, 0);
137 if (rv > 0)
138 return rv;
139
140 DCHECK_NE(rv, 0);
141 if (errno != EAGAIN && errno != EWOULDBLOCK) {
142 PLOG(DFATAL) << "recv";
143 return ERR_FAILED;
144 }
145
146 return ERR_IO_PENDING;
147 }
148
NetworkChangeNotifierLinux()149 NetworkChangeNotifierLinux::NetworkChangeNotifierLinux()
150 : notifier_thread_(new Thread) {
151 // We create this notifier thread because the notification implementation
152 // needs a MessageLoopForIO, and there's no guarantee that
153 // MessageLoop::current() meets that criterion.
154 base::Thread::Options thread_options(MessageLoop::TYPE_IO, 0);
155 notifier_thread_->StartWithOptions(thread_options);
156 }
157
~NetworkChangeNotifierLinux()158 NetworkChangeNotifierLinux::~NetworkChangeNotifierLinux() {
159 // We don't need to explicitly Stop(), but doing so allows us to sanity-
160 // check that the notifier thread shut down properly.
161 notifier_thread_->Stop();
162 }
163
IsCurrentlyOffline() const164 bool NetworkChangeNotifierLinux::IsCurrentlyOffline() const {
165 // TODO(eroman): http://crbug.com/53473
166 return false;
167 }
168
169 } // namespace net
170