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// Copyright (c) 2011 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 "net/base/network_change_notifier_linux.h"
#include <errno.h>
#include <sys/socket.h>
#include "base/bind.h"
#include "base/callback_old.h"
#include "base/compiler_specific.h"
#include "base/eintr_wrapper.h"
#include "base/file_util.h"
#include "base/files/file_path_watcher.h"
#include "base/task.h"
#include "base/threading/thread.h"
#include "net/base/net_errors.h"
#include "net/base/network_change_notifier_netlink_linux.h"
using ::base::files::FilePathWatcher;
namespace net {
namespace {
const int kInvalidSocket = -1;
class DNSWatchDelegate : public FilePathWatcher::Delegate {
public:
explicit DNSWatchDelegate(Callback0::Type* callback)
: callback_(callback) {}
virtual ~DNSWatchDelegate() {}
// FilePathWatcher::Delegate interface
virtual void OnFilePathChanged(const FilePath& path) OVERRIDE;
virtual void OnFilePathError(const FilePath& path) OVERRIDE;
private:
scoped_ptr<Callback0::Type> callback_;
DISALLOW_COPY_AND_ASSIGN(DNSWatchDelegate);
};
void DNSWatchDelegate::OnFilePathChanged(const FilePath& path) {
// Calls NetworkChangeNotifier::NotifyObserversOfDNSChange().
if (callback_.get())
callback_->Run();
}
void DNSWatchDelegate::OnFilePathError(const FilePath& path) {
LOG(ERROR) << "DNSWatchDelegate::OnFilePathError for " << path.value();
}
} // namespace
class NetworkChangeNotifierLinux::Thread
: public base::Thread, public MessageLoopForIO::Watcher {
public:
Thread();
virtual ~Thread();
// MessageLoopForIO::Watcher:
virtual void OnFileCanReadWithoutBlocking(int fd);
virtual void OnFileCanWriteWithoutBlocking(int /* fd */);
protected:
// base::Thread
virtual void Init();
virtual void CleanUp();
private:
void NotifyObserversOfIPAddressChange() {
NetworkChangeNotifier::NotifyObserversOfIPAddressChange();
}
void NotifyObserversOfDNSChange() {
NetworkChangeNotifier::NotifyObserversOfDNSChange();
}
// Starts listening for netlink messages. Also handles the messages if there
// are any available on the netlink socket.
void ListenForNotifications();
// Attempts to read from the netlink socket into |buf| of length |len|.
// Returns the bytes read on synchronous success and ERR_IO_PENDING if the
// recv() would block. Otherwise, it returns a net error code.
int ReadNotificationMessage(char* buf, size_t len);
// The netlink socket descriptor.
int netlink_fd_;
MessageLoopForIO::FileDescriptorWatcher netlink_watcher_;
// Technically only needed for ChromeOS, but it's ugly to #ifdef out.
ScopedRunnableMethodFactory<Thread> method_factory_;
// Used to watch for changes to /etc/resolv.conf and /etc/hosts.
scoped_ptr<base::files::FilePathWatcher> resolv_file_watcher_;
scoped_ptr<base::files::FilePathWatcher> hosts_file_watcher_;
scoped_refptr<DNSWatchDelegate> file_watcher_delegate_;
DISALLOW_COPY_AND_ASSIGN(Thread);
};
NetworkChangeNotifierLinux::Thread::Thread()
: base::Thread("NetworkChangeNotifier"),
netlink_fd_(kInvalidSocket),
ALLOW_THIS_IN_INITIALIZER_LIST(method_factory_(this)) {
}
NetworkChangeNotifierLinux::Thread::~Thread() {}
void NetworkChangeNotifierLinux::Thread::Init() {
resolv_file_watcher_.reset(new FilePathWatcher);
hosts_file_watcher_.reset(new FilePathWatcher);
file_watcher_delegate_ = new DNSWatchDelegate(NewCallback(this,
&NetworkChangeNotifierLinux::Thread::NotifyObserversOfDNSChange));
if (!resolv_file_watcher_->Watch(
FilePath(FILE_PATH_LITERAL("/etc/resolv.conf")),
file_watcher_delegate_.get())) {
LOG(ERROR) << "Failed to setup watch for /etc/resolv.conf";
}
if (!hosts_file_watcher_->Watch(FilePath(FILE_PATH_LITERAL("/etc/hosts")),
file_watcher_delegate_.get())) {
LOG(ERROR) << "Failed to setup watch for /etc/hosts";
}
netlink_fd_ = InitializeNetlinkSocket();
if (netlink_fd_ < 0) {
netlink_fd_ = kInvalidSocket;
return;
}
ListenForNotifications();
}
void NetworkChangeNotifierLinux::Thread::CleanUp() {
if (netlink_fd_ != kInvalidSocket) {
if (HANDLE_EINTR(close(netlink_fd_)) != 0)
PLOG(ERROR) << "Failed to close socket";
netlink_fd_ = kInvalidSocket;
netlink_watcher_.StopWatchingFileDescriptor();
}
// Kill watchers early to make sure they won't try to call
// into us via the delegate during destruction.
resolv_file_watcher_.reset();
hosts_file_watcher_.reset();
}
void NetworkChangeNotifierLinux::Thread::OnFileCanReadWithoutBlocking(int fd) {
DCHECK_EQ(fd, netlink_fd_);
ListenForNotifications();
}
void NetworkChangeNotifierLinux::Thread::OnFileCanWriteWithoutBlocking(
int /* fd */) {
NOTREACHED();
}
void NetworkChangeNotifierLinux::Thread::ListenForNotifications() {
char buf[4096];
int rv = ReadNotificationMessage(buf, arraysize(buf));
while (rv > 0) {
if (HandleNetlinkMessage(buf, rv)) {
VLOG(1) << "Detected IP address changes.";
#if defined(OS_CHROMEOS)
// TODO(oshima): chromium-os:8285 - introduced artificial delay to
// work around the issue of network load issue after connection
// restored. See the bug for more details.
// This should be removed once this bug is properly fixed.
const int kObserverNotificationDelayMS = 200;
message_loop()->PostDelayedTask(
FROM_HERE,
method_factory_.NewRunnableMethod(
&Thread::NotifyObserversOfIPAddressChange),
kObserverNotificationDelayMS);
#else
NotifyObserversOfIPAddressChange();
#endif
}
rv = ReadNotificationMessage(buf, arraysize(buf));
}
if (rv == ERR_IO_PENDING) {
rv = MessageLoopForIO::current()->WatchFileDescriptor(netlink_fd_, false,
MessageLoopForIO::WATCH_READ, &netlink_watcher_, this);
LOG_IF(ERROR, !rv) << "Failed to watch netlink socket: " << netlink_fd_;
}
}
int NetworkChangeNotifierLinux::Thread::ReadNotificationMessage(
char* buf,
size_t len) {
DCHECK_NE(len, 0u);
DCHECK(buf);
memset(buf, 0, len);
int rv = recv(netlink_fd_, buf, len, 0);
if (rv > 0)
return rv;
DCHECK_NE(rv, 0);
if (errno != EAGAIN && errno != EWOULDBLOCK) {
PLOG(DFATAL) << "recv";
return ERR_FAILED;
}
return ERR_IO_PENDING;
}
NetworkChangeNotifierLinux::NetworkChangeNotifierLinux()
: notifier_thread_(new Thread) {
// We create this notifier thread because the notification implementation
// needs a MessageLoopForIO, and there's no guarantee that
// MessageLoop::current() meets that criterion.
base::Thread::Options thread_options(MessageLoop::TYPE_IO, 0);
notifier_thread_->StartWithOptions(thread_options);
}
NetworkChangeNotifierLinux::~NetworkChangeNotifierLinux() {
// We don't need to explicitly Stop(), but doing so allows us to sanity-
// check that the notifier thread shut down properly.
notifier_thread_->Stop();
}
bool NetworkChangeNotifierLinux::IsCurrentlyOffline() const {
// TODO(eroman): http://crbug.com/53473
return false;
}
} // namespace net
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