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// Copyright 2014 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/socket/websocket_endpoint_lock_manager.h"
#include <utility>
#include "base/bind.h"
#include "base/location.h"
#include "base/logging.h"
#include "base/single_thread_task_runner.h"
#include "base/thread_task_runner_handle.h"
#include "net/base/net_errors.h"
#include "net/log/net_log.h"
namespace net {
namespace {
// This delay prevents DoS attacks.
// TODO(ricea): Replace this with randomised truncated exponential backoff.
// See crbug.com/377613.
const int kUnlockDelayInMs = 10;
} // namespace
WebSocketEndpointLockManager::Waiter::~Waiter() {
if (next()) {
DCHECK(previous());
RemoveFromList();
}
}
WebSocketEndpointLockManager* WebSocketEndpointLockManager::GetInstance() {
return base::Singleton<WebSocketEndpointLockManager>::get();
}
int WebSocketEndpointLockManager::LockEndpoint(const IPEndPoint& endpoint,
Waiter* waiter) {
LockInfoMap::value_type insert_value(endpoint, LockInfo());
std::pair<LockInfoMap::iterator, bool> rv =
lock_info_map_.insert(insert_value);
LockInfo& lock_info_in_map = rv.first->second;
if (rv.second) {
DVLOG(3) << "Locking endpoint " << endpoint.ToString();
lock_info_in_map.queue.reset(new LockInfo::WaiterQueue);
return OK;
}
DVLOG(3) << "Waiting for endpoint " << endpoint.ToString();
lock_info_in_map.queue->Append(waiter);
return ERR_IO_PENDING;
}
void WebSocketEndpointLockManager::RememberSocket(StreamSocket* socket,
const IPEndPoint& endpoint) {
LockInfoMap::iterator lock_info_it = lock_info_map_.find(endpoint);
CHECK(lock_info_it != lock_info_map_.end());
bool inserted =
socket_lock_info_map_.insert(SocketLockInfoMap::value_type(
socket, lock_info_it)).second;
DCHECK(inserted);
DCHECK(!lock_info_it->second.socket);
lock_info_it->second.socket = socket;
DVLOG(3) << "Remembered (StreamSocket*)" << socket << " for "
<< endpoint.ToString() << " (" << socket_lock_info_map_.size()
<< " socket(s) remembered)";
}
void WebSocketEndpointLockManager::UnlockSocket(StreamSocket* socket) {
SocketLockInfoMap::iterator socket_it = socket_lock_info_map_.find(socket);
if (socket_it == socket_lock_info_map_.end())
return;
LockInfoMap::iterator lock_info_it = socket_it->second;
DVLOG(3) << "Unlocking (StreamSocket*)" << socket << " for "
<< lock_info_it->first.ToString() << " ("
<< socket_lock_info_map_.size() << " socket(s) left)";
socket_lock_info_map_.erase(socket_it);
DCHECK_EQ(socket, lock_info_it->second.socket);
lock_info_it->second.socket = NULL;
UnlockEndpointAfterDelay(lock_info_it->first);
}
void WebSocketEndpointLockManager::UnlockEndpoint(const IPEndPoint& endpoint) {
LockInfoMap::iterator lock_info_it = lock_info_map_.find(endpoint);
if (lock_info_it == lock_info_map_.end())
return;
if (lock_info_it->second.socket)
EraseSocket(lock_info_it);
UnlockEndpointAfterDelay(endpoint);
}
bool WebSocketEndpointLockManager::IsEmpty() const {
return lock_info_map_.empty() && socket_lock_info_map_.empty();
}
base::TimeDelta WebSocketEndpointLockManager::SetUnlockDelayForTesting(
base::TimeDelta new_delay) {
base::TimeDelta old_delay = unlock_delay_;
unlock_delay_ = new_delay;
return old_delay;
}
WebSocketEndpointLockManager::LockInfo::LockInfo() : socket(NULL) {}
WebSocketEndpointLockManager::LockInfo::~LockInfo() {
DCHECK(!socket);
}
WebSocketEndpointLockManager::LockInfo::LockInfo(const LockInfo& rhs)
: socket(rhs.socket) {
DCHECK(!rhs.queue);
}
WebSocketEndpointLockManager::WebSocketEndpointLockManager()
: unlock_delay_(base::TimeDelta::FromMilliseconds(kUnlockDelayInMs)),
pending_unlock_count_(0),
weak_factory_(this) {
}
WebSocketEndpointLockManager::~WebSocketEndpointLockManager() {
DCHECK_EQ(lock_info_map_.size(), pending_unlock_count_);
DCHECK(socket_lock_info_map_.empty());
}
void WebSocketEndpointLockManager::UnlockEndpointAfterDelay(
const IPEndPoint& endpoint) {
DVLOG(3) << "Delaying " << unlock_delay_.InMilliseconds()
<< "ms before unlocking endpoint " << endpoint.ToString();
++pending_unlock_count_;
base::ThreadTaskRunnerHandle::Get()->PostDelayedTask(
FROM_HERE,
base::Bind(&WebSocketEndpointLockManager::DelayedUnlockEndpoint,
weak_factory_.GetWeakPtr(), endpoint),
unlock_delay_);
}
void WebSocketEndpointLockManager::DelayedUnlockEndpoint(
const IPEndPoint& endpoint) {
LockInfoMap::iterator lock_info_it = lock_info_map_.find(endpoint);
DCHECK_GT(pending_unlock_count_, 0U);
--pending_unlock_count_;
if (lock_info_it == lock_info_map_.end())
return;
DCHECK(!lock_info_it->second.socket);
LockInfo::WaiterQueue* queue = lock_info_it->second.queue.get();
DCHECK(queue);
if (queue->empty()) {
DVLOG(3) << "Unlocking endpoint " << lock_info_it->first.ToString();
lock_info_map_.erase(lock_info_it);
return;
}
DVLOG(3) << "Unlocking endpoint " << lock_info_it->first.ToString()
<< " and activating next waiter";
Waiter* next_job = queue->head()->value();
next_job->RemoveFromList();
next_job->GotEndpointLock();
}
void WebSocketEndpointLockManager::EraseSocket(
LockInfoMap::iterator lock_info_it) {
DVLOG(3) << "Removing (StreamSocket*)" << lock_info_it->second.socket
<< " for " << lock_info_it->first.ToString() << " ("
<< socket_lock_info_map_.size() << " socket(s) left)";
size_t erased = socket_lock_info_map_.erase(lock_info_it->second.socket);
DCHECK_EQ(1U, erased);
lock_info_it->second.socket = NULL;
}
} // namespace net
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