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// Copyright 2014 The Chromium Authors
// 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 <memory>
#include <utility>
#include "base/functional/bind.h"
#include "base/location.h"
#include "base/logging.h"
#include "base/task/single_thread_task_runner.h"
#include "net/base/net_errors.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::LockReleaser::LockReleaser(
WebSocketEndpointLockManager* websocket_endpoint_lock_manager,
IPEndPoint endpoint)
: websocket_endpoint_lock_manager_(websocket_endpoint_lock_manager),
endpoint_(endpoint) {
websocket_endpoint_lock_manager->RegisterLockReleaser(this, endpoint);
}
WebSocketEndpointLockManager::LockReleaser::~LockReleaser() {
if (websocket_endpoint_lock_manager_) {
websocket_endpoint_lock_manager_->UnlockEndpoint(endpoint_);
}
}
WebSocketEndpointLockManager::WebSocketEndpointLockManager()
: unlock_delay_(base::Milliseconds(kUnlockDelayInMs)) {}
WebSocketEndpointLockManager::~WebSocketEndpointLockManager() {
DCHECK_EQ(lock_info_map_.size(), pending_unlock_count_);
}
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 = std::make_unique<LockInfo::WaiterQueue>();
return OK;
}
DVLOG(3) << "Waiting for endpoint " << endpoint.ToString();
lock_info_in_map.queue->Append(waiter);
return ERR_IO_PENDING;
}
void WebSocketEndpointLockManager::UnlockEndpoint(const IPEndPoint& endpoint) {
auto lock_info_it = lock_info_map_.find(endpoint);
if (lock_info_it == lock_info_map_.end())
return;
LockReleaser* lock_releaser = lock_info_it->second.lock_releaser;
if (lock_releaser) {
lock_info_it->second.lock_releaser = nullptr;
lock_releaser->websocket_endpoint_lock_manager_ = nullptr;
}
UnlockEndpointAfterDelay(endpoint);
}
bool WebSocketEndpointLockManager::IsEmpty() const {
return 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() : lock_releaser(nullptr) {}
WebSocketEndpointLockManager::LockInfo::~LockInfo() {
DCHECK(!lock_releaser);
}
WebSocketEndpointLockManager::LockInfo::LockInfo(const LockInfo& rhs)
: lock_releaser(rhs.lock_releaser) {
DCHECK(!rhs.queue);
}
void WebSocketEndpointLockManager::RegisterLockReleaser(
LockReleaser* lock_releaser,
IPEndPoint endpoint) {
DCHECK(lock_releaser);
auto lock_info_it = lock_info_map_.find(endpoint);
CHECK(lock_info_it != lock_info_map_.end());
DCHECK(!lock_info_it->second.lock_releaser);
lock_info_it->second.lock_releaser = lock_releaser;
DVLOG(3) << "Registered (LockReleaser*)" << lock_releaser << " for "
<< endpoint.ToString();
}
void WebSocketEndpointLockManager::UnlockEndpointAfterDelay(
const IPEndPoint& endpoint) {
DVLOG(3) << "Delaying " << unlock_delay_.InMilliseconds()
<< "ms before unlocking endpoint " << endpoint.ToString();
++pending_unlock_count_;
base::SingleThreadTaskRunner::GetCurrentDefault()->PostDelayedTask(
FROM_HERE,
base::BindOnce(&WebSocketEndpointLockManager::DelayedUnlockEndpoint,
weak_factory_.GetWeakPtr(), endpoint),
unlock_delay_);
}
void WebSocketEndpointLockManager::DelayedUnlockEndpoint(
const IPEndPoint& endpoint) {
auto 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.lock_releaser);
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();
}
} // namespace net
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