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// Copyright 2020 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include <limits>
#include "base/atomic_ref_count.h"
#include "base/no_destructor.h"
#include "net/base/features.h"
#include "net/socket/udp_socket_global_limits.h"
namespace net {
namespace {
// Threadsafe singleton for tracking the process-wide count of UDP sockets.
class GlobalUDPSocketCounts {
public:
GlobalUDPSocketCounts() = default;
~GlobalUDPSocketCounts() = delete;
static GlobalUDPSocketCounts& Get() {
static base::NoDestructor<GlobalUDPSocketCounts> singleton;
return *singleton;
}
[[nodiscard]] bool TryAcquireSocket() {
int previous = count_.Increment(1);
if (previous >= GetMax()) {
count_.Increment(-1);
return false;
}
return true;
}
int GetMax() {
if (base::FeatureList::IsEnabled(features::kLimitOpenUDPSockets))
return features::kLimitOpenUDPSocketsMax.Get();
return std::numeric_limits<int>::max();
}
void ReleaseSocket() { count_.Increment(-1); }
int GetCountForTesting() { return count_.SubtleRefCountForDebug(); }
private:
base::AtomicRefCount count_{0};
};
} // namespace
OwnedUDPSocketCount::OwnedUDPSocketCount() : OwnedUDPSocketCount(true) {}
OwnedUDPSocketCount::OwnedUDPSocketCount(OwnedUDPSocketCount&& other) {
*this = std::move(other);
}
OwnedUDPSocketCount& OwnedUDPSocketCount::operator=(
OwnedUDPSocketCount&& other) {
Reset();
empty_ = other.empty_;
other.empty_ = true;
return *this;
}
OwnedUDPSocketCount::~OwnedUDPSocketCount() {
Reset();
}
void OwnedUDPSocketCount::Reset() {
if (!empty_) {
GlobalUDPSocketCounts::Get().ReleaseSocket();
empty_ = true;
}
}
OwnedUDPSocketCount::OwnedUDPSocketCount(bool empty) : empty_(empty) {}
OwnedUDPSocketCount TryAcquireGlobalUDPSocketCount() {
bool success = GlobalUDPSocketCounts::Get().TryAcquireSocket();
return OwnedUDPSocketCount(!success);
}
int GetGlobalUDPSocketCountForTesting() {
return GlobalUDPSocketCounts::Get().GetCountForTesting();
}
} // namespace net
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