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// Copyright 2013 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/tcp_socket.h"
#include "base/files/file_path.h"
#include "base/files/file_util.h"
#include "base/location.h"
#include "base/memory/ref_counted.h"
#include "base/threading/worker_pool.h"
namespace net {
namespace {
bool g_tcp_fastopen_enabled = false;
#if defined(OS_LINUX) || defined(OS_ANDROID)
typedef base::RefCountedData<bool> SharedBoolean;
// Checks to see if the system supports TCP FastOpen. Notably, it requires
// kernel support. Additionally, this checks system configuration to ensure that
// it's enabled.
void SystemSupportsTCPFastOpen(scoped_refptr<SharedBoolean> supported) {
supported->data = false;
static const base::FilePath::CharType kTCPFastOpenProcFilePath[] =
"/proc/sys/net/ipv4/tcp_fastopen";
std::string system_enabled_tcp_fastopen;
if (!base::ReadFileToString(base::FilePath(kTCPFastOpenProcFilePath),
&system_enabled_tcp_fastopen)) {
return;
}
// As per http://lxr.linux.no/linux+v3.7.7/include/net/tcp.h#L225
// TFO_CLIENT_ENABLE is the LSB
if (system_enabled_tcp_fastopen.empty() ||
(system_enabled_tcp_fastopen[0] & 0x1) == 0) {
return;
}
supported->data = true;
}
void EnableCallback(scoped_refptr<SharedBoolean> supported) {
g_tcp_fastopen_enabled = supported->data;
}
// This is asynchronous because it needs to do file IO, and it isn't allowed to
// do that on the IO thread.
void EnableFastOpenIfSupported() {
scoped_refptr<SharedBoolean> supported = new SharedBoolean;
base::WorkerPool::PostTaskAndReply(
FROM_HERE,
base::Bind(SystemSupportsTCPFastOpen, supported),
base::Bind(EnableCallback, supported),
false);
}
#else
void EnableFastOpenIfSupported() {
g_tcp_fastopen_enabled = false;
}
#endif
} // namespace
void SetTCPFastOpenEnabled(bool value) {
if (value) {
EnableFastOpenIfSupported();
} else {
g_tcp_fastopen_enabled = false;
}
}
bool IsTCPFastOpenEnabled() {
return g_tcp_fastopen_enabled;
}
} // namespace net
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