/* * Copyright (c) Meta Platforms, Inc. and affiliates. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #pragma once #include #include #include #if !defined(FOLLY_ALLOW_TFO) #if defined(__linux__) || defined(__APPLE__) // only allow for linux right now #define FOLLY_ALLOW_TFO 1 #endif #endif namespace folly { namespace detail { /** * TFOAvailability describes support for TCP Fast Open (TFO). */ enum class TFOAvailability { /** * TFOAvailability::None indicates that the current environment * does not support TFO (or we could not detect support via probing). */ None, /** * TFOAvailability::WithCookies indicates that TFO is supported by the * platform. However, in order for TFO data to be used or for TFO to * be attempted, a prior connection to the same peer must have successfully * taken place so that the peer could issue a cookie. */ WithCookies, /** * TFOAvailability::Unconditional indicates that TFO will always be * unconditionally sent or accepted, regardless of whether or not prior * connections have taken place. */ Unconditional }; /** * PlatformTFOSettings describes TFO support for client connections and * server connections. */ struct PlatformTFOSettings { TFOAvailability client{TFOAvailability::None}; TFOAvailability server{TFOAvailability::None}; }; /** * tfo_sendto has the same semantics as sendmsg, but is used to * send with TFO data. */ ssize_t tfo_sendmsg(NetworkSocket sockfd, const struct msghdr* msg, int flags); /** * Enable TFO on a listening socket. */ int tfo_enable(NetworkSocket sockfd, size_t max_queue_size); /** * Check if TFO succeeded in being used. */ bool tfo_succeeded(NetworkSocket sockfd); /** * Check if TFO is supported by the kernel. */ PlatformTFOSettings tfo_platform_availability(); } // namespace detail } // namespace folly