//go:build linux// +build linux // Copyright (c) 2015-2021 MinIO, Inc.//// This file is part of MinIO Object Storage stack//// This program is free software: you can redistribute it and/or modify// it under the terms of the GNU Affero General Public License as published by// the Free Software Foundation, either version 3 of the License, or// (at your option) any later version.//// This program is distributed in the hope that it will be useful// but WITHOUT ANY WARRANTY; without even the implied warranty of// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the// GNU Affero General Public License for more details.//// You should have received a copy of the GNU Affero General Public License// along with this program.  If not, see <http://www.gnu.org/licenses/>. package http import (	"context"	"net"	"syscall"	"time" 	"golang.org/x/sys/unix") func setTCPParameters(network, address string, c syscall.RawConn) error {	c.Control(func(fdPtr uintptr) {		// got socket file descriptor to set parameters.		fd := int(fdPtr) 		_ = unix.SetsockoptInt(fd, unix.SOL_SOCKET, unix.SO_REUSEADDR, 1) 		_ = unix.SetsockoptInt(fd, unix.SOL_SOCKET, unix.SO_REUSEPORT, 1) 		// Enable TCP open		// https://lwn.net/Articles/508865/ - 16k queue size.		_ = syscall.SetsockoptInt(fd, syscall.SOL_TCP, unix.TCP_FASTOPEN, 16*1024) 		// Enable TCP fast connect		// TCPFastOpenConnect sets the underlying socket to use		// the TCP fast open connect. This feature is supported		// since Linux 4.11.		_ = syscall.SetsockoptInt(fd, syscall.IPPROTO_TCP, unix.TCP_FASTOPEN_CONNECT, 1) 		// Enable TCP quick ACK, John Nagle says		// "Set TCP_QUICKACK. If you find a case where that makes things worse, let me know."		_ = syscall.SetsockoptInt(fd, syscall.IPPROTO_TCP, unix.TCP_QUICKACK, 1)	})	return nil} // DialContext is a function to make custom Dial for internode communicationstype DialContext func(ctx context.Context, network, address string) (net.Conn, error) // NewInternodeDialContext setups a custom dialer for internode communicationfunc NewInternodeDialContext(dialTimeout time.Duration) DialContext {	return func(ctx context.Context, network, addr string) (net.Conn, error) {		dialer := &net.Dialer{			Timeout: dialTimeout,			Control: setTCPParameters,		}		return dialer.DialContext(ctx, network, addr)	}} // NewCustomDialContext setups a custom dialer for any external communication and proxies.func NewCustomDialContext(dialTimeout time.Duration) DialContext {	return func(ctx context.Context, network, addr string) (net.Conn, error) {		dialer := &net.Dialer{			Timeout: dialTimeout,			Control: setTCPParameters,		}		return dialer.DialContext(ctx, network, addr)	}}