v2ray-core/transport/internet/sockopt_darwin.go

package internet

import (
	"syscall"
)

const (
	TCP_FASTOPEN        = 0x105
	TCP_FASTOPEN_SERVER = 0x01
	TCP_FASTOPEN_CLIENT = 0x02
)

func applyOutboundSocketOptions(network string, address string, fd uintptr, config *SocketConfig) error {
	if isTCPSocket(network) {
		switch config.Tfo {
		case SocketConfig_Enable:
			if err := syscall.SetsockoptInt(int(fd), syscall.IPPROTO_TCP, TCP_FASTOPEN, TCP_FASTOPEN_CLIENT); err != nil {
				return err
			}
		case SocketConfig_Disable:
			if err := syscall.SetsockoptInt(int(fd), syscall.IPPROTO_TCP, TCP_FASTOPEN, 0); err != nil {
				return err
			}
		}
	}

	return nil
}

func applyInboundSocketOptions(network string, fd uintptr, config *SocketConfig) error {
	if isTCPSocket(network) {
		switch config.Tfo {
		case SocketConfig_Enable:
			if err := syscall.SetsockoptInt(int(fd), syscall.IPPROTO_TCP, TCP_FASTOPEN, TCP_FASTOPEN_SERVER); err != nil {
				return err
			}
		case SocketConfig_Disable:
			if err := syscall.SetsockoptInt(int(fd), syscall.IPPROTO_TCP, TCP_FASTOPEN, 0); err != nil {
				return err
			}
		}
	}

	return nil
}