// SPDX-License-Identifier: GPL-2.0
`./defaults.sh
 ./set_sysctls.py /proc/sys/net/ipv4/tcp_fastopen=0x602 /proc/sys/net/ipv4/tcp_timestamps=0`

    0 socket(..., SOCK_STREAM|SOCK_NONBLOCK, IPPROTO_TCP) = 3
   +0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0
   +0 bind(3, ..., ...) = 0
   +0 listen(3, 1) = 0

   +0 < S 0:10(10) win 32792 <mss 1460,nop,nop,sackOK>
   +0 > S. 0:0(0) ack 11 win 65535 <mss 1460,nop,nop,sackOK>

// sk->sk_state is TCP_SYN_RECV
  +.1 accept(3, ..., ...) = 4

// tcp_disconnect() sets sk->sk_state to TCP_CLOSE
   +0 connect(4, AF_UNSPEC, ...) = 0
   +0 > R. 1:1(0) ack 11 win 65535

// connect() sets sk->sk_state to TCP_SYN_SENT
   +0 fcntl(4, F_SETFL, O_RDWR|O_NONBLOCK) = 0
   +0 connect(4, ..., ...) = -1 EINPROGRESS (Operation is now in progress)
   +0 > S 0:0(0) win 65535 <mss 1460,nop,nop,sackOK,nop,wscale 8>

// tp->fastopen_rsk must be NULL
   +1 > S 0:0(0) win 65535 <mss 1460,nop,nop,sackOK,nop,wscale 8>