__tcp_v4_send_synack  744 net/ipv4/tcp_ipv4.c 	return __tcp_v4_send_synack(sk, req, NULL);
__tcp_v4_send_synack 1311 net/ipv4/tcp_ipv4.c 	if (__tcp_v4_send_synack(sk, req, dst) || want_cookie)