mss = tcp_mtu_to_mss(sk, icsk->icsk_mtup.search_low) >> 1;
mss = min(sysctl_tcp_base_mss, mss);
mss = max(mss, 68 - tp->tcp_header_len);
mss = tcp_mtu_to_mss(sk, icsk->icsk_mtup.search_low) >> 1;
mss = min(sysctl_tcp_base_mss, mss);
mss = max(mss, 68 - tp->tcp_header_len);