void tcp_get_info(struct sock *sk, struct tcp_info *info)
{
	const struct tcp_sock *tp = tcp_sk(sk); /* iff sk_type == SOCK_STREAM */
	const struct inet_connection_sock *icsk = inet_csk(sk);
	unsigned long rate;
	u32 now;
	u64 rate64;
	bool slow;

	memset(info, 0, sizeof(*info));
	if (sk->sk_type != SOCK_STREAM)
		return;

	info->tcpi_state = inet_sk_state_load(sk);

	/* Report meaningful fields for all TCP states, including listeners */
	rate = READ_ONCE(sk->sk_pacing_rate);
	rate64 = (rate != ~0UL) ? rate : ~0ULL;
	info->tcpi_pacing_rate = rate64;

	rate = READ_ONCE(sk->sk_max_pacing_rate);
	rate64 = (rate != ~0UL) ? rate : ~0ULL;
	info->tcpi_max_pacing_rate = rate64;

	info->tcpi_reordering = tp->reordering;
	info->tcpi_snd_cwnd = tp->snd_cwnd;

	if (info->tcpi_state == TCP_LISTEN) {
		/* listeners aliased fields :
		 * tcpi_unacked -> Number of children ready for accept()
		 * tcpi_sacked  -> max backlog
		 */
		info->tcpi_unacked = sk->sk_ack_backlog;
		info->tcpi_sacked = sk->sk_max_ack_backlog;
		return;
	}

	slow = lock_sock_fast(sk);

	info->tcpi_ca_state = icsk->icsk_ca_state;
	info->tcpi_retransmits = icsk->icsk_retransmits;
	info->tcpi_probes = icsk->icsk_probes_out;
	info->tcpi_backoff = icsk->icsk_backoff;

	if (tp->rx_opt.tstamp_ok)
		info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
	if (tcp_is_sack(tp))
		info->tcpi_options |= TCPI_OPT_SACK;
	if (tp->rx_opt.wscale_ok) {
		info->tcpi_options |= TCPI_OPT_WSCALE;
		info->tcpi_snd_wscale = tp->rx_opt.snd_wscale;
		info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale;
	}

	if (tp->ecn_flags & TCP_ECN_OK)
		info->tcpi_options |= TCPI_OPT_ECN;
	if (tp->ecn_flags & TCP_ECN_SEEN)
		info->tcpi_options |= TCPI_OPT_ECN_SEEN;
	if (tp->syn_data_acked)
		info->tcpi_options |= TCPI_OPT_SYN_DATA;

	info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto);
	info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato);
	info->tcpi_snd_mss = tp->mss_cache;
	info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss;

	info->tcpi_unacked = tp->packets_out;
	info->tcpi_sacked = tp->sacked_out;

	info->tcpi_lost = tp->lost_out;
	info->tcpi_retrans = tp->retrans_out;

	now = tcp_jiffies32;
	info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime);
	info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime);
	info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);

	info->tcpi_pmtu = icsk->icsk_pmtu_cookie;
	info->tcpi_rcv_ssthresh = tp->rcv_ssthresh;
	info->tcpi_rtt = tp->srtt_us >> 3;
	info->tcpi_rttvar = tp->mdev_us >> 2;
	info->tcpi_snd_ssthresh = tp->snd_ssthresh;
	info->tcpi_advmss = tp->advmss;

	info->tcpi_rcv_rtt = tp->rcv_rtt_est.rtt_us >> 3;
	info->tcpi_rcv_space = tp->rcvq_space.space;

	info->tcpi_total_retrans = tp->total_retrans;

	info->tcpi_bytes_acked = tp->bytes_acked;
	info->tcpi_bytes_received = tp->bytes_received;
	info->tcpi_notsent_bytes = max_t(int, 0, tp->write_seq - tp->snd_nxt);
	tcp_get_info_chrono_stats(tp, info);

	info->tcpi_segs_out = tp->segs_out;
	info->tcpi_segs_in = tp->segs_in;

	info->tcpi_min_rtt = tcp_min_rtt(tp);
	info->tcpi_data_segs_in = tp->data_segs_in;
	info->tcpi_data_segs_out = tp->data_segs_out;

	info->tcpi_delivery_rate_app_limited = tp->rate_app_limited ? 1 : 0;
	rate64 = tcp_compute_delivery_rate(tp);
	if (rate64)
		info->tcpi_delivery_rate = rate64;
	info->tcpi_delivered = tp->delivered;
	info->tcpi_delivered_ce = tp->delivered_ce;
	info->tcpi_bytes_sent = tp->bytes_sent;
	info->tcpi_bytes_retrans = tp->bytes_retrans;
	info->tcpi_dsack_dups = tp->dsack_dups;
	info->tcpi_reord_seen = tp->reord_seen;
	unlock_sock_fast(sk, slow);
}