return useful listenq info in tcp_info and INET_DIAG_INFO

diff -r bdcdd0e1ee9d net/ipv4/tcp.c
@@ -2030,8 +2030,14 @@ void tcp_get_info(struct sock *sk, struc
 	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;
+	if (sk->sk_state == TCP_LISTEN) {
+		info->tcpi_unacked = sk->sk_ack_backlog;
+		info->tcpi_sacked = sk->sk_max_ack_backlog;
+	}
+	else {
+		info->tcpi_unacked = tp->packets_out;
+		info->tcpi_sacked = tp->sacked_out;
+	}
 	info->tcpi_lost = tp->lost_out;
 	info->tcpi_retrans = tp->retrans_out;
 	info->tcpi_fackets = tp->fackets_out;

diff -r bdcdd0e1ee9d net/ipv4/tcp_diag.c
@@ -25,11 +25,14 @@ static void tcp_diag_get_info(struct soc
 	const struct tcp_sock *tp = tcp_sk(sk);
 	struct tcp_info *info = _info;
 
-	if (sk->sk_state == TCP_LISTEN)
+	if (sk->sk_state == TCP_LISTEN) {
 		r->idiag_rqueue = sk->sk_ack_backlog;
-	else
+		r->idiag_wqueue = sk->sk_max_ack_backlog;
+	}
+	else {
 		r->idiag_rqueue = tp->rcv_nxt - tp->copied_seq;
-	r->idiag_wqueue = tp->write_seq - tp->snd_una;
+		r->idiag_wqueue = tp->write_seq - tp->snd_una;
+	}
 	if (info != NULL)
 		tcp_get_info(sk, info);
 }