[TCP]: Return useful listenq info in tcp_info and INET_DIAG_INFO.

Return some useful information such as the maximum listen backlog and
the current listen backlog in the tcp_info structure and
INET_DIAG_INFO.

Signed-off-by: Rick Jones <rick.jones2@hp.com>
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 7 insertions, 2 deletions

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 18c64c74f6d5..4f322003835d 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2031,8 +2031,13 @@ void tcp_get_info(struct sock *sk, struct tcp_info *info)
         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;