tcp: ipv6: Update MIB counters for drops

This patch updates LINUX_MIB_LISTENDROPS and LINUX_MIB_LISTENOVERFLOWS in
tcp_v6_conn_request() and tcp_v6_err(). tcp_v6_conn_request() in particular can
drop SYNs for various reasons which are not currently tracked.

Signed-off-by: Vijay Subramanian <subramanian.vijay@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 1 deletions

diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 93825dd3a7c0..4f43537197ef 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -423,6 +423,7 @@ static void tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
                 }
 
                 inet_csk_reqsk_queue_drop(sk, req, prev);
+                NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
                 goto out;
 
         case TCP_SYN_SENT:
@@ -958,8 +959,10 @@ static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
                         goto drop;
         }
 
-        if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
+        if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1) {
+                NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
                 goto drop;
+        }
 
         req = inet6_reqsk_alloc(&tcp6_request_sock_ops);
         if (req == NULL)
@@ -1108,6 +1111,7 @@ drop_and_release:
 drop_and_free:
         reqsk_free(req);
 drop:
+        NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
         return 0; /* don't send reset */
 }