netdev - [PATCH] tcp: Increment of LINUX_MIB_LISTENOVERFLOWS in tcp_v4_conn

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Date:	Thu, 24 Jan 2013 23:03:28 -0800
From:	Nivedita Singhvi <niveditasinghvi@...il.com>
To:	netdev@...r.kernel.org, David Miller <davem@...emloft.net>
Cc:	Leandro Lucarella <leandro.lucarella@...iomantic.com>,
	Nivedita Singhvi <niv@...ibm.com>
Subject: [PATCH] tcp: Increment of LINUX_MIB_LISTENOVERFLOWS in tcp_v4_conn_request()

We drop a connection request if the accept backlog, syn queue are full when processing reaches tcp_v4_conn_request(). Increment the appropriate counter so this isn't silent, for accurate stats and help in debugging.

Signed-off-by: Nivedita Singhvi <niv@...ibm.com>
---
 net/ipv4/tcp_ipv4.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index bbbdcc5..49b4f50 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1502,8 +1502,10 @@ int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
 	 * clogging syn queue with openreqs with exponentially increasing
 	 * timeout.
 	 */
-	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 = inet_reqsk_alloc(&tcp_request_sock_ops);
 	if (!req)
-- 
1.7.5.4

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