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authorYafang Shao <laoar.shao@gmail.com>2018-06-24 10:02:54 -0400
committerDavid S. Miller <davem@davemloft.net>2018-06-26 11:49:08 +0900
commitfb223502ec0889444965f602f57b1f45f9e9845e (patch)
tree08a4895a31a307722691a1f6abdb1e44c658dece /net/ipv4/tcp_input.c
parent7e55052783fd3a9202e9f7c4c480629a7270645f (diff)
downloadlinux-fb223502ec0889444965f602f57b1f45f9e9845e.tar.bz2
tcp: add SNMP counter for zero-window drops
It will be helpful if we could display the drops due to zero window or no enough window space. So a new SNMP MIB entry is added to track this behavior. This entry is named LINUX_MIB_TCPZEROWINDOWDROP and published in /proc/net/netstat in TcpExt line as TCPZeroWindowDrop. Signed-off-by: Yafang Shao <laoar.shao@gmail.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/tcp_input.c')
-rw-r--r--net/ipv4/tcp_input.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 76ca88f63b70..9c5b3415413f 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -4668,8 +4668,10 @@ static void tcp_data_queue(struct sock *sk, struct sk_buff *skb)
* Out of sequence packets to the out_of_order_queue.
*/
if (TCP_SKB_CB(skb)->seq == tp->rcv_nxt) {
- if (tcp_receive_window(tp) == 0)
+ if (tcp_receive_window(tp) == 0) {
+ NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPZEROWINDOWDROP);
goto out_of_window;
+ }
/* Ok. In sequence. In window. */
queue_and_out:
@@ -4735,8 +4737,10 @@ drop:
/* If window is closed, drop tail of packet. But after
* remembering D-SACK for its head made in previous line.
*/
- if (!tcp_receive_window(tp))
+ if (!tcp_receive_window(tp)) {
+ NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPZEROWINDOWDROP);
goto out_of_window;
+ }
goto queue_and_out;
}