@@ -279,6 +279,7 @@ enum
LINUX_MIB_TCPDELIVERED, /* TCPDelivered */
LINUX_MIB_TCPDELIVEREDCE, /* TCPDeliveredCE */
LINUX_MIB_TCPACKCOMPRESSED, /* TCPAckCompressed */
+ LINUX_MIB_TCPZEROWINDOWDROP, /* TCPZeroWindowDrop */
__LINUX_MIB_MAX
};
@@ -287,6 +287,7 @@ static int sockstat_seq_show(struct seq_file *seq, void *v)
SNMP_MIB_ITEM("TCPDelivered", LINUX_MIB_TCPDELIVERED),
SNMP_MIB_ITEM("TCPDeliveredCE", LINUX_MIB_TCPDELIVEREDCE),
SNMP_MIB_ITEM("TCPAckCompressed", LINUX_MIB_TCPACKCOMPRESSED),
+ SNMP_MIB_ITEM("TCPZeroWindowDrop", LINUX_MIB_TCPZEROWINDOWDROP),
SNMP_MIB_SENTINEL
};
@@ -4665,8 +4665,10 @@ 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:
@@ -4732,8 +4734,10 @@ static void tcp_data_queue(struct sock *sk, struct sk_buff *skb)
/* 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;
}
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> --- include/uapi/linux/snmp.h | 1 + net/ipv4/proc.c | 1 + net/ipv4/tcp_input.c | 8 ++++++-- 3 files changed, 8 insertions(+), 2 deletions(-)