net: tcp: add mib counters to track zero window transitions

Three counters are added:
- one to track when we went from non-zero to zero window
- one to track the reverse
- one counter incremented when we want to announce zero window,
  but can't because we would shrink current window.

Suggested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 0 deletions

diff --git a/include/uapi/linux/snmp.h b/include/uapi/linux/snmp.h
index bbaba22f2d1b..8d64a7e5d371 100644
--- a/include/uapi/linux/snmp.h
+++ b/include/uapi/linux/snmp.h
@@ -259,6 +259,9 @@ enum
         LINUX_MIB_TCPSPURIOUS_RTX_HOSTQUEUES, /* TCPSpuriousRtxHostQueues */
         LINUX_MIB_BUSYPOLLRXPACKETS,            /* BusyPollRxPackets */
         LINUX_MIB_TCPAUTOCORKING,               /* TCPAutoCorking */
+        LINUX_MIB_TCPFROMZEROWINDOWADV,         /* TCPFromZeroWindowAdv */
+        LINUX_MIB_TCPTOZEROWINDOWADV,           /* TCPToZeroWindowAdv */
+        LINUX_MIB_TCPWANTZEROWINDOWADV,         /* TCPWantZeroWindowAdv */
         __LINUX_MIB_MAX
 };