tcp: Add SNMP counters for backlog and min_ttl drops

Commit 6b03a53a (tcp: use limited socket backlog) added the possibility
of dropping frames when backlog queue is full.

Commit d218d111 (tcp: Generalized TTL Security Mechanism) added the
possibility of dropping frames when TTL is under a given limit.

This patch adds new SNMP MIB entries, named TCPBacklogDrop and
TCPMinTTLDrop, published in /proc/net/netstat in TcpExt: line

netstat -s | egrep "TCPBacklogDrop|TCPMinTTLDrop"
    TCPBacklogDrop: 0
    TCPMinTTLDrop: 0

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/linux/snmp.h b/include/linux/snmp.h
index e28f5a0182e8..4435d1084755 100644
--- a/include/linux/snmp.h
+++ b/include/linux/snmp.h
@@ -225,6 +225,8 @@ enum
         LINUX_MIB_SACKSHIFTED,
         LINUX_MIB_SACKMERGED,
         LINUX_MIB_SACKSHIFTFALLBACK,
+        LINUX_MIB_TCPBACKLOGDROP,
+        LINUX_MIB_TCPMINTTLDROP, /* RFC 5082 */
         __LINUX_MIB_MAX
 };