tcp: Change possible SYN flooding messages
"Possible SYN flooding on port xxxx " messages can fill logs on servers.
Change logic to log the message only once per listener, and add two new
SNMP counters to track :
TCPReqQFullDoCookies : number of times a SYNCOOKIE was replied to client
TCPReqQFullDrop : number of times a SYN request was dropped because
syncookies were not enabled.
Based on a prior patch from Tom Herbert, and suggestions from David.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
CC: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/snmp.h b/include/linux/snmp.h
index 12b2b18..e16557a 100644
--- a/include/linux/snmp.h
+++ b/include/linux/snmp.h
@@ -231,6 +231,8 @@
LINUX_MIB_TCPDEFERACCEPTDROP,
LINUX_MIB_IPRPFILTER, /* IP Reverse Path Filter (rp_filter) */
LINUX_MIB_TCPTIMEWAITOVERFLOW, /* TCPTimeWaitOverflow */
+ LINUX_MIB_TCPREQQFULLDOCOOKIES, /* TCPReqQFullDoCookies */
+ LINUX_MIB_TCPREQQFULLDROP, /* TCPReqQFullDrop */
__LINUX_MIB_MAX
};