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/net/request_sock.h b/include/net/request_sock.h
index 99e6e19..4c0766e 100644
--- a/include/net/request_sock.h
+++ b/include/net/request_sock.h
@@ -96,7 +96,8 @@
*/
struct listen_sock {
u8 max_qlen_log;
- /* 3 bytes hole, try to use */
+ u8 synflood_warned;
+ /* 2 bytes hole, try to use */
int qlen;
int qlen_young;
int clock_hand;