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>
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 1915f7d..8d51d39 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1651,8 +1651,10 @@
if (!sk)
goto no_tcp_socket;
- if (iph->ttl < inet_sk(sk)->min_ttl)
+ if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
+ NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
goto discard_and_relse;
+ }
process:
if (sk->sk_state == TCP_TIME_WAIT)
@@ -1682,8 +1684,9 @@
if (!tcp_prequeue(sk, skb))
ret = tcp_v4_do_rcv(sk, skb);
}
- } else if (sk_add_backlog(sk, skb)) {
+ } else if (unlikely(sk_add_backlog(sk, skb))) {
bh_unlock_sock(sk);
+ NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP);
goto discard_and_relse;
}
bh_unlock_sock(sk);