From 6cce09f87a04797fae5b947ef2626c14a78f0b49 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Sun, 7 Mar 2010 23:21:57 +0000 Subject: [PATCH] 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 Signed-off-by: David S. Miller --- include/linux/snmp.h | 2 ++ net/ipv4/proc.c | 2 ++ net/ipv4/tcp_ipv4.c | 7 +++++-- net/ipv6/tcp_ipv6.c | 3 ++- 4 files changed, 11 insertions(+), 3 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 }; diff --git a/net/ipv4/proc.c b/net/ipv4/proc.c index 242ed2307370..4f1f337f4337 100644 --- a/net/ipv4/proc.c +++ b/net/ipv4/proc.c @@ -249,6 +249,8 @@ static const struct snmp_mib snmp4_net_list[] = { SNMP_MIB_ITEM("TCPSackShifted", LINUX_MIB_SACKSHIFTED), SNMP_MIB_ITEM("TCPSackMerged", LINUX_MIB_SACKMERGED), SNMP_MIB_ITEM("TCPSackShiftFallback", LINUX_MIB_SACKSHIFTFALLBACK), + SNMP_MIB_ITEM("TCPBacklogDrop", LINUX_MIB_TCPBACKLOGDROP), + SNMP_MIB_ITEM("TCPMinTTLDrop", LINUX_MIB_TCPMINTTLDROP), SNMP_MIB_SENTINEL }; diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 1915f7dc30e6..8d51d39ad1bb 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -1651,8 +1651,10 @@ int tcp_v4_rcv(struct sk_buff *skb) 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 @@ process: 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); diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index 2c378b1bd5cf..9b6dbba80d31 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -1740,8 +1740,9 @@ process: if (!tcp_prequeue(sk, skb)) ret = tcp_v6_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);