Commit 6cce09f8 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller

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: default avatarEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 40456353
......@@ -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
};
......
......@@ -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
};
......
......@@ -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);
......
......@@ -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);
......
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