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

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

include/linux/snmp.h

+2 −0
Original line number Diff line number Diff line
@@ -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

};

net/ipv4/proc.c

+2 −0
Original line number Diff line number Diff line
@@ -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

};

net/ipv4/tcp_ipv4.c

+5 −2
Original line number Diff line number Diff line
@@ -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);

net/ipv6/tcp_ipv6.c

+2 −1
Original line number Diff line number Diff line
@@ -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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