Commit 18f02545 authored by Ilpo Järvinen's avatar Ilpo Järvinen Committed by David S. Miller
Browse files

[TCP] MIB: Add counters for discarded SACK blocks 



In DSACK case, some events are not extraordinary, such as packet
duplication generated DSACK. They can arrive easily below
snd_una when undo_marker is not set (TCP being in CA_Open),
counting such DSACKs amoung SACK discards will likely just
mislead if they occur in some scenario when there are other
problems as well. Similarly, excessively delayed packets could
cause "normal" DSACKs. Therefore, separate counters are
allocated for DSACK events.

Signed-off-by: default avatarIlpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 5b3c9882

include/linux/snmp.h

+3 −0
Original line number Diff line number Diff line
@@ -231,6 +231,9 @@ enum 
	LINUX_MIB_TCPABORTONLINGER,		/* TCPAbortOnLinger */

	LINUX_MIB_TCPABORTFAILED,		/* TCPAbortFailed */

	LINUX_MIB_TCPMEMORYPRESSURES,		/* TCPMemoryPressures */

	LINUX_MIB_TCPSACKDISCARD,		/* TCPSACKDiscard */

	LINUX_MIB_TCPDSACKIGNOREDOLD,		/* TCPSACKIgnoredOld */

	LINUX_MIB_TCPDSACKIGNOREDNOUNDO,	/* TCPSACKIgnoredNoUndo */

	__LINUX_MIB_MAX

};

net/ipv4/proc.c

+3 −0
Original line number Diff line number Diff line
@@ -244,6 +244,9 @@ static const struct snmp_mib snmp4_net_list[] = { 
	SNMP_MIB_ITEM("TCPAbortOnLinger", LINUX_MIB_TCPABORTONLINGER),

	SNMP_MIB_ITEM("TCPAbortFailed", LINUX_MIB_TCPABORTFAILED),

	SNMP_MIB_ITEM("TCPMemoryPressures", LINUX_MIB_TCPMEMORYPRESSURES),

	SNMP_MIB_ITEM("TCPSACKDiscard", LINUX_MIB_TCPSACKDISCARD),

	SNMP_MIB_ITEM("TCPDSACKIgnoredOld", LINUX_MIB_TCPDSACKIGNOREDOLD),

	SNMP_MIB_ITEM("TCPDSACKIgnoredNoUndo", LINUX_MIB_TCPDSACKIGNOREDNOUNDO),

	SNMP_MIB_SENTINEL

};

net/ipv4/tcp_input.c

+9 −1
Original line number Diff line number Diff line
@@ -1240,8 +1240,16 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_ 
		int fack_count;

		int dup_sack = (found_dup_sack && (i == first_sack_index));



		if (!tcp_is_sackblock_valid(tp, dup_sack, start_seq, end_seq))

		if (!tcp_is_sackblock_valid(tp, dup_sack, start_seq, end_seq)) {

			if (dup_sack) {

				if (!tp->undo_marker)

					NET_INC_STATS_BH(LINUX_MIB_TCPDSACKIGNOREDNOUNDO);

				else

					NET_INC_STATS_BH(LINUX_MIB_TCPDSACKIGNOREDOLD);

			} else

				NET_INC_STATS_BH(LINUX_MIB_TCPSACKDISCARD);

			continue;

		}



		skb = cached_skb;

		fack_count = cached_fack_count;

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