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[TCP] MIB: Add counters for discarded SACK blocks

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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: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Ilpo Järvinen 2007-08-24 22:55:52 -07:00 committed by David S. Miller
parent 5b3c98821a
commit 18f02545a9
3 changed files with 15 additions and 1 deletions
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3
include/linux/snmp.h
View file

@ -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
};

3
net/ipv4/proc.c
View file

@ -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
};

10
net/ipv4/tcp_input.c
View file

@ -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;