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authorIlpo Järvinen <ilpo.jarvinen@helsinki.fi>2007-08-24 22:55:52 -0700
committerDavid S. Miller <davem@sunset.davemloft.net>2007-10-10 16:48:30 -0700
commit18f02545a9a16c9a89778b91a162ad16d510bb32 (patch)
tree2b1c67a8168b695630d26216b7dd3be17179ca5c
parent5b3c98821a8753239aefc1c217409aa3e5c90787 (diff)
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[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: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--include/linux/snmp.h3
-rw-r--r--net/ipv4/proc.c3
-rw-r--r--net/ipv4/tcp_input.c10
3 files changed, 15 insertions, 1 deletions
diff --git a/include/linux/snmp.h b/include/linux/snmp.h
index 802b3a38b04..d24c5547382 100644
--- a/include/linux/snmp.h
+++ b/include/linux/snmp.h
@@ -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
};
diff --git a/net/ipv4/proc.c b/net/ipv4/proc.c
index 3b690cf2a4e..986d1c83a00 100644
--- a/net/ipv4/proc.c
+++ b/net/ipv4/proc.c
@@ -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
};
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index a2364ebf858..f9e4d7ad68b 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -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;