From 18f02545a9a16c9a89778b91a162ad16d510bb32 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Ilpo=20J=C3=A4rvinen?= Date: Fri, 24 Aug 2007 22:55:52 -0700 Subject: [PATCH] [TCP] MIB: Add counters for discarded SACK blocks MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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 Signed-off-by: David S. Miller --- include/linux/snmp.h | 3 +++ net/ipv4/proc.c | 3 +++ net/ipv4/tcp_input.c | 10 +++++++++- 3 files changed, 15 insertions(+), 1 deletion(-) diff --git a/include/linux/snmp.h b/include/linux/snmp.h index 802b3a38b0..d24c554738 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 3b690cf2a4..986d1c83a0 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 a2364ebf85..f9e4d7ad68 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; -- 2.39.5