2015-07-06 17:33:03

by Vitaly Andrianov

Subject: [PATCH] sctp: Add counters for out data chunk discards

This commit adds a MIB entry for out data chunk discards.
Number of outgoing SCTP DATA chunks for a SCTP association for which no
problems were encountered to prevent their transmission but were discarded.
Data chunks are discarded due to ungraceful closing of the SCTP
association.

Signed-off-by: Vitaly Andrianov <[email protected]>
---
include/net/sctp/sctp.h | 1 +
net/sctp/outqueue.c | 1 +
net/sctp/proc.c | 2 ++
3 files changed, 4 insertions(+)

diff --git a/include/net/sctp/sctp.h b/include/net/sctp/sctp.h
index ce13cf2..fd806ea 100644
--- a/include/net/sctp/sctp.h
+++ b/include/net/sctp/sctp.h
@@ -216,6 +216,7 @@ enum {
SCTP_MIB_IN_PKT_BACKLOG,
SCTP_MIB_IN_PKT_DISCARDS,
SCTP_MIB_IN_DATA_CHUNK_DISCARDS,
+ SCTP_MIB_OUT_DATA_CHUNK_DISCARDS,
__SCTP_MIB_MAX
};

diff --git a/net/sctp/outqueue.c b/net/sctp/outqueue.c
index 7e8f0a1..dc1a40f 100644
--- a/net/sctp/outqueue.c
+++ b/net/sctp/outqueue.c
@@ -315,6 +315,7 @@ int sctp_outq_tail(struct sctp_outq *q, struct sctp_chunk *chunk)
case SCTP_STATE_SHUTDOWN_RECEIVED:
case SCTP_STATE_SHUTDOWN_ACK_SENT:
/* Cannot send after transport endpoint shutdown */
+ SCTP_INC_STATS(net, SCTP_MIB_OUT_DATA_CHUNK_DISCARDS);
error = -ESHUTDOWN;
break;

diff --git a/net/sctp/proc.c b/net/sctp/proc.c
index 0697eda..1a10b81 100644
--- a/net/sctp/proc.c
+++ b/net/sctp/proc.c
@@ -67,6 +67,8 @@ static const struct snmp_mib sctp_snmp_list[] = {
SNMP_MIB_ITEM("SctpInPktBacklog", SCTP_MIB_IN_PKT_BACKLOG),
SNMP_MIB_ITEM("SctpInPktDiscards", SCTP_MIB_IN_PKT_DISCARDS),
SNMP_MIB_ITEM("SctpInDataChunkDiscards", SCTP_MIB_IN_DATA_CHUNK_DISCARDS),
+ SNMP_MIB_ITEM("SctpOutDataChunkDiscards",
+ SCTP_MIB_OUT_DATA_CHUNK_DISCARDS),
SNMP_MIB_SENTINEL
};

--
1.9.1

2015-07-06 18:46:38

by Vlad Yasevich

Subject: Re: [PATCH] sctp: Add counters for out data chunk discards

On 07/06/2015 01:37 PM, Vitaly Andrianov wrote:
> This commit adds a MIB entry for out data chunk discards.
> Number of outgoing SCTP DATA chunks for a SCTP association for which no
> problems were encountered to prevent their transmission but were discarded.
> Data chunks are discarded due to ungraceful closing of the SCTP
> association.
>
> Signed-off-by: Vitaly Andrianov <[email protected]>
> ---
> include/net/sctp/sctp.h | 1 +
> net/sctp/outqueue.c | 1 +
> net/sctp/proc.c | 2 ++
> 3 files changed, 4 insertions(+)
>
> diff --git a/include/net/sctp/sctp.h b/include/net/sctp/sctp.h
> index ce13cf2..fd806ea 100644
> --- a/include/net/sctp/sctp.h
> +++ b/include/net/sctp/sctp.h
> @@ -216,6 +216,7 @@ enum {
> SCTP_MIB_IN_PKT_BACKLOG,
> SCTP_MIB_IN_PKT_DISCARDS,
> SCTP_MIB_IN_DATA_CHUNK_DISCARDS,
> + SCTP_MIB_OUT_DATA_CHUNK_DISCARDS,
> __SCTP_MIB_MAX
> };
>
> diff --git a/net/sctp/outqueue.c b/net/sctp/outqueue.c
> index 7e8f0a1..dc1a40f 100644
> --- a/net/sctp/outqueue.c
> +++ b/net/sctp/outqueue.c
> @@ -315,6 +315,7 @@ int sctp_outq_tail(struct sctp_outq *q, struct sctp_chunk *chunk)
> case SCTP_STATE_SHUTDOWN_RECEIVED:
> case SCTP_STATE_SHUTDOWN_ACK_SENT:
> /* Cannot send after transport endpoint shutdown */
> + SCTP_INC_STATS(net, SCTP_MIB_OUT_DATA_CHUNK_DISCARDS);
> error = -ESHUTDOWN;
> break;

First, this is not the only case where a chunk is discarded on output. If you
are going to add an OUT_DATA_DISCARDS counter, you need to catch all such discards.
Second, in this particular case, you will count discarded messages, not chunks since
sctp_outq_tail is guaranteed to queue the whole message or none of it.

-vlad

>
> diff --git a/net/sctp/proc.c b/net/sctp/proc.c
> index 0697eda..1a10b81 100644
> --- a/net/sctp/proc.c
> +++ b/net/sctp/proc.c
> @@ -67,6 +67,8 @@ static const struct snmp_mib sctp_snmp_list[] = {
> SNMP_MIB_ITEM("SctpInPktBacklog", SCTP_MIB_IN_PKT_BACKLOG),
> SNMP_MIB_ITEM("SctpInPktDiscards", SCTP_MIB_IN_PKT_DISCARDS),
> SNMP_MIB_ITEM("SctpInDataChunkDiscards", SCTP_MIB_IN_DATA_CHUNK_DISCARDS),
> + SNMP_MIB_ITEM("SctpOutDataChunkDiscards",
> + SCTP_MIB_OUT_DATA_CHUNK_DISCARDS),
> SNMP_MIB_SENTINEL
> };
>
>