sctp: Add support to per-association statistics via a new SCTP_GET_ASSOC_STATS call

The current SCTP stack is lacking a mechanism to have per association
statistics. This is an implementation modeled after OpenSolaris'
SCTP_GET_ASSOC_STATS.

Userspace part will follow on lksctp if/when there is a general ACK on
this.
V4:
- Move ipackets++ before q->immediate.func() for consistency reasons
- Move sctp_max_rto() at the end of sctp_transport_update_rto() to avoid
  returning bogus RTO values
- return asoc->rto_min when max_obs_rto value has not changed

V3:
- Increase ictrlchunks in sctp_assoc_bh_rcv() as well
- Move ipackets++ to sctp_inq_push()
- return 0 when no rto updates took place since the last call

V2:
- Implement partial retrieval of stat struct to cope for future expansion
- Kill the rtxpackets counter as it cannot be precise anyway
- Rename outseqtsns to outofseqtsns to make it clearer that these are out
  of sequence unexpected TSNs
- Move asoc->ipackets++ under a lock to avoid potential miscounts
- Fold asoc->opackets++ into the already existing asoc check
- Kill unneeded (q->asoc) test when increasing rtxchunks
- Do not count octrlchunks if sending failed (SCTP_XMIT_OK != 0)
- Don't count SHUTDOWNs as SACKs
- Move SCTP_GET_ASSOC_STATS to the private space API
- Adjust the len check in sctp_getsockopt_assoc_stats() to allow for
  future struct growth
- Move association statistics in their own struct
- Update idupchunks when we send a SACK with dup TSNs
- return min_rto in max_rto when RTO has not changed. Also return the
  transport when max_rto last changed.

Signed-off: Michele Baldessari <michele@acksyn.org>
Acked-by: Vlad Yasevich <vyasevich@gmail.com>

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 10 insertions, 2 deletions

diff --git a/net/sctp/outqueue.c b/net/sctp/outqueue.c
index 1b4a7f8..379c81d 100644
--- a/net/sctp/outqueue.c
+++ b/net/sctp/outqueue.c
@@ -667,6 +667,7 @@ redo:
 				chunk->fast_retransmit = SCTP_DONT_FRTX;
 
 			q->empty = 0;
+			q->asoc->stats.rtxchunks++;
 			break;
 		}
 
@@ -876,12 +877,14 @@ static int sctp_outq_flush(struct sctp_outq *q, int rtx_timeout)
 			if (status  != SCTP_XMIT_OK) {
 				/* put the chunk back */
 				list_add(&chunk->list, &q->control_chunk_list);
-			} else if (chunk->chunk_hdr->type == SCTP_CID_FWD_TSN) {
+			} else {
+				asoc->stats.octrlchunks++;
 				/* PR-SCTP C5) If a FORWARD TSN is sent, the
 				 * sender MUST assure that at least one T3-rtx
 				 * timer is running.
 				 */
-				sctp_transport_reset_timers(transport);
+				if (chunk->chunk_hdr->type == SCTP_CID_FWD_TSN)
+					sctp_transport_reset_timers(transport);
 			}
 			break;
 
@@ -1055,6 +1058,10 @@ static int sctp_outq_flush(struct sctp_outq *q, int rtx_timeout)
 				 */
 				if (asoc->state == SCTP_STATE_SHUTDOWN_PENDING)
 					chunk->chunk_hdr->flags |= SCTP_DATA_SACK_IMM;
+				if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED)
+					asoc->stats.ouodchunks++;
+				else
+					asoc->stats.oodchunks++;
 
 				break;
 
@@ -1162,6 +1169,7 @@ int sctp_outq_sack(struct sctp_outq *q, struct sctp_chunk *chunk)
 
 	sack_ctsn = ntohl(sack->cum_tsn_ack);
 	gap_ack_blocks = ntohs(sack->num_gap_ack_blocks);
+	asoc->stats.gapcnt += gap_ack_blocks;
 	/*
 	 * SFR-CACC algorithm:
 	 * On receipt of a SACK the sender SHOULD execute the