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 1b4a7f8ec3fd..379c81dee9d1 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