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, 9 insertions, 1 deletions

diff --git a/net/sctp/associola.c b/net/sctp/associola.c
index b1ef3bc301a5..ba3f9cc4c047 100644
--- a/net/sctp/associola.c
+++ b/net/sctp/associola.c
@@ -321,6 +321,9 @@ static struct sctp_association *sctp_association_init(struct sctp_association *a
         asoc->default_timetolive = sp->default_timetolive;
         asoc->default_rcv_context = sp->default_rcv_context;
 
+        /* SCTP_GET_ASSOC_STATS COUNTERS */
+        memset(&asoc->stats, 0, sizeof(struct sctp_priv_assoc_stats));
+
         /* AUTH related initializations */
         INIT_LIST_HEAD(&asoc->endpoint_shared_keys);
         err = sctp_auth_asoc_copy_shkeys(ep, asoc, gfp);
@@ -760,6 +763,7 @@ struct sctp_transport *sctp_assoc_add_peer(struct sctp_association *asoc,
 
         /* Set the transport's RTO.initial value */
         peer->rto = asoc->rto_initial;
+        sctp_max_rto(asoc, peer);
 
         /* Set the peer's active state. */
         peer->state = peer_state;
@@ -1152,8 +1156,12 @@ static void sctp_assoc_bh_rcv(struct work_struct *work)
                  */
                 if (sctp_chunk_is_data(chunk))
                         asoc->peer.last_data_from = chunk->transport;
-                else
+                else {
                         SCTP_INC_STATS(net, SCTP_MIB_INCTRLCHUNKS);
+                        asoc->stats.ictrlchunks++;
+                        if (chunk->chunk_hdr->type == SCTP_CID_SACK)
+                                asoc->stats.isacks++;
+                }
 
                 if (chunk->transport)
                         chunk->transport->last_time_heard = jiffies;