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, 69 insertions, 0 deletions

diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index bc1624913c42..9e65758cb038 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -611,6 +611,7 @@ static int sctp_send_asconf_add_ip(struct sock		*sk,
                                     2*asoc->pathmtu, 4380));
                                 trans->ssthresh = asoc->peer.i.a_rwnd;
                                 trans->rto = asoc->rto_initial;
+                                sctp_max_rto(asoc, trans);
                                 trans->rtt = trans->srtt = trans->rttvar = 0;
                                 sctp_transport_route(trans, NULL,
                                     sctp_sk(asoc->base.sk));
@@ -5635,6 +5636,71 @@ static int sctp_getsockopt_paddr_thresholds(struct sock *sk,
         return 0;
 }
 
+/*
+ * SCTP_GET_ASSOC_STATS
+ *
+ * This option retrieves local per endpoint statistics. It is modeled
+ * after OpenSolaris' implementation
+ */
+static int sctp_getsockopt_assoc_stats(struct sock *sk, int len,
+                                       char __user *optval,
+                                       int __user *optlen)
+{
+        struct sctp_assoc_stats sas;
+        struct sctp_association *asoc = NULL;
+
+        /* User must provide at least the assoc id */
+        if (len < sizeof(sctp_assoc_t))
+                return -EINVAL;
+
+        if (copy_from_user(&sas, optval, len))
+                return -EFAULT;
+
+        asoc = sctp_id2assoc(sk, sas.sas_assoc_id);
+        if (!asoc)
+                return -EINVAL;
+
+        sas.sas_rtxchunks = asoc->stats.rtxchunks;
+        sas.sas_gapcnt = asoc->stats.gapcnt;
+        sas.sas_outofseqtsns = asoc->stats.outofseqtsns;
+        sas.sas_osacks = asoc->stats.osacks;
+        sas.sas_isacks = asoc->stats.isacks;
+        sas.sas_octrlchunks = asoc->stats.octrlchunks;
+        sas.sas_ictrlchunks = asoc->stats.ictrlchunks;
+        sas.sas_oodchunks = asoc->stats.oodchunks;
+        sas.sas_iodchunks = asoc->stats.iodchunks;
+        sas.sas_ouodchunks = asoc->stats.ouodchunks;
+        sas.sas_iuodchunks = asoc->stats.iuodchunks;
+        sas.sas_idupchunks = asoc->stats.idupchunks;
+        sas.sas_opackets = asoc->stats.opackets;
+        sas.sas_ipackets = asoc->stats.ipackets;
+
+        /* New high max rto observed, will return 0 if not a single
+         * RTO update took place. obs_rto_ipaddr will be bogus
+         * in such a case
+         */
+        sas.sas_maxrto = asoc->stats.max_obs_rto;
+        memcpy(&sas.sas_obs_rto_ipaddr, &asoc->stats.obs_rto_ipaddr,
+                sizeof(struct sockaddr_storage));
+
+        /* Mark beginning of a new observation period */
+        asoc->stats.max_obs_rto = asoc->rto_min;
+
+        /* Allow the struct to grow and fill in as much as possible */
+        len = min_t(size_t, len, sizeof(sas));
+
+        if (put_user(len, optlen))
+                return -EFAULT;
+
+        SCTP_DEBUG_PRINTK("sctp_getsockopt_assoc_stat(%d): %d\n",
+                          len, sas.sas_assoc_id);
+
+        if (copy_to_user(optval, &sas, len))
+                return -EFAULT;
+
+        return 0;
+}
+
 SCTP_STATIC int sctp_getsockopt(struct sock *sk, int level, int optname,
                                 char __user *optval, int __user *optlen)
 {
@@ -5776,6 +5842,9 @@ SCTP_STATIC int sctp_getsockopt(struct sock *sk, int level, int optname,
         case SCTP_PEER_ADDR_THLDS:
                 retval = sctp_getsockopt_paddr_thresholds(sk, optval, len, optlen);
                 break;
+        case SCTP_GET_ASSOC_STATS:
+                retval = sctp_getsockopt_assoc_stats(sk, len, optval, optlen);
+                break;
         default:
                 retval = -ENOPROTOOPT;
                 break;