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>

13 files changed, 192 insertions, 13 deletions

diff --git a/include/net/sctp/sctp.h b/include/net/sctp/sctp.h
index 9c6414f553f9..7fdf298a47ef 100644
--- a/include/net/sctp/sctp.h
+++ b/include/net/sctp/sctp.h
@@ -272,6 +272,18 @@ struct sctp_mib {
         unsigned long   mibs[SCTP_MIB_MAX];
 };
 
+/* helper function to track stats about max rto and related transport */
+static inline void sctp_max_rto(struct sctp_association *asoc,
+                                struct sctp_transport *trans)
+{
+        if (asoc->stats.max_obs_rto < (__u64)trans->rto) {
+                asoc->stats.max_obs_rto = trans->rto;
+                memset(&asoc->stats.obs_rto_ipaddr, 0,
+                        sizeof(struct sockaddr_storage));
+                memcpy(&asoc->stats.obs_rto_ipaddr, &trans->ipaddr,
+                        trans->af_specific->sockaddr_len);
+        }
+}
 
 /* Print debugging messages.  */
 #if SCTP_DEBUG
diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index 2b2f61dd4036..c2521016d646 100644
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -1312,6 +1312,40 @@ struct sctp_inithdr_host {
         __u32 initial_tsn;
 };
 
+/* SCTP_GET_ASSOC_STATS counters */
+struct sctp_priv_assoc_stats {
+        /* Maximum observed rto in the association during subsequent
+         * observations. Value is set to 0 if no RTO measurement took place
+         * The transport where the max_rto was observed is returned in
+         * obs_rto_ipaddr
+         */
+        struct sockaddr_storage obs_rto_ipaddr;
+        __u64 max_obs_rto;
+        /* Total In and Out SACKs received and sent */
+        __u64 isacks;
+        __u64 osacks;
+        /* Total In and Out packets received and sent */
+        __u64 opackets;
+        __u64 ipackets;
+        /* Total retransmitted chunks */
+        __u64 rtxchunks;
+        /* TSN received > next expected */
+        __u64 outofseqtsns;
+        /* Duplicate Chunks received */
+        __u64 idupchunks;
+        /* Gap Ack Blocks received */
+        __u64 gapcnt;
+        /* Unordered data chunks sent and received */
+        __u64 ouodchunks;
+        __u64 iuodchunks;
+        /* Ordered data chunks sent and received */
+        __u64 oodchunks;
+        __u64 iodchunks;
+        /* Control chunks sent and received */
+        __u64 octrlchunks;
+        __u64 ictrlchunks;
+};
+
 /* RFC2960
  *
  * 12. Recommended Transmission Control Block (TCB) Parameters
@@ -1830,6 +1864,8 @@ struct sctp_association {
 
         __u8 need_ecne:1,       /* Need to send an ECNE Chunk? */
              temp:1;            /* Is it a temporary association? */
+
+        struct sctp_priv_assoc_stats stats;
 };
 
 
diff --git a/include/net/sctp/user.h b/include/net/sctp/user.h
index 1b02d7ad453b..9a0ae091366d 100644
--- a/include/net/sctp/user.h
+++ b/include/net/sctp/user.h
@@ -107,6 +107,7 @@ typedef __s32 sctp_assoc_t;
 #define SCTP_GET_LOCAL_ADDRS    109             /* Get all local address. */
 #define SCTP_SOCKOPT_CONNECTX   110             /* CONNECTX requests. */
 #define SCTP_SOCKOPT_CONNECTX3  111     /* CONNECTX requests (updated) */
+#define SCTP_GET_ASSOC_STATS    112     /* Read only */
 
 /*
  * 5.2.1 SCTP Initiation Structure (SCTP_INIT)
@@ -719,6 +720,32 @@ struct sctp_getaddrs {
         __u8                    addrs[0]; /*output, variable size*/
 };
 
+/* A socket user request obtained via SCTP_GET_ASSOC_STATS that retrieves
+ * association stats. All stats are counts except sas_maxrto and
+ * sas_obs_rto_ipaddr. maxrto is the max observed rto + transport since
+ * the last call. Will return 0 when RTO was not update since last call
+ */
+struct sctp_assoc_stats {
+        sctp_assoc_t    sas_assoc_id;    /* Input */
+                                         /* Transport of observed max RTO */
+        struct sockaddr_storage sas_obs_rto_ipaddr;
+        __u64           sas_maxrto;      /* Maximum Observed RTO for period */
+        __u64           sas_isacks;      /* SACKs received */
+        __u64           sas_osacks;      /* SACKs sent */
+        __u64           sas_opackets;    /* Packets sent */
+        __u64           sas_ipackets;    /* Packets received */
+        __u64           sas_rtxchunks;   /* Retransmitted Chunks */
+        __u64           sas_outofseqtsns;/* TSN received > next expected */
+        __u64           sas_idupchunks;  /* Dups received (ordered+unordered) */
+        __u64           sas_gapcnt;      /* Gap Acknowledgements Received */
+        __u64           sas_ouodchunks;  /* Unordered data chunks sent */
+        __u64           sas_iuodchunks;  /* Unordered data chunks received */
+        __u64           sas_oodchunks;   /* Ordered data chunks sent */
+        __u64           sas_iodchunks;   /* Ordered data chunks received */
+        __u64           sas_octrlchunks; /* Control chunks sent */
+        __u64           sas_ictrlchunks; /* Control chunks received */
+};
+
 /* These are bit fields for msghdr->msg_flags.  See section 5.1.  */
 /* On user space Linux, these live in <bits/socket.h> as an enum.  */
 enum sctp_msg_flags {
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;
diff --git a/net/sctp/endpointola.c b/net/sctp/endpointola.c
index 1859e2bc83d1..32ab55b18281 100644
--- a/net/sctp/endpointola.c
+++ b/net/sctp/endpointola.c
@@ -480,8 +480,11 @@ normal:
                  */
                 if (asoc && sctp_chunk_is_data(chunk))
                         asoc->peer.last_data_from = chunk->transport;
-                else
+                else {
                         SCTP_INC_STATS(sock_net(ep->base.sk), SCTP_MIB_INCTRLCHUNKS);
+                        if (asoc)
+                                asoc->stats.ictrlchunks++;
+                }
 
                 if (chunk->transport)
                         chunk->transport->last_time_heard = jiffies;
diff --git a/net/sctp/inqueue.c b/net/sctp/inqueue.c
index 397296fb156f..2d5ad280de38 100644
--- a/net/sctp/inqueue.c
+++ b/net/sctp/inqueue.c
@@ -104,6 +104,8 @@ void sctp_inq_push(struct sctp_inq *q, struct sctp_chunk *chunk)
          * on the BH related data structures.
          */
         list_add_tail(&chunk->list, &q->in_chunk_list);
+        if (chunk->asoc)
+                chunk->asoc->stats.ipackets++;
         q->immediate.func(&q->immediate);
 }
 
diff --git a/net/sctp/output.c b/net/sctp/output.c
index 4e90188bf489..f5200a2ad852 100644
--- a/net/sctp/output.c
+++ b/net/sctp/output.c
@@ -311,6 +311,8 @@ static sctp_xmit_t __sctp_packet_append_chunk(struct sctp_packet *packet,
 
             case SCTP_CID_SACK:
                 packet->has_sack = 1;
+                if (chunk->asoc)
+                        chunk->asoc->stats.osacks++;
                 break;
 
             case SCTP_CID_AUTH:
@@ -584,11 +586,13 @@ int sctp_packet_transmit(struct sctp_packet *packet)
          */
 
         /* Dump that on IP!  */
-        if (asoc && asoc->peer.last_sent_to != tp) {
-                /* Considering the multiple CPU scenario, this is a
-                 * "correcter" place for last_sent_to.  --xguo
-                 */
-                asoc->peer.last_sent_to = tp;
+        if (asoc) {
+                asoc->stats.opackets++;
+                if (asoc->peer.last_sent_to != tp)
+                        /* Considering the multiple CPU scenario, this is a
+                         * "correcter" place for last_sent_to.  --xguo
+                         */
+                        asoc->peer.last_sent_to = tp;
         }
 
         if (has_data) {
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
diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c
index e0f01a4e8cd6..e1c5fc2be6b8 100644
--- a/net/sctp/sm_make_chunk.c
+++ b/net/sctp/sm_make_chunk.c
@@ -804,10 +804,11 @@ struct sctp_chunk *sctp_make_sack(const struct sctp_association *asoc)
                                  gabs);
 
         /* Add the duplicate TSN information.  */
-        if (num_dup_tsns)
+        if (num_dup_tsns) {
+                aptr->stats.idupchunks += num_dup_tsns;
                 sctp_addto_chunk(retval, sizeof(__u32) * num_dup_tsns,
                                  sctp_tsnmap_get_dups(map));
-
+        }
         /* Once we have a sack generated, check to see what our sack
          * generation is, if its 0, reset the transports to 0, and reset
          * the association generation to 1
diff --git a/net/sctp/sm_sideeffect.c b/net/sctp/sm_sideeffect.c
index c0769569b05d..c9577754a708 100644
--- a/net/sctp/sm_sideeffect.c
+++ b/net/sctp/sm_sideeffect.c
@@ -542,6 +542,7 @@ static void sctp_do_8_2_transport_strike(sctp_cmd_seq_t *commands,
          */
         if (!is_hb || transport->hb_sent) {
                 transport->rto = min((transport->rto * 2), transport->asoc->rto_max);
+                sctp_max_rto(asoc, transport);
         }
 }
 
diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
index e92079d27eae..ebcd1eedb115 100644
--- a/net/sctp/sm_statefuns.c
+++ b/net/sctp/sm_statefuns.c
@@ -6133,6 +6133,8 @@ static int sctp_eat_data(const struct sctp_association *asoc,
                 /* The TSN is too high--silently discard the chunk and
                  * count on it getting retransmitted later.
                  */
+                if (chunk->asoc)
+                        chunk->asoc->stats.outofseqtsns++;
                 return SCTP_IERROR_HIGH_TSN;
         } else if (tmp > 0) {
                 /* This is a duplicate.  Record it.  */
@@ -6232,10 +6234,14 @@ static int sctp_eat_data(const struct sctp_association *asoc,
         /* Note: Some chunks may get overcounted (if we drop) or overcounted
          * if we renege and the chunk arrives again.
          */
-        if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED)
+        if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) {
                 SCTP_INC_STATS(net, SCTP_MIB_INUNORDERCHUNKS);
-        else {
+                if (chunk->asoc)
+                        chunk->asoc->stats.iuodchunks++;
+        } else {
                 SCTP_INC_STATS(net, SCTP_MIB_INORDERCHUNKS);
+                if (chunk->asoc)
+                        chunk->asoc->stats.iodchunks++;
                 ordered = 1;
         }
 
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;
diff --git a/net/sctp/transport.c b/net/sctp/transport.c
index 206cf5238fd3..310f11eb2206 100644
--- a/net/sctp/transport.c
+++ b/net/sctp/transport.c
@@ -363,6 +363,7 @@ void sctp_transport_update_rto(struct sctp_transport *tp, __u32 rtt)
         if (tp->rto > tp->asoc->rto_max)
                 tp->rto = tp->asoc->rto_max;
 
+        sctp_max_rto(tp->asoc, tp);
         tp->rtt = rtt;
 
         /* Reset rto_pending so that a new RTT measurement is started when a
@@ -620,6 +621,7 @@ void sctp_transport_reset(struct sctp_transport *t)
         t->burst_limited = 0;
         t->ssthresh = asoc->peer.i.a_rwnd;
         t->rto = asoc->rto_initial;
+        sctp_max_rto(asoc, t);
         t->rtt = 0;
         t->srtt = 0;
         t->rttvar = 0;