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>

3 files changed, 75 insertions, 0 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 {